Bio Exam 2 Review – Flashcards
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The molecule most directly involved in energy transfer within cells is _____.
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ATP
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Which of the following statements concerning enzymes is true and correct? -Most enzymes are not proteins. -An enzyme is very specific in terms of which substrates it can bind. -Enzymes slow down the rate of chemical reactions. -An enzyme raises the activation energy of a chemical reaction. -An enzyme is consumed by the catalytic process.
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An enzyme is very specific in terms of which substrates it can bind.
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The diffusion of water across a selectively permeable membrane is called _____.
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osmosis (special case of passive transport)
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Ten kilocalories are equivalent to ______ calories.
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10,000
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Which one of the following is an example of osmosis? -the smell of freshly baked pie spreading throughout a house -the distant sound of church bells ringing -food in the refrigerator starting to taste like onions because the onions in the vegetable bin have been stored unwrapped -the smell of a backed-up sewer coming from a bathroom -the movement of a drink of water eventually into the cells lining the small intestine
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the movement of a drink of water eventually into the cells lining the small intestine
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Which one of the following is most similar to the mechanism of an enzyme inhibitor? -keeping someone from parking by parking in their designated spot -forgetting to put a cap back on a pen -changing the tires on a car -driving the wrong way on a one-way street -combining new ingredients in a new recipe
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keeping someone from parking by parking in their designated spot
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The sum total of all the chemical reactions that occur in organisms is called ______.
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metabolism
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A cell that neither gains nor loses water when it is immersed in a solution is ______.
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isotonic to its environment
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An enzyme is a protein that __________.
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changes the rate of a metabolic reaction without being consumed by the reaction
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A kilocalorie is equal to _______.
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1,000 calories
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Calories are units of___.
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energy
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An animal cell placed in a hypertonic solution will __________.
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lose water by osmosis and shrivel (Like fingers in water for long period of time will shrivel up)
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In osmosis, water always moves toward the _____ solution, that is, toward the solution with the _____ solute concentration.
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hypertonic ... greater
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Anything that prevents ATP formation will most likely ______.
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result in cell death
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A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via _____.
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endocytosis
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The concentration of calcium in a cell is 0.3%. The concentration of calcium in the surrounding fluid is 0.1%. How could the cell obtain more calcium?
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active transport
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Which of the following is the best example of a substance that contains chemical energy? -stored electrical charge -water behind a dam -food that you eat -falling off of a cliff -heat
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food that you eat
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Which is the best definition of energy?
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the capacity to do work
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Which one of the following statements about energy is correct? -We convert about 99% of our food energy to useful work. -A leaf falling from a tree represents potential energy. -Chemical energy is a form of kinetic energy. -Energy cannot be created or destroyed. -Entropy is the movement of molecules from areas of higher concentration to areas of lower concentration.
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energy cannot be created or destroyed
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The mechanism of enzyme action is __________.
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to lower the energy of activation or a reaction
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exocytosis
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A vescle inside the cell fuses with the plasma membrane and releases its contents outside of the cell
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facilitated diffusion
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Form of passive transport. Molecules move across the plasma membrane using a transport protein.
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Endocytosis
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The plasma membrane forms a pocket that pinches inward, forming a vesicle that contains material from outside the cell
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Diffusion
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A form of passive transport. Molecules move across the plasma membrane by crossing the lipid bilayer
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Active Transport
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Requires energy from the cell. Molecules move against their concentration gradient
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______ is to eating as ______ is to drinking.
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Phagocyosis.... pinocytosis
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Which component of the following reaction is the substrate? sucrose + sucrase + water → sucrase + glucose + fructose
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sucrose
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Which component of the following reaction is the enzyme? sucrose + sucrase + water → sucrase + glucose + fructose
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sucrase
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The movement of atoms, ions, or molecules from a region of higher concentration to regions of lower concentration is called _____.
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diffusion
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With the exception of gametes, a human cell contains _____ chromosomes.
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46
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Most human cancers are __________.
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caused by an accumulation of mutations
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Examples of carcinogens
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UV light, testosterone, cigarette smoke, fat
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_____ is a carcinogen that promotes colon cancer.
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Fat
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The cell cycle is a series of events that occur in which order?
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G1, S, G2, mitosis, cytokinesis
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What name is given to a gene that causes cancer?
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oncogene
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Inheritance of certain genes increases the risk of getting certain cancers; thus, it can be said that ______.
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predisposition to these cancers is inherited
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Most of an organism's DNA is carried by its ______.
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chromosomes
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All your cells contain proto-oncogenes, which can change into cancer-causing genes. Why do cells possess such potential time bombs?
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Proto-oncogenes are necessary for normal control of cell division.
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What is the order of the 4 main stages of mitosis?
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prophase, metaphase, anaphase, telophase
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A cancer cell _____.
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does not respond to the signals that control cell division
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The genes that malfunction and cause a cell to become cancerous usually __________.
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regulate cell division
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Replication of chromosomal DNA occurs __________.
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before a cell divides
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Which of the following best describes cancer cells? -Proto-oncogenes control their cell division. -They produce toxic compounds. -They are more highly differentiated than normal cells. -They will divide a certain number of times and then stop. -Controls governing cell division have been altered.
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Controls governing cell division have been altered
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In sexually reproducing multicellular organisms, the main functions of mitosis are _____.
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Growth and development; tissue repair/replacement of damaged cells
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What events occur during prophase?
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chromosomes condense and are attached to spindle fibers; the nuclear envelope breaking down
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Cyokinesis______.
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finishes mitosis by dividing the cytoplasm and organelles of the original parent cell into two separate daughter cells
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During _____, the cell carries out its normal functions and the chromosomes are thinly spread out throughout the nucleus.
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interphase
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Looking through a light microscope at a dividing cell, you see two separate groups of chromosomes on opposite ends of the cell. New nuclear envelopes are taking shape around each group. The chromosomes then begin to disappear as they unwind. You are witnessing _____.
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telophase
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Which of the following statements is correct? -Organisms that undergo asexual reproduction contribute only half of their chromosomes to their offspring. -Geneticists use the terms "son" and "daughter" to distinguish between cells resulting from cell division. -The sperm and egg have twice as many chromosomes as the parental cells. -Meiosis results in gametes that are used in reproduction. -Asexual reproduction requires the production of eggs and sperm.
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Meiosis results in gamees that are used in reproduction
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What is produced in meiosis?
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haploid gametes that are called eggs and sperm
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Meiosis and cytokinesis result in the formation of __________.
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four haploid cells
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Accidents can occur in meiosis wherein members of a chromosome pair fail to separate at anaphase. This is called _____.
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nondisjunction (the resulting gametes will have abnormal numbers of chromosomes)
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Orientation of homologous pairs of chromosomes at metaphase I results in alternative arrangements that contribute to genetic variation in offspring. The orientation is called _____.
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independent assortment
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The function(s) of meiosis is/are _____.
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Reproduction (production of gametes)
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Meiosis starts with _____ cells and produces _____ gametes.
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diploid... haploid
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Meiosis is typically accomplished in _____.
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three steps. All of the chromosomes are duplicated in a diploid cell, and then there are two cell divisions to produce a total of four haploid gametes.
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The _____ separate in meiosis I; the _____ separate in meiosis II.
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homologous chromosomes ... sister chromatids
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The process of meiosis accomplishes which of the following choices? -It produces four haploid cells and allows exchange of genetic material between homologous chromosomes. -It provides eight haploid gametes and can eliminate chromosomes. -It allows genetic exchange and eliminates the formation of haploid cells. -It provides mechanisms for sexual reproduction and eliminates the need for mitosis. -It provides for formation of four haploid cells and reduces the need for sister chromatids.
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It produces four haploid cells and allows exchange of genetic material between homologous chromosomes.
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Crossing over is______.
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the exchange of corresponding portions of homologous chromosomes
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Anaerobic respiration produces a maximum of ______ ATP per glucose
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2
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The ultimate source of the energy in food is ______.
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the sun
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Of the metabolic pathways listed below, the only pathway found in almost all organisms is __________.
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glycolysis
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Which of the following metabolic pathways is common to both aerobic and anaerobic processes of sugar breakdown? -conversion of pyruvic acid to acetyl CoA -the electron transport chain -conversion of pyruvic acid to lactic acid -glycolysis -the citric acid cycle
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glycolysis
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Humans use the calories they obtain from ______ as their source of energy.
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food
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Aerobic metabolism always requires _____.
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oxygen
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Respiration describes the exchange of gases between your blood and the outside air. Cellular respiration ______.
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produces ATP
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What waste product does yeast produce under anaerobic conditions?
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ethyl alcohol
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What is the name of the process in which glucose is converted to pyruvic acid?
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glycolysis
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What is glycolysis?
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the splitting of sugar, splits 6-carbon glucose into two 3-carbon pyruvic acid molecules
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The chemical ingredients needed for photosynthesis are _____ and _____.
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Carbon dioxide.... water
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What must pyruvic acid be converted to before it can enter the citric acid cycle?
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acetyl CoA
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Chemical reactions that require oxygen are called _____ while those that do not require oxygen are considered _____.
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aerobic... anaerobic
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_____ is used as food and _____ is produced as a waste in the overall process of cellular respiration.
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Glucose... carbon dioxide
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Where in a cell does glycolysis occur?
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cytosol
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Sports physiologists at an Olympic training center wanted to monitor athletes to determine at what point their muscles were functioning anaerobically. They could do this by checking for a buildup of _____.
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lactic acid
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What is the correct sequence of stages in cellular respiration?
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glycolysis, citric acid cycle, electron transport
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_____ is a chemical process that uses light energy from the sun to build organic molecules.
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photosynthesis
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Aerobic cellular respiration generates about ______ ATP from one glucose.
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38
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During photosynthesis in chloroplasts, O2 is produced from _____ via a series of reactions associated with __________.
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H2O... the water- splitting photosystem
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CAM plants conserve water by ______.
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opening the stomata only at night
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What is one reason why plants have accessory pigment molecules, like chlorophyll b and carotenoids?
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to absorb energy in parts of the electromagnetic spectrum that chlorophyll a cannot
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The reactions of the Calvin cycle are not directly dependent on light, but they usually do not occur at night. Why?
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The Calvin cycle depends on products of the light reactions.
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The most important role of pigments in photosynthesis is to __________.
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capture light energy
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In photosynthesis, what is the fate of the oxygen atoms present in CO2? They end up __________.
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in sugar molecules and in water
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Through what structure(s) do plants obtain most of their water?
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roots
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The overall function of the Calvin cycle is __________.
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making sugar
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C4 plants conserve water by ______.
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keeping their stomata closed when the weather is hot and dry
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What is the equation for photosynthesis?
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6 CO2 + 6 H2O → C6H12O6 + 6 O2
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Burning biofuels releases CO2 into the atmosphere, contributing to global warming. However, this is at least partially offset by __________.
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the CO2 absorbed during photosynthesis as the plants grow
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The end products of photosynthesis are _____ and _____.
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glucose ... oxygen
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If a plant appears blue to us, what wavelength of light is being reflected?
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blue
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Which of these wavelengths is least useful for photosynthesis?
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green
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Why are NASA scientists researching plants as a life support system for long-term space flight?
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packaged food takes up too much space
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What growing conditions are NASA scientists manipulating as they study plants for life support systems?
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light level, density, color of light, type of plant
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If you were gardening on a space station, which of these could you eliminate?
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soil
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Which of the following causes the growth of wasteful side shoots on wheat plants?
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fluorescent light
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Which of the following includes some of the benefits of photosynthesis? -It enhances the greenhouse effect. -It is a source of carbon dioxide. -It is an oxygen source as well as a source of stored energy. -It stores chemical energy. -It is a source of oxygen.
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It is an oxygen source as well as a source of stored energy.
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The "photo-" part of the word "photosynthesis" refers to __________, whereas "-synthesis" refers to __________.
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the light reactions that occur in the thylakoids ... the incorporation of carbon dioxide
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When light strikes chlorophyll molecules, they lose electrons, which are ultimately replaced by other electrons obtained by __________.
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splitting water
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What color is strongly reflected by chlorophyll?
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green
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What is a good reason for using fast-growing trees as fuel?
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Vigorously growing plants remove a lot of carbon dioxide from the air.
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In photosynthesis, plants use carbon from _____ to make sugar and other organic molecules.
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carbon dioxide
