mastering biology ch1,2,3 – Flashcards
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Your baby starts crying. Because she hasn't eaten in 2 hours, you declare, "The baby must be hungry." Based on the scientific method, your statement is a(n) __________.
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hypothesis
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A fundamental characteristic of life on Earth is that __________.
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living things grow and reproduce
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The three natural processes that form the basis for evolution are __________.
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genetic variation, inheritance, and natural selection
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The complexity of living systems __________.
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is also highly organized
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A scientific theory assumes all of the following except __________.
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a scientific theory can never be proven wrong
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Your textbook lists seven characteristics that living organisms possess as a group. However, if you could condense these seven characteristics down to two general descriptive properties exclusive to all living organisms, what would they be?
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Macromolecular complexity and multiple levels of organization
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Which scientist(s) is/are credited with developing the theory of evolution in the mid-1800s?
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Both Charles Darwin and Alfred Russel Wallac
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All of the following characteristics define life except __________.
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the ability to do math
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A group of researchers developed a hypothesis and tested it by designing an experiment. The results of the experiment did not support the original hypothesis. What should the researchers do next?
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They should reject the original hypothesis and develop a new hypothesis.
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Identify a characteristic that is representative of some, but not all, life-forms.
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movement over great distances
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A scientist is testing whether a new cancer drug will work on prostate cancer in humans. To properly interpret results of an experiment, control experiments are needed. Which of the following treatments would serve as a control in these experiments, so that the researchers can conclude that the changes they see in the patients are due to the drug?
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Some patients receive a "mock" injection that contains the same solution base and the same volume as the drug but does not actually contain the drug itself.
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An autotrophic organism __________.
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would be one that derives its energy from a renewable external energy source such as sunlight (i.e., photosynthetic organisms)
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The diversity of life is mainly due to __________.
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genetic variation
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Why is a control needed in an experiment?
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To provide a comparison with the experimental results obtained when changing the variable
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An understanding of basic biological concepts __________.
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permits a deeper, and sometimes profound, appreciation of the world around us
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Experiments are carefully designed in an attempt to __________.
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test a single experimental variable
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Simple experiments generally isolate and test one __________ at a time.
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variable
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A scientist examines an organism and finds that it is eukaryotic, heterotrophic, multicellular, and it absorbs nutrients. She concludes that the organism is most likely a member of the Kingdom __________.
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fungi
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The organic complexity and organization of living organisms depends on the periodic capture of raw materials and energy. Ultimately, the source of this energy is __________.
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the sun
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Which of these experiments would best test the following hypothesis: "Bacteria do not arise spontaneously on meat; they are carried onto meat by droplets of water"?
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Place meat in two separate containers: Add droplets of water to one container and no water to the second container. Cover the containers and compare the growth of bacteria in the two containers.
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Organisms that can make their own food are called __________; organisms that must obtain energy from molecules made by other organisms are called __________.
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autotrophs; heterotrophs
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The process of evolution involves __________.
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natural selection of organisms that produce more offspring under certain environmental conditions
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Natural selection would be best illustrated by which of the following?
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A bacterial cell in the human body with a genetic variation that allows it to survive when the person takes antibiotics
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Which of the following statements is correct?
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Mutations are accidental changes in genes.
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In a famous experiment that helped disprove the possibility of spontaneous generation, Francesco Redi hypothesized that, contrary to popular belief, maggots did not appear spontaneously but came from flies. He predicted that if flies were kept away from meat, then maggots would not appear. To test his hypothesis, Redi placed identical pieces of meat in two identical jars and placed the two jars on the same windowsill. He placed a lid on one jar and left the other uncovered for several days. In the experiment, the control is __________.
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the meat in the jar without the lid
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________ is the study of living things.
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biology
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a(n) _________ consists of all the organisms and their nonliving environment within a given area
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ecosystem
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____________________ is the process of generating hypotheses from a well-supported generalization such as scientific theory
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deductive reasoning
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a plant or other organism that can make its own food is known as a(n) ________. an animal or other organism that cannot make its own food is known as a(n) ________.
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autotroph; heterotroph
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a statement describing an expected observation outcome of a specific experiment is known as a ________.
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prediction
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bacteria are ______, or single-celled, organisms. in contrast, most fungi, plants, and animals are many-celled, or _________.
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unicellular; multicellular
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a(n) __________ cell lacks a nucleus. a(n) ___________ cell has a true membrane-enclosed nucleus
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prokaryotic; eukaryotic
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Which of the following is NOT a characteristic of living things?
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creating energy
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Homeostasis is a living organism's
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ability to maintain constant internal conditions even when environmental conditions change.
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Which of the following can be found in bacteria, but not viruses?
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a cell membrane
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Viruses are
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not alive because they are not made of cells and require a host cell for reproduction.
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Which of the following statements about viruses is FALSE?
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The widespread use of antibiotics has led to resistant strains of viruses.
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Why is combination drug therapy for HIV/AIDS less likely to lead to resistance than single drug therapy?
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The likelihood of one virus spontaneously mutating to be resistant to several different drugs at the same time is extremely small.
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Suppose you were in charge of sending an unmanned space probe to a new planet in search of life. The probe would be able to collect and test samples and make observations, but the planet is too far away for the probe to be able to bring samples back to Earth. The probe is small and would only be able to run a few tests, so you want to pick a test for evidence of life that is broad enough to incorporate all forms of life as we know it. Which one of the following tests would be the best to use in this situation?
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a test for the presence of cells that contain DNA
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An organ, such as the liver, is composed of _____.
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tissues
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Which of these is an organ system?
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digestive
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What are the two main types of cells?
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prokaryotes and eukaryotes
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What is the purpose of a control group in an experiment?
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to provide a standard for comparison
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Which of these is a characteristic of all life?
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growing
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What is the eventual fate of all energy acquired by life?
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It becomes heat.
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A scientist examines an organism and finds that it is eukaryotic, heterotrophic, multi-cellular, and it absorbs food molecules. Which kingdom will she likely place the organism in?
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Fungi
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A 57-year-old woman was admitted to a hospital with an infected toe, and the infection was spreading rapidly. The damage was being caused by an unknown microorganism that could not be cultured in the lab. Doctors observed that antibiotics, which kill only prokaryotes, were ineffective. They suspected that the microbe was a fungus, so they tried the drug Amphotericin, which targets the ergosterols in fungal cells. Because animal cells contain cholesterols, not ergosterols, they are unaffected by the drug. Shortly after receiving Amphotericin, the patient improved, her infection ceased, and she was released from the hospital. In this scenario, what was the hypothesis?
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Antibiotics will not kill the microbe because it is a fungal species.
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Scientific experimentation generally leads to more questions. True or False?
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true
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Which is the correct sequence of increasing organization?
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Cell, tissue, organ, organ system
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Francesco Redi designed an experiment to test the notion of spontaneous generation. He left the first jar of meat open to the air and covered the second jar. The first jar would be called the ________ jar.
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control
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Chromosomes are made of
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deoxyribonucleic acid
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Why do heterotrophs require "food" for survival?
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Food provides the organic chemicals needed by heterotrophs.
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All of the following are true of all living organisms EXCEPT that they
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possess either DNA or RNA.
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Imagine you are waiting backstage for your cue to come onstage when you notice that you are breathing rapidly and beginning to feel light-headed. As you try to control your anxiety and slow your breathing, you think about what you learned in your biology class this week and realize that your hyperventilation is changing your blood pH. Explain.
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Rapid breathing increases the pH of your blood, making it more basic.
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What allows one atom to physically interact with a second atom?
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Number of electrons in the outer energy shell
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Why are hydrophobic molecules such as fats and oils unable to dissolve in watery solutions?
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Water molecules form hydrogen bonds with each other, excluding the hydrophobic molecules.
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When an atom ionizes, what happens?
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It gives up or takes up one or more electrons.
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All elements are __________.
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a unique form of matter
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An atom has two electrons in its inner energy shell, eight in the second, and one in the outermost shell. What is the most likely outcome for this atom in terms of chemical bonding?
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The atom will lose its outermost electron, becoming an ion with a charge of +1.
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The molecule H2SO4 is ionized to H+ ions and SO4- ions in water. Would you predict this to result in a solution that is acidic or basic?
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The solution would be acidic, as there would be more H+ than OH- ions.
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Which of the following is not a subatomic particle?
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Ion
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One solution has a pH of 2 and another has a pH of 3. What would be the relative difference in H+ ion concentration?
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A tenfold difference in concentration
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Oxygen atoms have an atomic number of 8. Neon atoms have 10 electrons. Predict whether or not these atoms are generally reactive with other atoms (i.e., can form chemical bonds with other atoms). Explain your answer.
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Oxygen is reactive because its outermost electron shell contains six electrons (is not filled); neon is not reactive because its outermost electron shell contains eight electrons (is filled).
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Nonpolar covalent bonds are different from polar covalent bonds because __________.
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electrons are shared equally in nonpolar covalent bonds and are shared unequally in polar covalent bonds.
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The atomic number of carbon is 6. A carbon atom has __________ protons and __________ electrons.
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six, six
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The chemical bonding properties of an atom are determined directly by __________.
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the outer shell of electrons
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Isotopes are __________.
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atoms with the same number of protons but different numbers of neutrons
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Which of the following is not true of covalent bonds?
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They result when atoms gain or lose one or more electrons.
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The basic structural units of matter and life are __________.
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atoms
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Atoms are the basic building blocks of elements. Atoms are made up of three different subatomic particles (protons, neutrons, and electrons). Which subatomic particle defines the fundamental nature of each element?
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Protons
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Covalent bonds __________.
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share electrons with another atom
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If electrons in water molecules were equally attracted to the hydrogen and oxygen nuclei, water molecules would be __________.
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less polar
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Why is water essential for life?
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Water is a good solvent, water moderates the effects of temperature, and when water freezes, it forms ice that floats.
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How many covalent bonds can the nitrogen (atomic number = 7) atom form?
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Three
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Imagine that you wanted to make a time capsule in which you would seal important artifacts from your life (pictures, poems, a lock of your baby hair, etc.), to be opened by your heirs 1,000 years from now. To prevent these artifacts from decaying, you want to fill the capsule with a gas that would be least reactive. Which of these gases would you choose: oxygen gas (O2) carbon dioxide (CO2), argon gas (Ar), or hydrogen gas (H2)? (The atomic numbers of the atoms in these molecules are as follows: oxygen = 8; carbon = 6; argon = 18; and hydrogen = 2.)
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Argon gas
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An oxygen atom with eight protons in its nucleus would be expected to have how many electrons?
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Eight electrons
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A hypothetical atom has one electron shell that can hold 10 electrons. This atom has seven protons and is electrically neutral. How many covalent bonds can this atom form?
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Three
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Which of the following lists of terms is in the correct order of size, going from smallest to largest?
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Electron, proton, atomic nucleus, atom, molecule
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What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?
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6
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Which of these refers to atoms with the same atomic number but different atomic masses?
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These atoms are isotopes.
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Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?
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10
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An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many protons does boron have?
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5
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Atoms with the same number of protons but with different electrical charges _____.
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are different ions
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In salt, what is the nature of the bond between sodium and chlorine?
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ionic
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An ionic bond involves _____.
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an attraction between ions of opposite charge
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A(n) _____ refers to two or more atoms held together by covalent bonds.
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molecule
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A(n) _____ bond joins these two oxygen atoms.
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double covalent
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Each water molecule is joined to _____ other water molecules by ____ bonds.
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four ... hydrogen
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The unequal sharing of electrons within a water molecule makes the water molecule _____.
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polar
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The tendency of an atom to pull electrons toward itself is referred to as its _____.
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electronegativity
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In a neutral solution the concentration of _____.
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hydrogen ions is equal to the concentration of hydroxide ions
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In order to maintain a constant pH, buffers act to either accept or release H+. True or False?
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true
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Scientists recommend a diet rich in antioxidants to stay healthy. What occurs at the atomic level to explain this recommendation?
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Antioxidants stop the chain reaction of cellular damage caused by free radicals.
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What is meant by the statement that water has a high specific heat?
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It can absorb a lot of energy without changing temperature.
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Sweating is a useful cooling mechanism for humans because water
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takes up a great deal of heat in changing from its liquid state to its gaseous state.
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The innermost electron shell of an atom can hold up to _____ electrons.
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2
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Which of these relationships is true of an uncharged atom?
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The number of protons is equal to the number of electrons.
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What determines the types of chemical reactions that an atom participates in?
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the number of electrons in the outermost electron shell
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Cancer is caused by mutating DNA. What exactly do cigarette smoke and radiation do that can cause cancer?
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Cigarette smoke and radiation both cause free radicals, which damage DNA, leading to mutation.
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What is a hydrogen bond?
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a weak bond between a slightly positive hydrogen atom and a slightly negative atom in a neighboring molecule
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How do the hydrogen bonds between water molecules compare to the covalent bonds within water molecules?
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The hydrogen bonds are more easily broken than the covalent bonds.
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How does water dissolve salt?
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The partial positive charges of the hydrogen atoms on water surround the negative charge of a chlorine ion.
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Why are hydrophobic molecules such as fats and oils unable to dissolve in watery solutions?
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Hydrophobic molecules are nonpolar, so they can't form hydrogen bonds with water. Water molecules form hydrogen bonds with each other, excluding the hydrophobic molecules.
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Because the specific heat of land is less than the specific heat of water, which of the following should be true?
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After a warm day, lakes should be warmer at night than the land around them.
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Why does ice float?
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The hydrogen bonds in solid water force the molecules farther apart than the same bonds in liquid water.
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Which basic property of a single water molecule accounts for all of its special features, including adhesion and cohesion, its ability to act as a solvent, and its high specific heat?
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the polar nature of water
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A(n) ______ contains the same number of protons, but a different number of neutrons, than another form of the same element.
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isotope
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___________ compounds do not interact with water
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hydrophobic
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a(n) _______ is a subatomic particle found in an atoms nucleus that has no electrical charge.
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neutron
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a(n) ______________________ is a chemical bond in which atoms share a pair of electrons
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covalent bonds
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_____________ compounds will interact with water
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hydrophilic
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If you examined the human body, which of the following combinations of elements would be most common?
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O, N, H, C
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Radioactive isotopes are biological tools that are often used to
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detect brain tumors.
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What determines the cohesiveness of water molecules?
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Hydrogen bonds
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Water moves through a plant because of the property of
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cohesion
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The human body must maintain a constant pH. In the blood, bicarbonate serves as a(n) ________ to help maintain the necessary pH.
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buffer
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At the gym one day, you notice a new energy bar being sold that advertises quick energy for your workout. To impress you further, it is claimed that this bar contains only carbon, oxygen, and hydrogen atoms. What kind of biological molecule(s) would you be eating if you ate this energy bar?
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carbohydrates and lipids
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The general class of biological molecules containing large, nonpolar regions, which make them insoluble in water, is called __________.
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lipids
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Lipids contain fatty acids, which are made mostly of nonpolar bonds. Will these molecules be soluble or insoluble in water? Explain.
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they would be insoluble in water due to their nonpolar bonds
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Proteins are polymers of __________.
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amino acids
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Phospholipids contain a "head group" that is __________ and two fatty acid "tails" that are __________.
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hydrophilic;hydrophobic
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"Organic" is a term that can have different meanings. What does this term mean to a chemist?
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organic compounds are compounds of carbon and hydrogen.
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A nucleotide is composed of __________.
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a sugar, a phosphate group, and a nitrogen-containing base
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Saturated fats __________.
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contain the max # of hydrogen atoms possible
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Protein functions in cells include __________.
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defense, catalysis of biochemical reactions, structure and movement, and transport
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During the process of polymerization (synthesis of biological polymers), water is __________, and the reaction is consequently called a __________ reaction.
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removed; dehydration
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Which type(s) of organic molecules contain a phosphate functional group?
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both nucleic acids and phospholipids
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Which of the following functional groups would you expect to help make an organic molecule soluble in water?
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a carbon backbone with many hydroxyl groups, OH
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How are large organic molecules (macromolecules) synthesized?
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by a dehydration reaction utilizing monomers
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Which of the following choices does not properly pair an organic compound with one of its building blocks (subunits)?
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nucleic acid-glycerol
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If a lipid is completely saturated, would you predict it to be liquid or solid at room temperature?
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it would be solid at room temperature
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Fat accumulates in our bodies when we overeat. This is because __________.
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lipids are a form of long term energy storage
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A scientist is studying the metabolism of proteins in yeast and wants to follow the formation of proteins from the earliest possible point. In her experiment, she will feed the yeast's radioactive nutrients and follow the fate of the radioactivity in the cells. Which of the following atoms will allow her to exclusively follow proteins in the cell?
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radioactive sulfur
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Carbohydrates __________.
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can function as a source of energy or can function as an extremely durable structural material, depending on the specific nature of the chemical bonds between subunits(monomers)
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How are humans able to use the energy in the starch of a potato but not in the cellulose of celery?
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our bodies can't break the bonds in cellulose but can break those in starch.
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Foods that are high in fiber are most likely to be derived from __________.
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plants
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A characteristic of the carbon atom that contributes to its ability to form an immense diversity of organic molecules is its __________.
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ability to covalently bond with up to four other atoms
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What is the difference between a simple sugar and a complex carbohydrate?
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complex carbohydrates are polymers of single sugars
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Complex carbohydrates have numerous roles in plant cells, including __________.
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long term energy storage and giving of structure to plant cell walls
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The quaternary level of protein structure __________.
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refers to a functional complex of two or more 3-d proteins
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The earliest ancient Egyptians buried their dead in pits in the desert. The heat and dryness of the sand dehydrated the bodies relatively quickly, leaving lifelike mummies. The trunk region of the body dehydrates much more slowly than peripheral regions such as the hands or feet. Based on what you know about how biological molecules are broken apart by the process of hydrolysis, which regions of a mummy's body would give the most intact pieces of DNA?
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fingers
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Proteins are macromolecules that can perform many different functions within an organism. This diversity of function is due to the unique nature of one of the protein macromolecule's four functional groups, which is bound to a central carbon atom. Which functional group is responsible for the wide diversity of function attributed to proteins?
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the R group
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When a protein is denatured __________.
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the protein's normal three-dimensional structure is altered, leaving the primary structure and protein function compromised
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Whether hair is naturally straight or curly is determined by __________.
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the appropriate location of disulfide bonds in keratin
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Excess nitrogen wastes in our food are converted to urea. Which of the following types of foods would you expect to increase the levels of urea in your blood?
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meats that contain a lot of protein and legumes that contain a lot of nucleic acid
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Which functional group is polar, acidic, and involved in peptide bonds?
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carboxyl
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Which of the following forms the exoskeleton of insects, crabs, and spiders?
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chitin
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What is the role of DNA and RNA in cells?
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preserving and expressing genetic information
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The nucleotide base that is in DNA but not RNA is __________.
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thymine
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Each fatty acid contains __________.
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a long chain of carbon and hydrogen and a carboxyl group at one end
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Prions are __________.
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made of only proteins
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The components of triglycerides are __________.
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one glycerol and three fatty acids
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Which type of nucleic acid is found in the chromosomes of cells?
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DNA
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Why are functional groups on organic compounds important?
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functional groups are more likely to participate in chemical reactions and are mainly responsible for the properties and chemical reactivity or organic molecules.
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Which of the following carbohydrates is a disaccharide?
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sucrose
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Which functional group helps to change gene expression when it is attached to nucleotides?
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methyl
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Disulfide bridges form in proteins between __________ in the __________ structure.
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two cysteine molecules; tertiary
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Obesity and a diet rich in saturated fats __________ LDL, while exercise __________ HDL.
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increases; increases
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Complex macromolecules are separated into their component parts through the process of __________.
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hydrolysis
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Cholesterol is used by cells __________.
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as a component of cell membranes, to insulate nerve cells in the brain, and as a building block for steroid types of hormones
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You have identified a protein that is unable to form disulfide bridges. This would affect which of the following?
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tertiary structure of the protein
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In which of the following molecules would rearranging the order of the subunits have an effect on molecular function?
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both protein and DNA
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The bond that links amino acids in a protein is called a __________ bond.
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peptide
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Adenosine Triphosphate (ATP) functions as a(n) __________.
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form of energy storage
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The sequence of amino acids linked together form the __________ structure.
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primary
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All of the following compounds contain carbon. Which one is an inorganic compound?
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carbon dioxide
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You are telling your friend that organic molecules are all made up of carbon backbones with hydrogens. She doesn't understand how there can be so many different organic molecules if they all are made up of the same basic components. You explain that organic molecules
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vary because they possess different functional groups
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What is the difference between carbohydrates and lipids?
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carbohydrates have mostly polar bonds and lipids do not
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Which of these is NOT a lipid?
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RNA
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Which of these is rich in unsaturated fats?
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olive oil
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A function of cholesterol that does not harm health is its role _____.
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as a component of animal cell membranes
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Why are organic molecules so diverse compared to inorganic molecules?
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the carbon molecules in an organic compound can make four bonds
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Cholesterol, testosterone, and estrogen are examples of
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steroids
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Which fact is most important in explaining why wrong base pairs are rarely incorporated into the double helix?
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Nucleotide pairing affects the action of DNA polymerase.
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In an experiment, a scientist fed radioactive nucleotides to a cell that was previously non-radioactive. After the cell duplicated its DNA, which statement would be true?
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Each DNA helix would have one radioactive strand and one non-radioactive strand.
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In DNA replication,
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the replica strands are complementary to the templates.
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What is the difference between saturated and unsaturated fats?
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Unsaturated fats contain double bonds
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What is the most common bond in a lipid?
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nonpolar covalent bonds
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Enzymes are ________ that catalyze chemical reactions within the body.
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proteins
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What is the difference between an organic compound and an inorganic compound?
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Organic compounds contain carbon and hydrogen. Inorganic compounds don't.
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Proteins are polymers of _____.
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amino acids
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What type of bond joins the monomers in a protein's primary structure?
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peptide
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The secondary structure of a protein results from _____.
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hydrogen bonds
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Tertiary structure is NOT directly dependent on _____.
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peptide bonds
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Which nucleotide molecule functions as an energy carrier in the cell?
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ATP
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What maintains the secondary structure of a protein?
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hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
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An atom's nucleus is composed of
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protons and neutrons.
