Biology Content Practice Test – Flashcards
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A small non-protein substance such as iron that works with enzymes to promote catalysis is known as
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C -B B: Inorganic cofactors are substances that promote enzyme catalysis. These molecules may bind to the active site or to the substance itself. The most common inorganic cofactors are metallic elements such as iron, copper and zinc. Coenzymes are organic in nature; thus, they are organic cofactors. Hormones are also organic and are not cofactors. Similarly, inorganic cofactors are minerals but not all minerals are inorganic cofactors.
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A particular plant has individuals that are either male or female. A male individual of this plant may have
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C C: The filament and anther are parts of the male reproductive system in plants. The male structure is the stamen, consisting of the anther atop a long, hollow filament. The anther has four lobes and contains the cells that become pollen.
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The cells of which of the following organisms are prokaryotic?
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C C: Blue-green bacteria are prokaryotic organisms of the Kingdom Monera. Prokaryotes do not have a nucleus or any other membrane-bound organelles. The cells of mold, seaweed and hydra all have membrane-bound organelles and are therefore classified as eukaryotes.
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Which of the following represents a plausible progression in the evolution of plants?
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D D: Scientists conclude that in the evolution of life (including plants) the first cells were prokaryotic and that eukaryotic cells developed as cells with varying functions were incorporated into more complex cells (the endosymbiont theory). In addition, the early Earth atmosphere was devoid of oxygen, so early cells were anaerobic, with aerobic cells evolving later. Cyanobacteria are autotrophic ancestors of multicellular plants. Both answers (A) and (B) wrongly place eukaryotes before prokaryotes. Answer (C) wrongly places aerobic cells before anaerobic cells.
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Legumes perform a unique ecological function by
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A A: Types of nitrogen-fixing bacteria live in symbiosis on the nodules of the roots of legumes (beans, peas, clover, etc) supplying the roots with a direct source of ammonia--nitrogen in a form usable by plants. This unique niche (Changing nitrogen from an unusable to a usable form) filled by the symbiotic relationship of legumes with nitrogen-fixing bacteria.
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Which of the following is found in a carbohydrate molecule?
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D D: A carbohydrate molecule contains only carbon, hydrogen, and oxygen in the ratio CH2O. Nitrogen and Sulfur are elements that are not found in carbohydrates. Amine, NH2, groups are found in other organic molecules, but not in carbohydrates.
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Each of the following statements regarding the hydrologic cycle is true EXCEPT
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B B: The hydrologic cycle intersects with nearly all biogeochemical cycles. The cycle includes evaporation from bodies of water and plant leaves; water vapor is then redistributed over land via clouds that release water as precipitation. Water flows back into waterways that eventually flow into the ocean. Water vapor in the air is a greenhouse gas that traps heat in the lower atmosphere and resists rapid cooling.
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Which of the following is a monosaccharide?
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A A: Glucose is the only monosaccharaide listed. Cellulose and starch are both polysaccharides. Amylase is not a sugar at all. It is an enzyme important for the digestion of starches
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The study of the interaction of organisms with their living space is known as
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D D: Ecology is literally "the study of" ology a "place to live" eco It involves the study of all the living (including interaction with other organisms) and nonliving factors that contributed to an organism's life within its living space.
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Which of the following is likely to happen when a limited amount of enzyme is added to a reaction with an unlimited amount of substrate?
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A A: An enzyme is a special protein that acts as a catalyst for organic reactions. A catalyst is a substance that changes the speed of a reactions without being affected itself. The enzyme will speed up the initial reaction until all the enzymes are in use, and then the reaction will level off as all the limited amount of enzyme becomes engaged but substrate is still present. Enzymes will not decrease the reaction rate or stop the reaction completely. Furthermore, the reaction will not stop happening when all of the enzyme is engaged, but the reaction rate will level off. The rate cannot continue to rise after all the enzyme is engaged.
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Which of the following organs DOES NOT function in immunity to defend the body from infection?
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B--C C: The spinal cord is not directly involved with immunity. The organs of the immune system in humans and other higher invertebrates include all of the other organs listed in the question--the lymph nodes, spleen, and thymus
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A cell without a nucleus or membrane-bound organelles is
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A A: A prokaryote is derived from pro (meaning before) and karyo (meaning a nucleus) Prokaryotic cells have no nucleus or any other membrane-bound organelles. The DNA in prokaryotic cells floats freely within the cytoplasm. Even though the nuclear membrane is absorbed during replication, other membrane-bound organelles still exist in replicating cells--including those in tele phase. A eukaryotic cell, by contrast, contains a nucleus and other membrane-bound organelles.
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Which of the following are found in the cells of fungi?
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D D: Fungi are not photosynthetic--they absorb nutrients from their surroundings. Therefore, fungi cells do not have chloroplasts. The cells of fungi are eukaryotic and therefore do have a nucleus, mitochondria and ribosomes.
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Grana are embedded within which part of the chloroplast?
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A A: Grana are within the stroma (or body) of the chloroplasts in plant cells. Pigments, including chlorophyll and carotene (when present), are found within the grans. Cristae are found in mitochondria, not in chloroplasts.
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Anton van Leewenhoek is credited with inventing the first microscope in the 1600s. The invention of the microscope was most likely instrumental in which of the following?
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C C: Cell theory refers to the cell, which is the foundational unit of all life. The theory was developed by Robert Hooke as a direct result of the invention of the microscope in the 1600s that allowed for the direct viewing of cells. A) Natural selection is the law developed by Darwin much later in the 1850s B) Mendel described the laws of independent assortment as part of his laws of inheritance in the 1800s. D) Newton developed the laws of motion
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Charles Darwin described the laws concerning the changes in species that occur over long periods of time.
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B B: Natural selection describes the change in species characteristics over time
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The correct measurement of the following graduated cylinder is best described as
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A A: 29.35 mL is correct because you can measure to one decimal place beyond the specificity given by the device. Since this device is marked in tenths of a mL, you can measure to hundredths Also you measure to the bottom of the meniscus
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Which of the following is NOT true of regulations regarding human research?
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A A: The rights of the subject always take precedent in research, therefore the statement in option A is not true. In no case is the right of the subject not paramount. Common Rule instituted in 1974 (B) was the beginning of regulation protecting the rights of human research subjects through requiring qualifications such as having IRB approval (C) and informed consent (D)
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The ultimate source of energy for most life on Earth is
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C C: Nearly all life forms derive their energy from the Sun whether directly (through photosynthesis) or indirectly (by consuming other organisms)
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The conversion of light energy into chemical energy is accomplished by
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D D: The process of photosynthesis is the crucial reaction that converts light energy of the Sun into chemical energy that is usable by living things Catabolism, metabolism, and oxidative phosphorylation are necessary processes for most organisms, only photosynthetic organisms convert energy directly from light
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The sum total of a species' genetic information is known as its
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D D: The sum total of genetic information of a species is its genome. Genes are portions of chromosomes that determine the inheritance of an organism's characteristics.
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Which of the following is NOT a step in the translation part of protein synthesis?
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A A: Free bases line up along the DNA template and are bonded together, forming RNA during transcription, not translation. Translation begins as a ribosome attaches to the mRNA strand at a particular codon known as the start codon. This codon is only recognized by a particular initiator tRNA. The ribosome continues to link tRNA whose anticodons complement the next codon not he mRNA string. A third type of RNA or rRNA is utilized at this point--exists in concert with enzymes as a ribosome. In order for tRNA and mRNA to link up, enzymes connected to rRNA at the ribosome must be utilized. At the end of the translation process, a terminating codon stops the synthesis process and the protein is released.
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Transduction refers to the process whereby a bacterium's genetic makeup is altered when
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B B: transduction refers to the changing of a bacterium's genetic makeup by the transfer of a portion of genetic material from one bacterial cell to another. This is accomplished via a bacteriophage (a virus that targets bacteria) Transformation refers to the absorption and incorporation of pieces of DNA from a bacterium's environment (usually from dead bacterial cells).
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Chromosomes that are paired with another of similar size and shape within the nucleus are known as
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A A: Chromosomes that are paired with another of similar size and shape within the nucleus are known as homologous pairs or homologs. Each set of homologous chromosomes has a similar genetic constitution, but the genes are not necessarily the same.
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Restriction enzymes cut samples of DNA into fragments by
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A A: Restriction enzymes cut out sections of DNA molecules by cleaving the sugar-phosphate back-bone. In most cases, a particular enzyme cuts the strands of the double helix DNA within a length of a few bases.
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The figure below shows the exponential rise in world population in recent years. Which of the following are immediate implications that could impact the world in the next generation or two?
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D D: Global climate change would not be an immediate result of overpopulation. It may be a long-term impact of over-population and carbon emissions. However, pollution, disease and localized famine can all be exacerbated by increased population
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These pieces of equipment are
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C The picture is of petri dishes beaker, graduated cylinder, graduated pipette
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The invention of the microscope was essential and preliminary to the development of cell theory, the discovery of bacteria, and the understanding of concepts relating to disease and sanitation. Which of the following best states the relationship between science and technology demonstration by this example?
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A A: Students and teachers are often used to thinking that scientific progress influences technological advancement, but the reverse is also true and the example of the microscope shows this clearly: Progress in scientific knowledge was directly positively impacted by the technological advancement of the invention of the microscope. (B) While technological advancement benefits with new scientific knowledge it is not completely dependent on it. Neither is scientific knowledge completely stymied by lack of technological advance and neither is shown in this example. (C) Technological development is not always a direct result of scientific progress--and this case of the microscope does not show that (D)
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Which of the following laboratory safety considerations are NOT accurate?
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B B: Clothing should NOT be loose or baggy and sleeves should be short or rolled up out of the way to reduce fire hazard and contamination risk. In addition hair should be tied back and in most cases gloves worn.
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Which of the following best states the relationship, in science, between a law and a theory?
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C--D D: Scientific laws are broad generalizations related to an aspect of how the natural world behaves under certain conditions. A scientific law must be testable, internally constant, and compatible with available evidence and phenomena of the natural world. Theories explain laws,but not all laws have corresponding theories. Theories do not become laws with increasing testing or evidence. Rather, theories are a separate type of explanation, therefore a theory does not become a law (C) and neither does a law become a theory (A). A theory can be tested, and since it is a portion of a law, technically a law, in part may also be tested (B)
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Each of the following statements about meiosis is true EXCEPT:
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C--A A: Mitosis produces two exact copies of the original cell as daughter cells. Meiosis, on the other hand, is the process of producing four daughter cells that have single unduplicated chromosomes (haploid) The parent cell is diploid, that is, it has duplicated sets of chromosomes. Meiosis also results in the production of four new cells, rather than two (as in mitosis) and each cell has half the chromosomes of the parent. Meiosis, like mitosis, begins with chromosome duplication. In meiosis, two distinct nuclear divisions occur: the first is known as reduction (Meiosis 1) and the second division (or meiosis 2). Reduction affects the ploidy (referring to haploid or diploid) level, reducing it from 2n to n (diploid to haploid). Division then distributes the remaining set of chromosomes in a mitosis-like process among the four daughter cells.
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The iron-containing molecule that carries oxygen within red blood cells throughout the body via the circulatory system is the
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D D: Oxygen is carried by hemoglobin molecules (That contain iron) in red blood cells. Lymphocytes, erythrocytes, and neutrophils are all non-oxygen carrying types of blood cells.
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When sodium (Na+) ion concentration outside a cell increases, water molecules travel out of the cell through the cell membrane. This process is known as
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A A: Osmosis is a type of diffusion (passive transept) that occurs only with water molecules. The water on the side of the membrane with the highest water pressure will cross through the membrane until the concentration is equalized on both side. Facilitated diffusion is the mvmt of substances across the cell membrane with the help of specialized proteins. Exocytosis is the process where large molecules are engulfed in a pocket of cell membrane and exported from the cell. Endocytosis also involves large molecules that are engulfed in a pocket of membrane, but in this case the molecules are imported into the cell.
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The ____ is the organ that prevents food from entering the bronchial tubes
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B B: The epiglottis is the flap of tissue that covers the glottis, preventing food particles from entering the bronchial tubes. Before reaching the glottis (the opening that allows gases to pas into the bronchi), air passes through the pharynx and into the trachea. The glottis is the lower portion of the trachea.
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The site of transfer for nutrients, water, and wastes between a mammalian mother and embryo is the
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C C: The placenta is the connection between the mother and embryo; it is the site of transfer for nutrients, water and wastes between them. The yolk sac membrane encloses the yolk sac. The uterus is the organ in the female body that houses the developing embryo. A portion of the uterine lining becomes a part of the placenta, but the entire uterus is not involved. The allantois, contained by the allantoic membrane, develops into part of the umbilical cord
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The function of the gallbladder and pancreas is to aid digestion by producing digestive enzymes and secreting them into the
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B--A A: Digestive enzymes are released by the pancreas and gallbladder into the small intestine. Digesting food then passes from the small intestine to the large intestine. Food travels through the esophagus on its way to the stomach where food is digested through mechanical means as well as chemical means, but not with enzymes released by the pancreas and gallbladder. The stomach produces its own enzymes, mucus and gastric juices. The rectum connects the large intestine with the anus where waste products are transported out of the body
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Electrical shock can restart a heart that has stopped beating. Which of the following statements is a valid reason for this fact?
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D D: The heart is made of cardiac muscle. The electrical properties of cardiac muscle tissue cause the beating of the heart muscle that results in the pumping of blood through the body. When a heart stops beating, stimulating the cardiac muscle with electric schlock can sometimes restart it. Smooth muscle tissue is not found in the heart.
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All of the following may cause mutations in a DNA sequences EXCEPT
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D D: All the DNA in every cell of every organism is copied repeatedly to form new cells for growth, repair and reproduction. A mutation can be an error that occurs randomly during one of the many copying sequences that occur within the cell. Mutations can also be the result of damage to DNA through environmental agents such as sunlight, cigarette smoke, chemical exposure or x-rays. Crossing over is a process that may occur during meiosis, resulting in exchange of corresponding portions between homologous chromosomes. Crossing over is not a mutation.
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Bones perform many functions in the human body. All of the following are functions of bones EXCEPT
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C--D D: In addition to being the primary structure and support for the human frame, the 206 bones of the skeleton protect the soft internal organs of the human body, produce red blood cells from its marrow and allow for movement by providing a base for muscles and ligaments. While the bones do store calcium and phosphates, they do not produce them.
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The illustration above is called a
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C This illustration is called a punnett square and is used to illustrate genetic crosses. The genotype is the representation of the alleles present in a particular organism (for example, Tt, where uppercase T stands for the dominant allele for tall and lowercase t stands for the recessive allele for short) While Mendel was instrumental in the study of genetics, Reginald Punnett, not mendel, developed the punnett square; this it is not called a mendelian diagram. phenogram is not a term that is used in genetics.
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Which of the following genotypes are represented by the two parents?
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C C: Since the genotypes of the parents are always listed on the side and top of a punnett square, the genotypes of the parents are tt and TT
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The gametes for this cross will have which possible alleles
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B B: Every gamete will have either the T allele or the t allele since those are the only possibilities of gametes from the parents
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What will be the phenotypic ratios of the offspring in this cross?
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A A: all offspring will have a genotype Tt all have a dominant gene for tallness (T) so all will have a phenotype of tall; thus the ratio is 4 tall: 0 short
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If two of the offspring are crossed what will the phenotypic ratio of the next generation be?
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C C: The genotype ratio will be 1TT: 2Tt: 1tt Since T tall is dominant to t sort only one out of four will be short. the phenotypic ratio will be 3 tall to 1 short
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All of the following are major structural regions of plant roots EXCEPT
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B--C C: There is no epistematic region in plant roots. Roots have 4 major structural regions that run vertically from bottom to top. The root cap (not an answer choice) is composed of dead, thick-walled cells and covers the tip of the root, protecting it as the root pushes through the cell. The meristematic region is just above the root cap. It consists of undifferentiated cells that carry on mitosis, producing the cells that grow to form the elongation region. In the elongation region, cells differentiate, large vacuoles are formed, and cells grow. As the cells differentiate into various root tissues, they become part of the maturation region.
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Water molecules are attracted to each other due to which of the following?
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B--A A: The hydrogen atoms in water molecules have a partial positive charge and the oxygen atoms a partial negative charge, causing polarity. This polarity allows the oxygen of one water molecule to attract he hydrogen of another. The partial charges attract other opposite partial charges of other water molecules, allowing for weak (hydrogen) bonds between the molecules. Inert means non-reactive; it does not explain the attraction between H and O. There are no ionic bonds within water molecules, only covalent bonds. Brownian motion is the random movement of atoms or particles caused by collisions between them, it does not explain attraction between atoms or molecules.
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All of the following are true EXCEPT
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C Animal species are capable of sexual reproduction, though some, such as the hydra and other invertebrates, reproduce asexually. All animal cells are eukaryotic (have nuclei and membrane-bound organelles) Only plants and blue-green bacteria have cell walls and/or plastids. Animals do develop from embryos.
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Which of the following terms represent the movement of a species in or out of a given area?
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B--A A: Competition occurs when niches overlap between 2 species in the same community. The term competition does not indicate movement in or out of an area. Emigration (one-way movement out of the original range) is a form of dispersion (movement of species)
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An unknown plant found in the forest has 5 petals on its flower and a tap root system. Which of the following is most likely TRUE?
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D Five petals indicates the plant is a dicot (a plant with 2 cotyledons in each seed). Dicots also have taproot systems and leaves with networked or branching veins. A monocot would have random arrangement of its vascular bundles and leaves with parallel veins. There was no indication from the given information whether the plant was male or female.
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After school hours a student gained access to a teacher's classroom and took some Benedict's solution. The teacher was held responsible because
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C Teachers are responsible to keep all chemicals in locked storage facilities when not in use. Benedict's solution may or may not be a prohibited chemical in your school or locale (D) but regardless it still needs to be locked up (A) The teacher cannot be expected to be in the room and responsible 24/7 (B) but there are basic safety protocols for which the teacher IS responsible.
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Teachers should encourage students to present the results of a technology design or research project to students and teachers orally or in writing by means of all that follows EXCEPT
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D an editorial would not be an appropriate manner of presenting the results of a technology design or research project as it expresses opinion, not data. Students should present their results to students, teachers, and others in a variety of ways, such as orally, in writing and in other forms (including models, diagrams, and demonstrations)
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The biogeogrpahy of a tropical island is affected by all of the following factors EXCEPT
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D Dispersal of species to an island is dependent on geographical as well as historical factors. Distance from other landmasses, prevailing winds, and ocean currents are also geographical factors that will affect species introduction. Historical factors such as climate shifts (for instance the shift to an ice age), drought, volcanic action, plate shifting, and human intervention will also affect what species are able to travel to a given island. Fossil preservation or lack thereof would not affect any current conditions of biogeography
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A form of symbiosis in which one species benefits while the other is harmed is called
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A Parasitism is symbiosis in which one organism benefits, but the other is harmed. Mutualism is symbiosis that benefits both organisms. Amensalism is symbiosis where one organism is neither helped nor harmed but the growth of the other is inhibited. Habituation is not a form of symbiosis; it is a behavioral response where there is less and less response by an individual to a stimulus over time
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All of the following are steps in the carbon cycle EXCEPT
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A--C C: Animal respiration releases carbon dioxide back into the atmosphere in large quantities; it does not take in carbon dioxide for use. Most of the carbon within organisms is derived from the production of carbohydrates in plants through photosynthesis. CO2 is dissolved directly into oceans, where it is combined with calcium to form calcium carbonate--used by mollusks to form their shells. Organic matter that is left to decay may, under conditions of heat and pressure, be transformed into coal, oil, or natural gas--the fossil fuels. When fossil fuels are burned for their energy, the combustion process releases CO2 back into the atmosphere, where it is available to plants for photosynthesis
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Large protein molecules may be secreted from a cell by the process of
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B Large molecules such as proteins are not bale to pass through the cell membrane, but are instead engulfed by it. Endocytosis is the process whereby large molecules (some sugars, or proteins) are taken up by a sack of membrane and delivered to the interior of the cell where it can be used) This process, for instance, is used by WBCs to engulf bacteria. Exocytosis uses the same process but exports substances to the exterior of the cell. Active transport and facilitated diffusion are processes that involve passing substances through the cell membrane by various means
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The enzyme amylase is present in saliva and is instrumental in the breakdown of starches in early digestion. Which of the following is the most likely reason for amylase's suitability to aid in the catalysis of starches?
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A It is the shape of the active site of the enzyme that allows the enzyme to work on the substrate to form product(s). The active site of the amylase molecule matches the shape of starch molecules. The speed of the reaction and the amount of substrate do not enhance amylase's enzymatic functions. Specific enzymes are needed for specific reactants.
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Which of the following are autotrophs?
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D--B Plants (including asparagus ferns) produce their own food through photosynthesis and are known as autotrophs. Fungi, human fetuses, and bacteria do not produce their own food.
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Which of the following elements is/are found in organic tissue?
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D Argon is a noble gas; it does not occur naturally in organic tissue. All organic molecules contain carbon, but because answer choice I includes argon, this choice is eliminated. Also commonly found in organic molecules are oxygen, nitrogen, sulfur, hydrogen, and phosphorous.
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Organisms store energy within
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B Chemical bonds are where energy is stored within cells
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The diploid generation in plants is known as the
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A--B B: The diploid (2n) generation in plants is known as the sporophyte. The gametophyte is always haploid (n). What we consider the adult generation in a plant's life cycle may be haploid (ex. mosses) or diploid (ex. ferns). Spores are male haploid gametes.
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Cells of eukaryotes have all of the following EXCEPT
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D The DNA of eukaryotes is organized into chromosomes within the nucleus
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The process whereby molecules and ions flow through a cell membrane from an area of higher concentration to an area of lower concentration without an input of energy is known as
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A Diffusion is the process whereby molecules and ions flow through the cell membrane from an area of higher concentration to an area of lower concentration Where the substances exists in higher concentration, collisions occur that tend to propel them away toward lower concentration. Active transport requires added energy to move substances across a membrane. In endocytosis and exocytosis, the cell membrane surrounds the substance and moves it either into (endo) or out of (eco) a cell
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A species' ecological niche is defined as including
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B A species' habitat must include all the factors that will support its life and reproduction including biotic factors (living--food source, predators, place in the food chain) and abiotic factors (nonliving--weather, temperature, soil features,etc)
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A DNA strand in a double helix has a base sequence of ATACGT. The base sequence of its DNA complement is
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C Two base-pairing rules must be memorized for DNA strands A-T and C-G Thus, the given DNA strand of six bases dictates only one possible complement
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There are various types of plant stems that have different functions. All of the following are types of stems EXCEPT
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D There are many types of stems that have specialized functions The functions of stems generally may include transport of water and food between root and leaves, leaf support and food storage underground stems include tubers, rhizomes and corms. Tubers, found in the potato, function to store starch. Rhizomes, in ferms, function in vegetative propogation. Corms are found in gladiolus and are actually fleshy leaves that store food. Nodes are not stems, but rather are the site on the stem at which the leaves attach. Internodes are thus the region between the nodes
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A gas that causes asphyxiation by binding to hemoglobin, thus preventing oxygen from doing so, is known as
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B Carbon monoxide is a colorless, odorless gas that can bind to hemoglobin without the subject's awareness. As hemoglobin in red blood cells transports oxygen, oxygen's unavailability due to CO binding causes internal suffocation or asphyxiation
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Which of the following factors exerts the most influence over limiting cell cite?
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A--B The size of a cell is limited by the ratio of its surface area to volume. a cell will remain stable only if the surface area of the plasma membrane maintains a balance with the volume of cytoplasm only plant cells (and some bacteria) have cell walls the replication of mitochondria and the chemical composition of the cell membrane do not specifically limit cell size
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When a hamburger is consumed by an individual, it passes through all of the following organs EXCEPT the
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C Ingested food does not pass through the salivary gland; rather, the saliva secreted from this gland enters the digestive tract and helps digest the food. Food does pass through mouth, esophagus, stomach and small intestine
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In order for a species to be established on an island it must have all of the following features EXCEPT
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C in order to become an established part of the island ecosystem it must find a suitable ecological niche. ultimately the species must be able to reproduce in its new setting, or it will not remain a part of the ecosystem. organisms do not require a predator, though one may be necessary in some cases for population control. but many thriving organisms, including those that are at the highest trophic level, have no predators
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Which of the following are NOT involved in the immune system?
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B--D epithelial (skin) cells have no direct function in immunity. cells involved in immunity are called lymphocytes and are produced in the bone marrow as stem cells T cells are one of two classes of lymphocytes, B cells and T cells some T cells patrol the blood for antigens, but T cells are also equipped to destroy antigens themselves. T cells also regulate immune responses
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The process that releases energy for use by the cell is known as
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D Cellular respiration is the process that releases energy for use by the cell there are several steps involved in cellular respiration: some require oxygen (aerobic) and some do not (anaerobic) photosynthesis is a type of anabolism, a reaction that harnesses and stores solar energy in chemical bonds
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Which of the following are secreted by the stomach?
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B the stomach secretes digestive enzymes, hydrochloric acid, and gastric guides, which all aid in digestion the stomach also secretes mucus, which protects the stomach lining from the acids and gastric juices
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Plants and animals obtain usable nitrogen through the action of
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B Neither plants nor animals are bale to use nitrogen directly from the air instead a process known as nitrogen fixing makes nitrogen available for absorption by the roots of plants. nitrogen-fixing is the process of combining it with either hydrogen or oxygen. nitrogen fixing is accomplished in one of two ways either by nitrogen-fixing bacteria or by the action of lightning N is present in the atmosphere (including the air we breathe) but it is not used in the process of respiration digestion does not render nitrogen useful to living things
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All of the following statements about photosynthesis are true EXCEPT
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D though the process of photosynthesis actually occurs through numerous small steps, the entire process can be summed up with the following equation in notes chlorophyll is a green pigment that must be present in order for photosynthesis to occur chlorophyll has the ability to absorb a photon of light and is found in the grans of the chloroplast. chloropyhll is not used up in the photosynthetic process
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In Genetics, the Law of Segregation states that
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C The first law of M genetics is the law of segregation, stating that traits are expressed from a pair of genes in the individual, one of which came from each parent. the alleles are randomly separated as gametes are formed and are brought together in varying combinations through fertilization not all genetic crosses involve an allele tha tis dominant over the other and not all crosses involve multiple alleles. also, mutations may occur during the DNA replication process of gamete formation, however gamete formation itself does not cause mutation
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Sharks and dolphins have similar body shapes. Which of the following is the most likely explanation of this fact?
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B the similarity of body shapes between sharks and dolphins most likely results form the convergent evolution of traits that are favorable to survival in the ocean. Shark's (cartilaginous fish) and dolphins (mammals) do not share a common ancestry, nor did one evolve into the other Sharks and dolphins have different niches in the ocean community, so they are not in competition
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In humans, the ability to roll the tongue is an inherited trait and the allele for tongue-rolling is dominant. If 36% of the population cannot roll their tongue, what is the frequency of the heterozygous genotype within he population, according to the Hardy-Weinberg Equation?
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A--C According to the H-W Law p+q=1 where p and q represent frequencies of two alleles also p2 + 2pq + q2= 1 where the frequency of homozygous dominant genotypes is represented by p2, the homozygous recessive by q2 and the heterozygous genotype by 2pq so in the case of tongue rolling if the frequency of non tongue rollers is 36% or .36, then he frequency of the recessive allele q is .6 (the square root of .36) therefore the frequency of the dominant allele (p) is .4 (since p+q =1) the heterozygous genotype is represented by 2pq which equals 2(.6)(.4) or .48
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The term Homo sapiens is an example of
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D the term homo sapiens is an example of binomial nomenclature, the use of the genus and the species names together
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Members of which of the following categories are most closet related?
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B the order of classification from least specific to most specific is kingdom, phylum, class, order, family, genus, and species, so of those listed, genus is the most specific with members most closely related to each other
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Which of the following are included in the Oparin hypothesis?
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A Oparin's hypothesis included the idea that most water on E was in the form of water vapor and steam, not ice. Proposed that E was approx 4.6 billion yo and had a reducing atmosphere with very little oxygen present. there was an abundance of ammonia, hydrogen, methane, water vapor and steam (H2O) there was a great deal of heat energy available as the E was cooling. Recurring violent lightning storms also provided E. The cooling of the E also caused much of the water vapor surrounding the E to condense, forming hot seas
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Which of the following is an explanation of how altruistic traits evolve?
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C--B Though the presence of altruistic traits may actually decrease the individual's fitness to survive, ti increases the survival rate of the population. Altruistic traits are preserved through kins election. Kin selection accounts for the expression of altruistic traits toward close relatives, thus increasing the probability for those relatives to survive and to pass on their genetic traits
question
Streptococcus pyogenes bacteria cause throat infections in humans, but can be killed with antibiotic penicillin. If penicillin therapy is not administered correctly, some bacteria may survive. The surviving bacteria are those with a higher level of resistance to penicillin. The living resistant bacteria will reproduce, magnifying the traits of resistance in subsequent generations. This is an example of
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B Natural selection occurs when the surviving species is the one that is most adapted to the environment (in this case, resistant to penicillin). Clearly, only the surviving competitors reproduce. Therefore, traits that provide the competitive edge will be represented most often in succeeding generations. The survival of resistant bacteria does not represent genetic drift. Genetic drift is random fluctuation in allele frequency, including loss of alleles. It is most pronounced in small populations and therefore in populations that have become separated from a main population. in this example, mutation does not contribute to the survival of resistant bacteria; the genetic material has not changed. There is no genetic equilibrium, since a certain trait (resistance) is favored by the environment
question
The major driving force of the evolution of species is known as
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B The driving mechanism of evolution is natural selection. The oparin hypothesis involved only the earliest forms of organic life and does not involve speciation. Allopatric speciation depends upon natural selection, H-W equilibrium explains the preservation of genes within a population in spite of the occurrence of natural selection.
question
A ____ is a distinct group of individuals that are able to mate and produce viable offspring
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D By definition, a species is a distinct group of individuals that are able to mate and produce viable offspring. Class and phylum are taxonomic groups. A community includes all the species that interact in a particular area
question
Which of the following phylums of vertebrates contains animals with mammary glands?
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D Only mammals (mammal) have mammary glands
question
Which of the following kingdoms contains photosynthetic organisms?
answer
B Photosynthetic organisms are found in the Kingdom Plantae and the Kingdom Protista and are not found in the Kingdom Fungi, Kingdom Animalia or Kingdom Monera
question
There are 3 different genes that control skin color in humans. Each gene has a dominant and a recessive allele, so the possible alleles are A, a, B, b, C, c. The more dominant alleles inherited by offspring, the darker the skin color. Skin color in humans is an example of
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A When more than 1 gene controls a particular genetic trait,t hat trait is called polygenic. An autosome is any chromosome that does not determine the sex of an individual. A sex-linked trait is one whose genes are found on one of the sex chromosomes. A monohybrid cross is a genetic cross where only one trait is considered
question
The fossil of a fish is found in a limestone bed. The imprint of a skeleton is easily discernible, including several vertebrae. The fish most likely belonged to the class
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C Since the skeleton of the fish was easily identifiable, the fish must belong to the class of bony fish--Osteichthyes. Cephalachordates have a notochord, but not vertebrae. Porifera is the phylum including sponges; Cnidaria is the phylum including jellyfish and hydra
question
According to the Hardy-Weinberg Law, evolution can occur due to changes in allele frequencies. All of the following can contribute to change in allele frequencies EXCEPT
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C--D Hardy-Weinberg Equilibrium only occurs when mutation, immigration, emigration, as well as natural selection (not an answer choice) are not happing in a population. When mutation, immigration, emigration and natural selection are occurring, evolution is possible as allele possibilities are changed. Sexual recombination is a factor that will reinforce H-W Equilibrium
question
Protists are divided into 2 major subgroups by their
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D Members of the kingdom Protista may be autotrophic, heterotrophic or a combination of both depending on the presence or absence of chloroplasts. This criterion can be applied to the 3 types of protests: algae, slime molds and protozoa
question
Regarding the taxonomic classification of man,
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D--B Taxonomy refers to the scientific classification of all living things into a systematic scheme. It is based on evolutionary relationships. The largest category of classification is the kingdom, of which there are five: Monera (bacteria and blue-green algae), Protista, Fungi, Plantae, and Animalia. Within a kingdom, there are phyla (or divisions as in Fungi and Plantae). Phyla are divided into classes into orders and orders into families. Families are divided into genera. Each genus is then divided into species. When we refer to a specific organism we usually give its binomial name, the genus and species. Hence, a man is called Homo sapiens. Note that by convention, the genus name is capitalized and the specific epithet is not; the binomial name is underlies or italicized. The specific epithet never stands alone. Thus, man's species name is Homo sapiens, not sapiens. The specific name could be given to organisms of other genera. For example, multilora is a specific name. When used alone, you could be referring to Rosa or Bergonia, clearly two different species. By saying gRosa multilora, you are referring to one and only one species. Man's complete taxonomic classification is as follows. Kingdom-Animalia phylum-Chordata class-Mammalia order--Primates family-Hominidae genus-Homo species- Homo sapiens
question
The diversification of mammals that followed the extinction of dinosaurs is an example of
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C--D Adaptive radiation is a pattern that occurs when a lineage (single line of descent) branches into 2 or more lineages, and these further branch out. This pattern can occur when a species is able to invade environments that have previously been occupied by other species. In this case, when the dinosaurs became extinct, mammals invaded their vacated ecological niches and quickly diversified to adapt to the living conditions of the niches. In addition to invading vacant ecological niches, species can undergo adaptive radiation when they partition existing environments.
question
Which of the following conducted early research into the process of genetic inheritance?
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D Gregor Mendel studied the relationships between traits expressed in parents and offspring and the genes that caused the traits to be expressed. Hooke, Mendeleev and Schwann were all scientists not directly involved with genetics
question
In what way may a mass extinction event allow for diversification
answer
A Extinction events cause ecological niches to be available for other, newer species to fill.
question
Which of the following elements may proteins contain?
answer
C Carbon, hydrogen and oxygen are all common elements found in proteins
question
Which of the following are within the phylum Chordata?
answer
B--D Chordata have 4 defining characteristics: a notochord, a dorsal hollow nerve cord, pharyngeal gill slits, and a postanal tail during some point of their development. Of the given choices, only snakes have these characteristics during some point of their development
question
Work in science and engineering requires all of the following EXCEPT
answer
C It is not necessary for students to have a familiarity with science and engineering at home in order to become successful engineers. The others are required according to the NSES, "Creativity, imagination, and a good knowledge base are all required in the work of science and engineering
question
Which of the following is NOT true about disease processes in humans?
answer
C Unfortunately, even though there are technological answers that can provide sanitation in any situation, there are certain places in the world where these answers have yet to be applied. Further, when natural disasters hit, sanitation issues are always a problem that spreads disease such as dysentery and typhus.
question
The data for the 7 groups in Mr. Fernando's class are represented for the 0.2 M sucrose solution in the table. Looking at the data from Groups 1-7, which of the following statements is MOST LIKELY true?
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A The students in Group 4 likely needed more assistance in measuring mass as evidenced by the fact that their measurements are much different from the rest of the groups' measurements. Also, since the instructions note that the balance was marked to the nearest gram, the measurements should have been to the nearest tenth. The teacher could likely have helped this group to avoid some of these errors with some attention to their measuring procedures during the lab. (B) it is not evident from the figure that having fewer (or more) groups would impact the results in any way. (C) While Group Four had more significant figures, since the instructions state that the balance has markings to the nearest gram, the measurements should only be to the nearest tenth in significant figures. Therefore these are not more accurate, they are inappropriately measured. (D) The class average would be less accurate due to Group Four's inappropriate measurement techniques.
question
Which of the following best represents the difference in accuracy of the seven groups' results?
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D The graph, Percent Error for Each Group, best represents accurate as it graphs percent error for each group and shows that Group 4 has a 42.6% error in comparison to much lower percentages of the other groups. The potato core results table (A) scatter plot (B) and potato mass bar graph (C) represent the data directly and the information can be inferred from them, but (D) has the accuracy clearly defined numerically
question
Regarding the experiment completed by Mr. Fernando's class, all of the following are true EXCEPT
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D--C The percent error is not the independent variable for this experiment, rather it is a function of the dependent variable.
question
Which of the following factors would not contribute to poor water quality as a result of increased local population?
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B Nitrogenous wastes would go up, not down with increased population. With increased population comes increased industry, thus increased factory waste (A), sewage (C) and agriculture with corresponding pesticides and fertilizers (D) which ... nitrogenous wastes; they do not lower them
question
Which of the following is the weakest type of chemical bonds?
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B A hydrogen bond involves the attraction of atoms of different polarity and can be easily broken. Atomic bonds (Where electrons are transferred) as well as double bonds and disulfide bridges, are all stronger than hydrogen bonds
question
All of the following are myths or misconceptions about the evolution of Homo sapiens EXCEPT
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A Chimpanzees are more closely related to homo sapiens than to other apes but Homo sapiens did not evolve from chimpanzees. About 5 million years ago, the lineages that led to the modern homo sapiens diverged from the lineage that led to modern chimpanzee. It is a common misconception that the evolution leading to Homo sapiens occurred like a series of steps on a ladder. It is more like a branching tree with dead ends and new branches appearing simultaneously. The large brain and upright posture are important feature of Homo sapiens but the early hominoids stood upright before there was an increase in brain size
question
Algae and protozoa are organisms within which kingdom?
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D Algae and protozoa are within the Kingdom Protista, which contains one-celled eukaryotes. Kingdom Animalia contains organisms that are multicellular eukaryotes (including vertebrates and invertebrates) Mammalia is not a kingdom; it is a class within the subphylum vertebrate Kingdom Plantae contains organisms that are multicellular, photosynthetic eukaryotes (including gymnosperms, angiosperms, etc)
question
When the water pressure is equal inside and outside the cell, it is said to be
answer
A--D When the water concentration inside and outside the cell is equal, it is said to be in an isotonic state. Water will pass through the cell membrane by osmosis from an area of higher concentration to an area of lower concentration in order to produce isotonic concentration
question
Energy transformations that occur as chemicals that are broke apart or synthesized within the cell are collectively known as
answer
C Cellular metabolism is a general term that includes all types of energy transformation processes, including photosynthesis, respiration, growth, movement, etc. Energy transformations occur as chemicals are broken apart (catabolism) or synthesized within the cell (anabolism)
question
The largest number of ATP molecules are formed by
answer
C--B The electron transfer system (ETS) produces the most ATP molecules, yielding 34 ATPs per glucose molecule. Fermentation and glycolysis each produce 2 ATPs per glucose molecule. Some of the products of the Krebs cycle are easily converted to ATP, but the main energy products of the Krebs cycle are those that liberate electrons that are then used in the electron transfer reactions
question
How does DNA produce particular genetic traits?
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B The primary role of DNA in the cell is the control of protein synthesis. Genetic traits are expressed and specialization of cells occurs as a result of the combination of proteins produced by the DNA of a cell. DNA replication allows for the genetic code to be preserved in future generations of cells. When expression of genetic traits is determined by whether the trait is inherited from the mother or father, it is called genetic imprinting. Genetic maintenance simply refers to the preservation of the integrity of genetic information from one generation to another.
question
A single DNA strand that has the sequence GATACCA would be complemented by a strand of DNA with which sequence?
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B In DNA, guanine (G) pairs with cytosine (C) and thymine (T) with adenine (A). Therefore, the sequence of GATACCA would pair with the sequence of CTATGGT
question
The longest of the two major periods of the cell cycle in which the cell is carrying on its primary function is known as
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B--A There are 2 major periods of the cell cycle: interphase and mitosis. Interphase is the period when the cell is active in carrying on the function it was designed to perform within the organism. Cells spend much more time in interphase than in the cell division portion of their cycle, which includes the prophase, telophase, anaphase and metaphase phases of mitosis plus cytokinesis.
question
Three offspring of two normal-skinned parents have normal skin, but one of the offspring is albino. Which of the following must be true?
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D As shown in the following PS, the only wan offspring could be albino is if each parent has at least one recessive gene for albinism. Since both have a normal phenotype, both must have the Nn genotype
question
If these two normal-skinned parents have 8 offspring, approximately how may are likely to be albino?
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A The phenotype ratio for this generation of offspring will be 3 normal: 1 albino, so out of 8 offspring, 2 are likely to be albino
question
The albino offspring from the F1 generation described above produces one albino offspring and one normal offspring in the F2 generation. What must be the genotype of the alibino's mate?
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C The albino parent from the F1 cross must have the nn genotype. As shown in the following PS, if the mate was albino (nn) all the offspring would be albino, and if the mate was homozygous (NN) then ll the offspring would be normal. In order to produce both phenotypes, the second parent must be heterozygous (Nn)
question
What is the 78 degrees F in International System (SI) units
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C--B (78-32)/18 = 25.6 C (A) K is an SI unit, but 78F does not convert to 25.6 K (C) 78/1.8 = 43.3 but you must subtract 32 first (D) 78-32 = 46 but you also must divide by 1.8
question
Which of the following natural hazards is MOST likely to be predicted in advance by modern technology and therefore allow for preventive measures to be taken to save life and property?
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A There is the most opportunity to predict landfall of a hurricane even though they can still be devastating Unfortunately, most lives are lost in hurricanes from those not following evacuation procedures. Property damage cannot always be avoided. (B) Earthquakes are the least likely to be predicted, thought scientists are working on technology to do this. (C) and (D) While there is some predictability to volcanoes and tsunamis in that there may be some warning signs, there is still a great amount of unpredictability, making them deadly hazards.
question
Which of the following statements regarding the relationship of science, society and technology is true?
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C Policy makers and voters should have a basic understanding about a technology before debating about or voting on a particular technology-related issue. A, B, D are not true...rather--understanding basic concepts and principles of science and technology should precede active debate about the economics, policies, politics, and ethics of various science--and technology-related challenges. However, understanding science alone will not resolve local, national or global challenges. Progress in science and technology can be affected by social issues and challenges.
question
When scientists consider new research, they have to consider what risks are involved in conducting the research and if the purpose of conducting the research is worth the risk. Which of the following questions is LEAST important for a researcher to ask in assessing risk management?
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C In determining risk, the literature basis is the least important factor. Literature review is important to other factors of research, but for risk assessment other questions such as A, B and D come to the forefront
question
Ronda has taken a Biology teaching position in an urban school district. In her first week of classes she finds that one of her lab sessions has 32 students assigned to it. In addition, there is no fire blanket available in the room and the lab tables are too small to allow for each student to participate in the group work. Which of the following is NOT Ronda's responsibility?
answer
D Only the students can ensure that they meet expectations to pass the class. A, B, C are all true as the teacher is responsible to identify, document and notify school and district officials about existing or potential safety issues that impact the learning environment, including hazards such as class-size overcrowding. Research shows that classes containing more than 24 students engaged in science activities cannot safely be surprised by one teacher
question
Which of the following is NOT an energy storage molecule?
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C--B Ribonucleic acid (RNA) is a molecule that stores information for protein synthesis and genetic coding, not energy. Cellulose, starch, lipid and sugar molecules all store energy within their chemical bonds.
question
The organelle of a cell that engages in both passive and active transport is the
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D The selective permeability of the cell membrane serves to manage the concentrations of substances within the cell, preserving its health. There are 2 methods by which substances can cross the cell membrane, passive transport and active transport. The rough ER and smooth ER serve as channels for moving molecules through a cell. The Golgi complex stores and packages proteins and lipids for transport and use throughout the cell.
question
Stem tissue includes which of the following?
answer
D Stem tissue does not include the cuticle. The cuticle is found covering the leaf. The stem is made of vascular tissue, including both xylem and phloem
question
An ion that binds to an enzyme, making it more able to catalyze a reaction, is known as
answer
C--D Prosthetic groups, which may be ions or non-protein molecules, are similar to cofactors in that they facilitate the enzyme reaction. However, prothetic groups are tightly attached by covalent bonds to the enzyme, rather than being separate atoms or molecules. The enzyme itself is a protein; the prosthetic group is not. An inorganic cofactor does not bind with the enzyme. A coenzyme also does not bind to the enzyme itself and is not an ion
question
Which type of tissue is made up of stacked cells connected by sieve plates that allow nutrients to pass from cell to cell?
answer
D--C Phloem tissue, made of stacked cells connected by sieve plates (that allow nutrients to pass from cell to cell), transports food made in the leaves (by photosynthesis) to the rest of the plant. Xylem tissue transfers water and does not require sieve plates to allow nutrients through. Meristem is the tissue that is found in the root cap, and is responsible for quick growth in the roots. Internodal tissue is found on the stem between nodes.
question
All of the following characteristics of water make it valuable to living organisms EXCEPT
answer
D Water has a pH of approximately 7, making it neither basic (under 7) nor alkaline (over 7). Transparency, polarity, and density are characteristics that make water valuable to living things.
question
Each ecosystem can support a certain number of organisms; this number is known as the
answer
C Carrying capacity is the # of organisms that can be supported within a particular ecosystem. The term natality refers to the birth rate of a pop. The population includes the # of organisms in a given community, whether or not the community is at its carrying capacity. The community is comprised of all the organisms that interact within a given ecosystem whether or not it is at carrying capacity or not.
question
Many insects have special respiratory organs known as
answer
A Insects use spiracles for gas exchange. Alveoli are found within the lungs (not found in insects) The cephalothorax is the head and thorax or arachnids and crustaceans and is not found in insects
question
What happens to most chemical pollutants that are accidentally ingested by a human?
answer
B--A The liver filters out most chemical pollutants, which are then mixed with broken-down pigments in the bile. Bile is secreted into the small intestine, then proceeds to the large intestine and is expelled in the feces
question
The process of forming egg and sperm cells in the reproductive organs is known as
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A Egg and sperm cells are called gametes and are formed in the process of gametogenesis. Spermatagonium are cells that eventually may become sperm cells, and oogonium are cells that eventually may become egg cells. Gametocide refers to the destruction of gametes
question
The cells of a developing embryo (at the gastrula stage) differentiate into layers (called germ layers) that will later develop into various tissues and organs. Which layer will eventually form muscles, skeletal organs, and the circulatory, respiratory, reproductive and excretory systems?
answer
D The mesoderm (between the ectoderm and endoderm) layer will eventually form muscles and organs of the skeletal, circulatory, respiratory, reproductive and excretory systems. The endoderm will become the gut lining and some accessory structures. The ectoderm will become the skin, some endocrine glands, and the nervous system. The blastula develops into a thin layer of cells surrounding an internal cavity.
question
Behavior that benefits the group at the individual's expense is known as
answer
C Altruism is a social behavior of an organism that is beneficial to the group at the individual's expense. Imprinting is a behavior that is learned during a critical period of an organism's life. Fixed action pattern (FAP) is an innate behavior that is independent of the organism's environment. Sacrificial behavior is not a term that is used in this context
question
Learned behavior that results in not responding to a stimulus is called
answer
B Habituation occurs when an individual learns not to respond to a particular stimulus, for instance when a stimulus is repeated many times without consequence. Circadian rhythm is a cycle of daily behavior based on an internal clock and environmental cues. Imprinting is a behavior that is learned during a critical period of an organism's life. Altruism is a social behavior of an organism that is beneficial to the group at the individual's expense
question
The physical place where particular organism lives is called its
answer
D A habitat refers to the physical place where an organism lives. A species' habitat must include all the factors that will support its life and reproduction. The niche also includes the role played by the organism in its food chain. The biosphere is the part of the Earth that contains all living things. The lithosphere (Earth) is part of the biosphere.
question
All of the following are requirements of the habitat of an apple tree EXCEPT
answer
D A species' role in the food chain is a part of its niche, not its habitat. The niche includes the habitat, but the habitat is within the niche. A species' habitat includes all of the factors that will support its life and reproduction. These factors may be biotic (population, food source, etc) and abiotic (i.e. nonliving--weather, temperature, soil features, sunlight, etc)
question
Sugars synthesized by photosynthesis travel through ____ ____ to various parts of the plant.
answer
B The sugars produced by photosynthesis are transported throughout the plant via the vascular bundles. The vascular bundles make up the veins in the leaf and are also distributed throughout the stem. Epidermal tissue is the outermost layer of cells of the stem. Meristem tissue consists of undifferentiated cells capable of quick growth and specialization. Meristem tissue is responsible for elongation of the stem. Parenchyma tissue has loosely packed cells that allow for gas and moisture exchange.
question
Which of the following environmental factors are recycled?
answer
A Carbon, nitrogen and phosphorus are all recycled through biogeochemical cycles
question
As energy is transferred through the trophic levels, some energy
answer
B--D The energy cycle of the food chain is subject to the laws of thermodynamics--no energy can be created or destroyed, and as energy changes form and passes from one level to another, some becomes unusable
question
Channels in cell membranes that carry water between cells are called
answer
B One pathway for water to pass through cell walls and plasma membranes toward xylem tissue is through an intercellular route through channels in the cell membranes known as plasmodesmata. Guard cells and stomata are whole cells that regulate the intake and outflow of water, whereas plasmodesmata are channels within a cell membrane. Internodes are the areas on the stem between nodes (places on the stem where leaves can begin to grow)
question
All of the following are steps in the phosphorous cycle EXCEPT
answer
C Phosphorous is nearly always found in solid form, within rocks and soil. Phosphorus gas is very rare and is not absorbed by plant leaves. The usable reservoir of Earth's phosphorous is found within rocks and soil. Water dissolves phosphorous from rocks by erosion, and carries it into rivers and streams. Here phosphorous and oxygen unite to form phosphates that end up in bodies of water. Phosphates are absorbed by plants in and near the water and are used in the synthesis of organic molecules. As in the carbon and nitrogen cycles, phosphorous is then passed up the food chain and returned through animal wastes and organic decay of dead matter. New phosphorous enters the cycle as undersea sedimentary rocks are upthrust during the shifting of the Earth's tectonic plates. New rock-containing phosphorous is then exposed to eroding and enters the cycling process
question
A bilayer of phospholipids with protein globules interspersed is characteristic of which of the following organelles?
answer
A The cell membrane is composed of a double layer (bilayer) of phospholipids with protein globules imbedded within the layers. The construction of the membrane allows it to aid cell function by permitting entrance and exit of molecules as needed by the cell. Mitochondria are the organelles where cellular respiration occurs. A lysosome is packet of digestive enzyme that destroy cellular wastes. Chromatin is disorganized DNA with histones attached.
question
A pond ecosystem has sharp boundaries at the shorelines. The sharp boundary of an ecosystem is known as
answer
A--C The sharp boundary of a community is called an ecotone. None of the other terms applies to the boundary of an ecological community
question
Which of the following cell organelles is known as the cells "powerhouse" because it produces energy for the cell's use?
answer
B Mitochondria are called the cell's "powerhouses" as they constitute the center of cellular respiration. (Cellular respiration is stye process of breaking up covalent bonds within sugar molecules with the intake of oxygen and release of energy in the form of ATP [adenosine tri-phosphate] molecules. ATP is the energy form used by all cell processes). Mitochondrion are found wherever energy is needed within the cell, and are more numerous in cells that require more energy (muscle, etc). The nucleus contains mitochondria, but mitochondria also exist outside the nucleus. The smooth ER is a system of channels for moving substances within the cell. Ribosomes are the site of protein synthesis within the cell.
question
Which one of the following statements about cells is NOT true?
answer
D Only plant cells have cell walls, but all cells have a cell/plasma membrane.
question
The bee belongs to which phylum?
answer
B--A Insects (including bees) are within the phylum Arthropeda. Aves is the class composed of birds. Annelida is the phyla composed of segmented worms. Nematoda is the phyla of roundworms.
question
Which of the following is a polymer of amino acids?
answer
B Enzymes are proteins, which are polymers of amino acids. Enzymes generally have names ending in -ase--thus lactase is an enzyme. Lactose, glycogen and sucrose are carbohydrates, not proteins, and are not made of amino acids. Lactose is the sugar that lactase acts upon. Glycogen and sucrose are saccharides
question
Vertebrates with no jaws belong to the superclass
answer
A Vertebrates are divided into 2 main groups, the Agnatha (animals with no jaws) and the Gnathostomata (animals with jaws). Protista is a kingdom that includes algae and protozoa. Cnidaria is a phylum that contains jellyfish, hydra, etc.
question
Which of the following structures provide rigidity to plant cells but not animal cells?
answer
B While microtubules, microfilaments, and centrioles all provide structure to cells of plants and animals, cell walls provide structure to plant cells (and some bacteria). Animal cells do not have a cell wall.
question
The nervous system is an integrated circuit with many functions. Which of the following parts of the nervous system are matched with the wrong function?
answer
B The cerebrum controls sensory and motor responses, and it controls memory, speech and intelligence factors. It does not control involuntary muscles.
question
Nitrogen is made available to organisms of the food change through all of the following EXCEPT
answer
D Nitrogen is not absorbed into the ocean as part of the nitrogen cycle. Each of the other steps is included in the nitrogen cycle.
question
Scurvy is a disease caused by a lack of vitamin C, leaving the body unable to build up enough collagen (a major component of connective tissue). The most plausible explanation for this malfunction is
answer
B Vitamins are organic cofactors or coenzymes that are required by some enzymatic reactions. Vitamin C is required for collagens to be synthesized.
