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BIO 120 Final


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Evolution is "the biological theme that ties together all the others." This is because the process of evolution...
1) Explains how organisms become adapted to their environment. 2) Explains the diversity of organisms. 3) Explains why all organisms have characteristics in common. 4) Explains why distantly related organisms sometimes resemble one another.
Which of the following observations and ideas are incorporated into Darwin's concept of natural selection?
Through natural selection, a population may adapt to the environment over many generations.
The continuity of life is based on...
Heritable information in the form of DNA.
The cell theory...
Includes the idea that skin cells come from preexisting skin cells.
Most ecosystems are solar powered. This means that...
Plants and other photosynthetic organisms convert light energy to chemical energy, which is then available to animals.
The lowest structural level in which all of life's properties occur is...
The cell.
Why have domains been added to the present system of classification?
1) Additional information has been gained from molecular studies. 2) There are so many differences among bacteria that it is necessary to divide them.
Viruses do not...
Viruses do not belong to the kingdoms...
Monera, Protista, or Fungi.
Which of these is the correct representation of the hierarchical organization of life from least to most complex?
Hydrogen, Water, Nucleus, Heart Muscle Cell, Heart Muscle Tissue, Heart, Human.
In order to understand the chemical basic of inheritance, one must understand the molecular structure of DNA. This is an example of the application of...
Species that are in the same ____ are more closely related than the species in that are only in the same ____.
A new species was discovered. Individuals of this species are multicellular eukaryotes that obtain nutrients from decomposing organic matter. How should this species be classified?
Eukarya, Fungi
How are most unicellular eukaryotes classified?
You have just discovered a new species that has starch, rather than DNA, as its genetic material. You are elated because you may have just discovered a new...
Domain of life.
Which of these provides evidence of the common ancestry of all life?
The universality of the genetic code.
Which of these individuals is most likely to be successful in an evolutionary sense?
An individual who dies after 5 days of life but leaves 10 offspring, all of whom survive to reproduce.
In a hypothetical world, every 50 years people over 6 feet tall are eliminated from the population. Based on your knowledge of natural selection, you would predict that the average height of the human population will...
Gradually decline.
Which of the following questions is outside the realm of science?
Does God exist?
When applying the process of science, which of these is tested?
A prediction.
A controlled experiment is one in which...
There are at least two groups, one of which does not receive the experimental treatment.
Which of the following best explains the distinction between biology and chemistry?
There is no clear distinction because the two sciences are parts of the same whole.
The carbon present in all organic molecules...
1) Is incorporated into organic molecules by plants. 2) Comes from air.
3) Is processed into sugars through photosynthesis.
4) Is derived from Carbon Dioxide.
The shape of a molecule...
1) Determines it biological funtion.
2) Is determined by orbital positions of its atoms.
3) Determines how molecules recognize and respond to each other.
4) May aid in the formation of bonds.
Which of the following best describes chemical equilibrium?
Reactions continuing with no effect on the concentrations of reactants and products?
Each element is unique and different from other elements because of its...
Atomic number.
The mass number of an element can be easily approximated by adding together the number of...
Protons and neutrons.
Oxygen has an atomic number of 8. Therefore, it must have...
1) 8 Protons.
2) 8 Electrons.
How does one refer to an atomic form of an element containing the same number of protons but a different number of neutrons?
31/15 P ; 32/15 P
What's the relationship?
They are both isotopes of phosphorous.
The atomic number of carbon is 6. 14C is heaver than 12C because the atomic nucleus of 14C conatins...
Six protons and eight neutrons.
The reactive properties or chemical behavior of an atom depend on the number of...
Electrons in the outer valence shell in the atom.
A covalent chemical bond is one in which...
Outer-shell electrons are shared by two atoms so as to satisfactorily fill the outer electron shells of both.
When two atoms are equally electronegative, they will interact to form...
Nonpolar covalent bonds.
An unequal sharing of electrons between atoms.
Polar covalent bond.
Which of the following is NOT considered to be a weak molecular interaction?
Covalent bond.
3H2 + N2 *double arrow* 2NH3
Which of the following is TRUE for the above reaction?
Ammonia is being formed and decomposed.
The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. What is the attraction called?
A hydrogen bond.
Which of the following solutions has the greater concentration of hydrogen ions (H+)?
Gastric juice at pH 2. (The lower the pH number, the more hydrogen ions.)
A solution with a pH of 3 has how many more H+ than a solution with a pH of 6?
1,000 times more.
The nutritional information on a cereal box shows that one serving of dry cereal has 90 calories (actually kilocalories). If one were to burn a serving of cereal, the amount of heat given off would be sufficient to raise the temperature of one kilogram o
90.0 degrees Celsius.
(Picture: solute molecule/large circle, surrounded by a shell of water) The solute molecule is most likely...
Positively charged.
Assuming a temperature of 25 degrees Celsius, what does a pH of 7 indicate?
1) The solution is neutral.
2) The concentration of H+ ions is 10e-7 moles per liter.
What determines the cohesiveness of water molecules?
Hydrogen bonds.
If the pH of a solution is decreased from 7 to 6, it means that the...
concentration of H+ has increased to 10 times what it was at pH 7.
Which of the following is a CORRECT definition of a kilocalorie?
The amount of heat energy required to raise one gram of water by one degree Celsius.
Which of the following is possible due to the surface tension of water?
A waterstrider can walk across a small pond.
Which of the following statements is TRUE about buffer solutions?
They tend to maintain a relatively constant pH.
Organic chemistry is a science based on the study of...
Carbon compounds.
Early 19th-century scientists believed that living organisms differed from nonliving things as a result of possessing a "life force" that could create organic molecules from inorganic matter. The term given to this belief is...
Which property of the carbon atom gives it compatibility with a greater number of different elements than any other type of atom?
Carbon has a valence of 4.
What type of bonds does carbon have a tendency to form?
What is the reason why hydrocarbons are not soluble in water?
The C-H bond is nonpolar.
The formation of polymers is most precisely described as an example of...
Polysaccharides, lipids, and proteins are similar in that they...
Are synthesized from monomers by the process of condensation synthesis.
Which of the following best summarizes the relationship between condensation reactions and hydrolysis?
Condensation reactions assemble polymers and hydrolysis breaks them down.
A new organism is discovered in the deserts of New Mexico. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 68 amino acid differences from humans, 62 differences from a gibbon, 24 differences from a rat, an
Indicate that the new organism may be closely related to frogs.
Carbohydrates normally function in animals as...
Energy storage molecules.
What is a common feature of both starch and glycogen?
They are polymers of glucose.
Which type of lipid is most important in biological membranes?
What is a triacylglycerol?
A lipid made of three fatty acids and glycerol.
Which bonds are created during the formation of the primary structure of a protein?
Peptide bonds.
What maintains the secondary structure of a protein?
Hydrogen bonds.
At which level of protein structure are interactions between R groups MOST important?
The alpha helix and the beta pleated sheet are both common forms found in which level of structure of proteins?
Altering which of the following levels of structural organization could change the function of a protein?
All of them. (Primary/Secondary/Tertiary/Quarternary)
The tertiary structure of a protein is the...
Three-dimensional shape.
Upon chemical analysis, a particular protein was found to contain 438 amino acids. How many peptide bonds are present in this protein?
What would be an expected consequence of changing one amino acid in a particular protein?
1) The primary structure would be changed.
2) The tertiary structure might be changed.
3) The biological activity of this protein might be altered.
4) The number of amino acids present would stay the same.
Which of the following states BEST summarizes structural differences between DNA and RNA?
DNA contains a different sugar from RNA.
If one strand of a DNA molecule has the sequence of bases 5'-ATTGCA-3', the other strand would have the sequence...
All of the following bases are found in DNA EXCEPT...
The difference between the two sugars in DNA and RNA is that the sugar DNA...
Contains less oxygen.
The two strands making up the DNA molecule...
Are held together by hydrogen bonds.
Which of the following BEST describes the relationship between nucleic acids and genes?
One long DNA molecule includes many genes.
The number of possible base sequences in a gene is...
Effectively limitless.
The difference(s) between DNA and RNA is (are):
In RNA, Thymine (T) is replaced by Uracil (U).
Metabolism is best described as...
1) Synthesis of macromolecules.
2) Breakdown of macromolecules.
3) Control of enzyme activity.
Anabolic pathways...
1) Use enzymes.
2) Consume energy to build up polymers from monomers.
The transfer of free energy from catabolic pathways to anabolic pathways is best called...
Energy coupling.
According to the first law of thermodynamics...
Energy is neither created nor destroyed.
Of the following, the structure of ATP is most closely related to...
RNA nucleotides.
Which of these is an example of a negative feedback system?
Mammals are able to reduce the amount of glucose in their blood following a meal by increased pancreatic secretion of insulin.
All of the following statements are representative of the second law of thermodynamics EXCEPT...
Every time energy changes form, there is a decrease in entropy.
Whenever energy is transformed, there is always an increase in the...
Entropy of the universe.
According to the second law of thermodynamics...
The entropy of the universe is constantly increasing.
According to the second law of thermodynamics, all of the following statements are true EXCEPT that...
The synthesis of large molecules from small molecules is exergonic.
Evolution of biological order...
Is consistent with the second law of thermodynamics.
A chemical reaction that has a positive (Delta)G is correctly described as...
Which of the following statements is TRUE concerning catabolic pathways?
They are usually coupled with anabolic pathways to which they supply energy in the form of ATP.
Correct statements regarding ATP include:
1) ATP serves as a main energy shuttle inside cells.
2) ATP drives endergonic reactions in the cell by the enzymatic transfer of the phosphate group to specific reactants.
3)The regeneration of ATP from ADP and phosphate is an energonic reaction.
A solution of starch at room temperature does not decompose rapidly to a sugar solution because...
The activation energy barrier cannot be surmounted in most of the starch molecules.
Which of these statements regarding enzymes is FALSE?
Enzymes provide activation energy for the reactions they catalyze.
During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a (Delta)G of
-20 kcal/mol. You double the amount of enzyme in the reaction, and the (Delta)G now equals...
-20 kcal/mol.
According to the induced fit hypothesis of enzyme function, which of the following is CORRECT?
The binding of the substrate changes the shape of the enzyme slightly.
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
Competitive inhibition.
Which of the following is true of enzymes?
1) Enzymes may require a nonprotein cofactor or ion for catalysis to take place.
2) Enzyme function is reduced if the three-dimensional structure or conformation of an enzyme is altered.
3) Enzyme function is influenced by physical and chemical environment factors such as pH and temperature.
4) Enzymes increase the rate of chemical reaction by lowering activation energy barriers.
Zinc, an essential trace element, is presented in the active sit of the enzyme carboxypeptidase. The zince most likely functions as a...
Cofactor necessary for enzyme activity.
Consider the following: Succinic acid degydrogenase catalyzes the reaction of succinic acid to fumaric acid. The reaction is inhibited by malonic acid, which resembles succinic acid but cannot be catalyzed by succinic dehydrogenase. Increasing the ratio
Fumaric acid is the product, and malonic acid is a competitive inhibitor.
Which of the following statements is TRUE regarding enzyme cooperativity?
A substrate molecule bound to an active site affects the active site of several subunits.
Which of the following are prokaryotic cells?
Organelles are:
Structures inside cells that are enclose by membranes.
Which of the following is NOT found in a prokaryotic cell?
Endoplasmic Reticulum.
Plasma Membrane.
A feature of all cells.
Found in plant cells only.
Found in prokaryotic cells only.
Which of the following does NOT contain functional ribosomes?
A nucleolus.
Which of the following is NOT a part of the endomembrane system?
To which structure would you assign the function of secretion activities leading, for example, to the formation of a new cell wall in plants?
Golgi vesicles.
Of the following, which is probably the most common route for membrane flow in the endomembrane system?
Rough ER -> Vesicles -> Golgi -> Plasma Membrane.
Which of the following cell components is NOT directly involved in synthesis or secretion?
Conains hydrolytic enzymes.
One of the main energy transformers of cells.
Detoxifies alcohol in the liver.
An animal secretory cell and a photosynthetic leaf cell are similar in all of the following ways EXCEPT:
They both have chloroplasts.
Which of the following relationships between cell structures and their respective functions is NOT correct?
Chloroplasts: Cheif site of cellular respiration.
Which of the following is NOT a known function of the cytoskeleton?
To maintain a critical limit on cell size.
Which of the following types of molecules are the major structural components of the cell membrane?
Phospholipids and proteins.
All of the following molecules are part of the cell membrane EXCEPT...
Nucleic acids.
The presence of cholesterol in the plasma membranes of some animals...
Enables the membrane to stay fluid more easily when cell temperature drops.
According to the fluid mosaic model of cell membranes, which of the following is a TRUE statement about membrane phospholipids?
They can move laterally along the plane of the membrane.
What is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold?
By increasing the percentage of unsaturated phospholipids in the membrane.
Integral proteins...
Are usually transmembrane proteins.
One of the functions of cholesterol in animal cell membranes is to...
Maintain membrane fluidity.
A cell lacking oligosaccharides on the external surface of its plasma membrane would likely be inefficient in...
Cell-cell recognition.
Which of the following adheres to the extracellular surface of animal cell plasma membranes?
Fibers of the extracellular matrix.
According to the endomembrane model for the formation of cell membranes, what components of the membrane of an animal cell will be at the extracellular surface exposed directly to the cytosol?
1) Phospholipids.
2) Membrane carbohydrates.
All of the following cellular activities require ATP energy EXCEPT...
Movement of O2 into the cell.
Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?
Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are...
Hypertonic to fresh water but hypotonic to the salt solution.
A cell with an internal concentration of 0.02 molar glucose is placed in a test tube containing 0.02 molar glucose solution. Assuming that glucose is not actively transported into the cell, which of the following terms describes the internal concentratio
What are the membrane structures that function in active transport?
Integral proteins.
Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantitites of glucose form the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transpo
Facilitated diffusion.
All of the following situations are consistent with active transport EXCEPT...
The rate of movement of molecules across the cell membrane increases in an anaerobic environment.
Water passes quickly through cell membranes because...
It moves through aquaporins in the membrane.
All of the following processes take material into cells EXCEPT...
Which of the following statements concerning the breakdown of glucose to CO2 and water are true?
1) The breakdown of glucose is exergonic.
2) Adding electrons to another substance is known as reduction.
All of the following statements about NAD+ are true EXCEPT:
NAD+ has more chemical energy than NADH.
Glycolysis is believed to be one of the most ancient of metabolic processes. Which statement below LEAST supports this idea.
If run in reverse, glycolysis will build glucose molecules.
All of the following statements about glycolysis are true EXCEPT:
The end products of glycolysis are CO2 and H20.
All of the following substances are produced in a muscle cell under anaerobic conditions EXCEPT...
Acetyl CoA.
All of the following are products or intermediaries in glycolysis EXCEPT...
The Krebs cycle produces which of the following molecules that then transfer energy to the electron transport system?
Which of the following intermediary metabolites enters the Krebs cycle and is formed, in part, by the removal of CO2 from a molecule of pyruvate?
Acetal CoA.
Each time a molecule of glucose is completely oxidized via aerobic respiration, how many oxygen (02) molecules are required?
During oxidative phosphorylation, H20 is formed. Where do the oxygen atoms in the H20 come from?
Molecular oxygen.
During aerobic respiration, electrons travel downhill in which sequence?
Food -> NADH -> Electron Transport Chain -> Oxygen.
During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level?
Which metabolic process is most closely associated with intracellular membranes?
Oxidative phosphorylation.
In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert
ADP + Pi to ATP?
Energy released form movement of protons through the ATP synthase.
The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation is...
The difference in H+ concentrations on opposite sides of the inner mitochondrial membrane.
A major function of the mitochondrial inner membrane is the conversion of energy from elecrons to the stored energy of the phosphate bond in ATP. To accomplish this function, this membrane must have all of the following features EXCEPT...
High permeability to protons.
It is possible to prepare vesicles from portions of the inner membrane of the mitochondrial components. Which one of the following processes could still be carried on by this isolated inner membrane?
Oxidative phosphorylation.
The primary function of the mitochondrion is the production of ATP. To carry out this function, the mitochondrion must have all of the following EXCEPT...
Enzymes for glycolysis.
For each pyruvate, how many carbon atoms feed into the Krebs cycle?
Inside an active mitochondrion, most electrons follow which pathway?
Krebs cycle -> NADH -> Electron transport chain -> Oxygen.
How many molecules of CO2 would be released from the complete aerobic respiration of a molecule of sucrose, a disaccharide?
The electron transport chain energy is used to pump H+ ions into which location?
Mitochondrial intermembrane space.
Muscle cells in oxygen deprivation convert pyruvate to ____ and in this step gain ____.
The ATP made during fermentation is generated by which of the following?
Substrate-level phosphorylation.
Which of the following does NOT participate in glycolysis?
Fatty acids.
Assume a mitochondrion contains 58 NADH and 19 FADH2. If each of the 77 dinucleotides were used, approximately how many ATP molecules could be generated as a result of oxidative phosphorylation (chemiosmosis)?
Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose-6-phosphate to frutose-1,6-bisphosphate, an early step of glycolysis. In the presence of oxygen, an increase in the amount ATP in a cell would be expected to...
Inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle.
You have a friend who lost 7 kg(about 15 pounds) of fat on a "low carb" diet. How did the fat leave her body?
It was released as CO2 and H20.
Glycolysis is thought to be one of the most ancient of metabolic processes. Which statement supports this idea?
Gllycolysis is the most widespread metabolic pathway.
An organism is discovered that consumes a considerable amount of sugar, yet does not gain much weight when denied air. Curiously, the consumption of sugar increases as air is removed form the organism's environment, but the organism seems to thrive even
It is a facultative anaerobe.
Recall that the complete oxidation of a mole of glucose releases 686 kcal of energy (DeltaG = -686 kcal/mol). The phosphorylation of ADP to form ATP stores approximately 7.3 kcal per mole of ATP. What is the approximate efficiency of cellular respiration
Approximately how many molecules of ATP are produced from the complete oxidation of two molecules of glucose(C6H12O6) in cellular respiration?
How many molecules of carbon dioxide(CO2) would be released from the complete aerobic respiration of a molecule of sucrose (C12H22O11), a disaccharide?
Each time a molecule of glucose (C6H12O6) is completely oxidized via aerobic respiration, how many oxygen molecules(O2) are required?
Starting with citrate, how many of the following would be produced with three turns of the citric acid cycle?
3 ATP, 6 CO2, 9 NADH, and 3 FADH2.
The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mole and free energy fro the reduction of NAD+ to NADH is +53 kcal/mole. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could
Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis.
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed during glycolysis?
Organisms that metabolize organic molecules produced by other organisms.
1) Heterotrophs.
2) Decomposers.
A new flower species has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are NOT being absorbed by this pigment?
Red and yellow.
The reaction-center chlorophyll of photosystem I is known as P700 because...
This pigment is best at absorbing light with a wavelength of 700 nm.
All of the events listed below occur in the energy-capturing light reactions of photosynthesis EXCEPT...
Carbon dioxide is incorporated into PGA.
In the thylakoid membranes, what is the main role of the antenna pigment molecules?
To harvest photons and transfer light energy to the reaction-center chlorophyll.
Because bundle-sheath cells are relatively protected from atmospheric oxygen, the level of ______ is held to a minimum in C4 plants.
What are the products of the light reactions that are subsequently used by the Calvin cycle?
Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be...
To test for liberatoin of O2 in the light.
As a research scientist, you mesure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from?
Cyclic electron flow.
Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?
The synthesis of ATP.
In a plant cell, where is ATP synthase located?
1) Thylakoid membrane.
2) Inner mitochondrial membrane.
In mitochondria, chemiosmosis translocates protons fromt eh matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from...
The stroma into the thylakoid compartment.
Which of the following are true of the enzyme ribulose bisphosphate carboxylase?
1) It participates in the Calvin Cycle.
2) It has an affinity for both O2 and CO2.
All of the following statements are correct regarding the Calvin cycle of photosynthesis EXCEPT:
These reactions begin soon after sundown and end before sunrise.
Oxidation of Water.
Oxidative Phosphorylation.
Requires ATP.
The Calvin Cycle Alone.
Requires ADP.
Light Reactions Alone.
Produces NADH.
Neither the Light Reactions Nor the Calvin Cycle.
Produces NADPH.
Light Reactions Alone.
The three substrates (normal reactants) for the enzyme RuBP carboxylase/oxidase (rubisco) are...
CO2, O2, and RuBP.
Photorespiration lowers the efficiency of photosynthesis by...
Using ATP molecules.
Why are C4 plants able to photosynthesize with no apparent photorespiration?
They use PEP carboxylase to initially fix CO2.
In C4 photosynthesis, carbon fixation takes place in the ____ cells, and then is transferred as malic or aspartic acid to ____ cells, where carbon dioxide is released for entry into the Calvin cycle.
CAM plants can keep stomates closed in daytime, thus reducing loss of water They can do this because they...
Fix CO2 into organic acids during the night.
In an experiment studying photosynthesis performed during the day, you provide a plant with radioactive carbon (14C) dioxide as a metabolic tracer. The 14C is incorporated first into oxaloacetic acid. The plant is best characterized as a...
C4 plant.
Plants that fix CO2 into organic acids at night when the stoma are open and carry out the Calvin cyccle during the day when the stoma are closed are called...
CAM plants.
What could happen to target cells in an animal that lack receptors for local regulators?
They would not be expected to multiply in response to growth factors from nearby cells.
Which of the following is TRUE of synaptic signaling and hormone signaling?
Hormone signaling is important between cells that are greater distances apart than in synaptic signaling.
A small molecule that specifically binds to a larger one.
A ligand.
Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to...
A specific catalytic site of an enzyme binding to a substrate.
Most signal molecules...
1) Bind to specific sites on receptor proteins in a membrane.
2) Are able to pass through the plasma membrane by active transport.
Which of the following are hydrophobic chemical messengers that pass through the cell's plasma membrane and have receptor molecules in the cytosol?
1) Nitric Oxide
2) Testosterone
A selective advantage of cell signaling is...
1) That it allowed some organisms to evolve without having a nervous system.
2) To ensure proper timing of communication between cells in different parts of an organism.
3) To ensure that crucial activities occur in the right cells at the right time.
The activity of a protein regulated by phosphorylation...
Depends on the balance in the cell between active kinase and active phosphatase enzymes.
If there are 20 centromeres in a cell, how many chromosomes are there?
A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei containing how many chromosomes?
Where do the microtubules of the spindle originate during mitosis in both plant and animal cells?
If a cell has 8 chromosomes at metaphase of mitosis, how many chromosomes will it have during anaphase?
Regarding mitosis and cytokinesis, one difference between higher plants and animals is that in plants...
A cell plate begins to form at telophase, whereas in animals a cleavage furrow is initiated at that stage.
Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, what would be the result?
A cell with two nuclei.
Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor, tubulin. Surprisingly, this stops mitosis. Speci
The fibers of the mitotic spindle.
Which of the following organisms does NOT reproduce cells by mitosis and cytokinesis?
During which portions of the cell cycle and during which phases(s) of mitosis do we find chromosomes composed of two chromatids?
From G2 of interphase through metaphase.
Movement of the chromosomes during anaphase would be MOST affected by a drug that...
Prevented shortening of microtubules.
A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. Those cells would have ____ picograms at the end of the S phase and ____ picograms at the end of G2.
"Density-dependent inhibition" is explained by which of the following?
As cells become more numerous, the amount of required growth factors and nutrients per cell becomes insufficient to allow for cell growth.
What is a genome?
The complete complement of an organism's genes.
Which of the following is the term for a human cell that contains 22 pairs of autosomes and two X chromosomes.
A female somatic cell.
In animals, meiosis results in gametes, and fertilization results in...
The X and the Y chromosomes are called sex chromosomes because...
Genes located on these chromosomes play a role in determing the sex of the individual.
Syngamy occurs between...
Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do ALL sexual life cycles have in common?
(II, III, and IV)
II. Meiosis
III. Fertilization
IV. Gametes
Which of these statements is FALSE? (Meiosis)
At sexual maturity, ovaries and testes produce diploid gametes by meiosis.
How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis?
They have half the number of chromosomes and one-fourth the amount of DNA.
Which of the following is missing from the life cycle listed below?

When does the synaptonemal complex disappear?
Late prophase of meiosis I.
The phases of meiosis that produce the most genetic variation from crossing-over and independent assortment are...
Prophase I and anaphase I.
Recombinant chromosomes are the result of...
What is the end result of meiosis?
Four haploid cells.
Tetrads of chromosomes are aligned at the center of the cell; independent assortment soon follows.
II. Metaphase I.
Synapsis of homologous pairs occurs; crossing over may occur.
I. Prophase I.
Nuclear envelopes may form; no replication of chromosomes takes place.
V. Interkinesis or Interphase.
Centromeres of sister chromatids uncouple and chromatids separate.
VIII. Anaphase II.
Which of the following occurs in meiosis but not in mitosis?
1) Synapsis
2)Tetrads align at metaphase plate.
Which of the following events occurs during prophase I of meiosis?
Synapsis and crossing over.
For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes?
About 8 million.

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