ap biology midterm review
which is most efficient in exchanging oxygen with the environment by diffusion?
cuboidal cell: 1-7 ratio of surface area
Which of the following is the most likely effect of the mutation at nucleotide position 7 in the GULO gene of humans?
The deletion of the single nucleotide causes a frameshift, changing the primary structure downstream of the mutation and resulting in a nonfunctional protein.
Bacteriophages are viruses that infect bacteria. In an experiment, bacteriophages were labeled with either radioactive phosphorus or radioactive sulfur. The labeled bacteriophages were incubated with bacteria for a brief amount of time and then removed. The infected bacteria cells were found to contain significant amounts of radioactive phosphorus but not radioactive sulfur. Based on the results of the experiment, which of the following types of molecules did the bacteriophages most likely inject into the bacterial cells? a) simple carbohydrate b) amino acid c) DNA d) polypeptide
c) DNA
A researcher claims that the synthesis of ATP from ADP and inorganic phosphate (Pi) is essential to cellular function.Which of the following statements best helps justify the researcher's claim?
ATP hydrolysis is an energy-releasing reaction that is often coupled with reactions that require an input of energy.
Muscle contraction depends on ATP hydrolysis. During periods of intense exercise, muscle cells rely on the ATP supplied by three metabolic pathways: glycolysis, mitochondrial respiration, and the phosphagen system. Figure 1 shows the rates at which the three metabolic pathways produce ATP following the start of an intense period of exercise.Which of the following correctly uses the data to justify the claim that the phosphagen system is an immediate, short-term source of ATP for muscle cells?
ATP production by the phosphagen system increases and decreases rapidly following the start of the exercise period.
one solution is maintained at PH 4, other at PH 9. scientists find that mitochondria in the solution w/ a PH of 4 continue to produce ATP but those in PH dont. Evidence to support this?
ATP production in mitochondria requires a hydrogen ion gradient that focuses movement of protons into the mitochondrial matrix
In the reaction why did the disk rise to the top?
Higher substrate concentrations in more concentrated solutions sped up the reaction
Which of the following questions might scientists ask to most reliably determine if there has ever been life on mars?
Did mars have the elements to present in its atmosphere to support life?
Study about drug that hinders separation of chromosomes. Which wold be the best question answered from this experiment?
IS there a pattern of movement of homologous chromosomes in the presence of this compound?
which can be reasoning concluded from the experimental results?
Light from a lamp can substitute for sunlight in stimulating chloroplasts processes
In chloroplasts, ATP is synthesized from ADP plus inorganic phosphate (Pi) in a reaction catalyzed by ATP synthase molecules that are embedded in the thylakoid membrane.Which of the following statements 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 that allow the free passage of protons are inserted into the thylakoid membrane
PH of the inner thylakoid space has been measured, as has the PH of the stomata and of the cytosol of a particular plant cell. Which, if any relationship would you expect to find?
PH with in the thylakoid os less that of the stomata
which of the following is an example of polygenetic inheritance?
Skin pigmentation in humans
A researcher proposes a model of an enzyme-catalyzed reaction in which a reactant is converted to a product. The model is based on the idea that the reactant passes through a transition state within the enzyme-substrate complex before the reactant is converted to the product. Which explains how enzyme speeds up the reaction?
The enzyme's active site binds to and stabilizes the transition state, which decreases the activation energy of the reaction.
What is the role of ribosomes on the rough ER?
They are where proteins are synthesized
Exposure to UV in skin cancer in humans
UV photons cause dimers to form leading to misshaped RNA which results in replication+transcription errors
Butterflies of the genus Colias live in the Rocky Mountains, where they experience a wide range of temperatures. Different variants of a particular glycolytic enzyme in the flight muscles are optimally active at different temperatures. Within the same population, some individual butterflies fly most effectively at 29C, while others fly most effectively at 40C. Still others can be equally active at both temperatures.Which of the following claims is most consistent with the observed butterfly behavior? a) Butterflies that express two variants of the enzyme are active over a greater range of temperature. b) Butterflies that are active over a wide range of temperatures produce greater amounts of the enzyme. c) Temperature has little effect on the activity of butterflies. d) Butterflies that are active at warmer temperatures produce more offspring.
a) Butterflies that express two variants of the enzyme are active over a greater range of temperature.
The active site of an enzyme is the region that a) is involved in the catalytic reaction of the enzyme b) binds noncompetitive inhibitors of the enzyme c) binds allosteric regulators of the enzyme d) is inhibited by the presence of a coenzyme or a cofactor
a) is involved in the catalytic reaction of the enzyme
primary role of oxygen in cellular respiration?
act as an acceptor for electrons and hydrogen, forming water
The processes illustrated in the models depicted above result in which of the following?
an increase in genetic variation
A part of the promoter, called the TATA box, is said to be highly conserved in evolution. Which of the following might this illustrate?
any mutation in the sequence
How does a noncompetitive inhibitor decrease the rate of an enzyme reaction? a) by acting as a coenzyme for the reaction b) by changing the shape of the enzyme's active site c) by binding at the active site of the enzyme d) by changing the free-energy change of the reaction e) by decreasing the activation energy of the reaction
b) by changing the shape of the enzyme's active site
If cells are grown in a medium containing radioactive sulfur, which of these molecules will be labeled? a) nucleic acids b) proteins c) amylose d) both proteins and nucleic acids e) phospholipids
b) proteins
A student analyzed a viral genome and found that the genome had the following nucleotide composition. 28% adenine, 20% thymine, 35% cytosine, 17% guanine. Which of the following best describes the structure of the viral genome? a) Double-stranded DNA b) Single-stranded DNA c) Double-stranded RNA d) Double stranded RNA
b) single-stranded DNA
What is the difference between DNA and RNA
backbone of DNA contains deoxyribose, whereas the backbone of RNA contains ribose
Some of the drugs used to treat HIV patients are competitive inhibitors of the HIV reverse transcriptase enzyme. Unfortunately, the high mutation rate of HIV means that the virus rapidly acquires mutations with amino acid changes that make them resistant to these competitive inhibitors. Where in the reverse transcriptase enzyme would such amino acid changes most likely occur in drug-resistant viruses? a) anywhere, with equal probability b) at an allosteric site c) in or near the active site d) at a cofactor binding site e) in regions of the protein that determine packaging into the virus capsid
c) in or near the active site
Fusion of a cell in G1 phase with a cell in the early M phase would most likely result in?
condensation of chromatin in preparation of nuclear division in both cells
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?
contractile rate increases as the osmolarity decreases because the amount of water entering the paramecia by osmosis increases
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? a) Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable. b) Dehydration reactions can occur only after hydrolysis c) Hydrolysis creates monomers, and dehydration reactions break down polymers. d) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. e) Dehydration reactions ionize water molecules and add hydroxyl groups to polymers, hydrolysis reactions release hydroxyl groups from polymers.
d) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.
Which of the following statements regarding enzymes is true? a) enzymes change the equilibrium point of the reactions they catalyze b) enzymes increase the rate of a reaction by making the reaction more exergonic c) enzymes make the rate of a reaction independent of substrate concentrations d) enzymes increase the rate of a reaction by lowering the activation energy barrier e) enzymes increase the rate of a reaction by reducing the rate of reverse reactions
d) enzymes increase the rate of a reaction by lowering the activation energy barrier
Which of the following modifications of the DNA would produce the greatest change in the primary structure of the polypeptide chain?
deleting the first T in the second triplet
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? a) denaturation of the enzyme b) insufficient cofactors c) allosteric inhibition d) saturation of the enzyme activity e) competitive inhibition
e) competitive inhibition
Explain process replicated in Figure 1. It produces DNA molecules that are hybrids of the original and newly synthesized nucleotide strands
each newly synthesized strand remains associated w/ its template stand to form 2 copies of original DNA
Which of the following indicates a mean number per cross of F2 plants production of medium red flowers?
mean of medium red is 208. the distribution of phenotypes suggests that multiple genes are involved in grain color determination
eukaryotic DNA is ___________ _________________ chromosomes
multiple linear
which of the following occurs in all species of living organisms and may lead to an increase in genetic variation
mutations in the genome
a certain females chromosomes 12 both have blue and gene chromosomes 19 both have long genes . As cells in her ovaries undergo meiosis correctly her resulting eggs may have which of the following?
one chromosome 12 with 1 blue gene and 1 chromosome 19 with 1 long gene
which best describes the role of the p53 in response to DNA damage?
phosphorylated p53 stimulates transcription of p21; and the resulting p21 proteins suppresses cell division until DNA damage is repaired
which represents the best relationship between photosyntheses and cellular respiration
photosynthesis stores energy in complex organic molecules, while respiration releases it
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
properties of the molecule as a result of abnormal interactions between adjacent hemoglobin molecules
which enzyme was used the the macleod+mccarty experiments and why?
proteases+RNases to rule out protein and RNA as the transforming factors
Transcription in eukaryotes requires which of the following in addition to RNA polymerase?
several transcription factors
U shaped tube: Side A is 4M glucose/5M NaCl; side B has 0M glucose/4M NaCl
side a is hypertonic to side B
prokaryotic DNA is ___________ _________________ chromosomes
single circular
Which could be considered evidence in support of the of the RNA world model
some RNA molecules in contemporary cells have catalytic functions
animals breath in air containing oxygen and breath out air containing less oxygen and more CO2 . The CO2 comes from?
the citric acid cycle and oxidative phosphorylation
shortly after microscopically observing the open stomata of a Jade plant, the stomata became closed. Which of the following environmental factors could have caused the physiological change>
the light intensity of the environment increased