AP Bio midterm
If 30% of nucleotides in an RNA molecule are adenine, what percent is thymine
0%
The cell cycle of yeast cells grown in the nutrient-poor environment is approximately what percent of the cell cycle of yeast cells grown in the nutrient-rich environment?
168
The probability that individual will develop Friedreich's ataxia is closest to which of the following?
25%
What percent of the time required to complete a full cycle do the cells typically spend in interphase
95%
Cancer can result from a variety of different mutational events. Which of the following is LEAST likely to result in the initiation of a cancerous tumor?
A defect in a cell-cycle checkpoint prevents a cell from entering the S phase
Based on the information presented, which of the following genetic changes in an individual without diabetes is most likely to result in a disrupted cellular response to insulin signaling similar to that of an individual with type 2 diabetes?
A deletion in the gene encoding the insulin receptor that removes only the cytoplasmic domain of the protein
Which of the following describes a mutation that would lead to an increase in the frequency of nondisjunction?
A mutation affecting checkpoint 3 proteins that prevents attachment of spindle fibers
Based on the model, which of the following mutations is most likely to result in a cell that will generate a cancerous tumor?
A mutation in the gene encoding G-PIP that results in a nonfunctional protein
Which of the following best describes the production of by coral and coral symbionts?
A negative feedback mechanism that reverses the environmental change
Based on the inheritance pattern shown in Figure 1, which of the following best predicts the nature of the original mutation?
A recessive mutation on a somatic chromosome
Damaged tissue releases chemicals that activate platelets and stimulate the formation of blood clots. Which of the following predictions about the activity of platelets best describes a positive feedback mechanism?
Activated platelets release chemicals that activate more platelets
Which describes the hydrolysis of carbohydrates
Addition of water molecules breaks a covalent bond
Which explains how higher concentrations of nitrogen and phosphorus contribute to eutrophication
Algae require nitrogen and phosphorus
Which of the following best explains the differences in flower color of the African violets in the greenhouse?
An enzyme responsible for flower color does not fold correctly in cooler temperatures, and the greenhouse is warmest in the center
Based on the data in Figure 1, which of the following is most likely the primary cause of the pattern of frequency of trisomy 21 births in the selected maternal age-groups?
At older maternal ages, the incidence of errors in meiosis during egg production increases, which leads to an increase in nondisjunction
Based on the data in Figure 1, which of the following best describes the inheritance pattern of Friedreich's ataxia?
Autosomal recessive
Which describes a structural difference between DNA and RNA
Backbone of DNA contains deoxyribose, RNA contains ribose
Why do bile salts cause sulfur powder to sink?
Bile salts decrease surface tension
Which of the following claims is most consistent with the observed butterfly behavior?
Butterflies that express two variants of the enzyme are active over a greater range of temperature
Which describes process by which gas from the atmosphere is obtained by plants to build lipids
Carbon cycle
Ethylene gas is an organic molecule that serves many cell signaling roles in flowering plants. Which of the following best explains how a positive feedback mechanism involving ethylene works?
Cells of ripening fruit produce ethylene, which activates the ripening response in other fruit cells
What type of molecule did the bacteriophage most likely inject into the bacteria cells
DNA
Which best explains Delta's role in regulating cell communication through the Notch signaling pathway
Delta restricts cell communication to short distances within a developing embryo
Which of the following research questions would best guide an investigation of the link between the structure of the signaling molecules and the evolution of quorum sensing?
Did these species evolve from a common ancestor that used a similar signaling molecule?
Which describes the role of mitosis in the cell cycle
Distributing replicated chromosomes to daughter nuclei
Which question would provide the best direction for a researcher who wanted to study the impact of abnormally high blood-sugar levels on cellular homeostasis in diabetics
Does water move from cells into blood vessels more rapidly in diabetics than in non diabetics when blood-sugar levels are higher than normal
which of the following describes the role of cyclin in the regulation of the cell cycle?
During M phase, the cyclin level peaks, resulting in an increased binding frequency with CDK
The process depicted in the image above is best summarized by which of the following descriptions?
During meiosis, crossing over leads to recombination of alleles between homologous chromosomes
DNA replication occurs..
During the S phase of the cell cycle
Which best predicts the effect of disrupting the proton gradient in BAT
Electron transport and oxidative phosphorylation will be decoupled, generating more heat but less ATP
Which of the following most likely explains how the changing seasons result in changing fur color in an arctic fox?
Environmental factors cause changes in gene expression, resulting in seasonal variations in pigment production
Based on Figure 1, which of the following best explains how exercise causes blood glucose levels to rise?
Epinephrine activates alpha cells, causing the release of glucagon, and inhibits beta cells, blocking the release of insulin
Which describes the initial steps in the process whereby epinephrine stimulates glycogen breakdown
Epinephrine binds to a cell-surface receptor; the activated receptor stimulates production of the messenger, cAMP
Which of the following observations would provide evidence of a positive feedback mechanism in this system?
Estrogen from the ovaries stimulates the hypothalamus and anterior pituitary to secrete more GnRH, LH, and FSH
Which of the following describes the most likely connection between natural ethylene production and fruit ripening
Ethylene gas is a chemical signal through which ripening fruits trigger the ripening process in other fruits
What is most directly responsible for water's unique properties
Forms hydrogen bonds
What is the reaction specificity of hexokinase
Glucose has the right shape and charge to cause hexokinase to undergo a structural change
A researcher claims that the epinephrine signaling pathway controls a catabolic process in muscle cells. Which of the following statements best helps justify the researcher's claim?
Glycogen phosphorylase catalyzes the conversion of glycogen to glucose-1-phosphate
Hydrologic enzymes are most likely to accumulate where
Golgi complex
What best explains why a cell's plasma membrane is composed of two layers of phospholipids
Having two oppositely oriented layers of phospholipids allows only the hydrophilic heads to interact
How do the properties of water contribute to humans sweating
High heat of vaporization allows body to remove excess heat
Which of the following questions about genetic diversity could most appropriately be answered by analysis of the model in Figure 1 ?
How does the independent assortment of the two sets of homologous chromosomes increase genetic diversity?
How do the properties of water at an air-water interface enable an insect to walk on the surface
Hydrogen bonds between molecules provide surface tension
What is responsible for the cohesive property of water?
Hydrogen bonds between oxygen atom and hydrogen atom
Based on the experimental results, which of the following describes the most likely defect in muscle cells of patients with type 2 diabetes?
IRS-1 activation is reduced at high insulin concentrations
Which shows that fragment is RNA and not DNA
Identity of each nitrogenous base
Which of the following statements provides the most reasonable prediction to account for the deviation from the expected results?
In sweet pea plants, the gene for flower color and the gene for pollen grain shape are genetically linked
Which of the following best explains how the development of phenotypic female Australian dragon lizards with a genotype occurs when incubation temperatures are above 32 degrees C?
Incubation temperatures above 32C inhibit the genes on the Z chromosome that produce proteins necessary for male development
During prophase replicated homologous chromosomes pair up and undergo synapsis. What testable question is generated regarding synapsis and genetic variability by Figure 1 ?
Is the distance between two gene loci related to crossover rate?
Scientists have found that methylation suppresses crossing-over in the fungus Ascobolus immersus. Which of the following questions is most appropriately raised by this specific observation?
Is the level of genetic variation in the gametes related to the amount of DNA methylation observed?
Which of the following statements best describes the role of cyclic in the signal transduction pathway?
It acts as a second messenger that helps relay and amplify the signal within the cell
What predicts how the amino acid deletion will affect the structure of the CFTR protein
It will affect the primary, secondary, and tertiary structures
Process in which O2 is released as a by-product of oxidation-reduction reactions
Light dependent reactions of photosynthesis
Which is an important difference between light-dependent and light-independent reactions of photosynthesis
Light-dependent produce ATP and NADPH while the light-independent reactions use energy stored in ATP and NADPH
Which of the following best supports the claim that ethylene initiates the signal transduction pathway that leads to ripening of fruit?
Loss-of-function mutations in ethylene receptors result in changes to the ripening process
What contains hydrologic enzymes associated with the intracellular digestion of macromolecules
Lysosomes
Within the cell, many chemical reactions that, by themselves, require energy input (have a positive free-energy change) can occur because the reactions...
May be coupled to the hydrolysis of ATP
These cells are the result of nondisjunction during which phase
Meiosis 1
What evidence supports the endosymbiotic hypothesis
Mitochondria have their own DNA and divide independently of the cell
Both mitosis and meiosis begin with a parent cell that is diploid. Which of the following best describes how mitosis and meiosis result in daughter cells with different numbers of chromosomes?
Mitosis produces two identical diploid daughter cells after one round of division. Meiosis produces four haploid daughter cells after two rounds of division.
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?
Most offspring of a given cross have a combination of traits that is identical to that of either one parent or the other
Which of the following occurs in all species of living organisms and may lead to an increase in genetic variation?
Mutations in the genome
Which best matches the fertilizer components with the molecule in which it will be incorporated by organisms in the area
Nitrogen will be incorporated into nucleic acids
Which provides evidence to support the claim that no ATP will be synthesized in the absence of a proton gradient across the thylakoid membrane
No ATP is synthesized when channel proteins are inserted into the thylakoid membrane
If a ligand was large and polar where would it be found
On the cell
An advantage of eukaryotic cells having internal membranes
Organelles isolate specific reactions, increasing metabolic efficiency
Which molecule is likely to be solid at room temperature
Palmatic acid, because the absence of carbon-carbon double bonds
What do prokaryotic and eukaryotic cells have in common
Ribosomes
What is the functional difference between rough ER and smooth ER
Rough ER can synthesize and package proteins, smooth ER cannot
What is the reaction specificity of an enzyme
Shape and charge of the substrates
Carbon dioxide enters a cell through what
Simple diffusion
An explanation of how plant cells communicate across cell walls will most likely refer to the diffusion through plasmodesmata of which
Small, water-soluble molecules
A student claims that the chromosome contains the sex-determining region gene, known as the gene, which causes male fetuses to develop testes. Which of the following provides correct information about cell signaling that supports the claim?
The SRY gene produces a protein that binds to specific regions of DNA in certain tissues, which affects the development of these tissues
Which of the following best describes the hydrolysis of carbohydrates?
The addition of a water molecule breaks a covalent bond between sugar monomers
Which supports the claim that this species is better adapted to environmental changes than other photosynthetic species are
The additions pigments allow the species containing them to harvest energy from wavelengths of light
The data above represent the results of three different crosses involving the inheritance of a gene that determines whether a certain organism is blue or white. Which of the following best explains the mechanism of inheritance of the gene?
The allele for blue is an X-linked dominant allele because there are no blue male offspring in cross 2
Which of the following best describes how the amount of in the cell changes during phase?
The amount of DNA is halves as the \cell divides into two daughter cells
Based on the model of eukaryotic cell cycle regulation shown in the figure, which of the following best describes the effect of a drug that blocks the production of the mitotic cyclin?
The cell would be prevented from entering mitosis, and the cell would stop dividing
Which describes the effect of a greater number of cysteine amino acids on the stability of the proteins
The change leads to increased protein stability because an increased number of S-S bonds in the tertiary structure
Humans have a diploid number () of . Which of the following statements best predicts the consequence if meiosis did not occur during gametogenesis?
The chromosome number would double with each generation
Figure 1 shows the inheritance of a particular genetic condition in three generations of one family. Which of the following best explains the observed pattern of inheritance?
The condition is passed from mothers to offspring via a mitochondrial gene
Based on their calculation, the researchers would most likely conclude which of the following?
The differences between observed data and expected data are due to chance
Which of the following conditions will most likely cause a normal body cell to become a cancer cell?
The environment contains mutagens that induce mutations that affect cell-cycle regulator proteins
How does an enzyme speed up a reaction
The enzymes active site binds to the transition state, which decreases activation energy
An experiment was performed to induce mitotically dividing S. cerevisiae cells in to undergo meiosis. Which of the following best describes the steps these cells will follow to form gametes?
The first division will reduce the number of chromosomes by half for each daughter cell, and the second division will move single chromatids to each daughter cell
Which of the following statements best predicts the effect of a mutation that results in a loss of the glucocorticoid receptor's ligand binding function?
The glucocorticoid receptor will remain associated with the accessory proteins
Which describes how a growth factor stimulates cell division from outside a cell
The growth factor binds to receptors on the cell surface, initiating a signal transduction pathway that activates specific target genes
Which describes how amino acids affect the tertiary structure of a protein
The interactions of the different R-groups
Which of the following outcomes will most likely result from the irreversible binding of GDP to the G protein
The intracellular concentration of glycogen will increase
How would the extra chromosome affect the male offspring produced by the gamete?
The male offspring would have full-color vision, because of the presence of the extra XX chromosome
A mutation changes the shape of the extracellular domain of transmembrane receptor protein produced by the cell. Which of the following predictions is the most likely consequence of the mutation?
The molecule that normally binds to protein A will no longer attach, deactivating the cellular response
Which of the following best explains why triploid bananas do not produce seeds?
The production of gametes is disrupted because of unequal pairing of homologous chromosomes during meiosis
Which explains how cell surface proteins, such as MHC proteins and T cell receptors, mediate cell communication over short distances
The proteins interact directly with proteins on the surfaces of other cells
Argatroban is a competitive inhibitor of thrombin. Which of the following effects on the coagulation cascade is most likely to result from inhibiting thrombin activity with argatroban?
The rate of fibrin formation will decrease
Which best explains why ATP production is greater in the tube with oxygen than in the tube without oxygen
The rate of proton pumping across the inner mitochondrial membrane is lower in the sample without oxygen
Which of the following observations provides the best evidence that acetyl-CoA negatively regulates pyruvate dehydrogenase activity?
The rate of the pyruvate dehydrogenase-catalyzed reaction is slower in the presence of a higher concentration of acetyl-CoA
Which of the following best predicts the effect of inserting this gene into the DNA of a bacterial cell?
The recombinant bacterium will produce human insulin using its own transcription and translation machinery
Which of the following is a valid interpretation of the experimental results that explains how individuals with type 2 diabetes differ from individuals without diabetes?
The relatively low levels of glucose uptake in individuals with type 2 diabetes indicate that mobilization of GLUT4 to the cell surface is reduced in muscle cells of those individuals
how does amino acid substitution result in decreased catalytic activity by the mutated enzyme
The substitution altered the secondary and tertiary structure
Which of the following best explains the cause of the phenotypic variation observed in the butterflies?
There was differential gene expression of wing color and body size in response to the colors of light the caterpillars were exposed to
UV radiation can damage DNA by breaking weak bonds- which explains how this occurs?
UV radiation disrupts double helix structure by breaking hydrogen bonds between nitrogenous base pairs
The synthesis of protein or carbohydrate polymers always produces what as a byproduct?
Water
Which explains how water is able to move upward from roots through its xylem and to the leaves
Water and xylem are both polar
Which of the following questions will best help the genetic counselor to evaluate the risk of the young man developing Huntington's disease and transmitting it to his children?
We're your parents or grandparents ever diagnosed with Huntington's disease?
What evolutionary advantage does compartmentalization of core metabolic process offer eukaryotes
With the evolution of mitochondria
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...
condensation of chromatin in preparation of nuclear division in both cells
