Bio midterm

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A. Glycolysis B. Krebs cycle C. Calvin cycle D. Light-dependent reactions of photosynthesis E. Chemiosmosis Process in which sugar is oxidized to pyruvic acid

A. Glycolysis

A characteristic shared by fungi and protists is that both are generally (A) aerobic (B) haploid at all stages (C) composed of mycelia (D) propagated by spores (E) capable of phagocytosis

(A) aerobic

When a substance moves across the plasma membrane along a concentration gradient at a rate faster than would be expected by simple diffusion alone but without the expenditure of metabolic energy, the process is best described as (A) facilitated diffusion (B) osmosis (C) active transport (D) pinocytosis (E) the work of an ion pump

(A) facilitated diffusion

(diagram mouse/cricket) During aerobic cellular respiration, oxygen gas is consumed at the same rate as carbon dioxide gas is produced. In order to provide accurate volumetric measurements of oxygen gas consumption, the experimental setup should include which of the following? (A) A substance that removes carbon dioxide gas (B) A plant to produce oxygen (C) A glucose reserve (D) A valve to release excess water

(A) A substance that removes carbon dioxide gas

(A) Cytochrome (B) FADH2 (C) NAD+ (D) NADP+ (E) Oxygen (O2) A membrane-bound electron carrier found in the electron transport systems of both aerobic respiration and photosynthesis

(A) Cytochrome

(mitochondria v chloroplast) The figures can best assist in answering which of the following questions? (A) Do electron transport chains create a gradient so that ATP synthase can generate ATP molecules? (B) What are the sources of energy that drive mitochondrial and chloroplast electron transport systems? (C) What is the optimal temperature at which ATP synthase chemically converts ADP and a phosphate group into one molecule of ATP? (D) What is the evolutionary relationship between the ATP synthase in mitochondria and the ATP synthase in chloroplasts?

(A) Do electron transport chains create a gradient so that ATP synthase can generate ATP molecules?

A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size (both length and mass) of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds. Which of the following statements might best explain the increase in average beak size in the finch population during the drought? (A) Finches with bigger beaks are better able to crack thick-walled seeds and produce more surviving offspring. (B) Finches with bigger beaks can attack and kill finches with smaller beaks. (C) Finches with bigger beaks possess more- powerful flight muscles and are able to find more food. (D) Finches that crack large seeds develop larger beaks over time.

(A) Finches with bigger beaks are better able to crack thick-walled seeds and produce more surviving offspring.

(A) Proteins (B) Carbohydrates (C) Nucleic acids (D) Lipids (E) Steroids Synthesized at the ribosome

(A) Proteins

Arctic foxes typically have a white coat in the winter. In summer, when there is no snow on the ground, the foxes typically have a darker coat. Which of the following is most likely responsible for the seasonal change in coat color? (A) The decrease in the amount of daylight in winter causes a change in gene expression, which results in the foxes growing a lighter- appearing coat. (B) The diet of the foxes in summer lacks a particular nutrient, which causes the foxes to lose their white coat and grow a darker- colored coat. (C) Competition for mates in the spring causes each fox to increase its camouflage with the environment by producing a darker- appearing coat. (D) The lower temperatures in winter denature the pigment molecules in the arctic fox coat, causing the coat to become lighter in color.

(A) The decrease in the amount of daylight in winter causes a change in gene expression, which results in the foxes growing a lighter- appearing coat.

(diagram mouse/cricket) According to the data, the mice at 10∞C demonstrated greater oxygen consumption per gram of tissue than did the mice at 25∞C. This is most likely explained by which of the following statements? (A) The mice at 10∞C had a higher rate of ATP production than the mice at 25∞C. (B) The mice at 10∞C had a lower metabolic rate than the mice at 25∞C. (C) The mice at 25∞C weighed less than the mice at 10∞C. (D) The mice at 25∞C were more active than the mice at 10∞C.

(A) The mice at 10∞C had a higher rate of ATP production than the mice at 25∞C.

tobacco - According to the results of this experiment, germination of tobacco seeds during the first week is (A) increased by exposure to light (B) unaffected by light intensity (C) prevented by paper towels (D) accelerated in green-leaved seedlings

(A) increased by exposure to light

Sickle-cell anemia results from a point mutation in the HBB gene. The mutation results in the replacement of an amino acid that has a hydrophilic R-group with an amino acid that has a hydrophobic R-group on the exterior of the hemoglobin protein. Such a mutation would most likely result in altered (A) properties of the molecule as a result of abnormal interactions between adjacent hemoglobin molecules (B) DNA structure as a result of abnormal hydrogen bonding between nitrogenous bases (C) fatty acid structure as a result of changes in ionic interactions between adjacent fatty acid chains (D) protein secondary structure as a result of abnormal hydrophobic interactions between R-groups in the backbone of the protein

(A) properties of the molecule as a result of abnormal interactions between adjacent hemoglobin molecules

Assume that the alleles referred to all assort independently. (A) 0 (B) 1/16 (C) 1/4 (D) 1/2 (E) 3/4 Probability that the genotype ccdd will be produced by the parents CcDd x CcDd

(B) 1/16

A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size (both length and mass) of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds. Which of the following best describes the mechanism behind the change in beak size in the finch population? (A) The formation of two new finch species from a single parent species (B) A change in gene frequencies in the finch population due to selective pressure from the environmental change (C) A new allele appearing in the finch population as a result of mutation (D) The achievement of dynamic equilibrium in the finch population as a result of homeostasis

(B) A change in gene frequencies in the finch population due to selective pressure from the environmental change

The mechanism of action of many common medications involves interfering with the normal pathways that cells use to respond to hormone signals. Which of the following best describes a drug interaction that directly interferes with a signal transduction pathway? (A) A medication causes the cell to absorb more of a particular mineral, eventually poisoning the cell. (B) A medication enters the target cell and inhibits an enzyme that normally synthesizes a second messenger. (C) A medication enters the target cell's nucleus and acts as a mutagen. (D) A medication interrupts the transcription of ribosomal RNA genes.

(B) A medication enters the target cell and inhibits an enzyme that normally synthesizes a second messenger.

The endocrine system incorporates feedback mechanisms that maintain homeostasis. Which of the following demonstrates negative feedback by the endocrine system? (A) During labor, the fetus exerts pressure on the uterine wall, inducing the production of oxytocin, which stimulates uterine wall contraction. The contractions cause the fetus to further push on the wall, increasing the production of oxytocin. (B) After a meal, blood glucose levels become elevated, stimulating beta cells of the pancreas to release insulin into the blood. Excess glucose is then converted to glycogen in the liver, reducing blood glucose levels. (C) At high elevation, atmospheric oxygen is more scarce. In response to signals that oxygen is low, the brain decreases an individual's rate of respiration to compensate for the difference. (D) A transcription factor binds to the regulatory region of a gene, blocking the binding of another transcription factor required for expression.

(B) After a meal, blood glucose levels become elevated, stimulating beta cells of the pancreas to release insulin into the blood. Excess glucose is then converted to glycogen in the liver, reducing blood glucose levels.

(A) Proteins (B) Carbohydrates (C) Nucleic acids (D) Lipids (E) Steroids Includes glycogen, chitin, cellulose, and glucose

(B) Carbohydrates

Which of the following methods for the transport of carbon dioxide provides a buffering system for the blood? (A) Carbon dioxide is dissolved in the plasma. (B) Carbon dioxide combines with water to form carbonic acid then bicarbonate. (C) Carbon dioxide combines with hemoglobin to form carboxyhemoglobin. (D) Carbon dioxide is carried in small gas bubbles. (E) Carbon dioxide is converted to CO for plasma transport.

(B) Carbon dioxide combines with water to form carbonic acid then bicarbonate.

(A) DNA ligase (B) DNA polymerase (C) RNA polymerase (D) Restriction enzyme (E) Reverse transcriptase Enzyme used to position nucleotides during DNA replication

(B) DNA polymerase

The chemical reaction for photosynthesis is 6CO2 +12H2O+lightenergy→ C6H12O6 +6O2 +6H2O If the input water is labeled with a radioactive isotope of oxygen, 18O, then the oxygen gas released as the reaction proceeds is also labeled with 18O. Which of the following is the most likely explanation? (A) During the light reactions of photosynthesis, water is split, the hydrogen atoms combine with the CO2, and oxygen gas is released. (B) During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released. (C) During the Calvin cycle, water is split, regenerating NADPH from NADP+, and oxygen gas is released. (D) During the Calvin cycle, water is split, the hydrogen atoms are added to intermediates of sugar synthesis, and oxygen gas is released.

(B) During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released.

Which of the following directly produces the most ATP per mole of glucose during aerobic cellular respiration? (A) Which of the following directly produces the most ATP per mole of glucose during aerobic cellular respiration? (B) Electron transport chain and chemiosmosis (C) Substrate-level phosphorylation (D) Kreb's cycle (E) Alcoholic fermentation

(B) Electron transport chain and hemiosmosis

tobacco- The most probable cause for the difference in mean stem length between plants in dish A and plants in dish B is which of the following? (A) Shortening of cells in the stem in response to the lack of light (B) Elongation of seedlings in response to the lack of light (C) Enhancement of stem elongation by light (D) Genetic differences between the seeds

(B) Elongation of seedlings in response to the lack of light

(A) Cytochrome (B) FADH2 (C) NAD+ (D) NADP+ (E) Oxygen (O2) Coenzyme that transfers electrons from the Krebs cycle to the mitochondrial electrontransport chain at a lower energy level than that of electrons entering at the beginning of the chain

(B) FADH2

Which metabolic process is common to both aerobic cellular respiration and alcoholic fermentation? (A) Krebs cycle (B) Glycolysis (C) Electron transport chain (D) Conversion of pyruvic acid to acetyl CoA (E) Production of a proton gradient

(B) Glycolysis

Experimental evidence shows that the process of glycolysis is present and virtually identical in organisms from all three domains, Archaea, Bacteria, and Eukarya. Which of the following hypotheses could be best supported by this evidence? (A) All organisms carry out glycolysis in mitochondria. (B) Glycolysis is a universal energy-releasing process and therefore suggests a common ancestor for all forms of life. (C) Across the three domains, all organisms depend solely on the process of anaerobic respiration for ATP production. (D) The presence of glycolysis as an energy- releasing process in all organisms suggests that convergent evolution occurred.

(B) Glycolysis is a universal energy-releasing process and therefore suggests a common ancestor for all forms of life.

Which of the following is true of mitosis? (A) It is also known as cytokinesis. (B) It maintains the same chromosome number in the daughter cells as in the parent cell. (C) It is the last phase of interphase. (D) It regulates the transfer of genetic information from one daughter cell to another. (E) It moves homologous chromosomes to opposite poles.

(B) It maintains the same chromosome number in the daughter cells as in the parent cell.

Which of the following components of the cell membrane is responsible for active transport? (A) Phospholipid (B) Protein (C) Lipid (D) Phosphate (E) Cholesterol

(B) Protein

(osmolarity pic) Paramecia are unicellular protists that have contractile vacuoles to remove excess intracellular water. In an experimental investigation, paramecia were placed in salt solutions of increasing osmolarity. The rate at which the contractile vacuole contracted to pump out excess water was determined and plotted against osmolarity of the solutions, as shown in the graph. Which of the following is the correct explanation for the data? (A) At higher osmolarity, lower rates of contraction are required because more salt diffuses into the paramecia. (B) The contraction rate increases as the osmolarity decreases because the amount of water entering the paramecia by osmosis increases. (C) The contractile vacuole is less efficient in solutions of high osmolarity because of the reduced amount of ATP produced from cellular respiration. (D) In an isosmotic salt solution, there is no diffusion of water into or out of the paramecia, so the contraction rate is zero.

(B) The contraction rate increases as the osmolarity decreases because the amount of water entering the paramecia by osmosis increases.

A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size (both length and mass) of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds. 10. The biologist discovered that from 1988 to 1993, the average beak size declined to pre-1981 levels. The reversal in beak size from 1988 to 1993 was most likely related to which of the following events? (A) A loss of food supply for the finches (B) The end of the drought (C) An increase in drought conditions (D) An increase in predators consuming finches

(B) The end of the drought

(There is an image in your packet #93-96) 2002 test Based solely on the curve, what can be said concerning the calculated reaction rates at 1 minute and at 2 minutes? (A) The rate after 2 minutes is greater than the rate after 1 minute. (B) The rates are the same at 1 minute and at 2 minutes. (C) The rates are affected by high concentrations of inhibitors. (D) The rates are both zero. (E) The greater the rate, the faster the enzyme is denatured

(B) The rates are the same at 1 minute and at 2 minutes.

Simple diffusion and facilitated diffusion are related in that both (A) require protein carriers (B) depend on a concentration gradient (C) occur via contractions of cytoskeletal elements attached to membrane proteins (D) are endergonic processes and thus require the hydrolysis of ATP (E) occur in eukaryotic cells but not in prokaryotic cells

(B) depend on a concentration gradient

(There is an image in your packet #93-96) 2002 test The rate of the reaction could also be determined by (A) measuring the change in the amount of enzyme (B) measuring the change in the amount of substrate (C) measuring the change in salt concentration (D) adding more substrate (E) adding more enzyme

(B) measuring the change in the amount of substrate

Evolutionary fitness is measured by (A) physical strength (B) reproductive success (C) length of life (D) resistance to disease (E) competitiveness

(B) reproductive success

Assume that the alleles referred to all assort independently. (A) 0 (B) 1/16 (C) 1/4 (D) 1/2 (E) 3/4 Probability that the genotype Rr will be produced by the parents Rr x rr

Assume that the alleles referred to all assort independently. (A) 0 (B) 1/16 (C) 1/4 (D) 1/2 (E) 3/4 Probability that the genotype TTSs will be produced by the parents TTSs x TtSS

(There is an image in your packet #93-96) 2002 test What is the most likely explanation for the change in the slope of the line between 3 and 5 minutes? (A) The enzyme had denatured. (B) The enzyme had achieved its maximum velocity. (C) A large amount of the substrate had been consumed. (D) An allosteric inhibitor appeared. (E) There was a dramatic change in the pH.

The movement of the organic products of photosynthesis from the leaf to the roots is the result of what process? (A) Cellular respiration (B) Replication (C) Germination (D) Transcription (E) Translocation

(E) Translocation

Which of the following statements best supports the claim that organisms share fundamental processes as a result of evolution? (A) All organisms that are introduced into new environments have the capacity to fill vacant ecological roles. (B) All organisms have the ability to utilize oxygen to harness energy from the chemical breakdown of organic compounds. (C) All organisms share a genetic code organized into triplet codons, making it possible for one organism to express a gene from another organism. (D) All organisms possess structures such as chloroplasts and mitochondria within their cells that reflect past symbiotic relationships between prokaryotic precursors.

(C) All organisms share a genetic code organized into triplet codons, making it possible for one organism to express a gene from another organism.

Cells that contain only circular chromosomes are most probably which of the following? (A) Protist cells (B) Fungal cells (C) Bacterial cells (D) Plant cells (E) Animal cells

Which two cellular organelles in eukaryotes have both electron transport systems and chemiosmotic mechanisms? (A) Ribosomes and endoplasmic reticulum (B) Chloroplasts and endoplasmic reticulum (C) Chloroplasts and mitochondria (D) Mitochondria and nuclei (E) Nuclei and Golgi apparatus

Which of the following can be diagnosed by examining a karyotype of an individual's white blood cells? (A) Sickle cell anemia (B) Alzheimer disease (C) Down syndrome (D) Cystic fibrosis (E) Duchenne muscular dystrophy

Which of the following is responsible for the cohesive property of water? (A) Hydrogen bonds between the oxygen atoms of two adjacent water molecules (B) Covalent bonds between the hydrogen atoms of two adjacent water molecules (C) Hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule (D) Covalent bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule (E) Hydrogen bonds between water molecules and other types of molecules

(A) Cytochrome (B) FADH2 (C) NAD+ (D) NADP+ (E) Oxygen (O2) An intermediate electron acceptor for oxidations that occur in both glycolysis and in Krebs cycle reactions

(A) Proteins (B) Carbohydrates (C) Nucleic acids (D) Lipids (E) Steroids Used to carry the genetic code

Membrane-bound organelles have been an important component in the evolution of complex, multicellular organisms. Which of the following best summarizes an advantage of eukaryotic cells having internal membranes? (A) Eukaryotic cells are able to reproduce faster because of the presence of organelles. (B) Some organelles, such as mitochondria and chloroplasts, are similar to prokaryotic cells in structure. (C) Organelles isolate specific reactions, increasing metabolic efficiency. (D) Compartmentalization leads to a higher mutation rate in DNA, which leads to more new species.

(A) DNA ligase (B) DNA polymerase (C) RNA polymerase (D) Restriction enzyme (E) Reverse transcriptase Enzyme used in the synthesis of mRNA

The sequences for two short fragments of DNA are shown above. Which of the following is one way in which these two segments would differ? (A) Segment 1 would not code for mRNA because both strands have T, a base not found in RNA. (B) Segment 1 would be more soluble in water than segment 2 because it has more phosphate groups. (C) Segment 1 would become denatured at a lower temperature than would segment 2 because A-T base pairs have two hydrogen bonds whereas G-C base pairs have three. (D) Segment 1 must be from a prokaryote because it has predominantly A-T base pairs.

(C) Segment 1 would become denatured at a lower temperature than would segment 2 because A-T base pairs have two hydrogen bonds whereas G-C base pairs have three.

A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size (both length and mass) of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds. 7. Which of the following procedures was most likely followed to determine the change in beak size? (A) A few finches were trapped in 1981 and again in 1987, and their beak sizes were compared. (B) The beak size in fifteen finches was measured in 1987, and the beak size in the original finches was determined by estimation. (C) The beak size in a large number of finches was measured every year from 1981 to 1987. (D) Finches were captured and bred in 1981, and the beak size of the offspring was measured.

By discharging electric sparks into a laboratory chamber atmosphere that consisted of water vapor, hydrogen gas, methane, and ammonia, Stanley Miller obtained data that showed that a number of organic molecules, including many amino acids, could be synthesized. Miller was attempting to model early Earth conditions as understood in the 1950s. The results of Miller's experiments best support which of the following hypotheses? (A) The molecules essential to life today did not exist at the time Earth was first formed. (B) The molecules essential to life today could not have been carried to the primordial Earth by a comet or meteorite. (C) The molecules essential to life today could have formed under early Earth conditions. (D) The molecules essential to life today were initially self-replicating proteins that were synthesized approximately four billion years ago.

All of the following are examples of prezygotic genetic isolating mechanisms EXCEPT: (A) Male fireflies of different species have differing flash patterns. (B) Three closely related orchid species flower on different days. (C) The progeny of a cross between two different lizard (D) One species of snake lives in water and another is terrestrial. (E) Peeper frogs mate in April, and tree frogs mate in June.

MRSA is the acronym for methicillin-resistant Staphylococcus aureus. Many of the strains of the common bacterium are also resistant to other antibiotics in use today. The resistance is linked to a collection of genes carried on plasmids that are passed from one bacterium to another by conjugation. Suppose a newly discovered, chemically different antibiotic is used in place of methicillin. Which of the following would be the most likely effect on Staphylococcus aureus antibiotic resistance? (A) The gene for methicillin resistance, no longer needed, would disappear entirely from Staphylococcus aureus populations within a few generations. (B) Transmission of the methicillin-resistance plasmid by conjugation would increase among the Staphylococcus aureus population as the genes would confer resistance to the new antibiotic. (C) Transmission of the methicillin-resistance plasmid would gradually decrease but the plasmid would not entirely disappear from the Staphylococcus aureus population. (D) Transmission of the methicillin-resistance plasmid by conjugation would increase among the Staphylococcus aureus population due to destruction of bacteria without the plasmid through use of the new antibiotic.

(C) Transmission of the methicillin-resistance plasmid would gradually decrease but the plasmid would not entirely disappear from the Staphylococcus aureus population.

(hedgehog) One approach to treating patients with pancreatic cancer and other cancers in which the Hedgehog protein is detected is to modify the Hedgehog signaling pathway. Which of the following is the most useful approach? (A) Treating patients with a molecule that is structurally similar to Hedgehog and that will bind to and interact with Ptc in the same fashion as Hedgehog (B) Injecting patients with embryonic cells so that Hedgehog will bind to those cells instead of the cancer cells (C) Treating patients with a membrane-soluble compound that can bind to Smo and block its activity (D) Injecting patients with a preparation of purified membrane-soluble Ci that will enter the nuclei of the cancercells and induce gene transcription

The FtsZ protein is present in prokaryotes and in chloroplasts. The protein is structurally and functionally similar to tubulin proteins of eukaryotic cells. Which of the following is a likely conclusion to draw from this information? (A) FtsZ and tubulin proteins were both present in a common ancestor. (B) Microtubules are involved in the mechanics of photosynthesis. (C) Tubulin genes are evolutionarily derived from the gene that codes for the FtsZ protein. (D) The sequences of the genes encoding the FtsZ and tubulin proteins are identical.

The synthesis of protein or carbohydrate polymers always produces which of the following as a byproduct? (A) ATP (B) Oxygen (C) Carbon dioxide (D) Urea (E) Water

(E) Water

(blood cell pic) Which of the following best predicts which diagrammed microscope view the laboratory worker would see and best explains why? (A) View 1 because RBC membranes are freely permeable to water (B) View 2 because the RBCs use energy to allow sodium entry and to pump water out (C) View 2 because the rate of water movement into the RBCs equals the rate of water movement out of the cells (D) View 3 because the sodium-potassium pumps in the RBC membranes use energy to keep the sodium out but allow water to freely flow into the cells

There is a table in your packet #118-120 2002 test A culture of white-eyed fruit flies (Drosophila melanogaster) was maintained for many generations. Females from the stock white-eyed culture were crossed with red-eyed (wild-type) males. The F1 females were crossed with the white-eyed males from the original culture. The resulting phenotypes of the progeny are summarized below. The best explanation for the red-eyed F1 females is A) mutation (B) culture contamination (C) dominance (D) multiple loci (E) sex-influenced traits

ATP serves as a common energy source for organisms because (A) it is the smallest energy molecule (B) it stores the least energy of any energy source (C) its energy can be easily transferred to do cellular work (D) it is extremely stable and can be stored in the cell for long periods of time (E) traces of it have been found in fossils of ancient organisms dating back to the beginning of life on Earth

(diagram mouse/cricket) According to the data, the crickets at 25∞C have greater oxygen consumption per gram of tissue than do the crickets at 10∞C. This trend in oxygen consumption is the opposite of that in the mice. The difference in trends in oxygen consumption among crickets and mice is due to their (A) relative size (B) mode of nutrition (C) mode of internal temperature regulation (D) mode of ATP production

ATP is produced in all of the following EXCEPT: (A) glycolysis (B) the Krebs cycle (C) the Calvin cycle (D) cyclic and noncyclic light reactions (E) the electron transport system with chemiosmosis

tobacco - Additional observations were made on day 21, and no yellow-leaved seedlings were found alive in either dish. This is most likely because (A) yellow-leaved seedlings were unable to absorb water from the paper towels (B) taller green-leaved seedlings blocked the light and prevented photosynthesis (C) yellow-leaved seedlings were unable to convert light energy to chemical energy (D) a higher rate of respiration in yellow-leaved seedlings depleted their stored nutrients

Assume that the alleles referred to all assort independently. (A) 0 (B) 1/16 (C) 1/4 (D) 1/2 (E) 3/4 Probability that the genotype Aa will be produced by the parents Aa x Aa

(D) 1/2

Living cells typically have biosynthetic pathways to synthesize at least some of the amino acids used in making proteins. Some strains of E. coli, a prokaryote, can synthesize the amino acid tryptophan, while other E. coli strains cannot. Similarly, some strains of the yeast S. cerevisiae, a eukaryote, can synthesize tryptophan, while other S. cerevisiae strains cannot. Which of the following describes the most likely source of genetic variation found in the tryptophan synthesis pathways of both species? (A) Exchange of genetic information occurs through crossing over. (B) Viral transmission of genetic information required to synthesize tryptophan occurs. (C) Random assortment of chromosomes leads to genetic variation. (D) Errors in DNA replication lead to genetic variation.

(D) Errors in DNA replication lead to genetic variation.

Coat color in mice is determined by genes at two loci. When black mice from a particular population mate, they produce offspring in the following ratios: 9 black : 3 brown : 4 white. These results suggest that white coat color is expressed as a result of (A) dominance (B) incomplete dominance (C) codominance (D) a sex-linked trait (E) epistasis

(E) epistasis

The tiny blue-eyed Mary flower is often one of the first flowers seen in the spring in some regions of the United States. The flower is normally blue, but sometimes a white or pink flower variation is found. (blue, white, pink table) Which of the following statements best explains the data? (A) The appearance of blue in the F1 generation of the pink and white cross demonstrates that flower color is not an inherited trait but is determined by the environment. (B) Flower color depends on stages of flower development, and young flowers are white, advancing to pink and then blue. (C) Since the F1 and F2 phenotypes of the pink and white cross do not fit the expected genotypic and phenotypic ratios, blue-eyed Mary must reproduce by vegetative propagation. (D) Flower color is an inherited trait, and the F1 and F2 phenotypes of the flowers arising from the pink and white cross can best be explained by another gene product that influences the phenotypic expression.

(D) Flower color is an inherited trait, and the F1 and F2 phenotypes of the flowers arising from the pink and white cross can best be explained by another gene product that influences the phenotypic expression.

Which of the following is most directly responsible for water's unique properties? (A) It contains oxygen atoms. (B) It contains hydrogen atoms. (C) It is an ionic compound. (D) It forms hydrogen bonds. (E) It is nonpolar.

(D) It forms hydrogen bonds.

(A) Proteins (B) Carbohydrates (C) Nucleic acids (D) Lipids (E) Steroids Used for insulation and buoyancy in marine Arctic animals

(D) Lipids

A spermatocyte produces the following four sperm cells. n +1 n+1 n-1 n-1 These cells are the result of nondisjunction during which of the following phases? (A) Interphase (G1 or G2) (B) Interphase (S) (C) Mitosis (D) Meiosis I (E) Meiosis II

(D) Meiosis I

Which of the following processes is associated with some prokaryotic cells but not with eukaryotic cells? (A) Photosynthesis (B) Aerobic respiration (C) Meiosis (D) Nitrogen fixation (E) Endocytosis

(D) Nitrogen fixation

Which of the following statements most directly supports the claim that different species of organisms use different metabolic strategies to meet their energy requirements for growth, reproduction, and homeostasis? (A) During cold periods pond-dwelling animals can increase the number of unsaturated fatty acids in their cell membranes while some plants make antifreeze proteins to prevent ice crystal formation in tissues. (B) Bacteria lack introns while many eukaryotic genes contain many of these intervening sequences. (C) Carnivores have more teeth that are specialized for ripping food while herbivores have more teeth that are specialized for grinding food. (D) Plants generally use starch molecules for storage while animals use glycogen and fats for storage.

(D) Plants generally use starch molecules for storage while animals use glycogen and fats for storage.

There is a table in your packet #118-120 2002 test A culture of white-eyed fruit flies (Drosophila melanogaster) was maintained for many generations. Females from the stock white-eyed culture were crossed with red-eyed (wild-type) males. The F1 females were crossed with the white-eyed males from the original culture. The resulting phenotypes of the progeny are summarized below. Which of the following best describes the mode of inheritance of eye color in the white culture? (A) Autosomal (B) Dominant (C) Located on the Y chromosome (D) Sex-linked (E) Lethal

(D) Sex-linked

beetle graphs - Which of the following includes the most likely change in the coloration of the beetle population after pollution and a correct rationale for the change? (A) The coloration range shifted toward more light-colored beetles, as in diagram I. The pollution helped the predators find the darkened tree trunks. (B) The coloration in the population split into two extremes, as in diagram II. Both the lighter-colored and the darker-colored beetles were able to hide on the darker tree trunks. (C) The coloration range became narrower, as in diagram III. The predators selected beetles at the color extremes. (D) The coloration in the population shifted toward more darker-colored beetles, as in diagram IV. The lighter- colored beetles were found more easily by the predators than were the darker-colored beetles.

(D) The coloration in the population shifted toward more darker-colored beetles, as in diagram IV. The lighter- colored beetles were found more easily by the predators than were the darker-colored beetles.

AIDS is caused by the retrovirus HIV, which makes DNA complementary to the viral RNA using (A) RNA polymerase (B) beta-galactosidase (C) RNA synthase (D) ATPase (E) reverse transcriptase

(E) reverse transcriptase

tobacco - Which of the following best supports the hypothesis that the difference in leaf color is genetically controlled? (A) The number of yellow-leaved seedlings in dish A on day 7 (B) The number of germinated seeds in dish A on days 7 and 14 (C) The death of all the yellow-leaved seedlings (D) The existence of yellow-leaved seedlings as well as green-leaved ones on day 14 in dish B

(D) The existence of yellow-leaved seedlings as well as green-leaved ones on day 14 in dish B

A human kidney filters about 200 liters of blood each day. Approximately two liters of liquid and nutrient waste are excreted as urine. The remaining fluid and dissolved substances are reabsorbed and continue to circulate throughout the body. Antidiuretic hormone (ADH) is secreted in response to reduced plasma volume. ADH targets the collecting ducts in the kidney, stimulating the insertion of aquaporins into their plasma membranes and an increased reabsorption of water. If ADH secretion is inhibited, which of the following would initially result? (A) The number of aquaporins would increase in response to the inhibition of ADH. (B) The person would decrease oral water intake to compensate for the inhibition of ADH. (C) Blood filtration would increase to compensate for the lack of aquaporins. (D) The person would produce greater amounts of dilute urine.

(D) The person would produce greater amounts of dilute urine.

Certain metabolic pathways are affected by the buildup of a product which interacts with an enzyme catalyzing one of the initial steps of the pathway; this can be an example of (A) transcriptional regulation (B) thermodynamic regulation (C) translational regulation (D) feedback inhibition (E) posttranslational modification

(D) feedback inhibition

All the following are included in the modern concept of a biological species EXCEPT (A) genetic compatibility (B) viable offspring (C) fertile offspring (D) gene flow inhibition (E) reproductive compatibility

(D) gene flow inhibition

All of the following could reduce the yield of photosynthetic products EXCEPT (A) lower concentrations of carbon dioxide in the atmosphere (B) Increased photorespiration (C) reduced carbon dioxide concentrations in the air spaces of the leaf (D) increased frequency of stomata openings (E) fewer Calvin cycle enzymes

(D) increased frequency of stomata openings

There is a table in your packet #118-120 2002 test A culture of white-eyed fruit flies (Drosophila melanogaster) was maintained for many generations. Females from the stock white-eyed culture were crossed with red-eyed (wild-type) males. The F1 females were crossed with the white-eyed males from the original culture. The resulting phenotypes of the progeny are summarized below. There are white-eyed females in the F2 generation because (A) white is a dominant allele (B) the white allele is autosomal (C) a mutation has occurred (D) these F2 females have two white alleles (E) the white allele is located on the Y chromosome

(D) these F2 females have two white alleles

(There is an image in your packet #93-96) 2002 test During which time interval is the reaction rate lowest? (A) 0-1minute (B) 1-2 minutes (C) 2-3 minutes (D) 3-4 minutes (E) 4-5 minutes

(E) 4-5 minutes

Which of the following statements about mitochondrial chemiosmosis is NOT true? (A) A proton gradient is established across the inner membrane of the mitochondrion. (B) The potential energy released from the mitochondrial proton gradient is used to produce ATP. (C) The mitochondrial proton gradient provides energy for muscle contraction. (D) Proteins embedded in the inner mitochondrial membrane play an important role in ATP synthesis. (E) Heat energy is required to establish the electron transport chain.

(E) Heat energy is required to establish the electron transport chain.

(A) Cytochrome (B) FADH2 (C) NAD+ (D) NADP+ (E) Oxygen (O2) The final electron acceptor for cellular respiration

(E) Oxygen (O2)

(A) DNA ligase (B) DNA polymerase (C) RNA polymerase (D) Restriction enzyme (E) Reverse transcriptase Enzyme found in retroviruses that produce DNA from an RNA template

(E) Reverse transcriptase

Which of the following factors is the most effective in changing the allele frequency in a natural population? (A) Large population size (B) Low rate of mutation (C) Negligible migration (D) Random mating (E) Selection

(E) Selection

A customer observed that a particular potted plant in a restaurant was bigger and greener than other plants in the room. When asked, the owner said that he poured leftover club soda (carbonated water) into that plant's pot every day. Which of the following best explains how the club soda affected that plant's growth? (A) The basic pH of the club soda caused the plant to grow rapidly. (B) The temperature of the club soda promoted faster growth. (C) Oxygen bubbles from the club soda oxygenated the soil. (D) The roots absorbed the CO2 necessary for photosynthesis. (E) The roots received more moisture, and the leaves were exposed to more CO2.

(E) The roots received more moisture, and the leaves were exposed to more CO2.

Which of the following would happen to an individual playing a long game of basketball outdoors on a hot afternoon? (A) The production of thyroxin by the thyroid gland would decrease. (B) The osmotic pressure of the blood would decrease. (C) The volume of urine produced would increase. (D) The concentration of urea in the urine would decrease. (E) The secretion of antidiuretic hormone from the pituitary gland would increase.

(E) The secretion of antidiuretic hormone from the pituitary gland would increase.

All of the following are typical components of the plasma membrane of a eukaryotic cell except A. Glycoproteins B. Cytochromes C. Cholesterol D. Phospholipids E. Integral proteins

B. Cytochromes

The energy required to run the Calvin Cycle reactions of photosynthesis comes from which 2 substances produced during light dependent reactions? (A) ATP and NADPH (B) ADP and PO4 (C) H+ and O2 (D) oxygen and carbon dioxide (E) water and carbon dioxide

A) ATP And NADPH

The diagram above illustrates which of the following processes? (Diagram #1) (A) Crossing over (B) Base pair substitution (C) Duplication (D) Deletion (E) Posttranscriptional processing

A) Crossing over

A) DNA ligase (B) DNA polymerase (C) RNA polymerase (D) Restriction enzyme (E) Reverse transcriptase Enzyme used during replication to attach Okazaki fragments to each other

A) DNA ligase

Assume that genes A and B are not linked. If the probability of allele A in a gamete is 1/2 and the probability of allele B in a gamete is 1/2, then the probability that both A and B are in the same gamete is A. 1/2 X 1/2 B. 1/2 + 1/2 C. 1/2 divided by 1/2 D. The square root of 1/2 E. | 1/2 - 1/2 |

A. 1/2 X 1/2

Which of the following is best observed by using a compound light microscope? A. A eukaryotic cell B. a virus C. A DNA sequence D. The inner structure of a mitochondrion E. A nuclear pore

A. A eukaryotic cell

Which of the following best supports the statement that mitochondria are descendants of endosymbiotic bacteria-like cells? A. Mitochondria and bacteria possess similar ribosomes and DNA B. Mitochondria and bacteria possess similar nuclei. C. Glycolysis occurs in both mitochondria and bacteria D. Both mitochondria and bacteria have microtubules E. Neither mitochondria nor bacteria possess chloroplasts

A. Mitochondria and bacteria possess similar ribosomes and DNA

Which of the following is the most likely explanation for a high rate of crossing-over between two genes? A. The two genes are far apart on the same chromosome. B. The two genes are both located near the centromere C. The two genes are sex-linked D. The two genes code for the same protein E. The two genes are on different chromosomes

A. The two genes are far apart on the same chromosome.

On a sunny day, the closing of stomata in plant leaves results in A. a decrease in CO2 intake B. a shift from C3 photosynthesis to C4 C. an increase in transpiration D. an increase in the concentration of CO2 in mesophyll cells E. an increase in the rate of production of starch

A. a decrease in CO2 intake

A prokaryotic cell has which of the following? A. centrioles B. lysosomes C. Plasma membrane D. mitochondria E. Endoplasmic reticulum

A. centrioles

Membranes are components of all of the following EXCEPT a A. microtubule B. nucleus C. golgi apparatus D. mitochondrion E. lysosome

A. microtubule

Oxygen consumption can be used as a measure of metabolic rate because oxygen is A. necessary for ATP synthesis by oxidative phosphorylation B. necessary to replenish glycogen levels C. necessary for fermentation to take place D. required by all living organisms E. required to break down the ethanol that is produced in muscles

A. necessary for ATP synthesis by oxidative phosphorylation

Which of the following best describes the parents in a testcross? A. one individual has the dominant phenotype and the other has the recessive phenotype B. Both individuals are heterozygous C. Both individuals have the dominant phenotype D. Both individuals have the recessive phenotype E. Both individuals have an unknown phenotype

A. one individual has the dominant phenotype and the other has the recessive phenotype

Most cells that have become transformed into cancer cells have which of the following characteristics when compared to normal, healthy cells? A. shorter cell cycle B. More carefully regulated rates of cell devision C. Lower rates of mitosis D. Higher rates of protein translation E. Identical DNA

A. shorter cell cycle

Which of the following physiological effects would likely occur first in a volunteer who was breathing air from which the CO2 was removed? A. decreased blood pH B. Decreased respirator rate C. Increased respiratory rate D. increase pulse rate E. increase blood pressure

B. Decreased respirator rate

Which of the following levels of organization includes all of the others? A. Population B. Ecosystem C. Community D. Organism E. Habitat

B. Ecosystem

A. Glycolysis B. Krebs cycle C. Calvin cycle D. Light-dependent reactions of photosynthesis E. Chemiosmosis Process in which CO2 is released as a by product of oxidation-reduction reactions

B. Krebs cycle

The function of which of the following organelles directly requires oxygen? A. Ribosome B. Mitochondrion C. Nucleus D. Centriole E. Golgi apparatus

B. Mitochondrion

A couple has 5 children, all sons. If the women gives birth to a sixth child, what is the probability that the sixth child will be a son? A. 5/6 B. 1/2 C. 1/5 D. 1/6 E. 1/64

B. 1/2

In sheep, eye color is controlled by a single gene with two alleles. When a homozygous brown-eyed sheep is crossed with a homozygous green-eyed sheep, blue eyes offspring are produced. If the blue eyed sheep are mated with each other, what percent of their offspring will most likely have brown eyes? A. 0% B. 25% C. 50% D. 75% E. 100%

B. 25%

Which of the following cellular processes is coupled with the hydrolysis of ATP? A. Facilitated diffusion B. Active transport C. Chemiosmosis D. Osmosis E. Na+ influx into a nerve cell

B. Active transport

Which of the following groups contains prokaryotic organisms capable of surviving the greatest extremes in temperature or salt concentration? A. Protista B. Archaebacteria C. Plantae D. Fungi E. viruses

B. Archaebacteria

Carbon dioxide is transported in human blood primary in which of the following ways? A. As oxyhemoglobin B. As bicarbonate ions C. Attached to plasma proteins D. Attached to the amino groups of hemoglobin E. Attached to the heme groups of hemoglobin

B. As bicarbonate ions

In an experiment on birds learning to sing, young male chicks were exposed only to the songs sung by another specie. Later, as they approached maturity, songs of their own species were played to them. When the birds reached maturity, they were able to sing neither the typical song of their species nor the full song of the second species. Which of the following accounts for this result? A. Birds innately sing the song typical of their species B. Birds pass through a critical period early in life when learning their species-typical song is possible C. Birds can learn their typical song if they hear it at any time D. Birds must be able to practice their song in order to develop it. E. Birds are capable of imitating any song that they hear

B. Birds pass through a critical period early in life when learning their species-typical song is possible

Toads in a particular population vary in size. A scientist observes that in this population, large males mate with females significantly more often than small males do. All the following are plausible hypotheses to explain this observation EXCEPT: A. Females select large males more often than they select small males as mates B. Small females are more likely to mate with small males and large females are more likely to mate with large males C. Large males are successful in competing for mates more often than small males are D. Large males occupy more breeding territory than small males do E. The calls produced by large males are more attractive to females than the calls made by small males

B. Small females are more likely to mate with small males and large females are more likely to mate with large males

Which of the following occurs during mitosis but not during meiosis 1? A. The chromosomes are pulled to opposite poles of the spindle apparatus B. The chromatids of each chromosome are separated C. The nuclear envelope breaks down D. Both synapsis and crossing over take place E. The diploid number of chromosomes is reduced to the haploid number

B. The chromatids of each chromosome are separated

Which of the following organelles modifies and packages for secretion the materials produced by the ribosomes? A. The chloroplast B. The golgi apparatus C. the nucleus D. the nucleolus E. The mitochondrion

B. The golgi apparatus

Which of the following statements regarding coenzymes is true? A. they are essential for metabolic reactions in animals but not in plants B. They can facilitate metabolic reactions by combining with enzymes at their active sites C. They are minerals that alter the pH of cells and thus increase the probability of chemical reactions D. They are synthesized in the rough endoplasmic reticulum of eukaryotic cells. E. They typically work best at temperatures below 37C

B. They can facilitate metabolic reactions by combining with enzymes at their active sites

The driving force for the movement of materials in the phloem of plants it A. gravity B. a difference in osmotic potential between the source and the sink C. root pressure D. transpiration of water through the stomates E. adhesion of water to vessel elements

B. a difference in osmotic potential between the source and the sink

During respiration most ATP is formed as a direct result of the net movement of A. Potassium against a concentration gradient B. protons down a concentration gradient C. electrons against a concentration gradient D. electrons through a channel E. sodium ions into the cells

B. protons down a concentration gradient

Which of the following cells would most likely hav the greatest concentration of densely packed rough endoplasmic reticulum? A. An amoeba engulfing small ciliates B. A bioluminescent bacterial cell C. A pancreatic cell engaged in the production of digestive enzymes D. A functional phloem cell at maturity E. An epithelial cell whose DNA is replicating before mitosis

C. A pancreatic cell engaged in the production of digestive enzymes

A. Glycolysis B. Krebs cycle C. Calvin cycle D. Light-dependent reactions of photosynthesis E. Chemiosmosis Process in which carbon from CO2 is incorporated into organic molecules

C. Calvin cycle

Which of the following best describes why the polymerase chain reaction is a standard technique used in molecular biology research? A. It uses inexpensive materials and produces perfect results B. It can purify specific section of a DNA molecule C. It can produce large amounts of specific DNA sequences D. It can duplicate the entire human genome E. It can produce large amounts of mRNA

C. It can produce large amounts of specific DNA sequences

Which of the following principles is NOT part of Darwin's theory of evolution by natural selection? A. Evolution is a gradual process that occurs over long periods of time B. Variation occurs among individuals in a population C. Mutations are the ultimate source of genetic variation D. More individuals are born than will survive E. Individuals that possess the most favorable variations have the best chance of reproducing

C. Mutations are the ultimate source of genetic variation

Prokaryotic and eukaryotic cells generally have which of the following features in common? A. A membrane bound nucleus B. a cell wall made of cellulose C. Ribosomes D. Flagella or Cilia that contain microtubules E. linear chromosomes made of DNA and protein

C. Ribosomes

Which of the following best describe the cells that result from the process of meiosis in mammals? A. They are diploid B. They can be used to repair injuries C. They are genetically different from the parent cell D. They are genetically identical to all the other cells in the body E. They are idenctical to each other

C. They are genetically different from the parent cell

Which of the following groups is best characterized as being eukaryotic and heterotrophic and having chitinous cell walls? A. Plantae B. Animalia C. fungi D. Virus E. Monera

C. fungi

In a mesophyll cell of a leaf, the synthesis of ATP occurs in which of the following: 1. Ribosomes 2. Mitochondria 3. Chloroplasts A. 1 only B. 2 only C. 3 only D. 2 and 3 only 4. 1, 2 and 3

D. 2 and 3 only

See diagram question 56 1999 test In the pedigree above, squares represent males and circles represent females. Individuals who express a particular trait are represented by shaded figures. Which of the following patterns of inhertiance best explains the transmission of the trait? A. Sex-linked dominant B. Sex-linked recessive C. Autosomal recessive D. Autosomal dominant E. Incompletely dominant

D. Autosomal dominant

Which of the following statements best expresses the concept of punctuated equilibrium A. Small variations gradually accumulate in evolving lineages over periods of millions of years B. Random mating ensures that the proportions of genotypes in a population remain unchanged from generation to generation C. Stability is achieved when selection favors the heterozygote, while both types of homozygotes are at a relative disadvantage D. Evolutionary changes consist of rapid bursts of speciation alternating with long periods which species remain essentially unmodified E. Under competition for identical resources, one of the two competing species will be eliminated or excluded D

D. Evolutionary changes consist of rapid bursts of speciation alternating with long periods which species remain essentially unmodified

Which of the following processess is carried out more efficiently by a C4 plant than by a C3 plant? A. Light absorption B. Chemiosomtic coupling C. Photolysis D. Fixation of CO2 E. transport of sugars

D. Fixation of CO2

The different species of finches on the Galapagos Islands are believed to have arisen as a result of natural selection acting on populations of finches that had experienced A. Convergent evolution B. Gene flow C. The bottleneck effect D. Geographic isolation E. hybrid sterility

D. Geographic isolation

A biologist counted 2,500 cells from an embryo on a microscope slide and recorded the following data. Stage/Number of cells Prophase:125 Metaphase:50 Anaphase:50 Telophase:25 Interphase:2,250 Total:2,500 If these cells had been dividing randomly, it could be reasonably concluded that A. the duration of anaphase is approximately one-half of telophase B. Prophase is approximately three times as long as telophase C. Metaphase is the shortest stage of the cell cycle D. Interphase is the longest stage of the cell cycle E. The chromosomes can first be seen in prophase

D. Interphase is the longest stage of the cell cycle

A. Glycolysis B. Krebs cycle C. Calvin cycle D. Light-dependent reactions of photosynthesis E. Chemiosmosis Process in which O2 is released as a by-product of oxidation-reduction reactions

D. Light-dependent reactions of photosynthesis

A biologist isolates numerous tiny, green pigment cells from a sample of lake water. The cells are covered with a mucilaginous sheath. They contain relatively large amounts of chlorophyll a and phycobilin pigments and lack a compact, organized nucleus. Electron microscopy will reveal that these cells are also contain which of the following pairs of subcellular structures? A. Ribosomes and chloroplasts B. Ribosomes and mitochondria C. Golgi bodies and a cell wall D. Thylakoids and a cell wall E. Chloroplasts and mitochondria

D. Thylakoids and a cell wall

A tabacco plant can be made to express a gene from fireflies, resulting in the emission of light. Which of the following is the basis for this phenomenon? A. Chloroplasts can be made to produce light if firefly proteins are injected into plant cells B. Fireflies and tobacco plants share a recent common ancestor C. Fireflies and tabacco plants are infected by the same kinds of bacteria D. Transcription and translation are fundamentally similar in both fireflies and tobacco plants E. Most enzymes in fireflies have the same amino acid sequence as the enzymes in tabacco plants

D. Transcription and translation are fundamentally similar in both fireflies and tobacco plants

Which of the following terms refers to both the movement of a ribosome along a piece of mRNA and the movement of a piece of one chromosome to another chromosome A. Transduction B. Transgenesis C. Transformation D. Translocation E. Transplantation

D. Translocation

In peas the trait for tall plants is dominant (T) and the trait for short plants is recessive (t). The trait for yellow seed color is dominant (Y) and the trait for the green seed color is recessive (y). A cross between two plants results in 296 tall yellow plants and 104 tall green plants. Which of the following are most likely to be the genotypes of the parents? A. TTYY x TTYY B. TTyy x TTYy C. TtYy x TtYy D. TtYy x TTYy E. TtYY x Ttyy

D. TtYy x TTYy

A student using a light microscope observes a cell and correctly decides that it is a plant cell because A. ribosomes are visible B. An endoplasmic reticulum can be seen C. A cell membrane is present D. it has a large central vacuole E. centrioles are present

D. it has a large central vacuole

The amino acid sequence of cytochrome c is exactly the same in humans and chimpanzees. There is a difference of 13 amino acids between cytochrome c of humans and dogs, and a difference of 20 amino acids between the cytochrome c of humans and rattlesnakes. Which of the following statements is best supported by these data? (A) Rattlesnakes apparently give rise evolutionarily to dog, chimpanzee, and human. (B) Cytochrome c apparently has an entirely different function in rattlesnakes than in mammals, which explains the difference in the number of amino acids. (C) Cytochrome c is not found universally in animals. (D) Cytochrome c from a rattlesnake could function in a dog, but not in a chimpanzee. (E) The human is apparently more closely related to the chimpanzee than to the dog or rattlesnake.

E) The human is apparently more closely related to the chimpanzee than to the dog or rattlesnake

In certain Native American groups, albinism due to a homozygous recessive condition in the biochemical pathway for melanin is sometimes seen. If the frequency of the allele for this condition is 0.06, which of the following is closest to the frequency of the dominant allele in this population? A. 0.04 B. 0.06 C. 0.16 D. 0.36 E. 0.94

E. 0.94

A. Glycolysis B. Krebs cycle C. Calvin cycle D. Light-dependent reactions of photosynthesis E. Chemiosmosis Process found in both photosynthesis and cellular respiration

E. Chemiosmosis

Analysis of DNA sequences from two individuals of the same species results in a greater estimate of genetic variability than does analysis of amino acid sequences from the same individuals because A. different DNA sequences can code for the same amino acid B. Some amino acid variations cannot be detected b protein electrophoresis C. DNA sequencing is more reliable technique than protein electrophoresis D. proteins are more easily damaged than is DNA E. DNA is more heat-sensitive and therefore varies more

E. DNA is more heat-sensitive and therefore varies more

If organisms A, B, and C belong to the same order but to different families and if organisms D, E, and F belong to the same family but to different genera, which of the following pairs of organisms would be expected to show the greatest degree of structural homology? A. A and B B. A and C C. B and D D. C and F E. E and F

E. E and F

A + B + energy -----> AB Which of the following best characterizes the reaction represented above? A. Hydrolysis B. Catabolism C. Oxidation-reduction D. Exergonic reaction E. Endergonic reaction

E. Endergonic reaction

Which of the following pathways for the transformation of cellular energy most likely evolved first? A. Cyclic photophosphorylation B. Citric acid cycle C. Calvin cycle D. C4 photosynthesis E. Glycolysis

E. Glycolysis

Which of the following provides he weakest evidence that mitochondria were once free living prokaryotes A. Mitochondrial ribosomes resemble those of prokaryotes B. Mitochondria have DNA that is circular and does not have associated protein C. Enzyme pathways on mitochondrial membranes resemble those found on modern prokaryotes membranes D. Mitochondria reproduce by a process similar to binary fission E. Mitochondria and prokaryotes both are found in a variety of sizes

E. Mitochondria and prokaryotes both are found in a variety of sizes

In humans red-green color blindness is a sex-linked recessive trait. If a man and a women produce a color-blind son, which of the following must be true? A. The father is color-blind B. Both parents carry the allele for color blindness C. Neither parent carries the allele for color blindness D. The father carries the allele for color blindness E. The mother carries the allele for color blindness

E. The mother carries the allele for color blindness

Which of the following is an example of active transport across a membrane? A. The movement of water from a nephron into the collecting duct of the kidney B. The movement of glucose by facilitated diffusion into a liver cell C. The movement of water from the inside of a cell into a surrounding hypertonic medium D. The movement of Na+ into a neuron as a nerve impulse is generated E. The movement of H+ into a thylakoid disc during photosynthesis

E. The movement of H+ into a thylakoid disc during photosynthesis

all of the following were likely present on the primitive Earth during the evolution of self replicating molecules EXCEPT A. amino acids and nucleotides B. nitrogen C. simple carbohydrates D. freestanding liquid water E. an O2 rich atmosphere

E. an O2 rich atmosphere

The condition in which there are barries to successful interbreeding between individuals of different species in the same community is referred to as A. latent variations B. Sterility C. structural differences D. Geographic isolation E. reproductive isolation

E. reproductive isolation

(Diagram for #86-88) The rate of oxygen production equaled the rate of oxygen consumption during which of the following time periods? a. G to H b. H to I c. I to J d. J to K e. G to K

d. J to K

(Diagram for #86-88) An increase in the rate of oxygen production by algae would be accompanied by a comparable increase in the rate of production of which of the following substances? a. C6H12O6 b. CO2 c. CH4 d. NH3 e. H2O

a. C6H12O6

Most photosynthesis in typical C3 angiosperms takes place in the a. palisade mesophyll b. spongy mesophyll c. epidermis d. pericycle e. vascular bundles

a. palisade mesophyll

(Diagram for #73-76) Which of the following correctly shows the order in which protein X moves through the cell? a. Endoplasmic reticulum -> Golgi apparatus -> lysosomes b. Endoplasmic reticulum -> Golgi apparatus -> nucleus -> cytoplasm -> lysosomes c. Extracellular space -> mitochondria -> cytoplasm d. Golgi apparatus -> cytoplasm -> lysosomes e. Cytoplasm -> mitochondria -> extracellular space

a. Endoplasmic reticulum -> Golgi apparatus -> lysosomes

(Diagram for #73-76) The same procedure was repeated with a second protein (protein Y). If the function of Y is protein processing and packaging, the most radioactivity would be found in the a. Golgi apparatus b. Nucleus c. Mitochondria d. Lysosomes e. Cytoplasm

a. Golgi apparatus

Associated with inactivated DNA a. Methylation b. Enhancer activity c. RNA capping d. RNA spliceosome activity e. Reverse transcription

a. Methylation

(Data table for #97-100) Which of the following experimental designs should the students use as a control for the experiment? a. Place a catalase-soaked disk in a beaker of water. b. Drop the disks from different heights into the solution. c. Poke the floating disks back down to the bottom of the beaker and retime the rise of the disks. d. Shake the beakers during the time the disks are rising. e. Dip the disks in the 5% solution before putting them in any other solution.

a. Place a catalase-soaked disk in a beaker of water.

A survey reveals that 25 percent of a population of 1,000 individuals have attached earlobes (are homozygous recessive for the trait). For the following questions, assume that the population fits the parameters of the Hardy-Weinburg law. Unlike most natural populations, this population is best characterized in which of the following ways? a. There is genetic equilibrium. b. There is gene flow. c. There is genetic drift. d. Mutations occur. e. Mating is nonrandom.

a. There is genetic equilibrium.

Tetrads fail to separate correctly during anaphase in this process. a. Crossing-over b. Inversion c. Translocation d. Nondisjunction e. Deletion

d. Nondisjunction

Increases RNA polymerase activity a. Methylation b. Enhancer activity c. RNA capping d. RNA spliceosome activity e. Reverse transcription

b. Enhancer activity

Activated by directly binding to GTP a. Adenylate cyclase b. G-protein c. Carrier protein d. cAMP e. Ion channel receptor protein

b. G-protein

Part of a chromosome breaks away and then reattaches to the same chromosome in reverse orientation. a. Crossing-over b. Inversion c. Translocation d. Nondisjunction e. Deletion

b. Inversion

(Diagram for #83-85) If Individual 2 were to marry a woman with no family history of the disease, which of the following would most likely be true of their children? a. All of the children would have the disease. b. None of the children would have the disease. c. Only the sons would have the disease. d. All of the sons would be carriers of the disease. e. None of the daughters would be carriers of the disease.

b. None of the children would have the disease.

During mitosis, which of the following normally occurs? a. Homologous chromosomes pair. b. Replicated chromosomes line up on the equatorial plate. c. Tetrads form. d. Unreplicated chromosomes become oriented in the center of the cell. e. Maternal and paternal chromatids pair.

b. Replicated chromosomes line up on the equatorial plate.

(Data table for #91-94) Which of the following would be useful as a substrate to measure the activity of amylase in crayfish? a. Cellulose b. Starch c. Glucose d. An amino acid e. A nucleic acid

b. Starch

Nine percent of a population is homozygous recessive (aa) at a certain locus. Assuming that the population is in Hardy-Weinburg equilibrium, which of the following is closest to the frequency of the recessive allele (a)? a. 0.09 b. 0.27 c. 0.30 d. 0.90 e. 0.97

c. 0.30

(Diagram for #83-85) If Individual 6 marries a woman with the disease, what is the probability that their first child will have the disease? a. 0 b. 25% c. 50% d. 75% e. 100%

c. 50%

Researchers applied radioactive phosphorus and radioactive calcium to a freshly cut tree stump. Eight days later, they came back to measure the distribution of the radioisotopes. They found that nineteen different species of shrubs and trees within a seven-meter radius had taken up the radioactive elements. No radioactivity was detected in the air. Radioactively labeled starch was later added to the stump; in subsequent observations, no labeled starch molecules were ever detected in neighboring plants. Which of the following is the most logical explanation for the observation? a. During transport, the radioactive atoms are removed from the starch molecules. b. Starch molecules are too large to cross cell membranes. c. The radioactivity caused the starch molecules to break down. d. Water in the soil dissolved the starch molecules. e. The radioactive carbon atoms decayed into other atoms that are undetectable.

b. Starch molecules are too large to cross cell membranes.

(Data table for #97-100) Which of the following best describes why ice was used during this experiment? a. To increase the activity of the enzyme b. To retard the breakdown of the catalase c. To purge the solution of excess air trapped during blending d. To slow the catalase molecules to increase the probability of contact with the hydrogen peroxide molecules e. To increase the size of the active site on the enzyme

b. To retard the breakdown of the catalase

An airtight, temperature-controlled glass box containing actively growing tomato plants was placed under a light source. Plastic wrapping that only transmits green light was placed over the box, and two days later air samples from inside the box were collected and analyzed. The most likely change in air quality is a. an increase in nitrogen (N2) b. an increase in carbon dioxide (CO2) c. an increase in oxygen (O2) d. a decrease in nitrogen (N2) e. a decrease in carbon dioxide (CO2)

b. an increase in carbon dioxide (CO2)

(Diagram for #86-88) Based on the data shown, changes in the light intensity resulted in changes in the rate of which of the following processes? a. excretion b. photosynthesis c. respiration d. translation e. transcription

b. photosynthesis

(Diagram for #83-85) Which of the following is the most likely mode of inheritance for the disease? a. Codominance b. Autosomal dominant c. Autosomal recessive d. Sex-linked dominant e. Sex-linked recessive

c. Autosomal recessive

Enhances the transport of lipophilic signals in the blood a. Adenylate cyclase b. G-protein c. Carrier protein d. cAMP e. Ion channel receptor protein

c. Carrier protein

(Data table for #91-94) Based on the data presented, which of the following statements regarding crayfish digestion is consistent with the data? a. Little digestion occurs before food enters the stomach. b. Most digestion occurs in the stomach. c. Little digestion occurs in the intestine. d. Enzymes are used up as they catalyze. e. Digestion is optimal at 25 degrees C.

c. Little digestion occurs in the intestine.

(Data table for #91-94) From the data presented, which of the following can correctly be concluded about crayfish? a. Their diet contains no fat. b. Most digestive enzymes are produced in the stomach. c. Most digestive enzymes are found in the digestive gland. d. Amylase is produced in the esophagus. e. The primary function of the intestine is to digest proteins.

c. Most digestive enzymes are found in the digestive gland.

Protects RNA from hydrolysis a. Methylation b. Enhancer activity c. RNA capping d. RNA spliceosome activity e. Reverse transcription

c. RNA capping

Part of a chromosome breaks away and attaches to a nonhomologous chromosome a. Crossing-over b. Inversion c. Translocation d. Nondisjunction e. Deletion

c. Translocation

Researchers applied radioactive phosphorus and radioactive calcium to a freshly cut tree stump. Eight days later, they came back to measure the distribution of the radioisotopes. They found that nineteen different species of shrubs and trees within a seven-meter radius had taken up the radioactive elements. No radioactivity was detected in the air. Radioactive isotopes were never detected in any samples containing just soil taken during the experiment. The finding implies that the a. soil does not provide the ecosystem with minerals b. isotopes were undetectable in very small amounts c. isotopes were transported via vascular tissues d. plants quickly return minerals to the soil in which they grow e. soil speeds up radioactive decay

c. isotopes were transported via vascular tissues

(Diagram for #73-76) What is the most likely identity of protein X? a. An enzyme that is involved in transcription b. An electron transport protein that participates in respiration reactions c. A protein secreted from liver cells into the blood stream that permits proper capillary function d. An enzyme that participates in the degradation and recycling of cell components e. A building block of the microtubules that are part of the cytoskeleton

d. An enzyme that participates in the degradation and recycling of cell components

(Data table for #91-94) The experiment demonstrates which of the following about the digestive system of crayfish? a. Amylase is the most active digestive enzyme. b. Crayfish have only three kinds of digestive enzymes. c. Most enzyme activity occurs in the intestine. d. Different regions of the digestive system are specialized for different functions. e. The esophagus serves no real function

d. Different regions of the digestive system are specialized for different functions.

Selectively removes RNA segments a. Methylation b. Enhancer activity c. RNA capping d. RNA spliceosome activity e. Reverse transcription

d. RNA spliceosome activity

(Data table for #97-100) Which of the following best describes why the disks rose to the surface faster in the more concentrated hydrogen peroxide solutions? a. There was more enzyme present in the more concentrated solutions. b. A greater amount of heat was generated in the more concentrated solutions. c. The more concentrated solutions lowered the activation energy of the reaction. d. The higher substrate concentrations in the more concentrated solutions speeded the reaction. e. The density of the water was lower in the more concentrated solutions.

d. The higher substrate concentrations in the more concentrated solutions speeded the reaction.

Which of the following is true of intercellular junctions, such as tight junctions, desmosomes, and gap junctions? a. They are specialized forms of communication among nerve cells. b. They are of primary importance in the contraction of skeletal muscle fibers. c. They are equally distributed among all tissue types. d. They help to integrate cells into a functioning unit. e. They aid in distributing DNA among cells.

d. They help to integrate cells into a functioning unit.

Serves as an intracellular second-messenger molecule a. Adenylate cyclase b. G-protein c. Carrier protein d. cAMP e. Ion channel receptor protein

d. cAMP

A survey reveals that 25 percent of a population of 1,000 individuals have attached earlobes (are homozygous recessive for the trait). For the following questions, assume that the population fits the parameters of the Hardy-Weinburg law. If p equals the frequency of the dominant allele and q equals the frequency of the recessive allele, which of the following terms represents the frequency of the individuals who show the dominant phenotype? a. pxp b. qxq c. 2pq d. pxp +2pq e. pxp + qxq

d. pxp +2pq

d. √0.25

Part of a chromosome lacking a centromere breaks away and does not reattach to another chromosome a. Crossing-over b. Inversion c. Translocation d. Nondisjunction e. Deletion

e. Deletion

This protein functions optimally in high H+ concentrations. a. Keratin b. Hemoglobin c. Actin d. Insulin e. Pepsin

e. Pepsin

Data table for #97-100) If the potato solution was boiled for 10 minutes and cooled for 10 minutes before being tested, the average time for the disks to float to the surface of the hydrogen peroxide solution would be a. less than 1 second b. 5 seconds c. 10 seconds d. 30 seconds e. more than 30 seconds

e. more than 30 seconds

(Diagram for #73-76) In graphing the data from this experiment, the sampling time would be shown on the x-axis because a. cell components were shown on the y-axis b. radioactivity level shows the most variation c. time values are always located on the horizontal axis d. all quantitative values are represented on the x-axis e. sampling time is the independent variable

e. sampling time is the independent variable

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