Biology Review Game

If ATP breakdown (hydrolysis) is inhibited, which of the following types of movement across cell membranes is also inhibited?
(A) Movement of oxygen into a cell
(B) Movement of water through aquaporins
(C) Passage of a solute against its concentration
gradient
(D) Facilitated diffusion of a permeable
substance

Undersea landslides can disrupt marine habitats by burying organisms that live on the ocean floor. The population was affected by a recent landslide at the time indicated on the graph. Which of the following best predicts how the population will be affected by the landslide?
(A) The surviving organisms will evolve into a new species.
(B) The reduced population will likely have allelic frequencies that are different from the initial population.
(C) The population will adapt to deeper waters to avoid future landslides.
(D) The reduced population will have a greater number of different genes than the initial population.

Which of the following questions is most relevant to understanding the Calvin cycle?
(A) How does chlorophyll capture light?
(B) How is ATP used in the formation
of 3-carbon carbohydrates?
(C) How is NADP+ reduced to NADPH?
(D) How is ATP produced in chemiosmosis?

Rosalind Franklin’s x-ray diffraction images taken in the 1950s most directly support which of the following claims about DNA?
(A) The ratios of base pairs are constant.
(B) The nucleotide sequence determines
genetic information.
(C) The two strands of DNA are antiparallel.
(D) The basic molecular structure is a helix.

After exercise, an athlete’s blood pH has dropped below the normal level. How will normal blood pH be restored?
(A) An increase in O2 concentration in the plasma will lead to an increase in H+ concentration.
(B) An increase in temperature will lead to an increase in H+ concentration.
(C) An increase in sweating will lead to a decrease in OH- and H+ concentration.
(D) An increase in breathing rate will lead to a decrease in blood CO2 and H+ concentration.

Beaked whales feed at various depths, but they defecate at the ocean’s surface. Nitrogen-rich whale feces deposited in surface waters supply nutrients for algae that are eaten by surface- dwelling fish. Which of the following best predicts what would happen if the whale population decreased?
(A) There would be a reduction in surface nitrogen concentration, which would cause an algal bloom.
(B) The surface fish populations would decline due to reduced populations of algae.
(C) The remaining whales would accumulate mutations at a faster rate.
(D) The remaining whales would be forced to forage in the deepest parts of the ocean.

The vertebrate forelimb initially develops in the embryo as a solid mass of tissue. As development progresses, the solid mass near the end of the forelimb is remodeled into individual digits. Which of the following best explains the role
of apoptosis in remodeling of the forelimb?
(A) Apoptosis replaces old cells with new ones that are less likely to contain mutations.
(B) Apoptosis involves the regulated activation of proteins in specific cells of the developing forelimb that leads to the death of those cells.
(C) Apoptosis involves the destruction of extra cells in the developing forelimb, which provides nutrients for phagocytic cells.
(D) Apoptosis in the developing forelimb triggers the differentiation of cells whose fate was not already determined.

Scientists have found that the existing populations of a certain species of amphibian are small in number, lacking in genetic diversity, and separated from each other by wide areas of dry land. Which of the following human actions is most likely to improve the long-term survival of the amphibians?
(A) Cloning the largest individuals to counteract the effects of aggressive predation
(B) Reducing the population size by one-fifth to decrease competition for limited resources
(C) Constructing a dam and irrigation system to
control flooding
(D) Building ponds in the areas of dry land to
promote interbreeding between the separated populations

A new mutation that arose in one copy of gene X in a somatic cell resulted in the formation of a tumor. Which of the following pieces of evidence best describes how the new mutation directly caused the tumor?
(A) Protein X normally stimulates cell division, and the mutation created an overactive version of protein X.
(B) Protein X normally activates a growth hormone receptor, and the mutation decreased the stability of protein X.
(C) Protein X normally prevents passage through the cell cycle, and the mutation created an overactive version of protein X.
(D) Protein X normally regulates gene expression, and the mutation created an underactive version of protein X that blocked the cell cycle.

If chemical signals in the cytoplasm control the progression of a cell to the M phase of the cell cycle, then fusion of a cell in G1 with a cell in early M phase would most likely result in the
(A) replication of chromosomes only in the G1 cell
(B) exiting of both cells from the cell cycle and into the G0 phase
(C) condensation of chromatin in preparation of nuclear division in both cells
(D) transfer of organelles from the G1 cell to the cell in the M phase

Antidiuretic hormone (ADH) is important in maintaining homeostasis in mammals. ADH is released from the hypothalamus in response to high tissue osmolarity. In response to ADH, the collecting duct and distal tubule in the kidney become more permeable to water, which increases water reabsorption into the capillaries. The amount of hormone released is controlled by a negative feedback loop.
Based on the model presented, which of the following statements expresses the proper relationship between osmolarity, ADH release, and urine production?
(A) As tissue osmolarity rises, more ADH is released, causing less water to be excreted as urine.
(B) As tissue osmolarity rises, less ADH is released, causing less water to be excreted as urine.
(C) As tissue osmolarity rises, more ADH is released, causing more water to be excreted as urine.
(D) As tissue osmolarity rises, less ADH is released, causing more water to be excreted as urine.

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.

The area covered by tropical rain forest is reduced by millions of hectares per year due to agriculture and logging. Which of the following best describes a likely result of tropical rain forest deforestation?
(A) Populations of plants and animals will decrease as more rain forest disappears, leading to a decrease in biodiversity.
(B) An increase of soil moisture will lead to a rapid increase in new vegetation coverage.
(C) An increase in atmospheric carbon dioxide will lead to higher levels of ultraviolet radiation reaching the surface of Earth.
(D) More oxygen will be available to other organisms as plant numbers decrease.

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.

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.

In most freshwater fish, nitrogenous waste is primarily excreted as ammonia, which is highly soluble in water and is toxic at low concentrations. In terrestrial mammals, ammonia is converted to urea before it is excreted. Urea is also highly soluble in water but is less toxic than ammonia at low concentrations. Which of the following best explains why freshwater fish do NOT convert ammonia to urea for excretion?
(A) The metabolic pathways of fish do not normally involve nitrogen consumption.
(B) The dilution of ammonia by direct excretion into freshwater conserves energy.
(C) Ammonia is concentrated in tissues, where it is stored prior to excretion.
(D) The nitrogen in ammonia is recycled for use in protein and nucleotide synthesis.

During the infection cycle for a typical retrovirus, such as HIV, which uses RNA as genetic material, the genetic variation in the resulting population of new virus particles is very high because of
(A) damage to the virus particle from envelope loss during infection
(B) errors introduced in the DNA molecule through reverse transcription
(C) errors in the protein molecules produced in translation
(D) recombination of the genomes of free virus particles

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.

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.

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.

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.

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.

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

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.

The last part of the metamorphosis of a tadpole to an adult frog results in the disappearance of the tail. This stage of development most likely occurs by
(A) cells of the tail dying and the nutrients being absorbed and reused by the body
(B) shedding of the tail so energy is not spent on maintenance of an unneeded part
(C) bilateral division of the tail and fusion with the developing hind limbs
(D) individual cells of the tail migrating to the developing gonads

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.

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.

The chemical reaction for photosynthesis is

6CO2 +12H2O+light energy→ 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.

The lionfish is a venomous fish found primarily in the Red Sea and the Indian Ocean. In the 1990s, lionfish were accidentally released into the Atlantic Ocean, where they found abundant resources and favorable environmental conditions. Which of the following scenarios is most likely to result in the lionfish having a major impact on the communities into which they were introduced?
(A) With no natural predators, the lionfish population will become very large.
(B) Some native species of invertebrates will develop a resistance to lionfish venom.
(C) Random mating will allow the lionfish population to reach Hardy-Weinberg equilibrium.
(D) A virus that specifically infects lionfish will become more prevalent.

Cell communication is critical for the function of both unicellular and multicellular eukaryotes. Which of the following is likely true of cell signaling?
(A) Cell signaling uses the highest molecular weight molecules found in living cells.
(B) Cell signaling has largely been replaced by other cell functions in higher mammals.
(C) Similar cell signaling pathways in diverse eukaryotes are evidence of conserved evolutionary processes.
(D) Cell signaling functions mainly during early developmental stages.

A colony of termites was exposed to an atmosphere of 100 percent oxygen for three days. The insects were not immediately harmed by the treatment, but the protozoa that lived in the termites’ guts were eliminated. The treated termites continued to behave normally and to eat wood, but they began to starve after a short time.
When the treated termites were instead fed wood contaminated with the feces of untreated termites, the treated termites regained the ability to digest wood and no longer starved. The best analysis of the results of the experiment is that
(A) infection with protozoa causes the termites to switch to fermentation
(B) cooperative interactions between the termites and the protozoa allow termites to extract energy from wood to survive
(C) the termite immune system eliminates protozoa from the gut
(D) termites digest protozoa as their main source of energy

Ethylene is an organic compound produced by ripening fruits. In a controlled experiment, researchers found that ethylene gas stimulated the ripening process in newly harvested fruits. Which of the following describes the most likely connection between natural ethylene production and fruit ripening?
(A) As a result of metabolic inactivity, newly harvested fruits are unable to absorb ethylene gas from the atmosphere.
(B) Ethylene gas is a chemical signal through which ripening fruits trigger the ripening process in other fruits.
(C) Because of normal phenotypic variation, only some of the fruits in a given generation are expected to produce ethylene gas.
(D) The rate of ethylene gas production by ripening fruits is an indicator of the relative age of an ecosystem.

Water in a pond contaminated with the
weed killer atrazine is suspected of inhibiting metamorphosis in northern leopard frogs.
A team of scientists collected fertilized northern leopard frog eggs from a different pond that is not contaminated. Which of the following is the best experimental design to determine whether atrazine is responsible for inhibiting metamorphosis in northern leopard frogs?
(A) Place half of the fertilized eggs in a pool of water with the same concentration of atrazine as the contaminated pond and place the other half of the fertilized eggs in a pool of water that has no atrazine. Monitor the development of the embryos through metamorphosis into adulthood.
(B) Place all of the fertilized eggs in a pool of pond water with the same concentration of atrazine as the contaminated pond and compare the number of frogs that reach metamorphosis to those that reach adulthood in the contaminated pond.
(C) Allow all fertilized eggs to develop into adults. Expose one-third of the frogs to one-half of the concentration of atrazine
in the contaminated pond and expose another one-third of the frogs to the
same concentration of atrazine as the contaminated pond. Leave the last one-third of the frogs in water with no atrazine and note any adverse changes in the physical condition of the atrazine-treated frogs in three months.
(D) Divide the fertilized eggs into three groups and expose each group to a different concentration of atrazine. Release the eggs back into the contaminated pond and check for metamorphosis after three months.

On a large volcanic island, researchers are studying a population of annual herbaceous plants. Which of the following observations best supports the prediction that speciation will occur within the existing plant population?
(A) Individuals of the species sometimes reproduce asexually by producing runners.
(B) Lava has separated the population into two areas: an upland forest and a lowland marsh.
(C) Multiple groups of birds depend on the fruit produced by the plants as a source of food.
(D) The plants produce more seeds during warm
summers than they do during cool summers.

Individuals with an inherited autosomal recessive disorder called primary ciliary dyskinesia (PCD) often have severe respiratory problems due to defective cilia. Males with PCD are often sterile because they produce sperm with defective flagella. Which of the following most likely explains the effect of the recessive allele?
(A) The mitochondria are defective and do not produce sufficient protein to synthesize microtubules in the cilia and flagella.
(B) The plasma membrane of the alveoli is not permeable to carbon dioxide during respiration because it is too hydrophobic.
(C) The Golgi bodies secrete an enzyme that destroys the proteins in the flagella and cilia.
(D) The cells do not produce functional motor proteins in flagella and cilia.

The salinity of a small inland lake has recently started to increase. Researchers are planning to study the lake over several decades to investigate how freshwater organisms survive significant changes in their natural habitat. Which of the following physiological mechanisms will the researchers most likely observe among the surviving organisms in the lake?
(A) Prokaryotic organisms will use various mechanisms to counteract swelling of cells as a result of increased water uptake.
(B) Single-celled organisms will use various mechanisms to counteract the increased flow of water from cells to the environment.
(C) Eukaryotic organisms will use various mechanisms to counteract the diffusion of positively charged ions across the cell membrane.
(D) Multicellular organisms will use various mechanisms to counteract the loss of cell adhesion as a result of calcium deficiencies.

Which of the following occurs in all species of living organisms and may lead to an increase in genetic variation?
(A) Mutations in the genome
(B) Crossing-over in meiosis
(C) Random assortment of chromosomes
(D) Alternative splicing of mRNA

A researcher examining a root tip observes
a plant cell with condensed sister chromatids, kinetochores with attached microtubules, and individual chromosomes that are aligned at the equatorial plate of the cell. Which of the following best describes what the next process will be in the cell?
(A) Homologous chromosomes (each with two sister chromatids) will move toward opposite poles of the cell.
(B) Paired chromatids will separate, and the new daughter chromosomes will move toward opposite poles of the cell.
(C) The nuclear envelope will break down, and the spindle will begin to form.
(D) The chromatin will decondense, and the daughter cell will enter interphase.

Which of the following best describes how the Rough ER, Golgi Apparatus, and Vesicles work together?

The pesticide DDT was widely used in the 1940s as a method of insect control. In the late 1950s the first DDT-resistant mosquitoes were discovered, and eventually DDT-resistant mosquitoes were found globally. When DDT is used now, the development of DDT resistance in mosquito populations occurs in months rather than years.
Which of the following best explains the observations concerning DDT resistance in mosquitoes?
(A) Competition for limited resources causes mosquitoes to migrate to geographical areas that have richer supplies of DDT.
(B) The proportion of DDT-resistant mosquitoes in a population remains constant due to the metabolic costs of DDT utilization.
(C) Natural selection favors DDT-resistant mosquitoes that are already present in a population when DDT exposure occurs.
(D) DDT is a chemical signal that delays normal reproductive cycles in many mosquito populations.

Two nutrient solutions are maintained at the same pH. Actively respiring mitochondria are isolated and placed into each of the two solutions. Oxygen gas is bubbled into one solution. The other solution is depleted of available oxygen. Which of the following best explains why ATP production is greater in the tube with oxygen than in the tube without oxygen?
(A) The rate of proton pumping across the inner mitochondrial membrane is lower in the sample without oxygen.
(B) Electron transport is reduced in the absence of a plasma membrane.
(C) In the absence of oxygen, oxidative phosphorylation produces more ATP than does fermentation.
(D) In the presence of oxygen, glycolysis produces more ATP than in the absence of oxygen.

When a stimulus is applied to a receptor in the skin, an action potential is propagated along
a neuron to the brain, where another signal is sent back to the muscle for a response.
Which of the following best describes what occurs when the action potential reaches
a chemical synapse at the end of an axon?
(A) The action potential jumps from one axon to the next connecting axon.
(B) The action potential travels through the synapse to the next connecting dendrite.
(C) The action potential jumps the synapse to
the next connecting dendrite.
(D) The action potential causes a release of
neurotransmitters that travel across the synapse.

Methicillin-resistant Staphylococcus aureus (MRSA) can be a serious threat to human health. There is evidence that S. aureus infections are common in hospitals and that MRSA have become resistant to other antibiotics besides methicillin. This suggests that the rapid evolution of resistance in the bacteria poses a serious public-health challenge. Which of the following best explains the ability of MRSA to evade existing drug therapies?
(A) MRSA have very long generation times and very large population sizes.
(B) MRSA develop new alleles by intentionally introducing specific mutations that will give them a selective advantage over other bacteria.
(C) MRSA metabolize many drugs in their lysosomes and therefore evolve resistance at a high rate.
(D) MRSA exchange genetic material with other antibiotic-resistant bacteria, which can spread resistance in the S. aureus population.

Which of the following best describes an advantage that eukaryote organisms have over prokaryote organisms?
(A) Prokaryotes lack a cell membrane and therefore are unable to control what enters or exits the cell.
(B) Eukaryotes have a nuclear envelope separating their DNA from the rest of the cell, which increases the likelihood of advantageous mutations.
(C) Eukaryotes have mitochondria and chloroplasts that contain their own genome, which allows the cells to reproduce more rapidly.
(D) Eukaryotes have organelles that allow for compartmentalization of cellular processes, which increases the efficiency of those processes.

Gregor Mendel’s pioneering genetic experiments with pea plants occurred before the discovery of the structure and function of chromosomes. Which of the following observations about inheritance in pea plants could be explained only after the discovery that genes may be linked on a chromosome?
(A) Pea color and pea shape display independent inheritance patterns.
(B) Offspring of a given cross show all possible combinations of traits in equal proportions.
(C) Most offspring of a given cross have a combination of traits that is identical to that of either one parent or the other.
(D) Recessive phenotypes can skip a generation, showing up only in the parental and
F2 generations.

DNA replication occurs
(A) during the S phase of the cell cycle
(B) as the nuclear envelope breaks down in early
mitosis
(C) during mitosis but not during meiosis
(D) in animal cells but not in plant cells

An allele on the X chromosome is responsible for the recessive trait of red-green color blindness in humans. The daughter of a woman who is color-blind has normal vision and marries a man who is color-blind. This couple has a son, what is the probability that the son will be color-blind?
(A) 0
(B) 1/4
(C) 1/2
(D) 3/4

Which of the following depicts the most probable pathway of processing and packaging a secretory protein within a eukaryotic cell?
(A) Secretory vesicles → rough endoplasmic reticulum → Golgi body → cell membrane
(B) Rough endoplasmic reticulum → Golgi body → secretory vesicles → cell membrane
(C) Golgi body → secretory vesicles → rough endoplasmic reticulum → cell membrane
(D) Secretory vesicles → Golgi body → rough endoplasmic reticulum → cell membrane

Which of the following best describes the function of the coenzymes NAD+ and FAD in eukaryotic cellular respiration?
(A) They participate in hydrolysis reactions by accepting protons from water molecules.
(B) They participate directly in the phosphorylation of ADP to ATP.
(C) They serve as final electron acceptors in the electron transport chain.
(D) They accept electrons during oxidation-reduction reactions.

A group of people whose ancestors immigrated to North America 200 years ago have certain allele frequencies that differ significantly from those in surrounding populations in the United States. Which of the following is the most likely explanation for the difference in allele frequencies?
(A) Mutation
(B) Independent assortment
(C) Reproductive isolation
(D) Sex linkage

There is strong evidence that two species of cliff-dwelling birds have nested in the same environment and fed in the same water for thousands of years, with each having stable population sizes. Based on this information, which of the following statements is the best conclusion?
(A) One species is a better diver than the other species is.
(B) The two birds compete for food.
(C) One species will displace the other.
(D) The two birds have different ecological niches that allow coexistence.

When the dorsal lip of the blastopore is removed from one developing embryo and successfully implanted into a different location in a second embryo of the same species at the same developmental stage, which of the following
is the most likely result?
(A) Two neural tubes form in the second embryo.
(B) Both embryos continue to develop normally.
(C) The second embryo fails to develop a head.
(D) The second embryo splits into two almost immediately.

Which of the following normally leads to the production of functional messenger RNA in eukaryotic cells?
(A) A decrease in the rate of ribosome synthesis
(B) The removal of portions of RNA known as intervening sequences (introns)
(C) A decrease in RNA polymerase activity
(D) The replication of new messenger RNA molecules from existing messenger RNA molecules

Offspring from this cross are expected to exhibit a 1 : 1 : 1 : 1 phenotypic ratio.
(A) ttrr x ttrr
(B) TtRr x TtRr
(C) TTRr x TtRR
(D) TtRr x ttrr
(E) TtRr x ttRr

Offspring from this cross are expected to exhibit a 3 : 3 : 1 : 1 phenotypic ratio.
(A) ttrr x ttrr
(B) TtRr x TtRr
(C) TTRr x TtRR
(D) TtRr x ttrr
(E) TtRr x ttRr

All offspring from this cross are expected to exhibit both dominant traits.
(A) ttrr x ttrr
(B) TtRr x TtRr
(C) TTRr x TtRR
(D) TtRr x ttrr
(E) TtRr x ttRr

This cross is an example of a dihybrid cross in which both parents are heterozygous.
(A) ttrr x ttrr
(B) TtRr x TtRr
(C) TTRr x TtRR
(D) TtRr x ttrr
(E) TtRr x ttRr

Which of the following is true of both mitochondria and chloroplasts?
(A) They are found in the cells of eukaryotic autotrophs and heterotrophs.
(B) They include stacks of membranes that absorb light.
(C) They include compartments where hydrogen ions are concentrated.
(D) They produce sugars using energy harvested in the cytoplasm.

The tertiary structure and function of a polypeptide is principally determined by the
(A) length of the polypeptide
(B) number of nucleotides present in the
polypeptide
(C) repeated units of glycerol making up the
polypeptide
(D) interactions between amino acids present in
the polypeptide

In a species that has five different alleles for
a gene at a particular locus, how many different alleles may be present in the somatic cells of one diploid individual?
(A) One
(B) Two
(C) Three
(D) Four

If red blood cells cultured in an isotonic medium are placed in distilled water, they will most likely
(A) remain unchanged
(B) shrivel
(C) swell and lyse
(D) divide

Which of the following characteristics distinguishes prokaryotic organisms from eukaryotic organisms?
(A) Prokaryotes are unicellular, while all eukaryotes are multicellular.
(B) Prokaryotes are aquatic, while eukaryotes are terrestrial.
(C) Prokaryotes are structurally less complex than eukaryotes are.
(D) Prokaryotes require a host to replicate, while eukaryotes do not.

Which of the following diseases is caused by the lack of a functional gene responsible for a specific enzyme?
(A) Down Syndrome
(B) Tay-Sachs disease
(C) Ricketts
(D) Malaria

AaBb x AaBb

How many different genotypes are possible from
the cross shown above?
(A) 2
(B) 4
(C) 9
(D) 16

All of the following statements concerning the theory of evolution by natural selection are true EXCEPT:
(A) Organisms produce far more offspring than are required for replacement.
(B) The individuals in a population show variation in survivability and in their ability to cope with environmental stress.
(C) The number of offspring that survive
to reproduce varies among individuals.
(D) The bodies of organisms in a population change by use and disuse, and the changes are inherited by the next generation.

Which of the following sequences best represents the life cycle of a typical angiosperm?
(A) Gametophyte → meiosis → gametes → fertilization → sporophyte → spores → zygote → gametophyte
(B) Gametophyte → gametes → meiosis → fertilization → sporophyte → spores → zygote → gametophyte
(C) Sporophyte → meiosis → gametophyte → spores → fertilization → zygote → sporophyte
(D) Sporophyte → meiosis → gametophyte → gametes → fertilization → zygote → sporophyte

Birds associating the bright colors of certain butterflies with an unpleasant taste is an example of
(A) instinct
(B) imprinting
(C) insight learning
(D) trial-and-error learning

Which of the following organelles is correctly matched with its function?
(A) Lysosome . . lipid hydrolysis
(B) Nucleolus . . protein synthesis
(C) Ribosome . . carbohydrate synthesis
(D) Mitochondrion . . Calvin cycle

Which of the following is the most direct result of the heating up of pond water during the summer?
(A) The water’s ability to hold oxygen decreases.
(B) The water’s ability to act as a buffer changes.
(C) The viscosity of the water increases.
(D) Hydrogen bonding at the surface of the water
increases.

In mammals, which of the following substances is produced in a muscle that operates anaerobically?
(A) Citrate
(B) NADPH
(C) Lactate
(D) Oxygen

Which of the following immune system cells is most severely depleted by HIV/AIDS ?
(A) Plasma B cells
(B) Memory B cells
(C) Helper T cells
(D) Cytotoxic (“Killer”) T cells

A scientist studying the oxygen concentration in sealed chambers containing cultured plant cells finds that when the chambers are illuminated, the concentration of oxygen increases. However, when the chambers are kept in the dark, the concentration of oxygen decreases. Why does the oxygen concentration decrease when the chamber is kept in the dark?
(A) Plant cell mitochondria consume oxygen by aerobic respiration.
(B) Plant cell chloroplasts run the photosynthetic pathways backward to consume oxygen.
(C) Plant cell chloroplasts switch their structure and function and become mitochondria.
(D) The chambers must not be properly sealed, so that oxygen is leaking out.

Production of ATP occurs in all of the following processes EXCEPT
(A) glycolysis
(B) Krebs cycle
(C) electron transport system and chemiosmosis
(D) light-dependent reactions of photosynthesis
(E) light-independent reactions of photosynthesis

Which of the following occurs in both fermentation and aerobic cellular respiration?
(A) Oxygen and carbon dioxide are consumed.
(B) FAD is reduced, driving ATP synthesis.
(C) Proton gradients are produced acrossmembranes.
(D) ATP is synthesized from ADP and inorganic phosphate.

Which of the following ions is significantly involved in the opening and closing of the stomata?
(A) Calcium
(B) Nitrogen
(C) Potassium
(D) Magnesium

Which of the following best explains why many different species can live together within an ecosystem with limited resources?
(A) Each species lives in a slightly different habitat.
(B) Each species occupies a different niche.
(C) Each species inhabits a different biome.
(D) Each species makes up a different population.

In evolutionary terms, which of the following organisms is the most successful?
(A) The one that lives the longest
(B) The one that grows the most rapidly
(C) The one that leaves the greatest number
of offspring that survive to reproduce
(D) The one that has the best characteristics
for the current environment

The flow of which of the following into the mitochondrial matrix provides the chemiosmotic energy for the synthesis of ATP?
(A) Inorganic phosphate
(B) ADP
(C) Glucose
(D) Protons

If a population is at Hardy-Weinberg equilibrium, which of the following can be predicted for the recessive alleles in the population?
(A) They will eventually disappear.
(B) They will be selected against.
(C) They will be maintained at the same frequency.
(D) They will be expressed in the heterozygous condition.

All of the following adaptations prevent dehydration in land plants EXCEPT
(A) many guard cells in the flaccid condition
(B) many stomates on the top leaf surface
(C) water-resistant cuticle
(D) the presence of many epidermal hairs
(E) recessed stomates

Which of the following causes the rapid change of membrane polarity during an action potential?
(A) Diffusion of neurotransmitters such as acetylcholine
(B) Diffusion of positively charged ions across the cell membrane
(C) Release of electrons from inside the cell
(D) Release of protons from inside the cell

Protein synthesis termination triplet
(A) Nonsense codon
(B) Anticodon
(C) Ribosome
(D) Exon
(E) Poly-A tail

Site of protein synthesis
(A) Nonsense codon
(B) Anticodon
(C) Ribosome
(D) Exon
(E) Poly-A tail

Base sequence on messenger RNA that aids its transport across the nuclear envelope
(A) Nonsense codon
(B) Anticodon
(C) Ribosome
(D) Exon
(E) Poly-A tail

Triplet on tRNA
(A) Nonsense codon
(B) Anticodon
(C) Ribosome
(D) Exon
(E) Poly-A tail

Which of the following does not occur in both mitosis and meiosis?
(A) Splitting of homologous pairs of chromosomes
(B) Replication of DNA during the S phase of Interphase
(C) Cytokenesis
(D) Formation of Spindle fibers

What major concept of DNA did Watson and Crick design in their DNA model?
(A) DNA was a double helix
(B) DNA was the hereditary molecule
(C) DNA copies itself through semiconservative replication
(D) Amino acid may have been the first biological molecules formed on earth

A cell that has 36 chromosomes at the start of interphase will have __________ following the conclusion of mitosis in a eukaryote
(A) 18 replication chromosomes
(B) 36 single-stranded chromosomes
(C) 72 single-stranded chromosomes
(D) 18 single-stranded chromosomes

Which of these statements is true of meiosis?
(A) Meiosis plays a role in growth, reproduction, and repair
(B) Meiosis produces gametes that contain one complete haploid set of chromosomes
(C) Meiosis occurs after DNA replication
(D) Meiosis, followed by cytokinesis, produces two genetically identical daughter cells

Which of the following is characteristic of cancerous cells?
(A) Regulation of cyclins and CDK levels
(B) Exhibiting density-dependent inhibitions
(C) Activation of oncogenes
(D) Adherence to checkpoints on the cell cycle

Which of the following is true of RNA but not DNA?
(A) RNA contains ribose
(B) RNA contains adenine, guanine, cytosine, and thymine
(C) RNA is usually double-stranded
(D) RNA is produced using complementary base pairing

The structure of DNA and RNA are similar in that
(A) both molecules are made of the same 5-carbon sugar
(B) both molecules are composed of the same 4 nitrogenous base
(C) the nucleotides of both molecules contain a phosphate group
(D) both molecules are double stranded which are antiparallel in directionality

Which of the following is not a source of variation in populations?
(A) independent assortment
(B) crossing over in meiosis
(C) random fertilization
(D) there are all sources of variation

Genetic mutations can have serious effects that are incompatible when they are essential for development. Sometimes chromosomal mutation is survivable, as in the case of trisomy 21.
The condition that is caused by these mutations is termed
(A) a chromosomal disorder
(B) a genetic trait
(C) polygenetic inheritance
(D) oncogenetic

Which of the following is a true statement regarding mitosis?
(A) Replication of chromosomes occurs at the start of mitosis
(B) Cytokinesis precedes alignment of replicated chromosomes along the equatorial plate
(C) Replicated chromosomes pairs up in tetras prior to separation of chromatids
(D) Mitosis plays a role in growth, repair, and asexual reproduction

Prokaryotes produce proteins faster than eukaryotes. Which of the following does not apply to this concept?
(A) Transcription and translation are coupled due to a lack of a nuclear membrane in prokaryotes
(B) Prokaryotes do not have introns to splice out as eukaryotes do
(C) Prokaryotes do not add a poly-A tail post-transcription
(D) Prokaryotes can skip transcription and go directly into translation

Which of the following best describes the process of DNA replication?
(A) Multiple “bubbles” form in the DNA and proceed with replication in both directions from the bubble
(B) A single “bubble” forms in the DNA and proceeds with replication in a single direction from the bubble
(C) DNA polymerase adds nucleotides to each separated strand of the DNA molecule at the replication fork, replication two leaded strands at one end of the “bubble” and two lagging strands at the other side of the “bubble”
(D) Replication occurs at a single replication fork that replications lagging and leading strands in the same direction

Which of the following is an example of positive gene regulation?
(A) the tryptophan gene, in which the presence of tryptophan functions as a corepressor to prevent its own transcription
(B) The lac gene in which the repress or preventing the synthesis of the enzymes that degrade lactose is deactivated by the presence of lactose
(C) CAP, which acts as a required transcription factor for the enzymes that degrade lactose
(D) inducible operons in which the inducer is a substrate

The way in which different genes in eukaryotes are turned on and off and the subsequent differential gene expression and regulation results in
(A) species diversity
(B) translation
(C) a relatively small genome
(D) homeostasis

Why are viruses considered to be nonliving?
(A) They do not have cells
(B) They cannot reproduce on their own
(C) They have no metabolic activity
(D) All of the above

According to the biological species concept, which of the following statements is not correct?
(A) To be considered a species, a population must be reproductively isolated from other species
(B) For a new species to arise, it must be geographically isolated from its parent species for long periods of time
(C) Organisms that are phenotypically identical yet have distinct mating behavior are considered distinct species since they do not naturally interbreed
(D) Organisms that can interbreed and produce sterile offspring are considered distinct species

Which of the following statements regarding the process of speciation is correct?
(A) Speciation occurs so slowly that scientists have never observed the emergence of a new species
(B) Speciation only occurs slowly as small genetic changes accumulate from generation to generation
(C) Speciation can occur as a result of changes in a single gene
(D) Speciation requires the geographic isolation of a small population from a larger parent population

In which of the following would the most highly conserved sequences of nuclei acids be located?
(A) Structually critical regions of a polypeptide such as an active site region
(B) The intron regions of pre-mRNA sequences
(C) Ribosomal RNA sequences
(D) Bacterial genes conferring antibiotic resistance

Which of the following depicts structures that are analogous but not homologous?
(A) Bluebird wing and penguin wing
(B) Bluebird wing and dragonfly wing
(C) Penguin wing and seal flipper
(D) Seal flipper and dragonfly wing

When considering the biomass of a photosynthetic organism for energy transfer studies, which of the following best explains why it is necessary to use the dry mass rather than the wet mass to determine productivity?
(A) The wet mass can vary widely due to differing concentrations of minerals in soil
(B) The mass that is produced and added to the organism does not include the mass of water
(C) Water has no caloric value
(D) Water plays no role in primary productivity

Which of the following explains the fact that there are a variety of proteins found in the cell membrane which affect the immune system?
(A) Our immune system recognizes proteins within the cell membrane that are calle “self-proteins” that enables the cells of the immune system to recognize the organism’s own cells and not destroy them
(B) Those proteins assist the immune system in destroying pathogens such as bacteria and viruses. They use the process of phagocytosis to kill viruses and bacteria.
(C) Those proteins decide if the cell is part of the immune system. If the cell is not part of the immune system, then the proteins will engulf the cell.
(D) Our immune system recognizes proteins within the cell membrane that are called “immune proteins” that enables the cells of the immune system to recognize the organism’s own cells and not destroy them.

If a spontaneous mutation introduced a new allele into a population’s gene pool at a chromosomal locus that had previously been static, which of the following would experience the largest change in value as a result?
(A) Average number of gene loci per chromosome
(B) Average frequency of heterozygosity in the gene pool
(C) Nucleotide base-pairing variability at the site of the wobble effect in codon-anticodon recognition
(D) Geographic variability

If bacterial DNA is cut in three locations with restriction enzymes, how many separate sections of DNA will results?
(A) 1
(B) 2
(C) 3
(D) 4

Molecules that are involved in the regulation of gene expression, which are usually comprised of proteins?
(A) translation factors
(B) RNA polymerase
(C) RNA codons
(D) transcription factors

Which of the following does not apply to the technique known as gel electrophoresis?
(A) The DNA is pulled to the positive end of the gel box
(B) The agarose gel provides for a porous matrix
(C) The buffer solution helps supply ions needed to conduct an electric current
(D) The larger fragments move further down the gel than the smaller ones due to their heavier weight

When a molecule is heated, hydrogen bonds break readily. Which of the following describes how DNA will react if it is heated?
(A) The DNA will separate into individual nucleotides
(B) The sugars will separate from the phosphates
(C) The DNA will separate into 2 singles stranded sections
(D) The DNA will remain intact

Which of the following would not be a valid reason to use PCR?
(A) Help in analyzing DNA of ancient remains of fossilized wholly mammoth
(B) Help in determining the DNA of a hair sample found at a crime scene
(C) Help in analyzing the genome of a virus
(D) Help transferring DNA from a plasmid containing GFP into E. coli