What is the process by which monomers are linked together to form polymers?
B) Dehydration/ condensation reactions
The subunits (monomers) in cellulose are linked together by __
A) glycosidic linkages
If a small droplet of triacylglycerol molecules is suspended in water, the fat molecules form a "ball of spaghetti" with no particular orientation. But if a droplet of phospholipid molecules is put in water, all the molecules point outward, toward the water. Phospholipids are forced into this orientation because phospholipids have __.
C) a polar end and a nonpolar end
Which of the following describes protein structure when more than one polypeptide chain is involved?
D) Quaternary Structure
Which of the following are pyrimidines found in the nucleic acid DNA?
B) Thymine and Cytosine
Which of the following states the relevance of the first law of thermodynamics to biology?
A) Energy can be freely transformed among different forms as long as the total energy is conserved
A chemical reaction that has a positive ΔG value is correctly described as __.
The mechanism of enzyme action is __
B) lowering the energy of activation for a reaction
What best characterizes the role of ATP in cellular metabolism?
B) Its free energy is coupled to an endergonic process via the formation of a phosphorylated intermediate
The process of stabilizing the structure of an enzyme in either its active or inactive form by the binding of a molecule is an example of __.
C) allosteric regulation
A certain cell has ribosomes and DNA, and is surrounded by a membrane. But there are no mitochondria present. Based on this information, this cell is most likely ___.
A) a bacterium
The protein actin is the key constituent of a(n) ___.
You would expect a cell with an extensive Golgi apparatus to__.
D) secrete a lot of protein
Which of the following relationships between cell structures and their respective functions is not correct?
B) chloroplasts: chief site of cellular respiration
Which of the following cellular processes or characteristics is/are related to the cytoskeleton?
D) All of the above
Which of the following best describes the general structure of a cell membrane?
D) Proteins embedded in two layers of phospholipid
Which of the following functional processes result(s) from the presence of proteins in or on the plasma membrane?
C) All of the above
Which one of the following statements about diffusion is true?
C) It is a passive process
The internal solute concentration of a plant cell is about 0.8M. To demonstrate plasmolysis, it would be necessary to suspend the cell in what solution?
White blood cells engulf bacteria through what process?
The energy given up by the electrons as they move through the electron transport chain is used in which of the following processes?
D) Pumping H+ across a membrane
In the Krebs cycle (also called the citric acid cycle), the energetic production per glucose molecule is __.
B) 2 ATP, 6 NADH, 2 FADH2
In preparing pyruvate to enter the citric acid cycle, which of the following steps does occur?
D) All of the above
During aerobic respiration, molecule oxygen (O2) is used __.
D) at the end of the electron transport chain to accept electrons and form H2O
Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide. This last step___.
D) enable the cell to recover NAD+
In mechanism, photophosphorylation is most similar to
B) Oxidative phosphorylation in cellular respiration
What is the role of NADP+ in photosynthesis?
C) It is reduced and then carries electrons to the Calvin cycle
Which of the following statements correctly describes the relationship between the light reactions and the Calvin cycle?
B) The light reactions produce ATP and NADPH for the Calvin cycle
In the Calvin cycle, CO2 is combined ___.
C) with a 5-carbon compound to form an unstable 6-carbon compound, which decompose into two molecules of 3-phosphoglycerate
When pigments in an excited state relax back to ground state, they ___.
A) both "release energy"
Where do the light reactions of photosynthesis occur in eukaryotes?
B) The thylakoid membrane
Why would a figure showing the absorption spectrum and action spectrum for chlorophyll a be different?
D) Other pigments absorb light in addition to chlorophyll a
A signal transduction pathway is initiated when a(n) __ binds to a receptor
C) signal molecule
Which of the following is true of steroid receptors?
B) The receptor may be inside the nuclear membrane
One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this?
D) Receptor tyrosine kinases
G-proteins, once activated, do the following:
B) activates another enzyme located on the membrane
Sister chromatids __.
D) are identical copies of each other formed during DNA synthesis
Mitosis and cytokinesis occurs __
A) in somatic cells
Which one of the following occurs in meiosis, but not mitosis?
A) Non sister chromatids undergo crossing-over
What is the end result of meiosis?
C) Four haploid cells
A cell with 2n=20 chromosomes goes through the cell cycle. The number of chromatids after doubling the DNA in the S phase is __
Which of the following happens at the conclusion of meiosis I?
C) The chromosome number is halved
Ignoring crossover, how many kinds of gametes can be produced by an organism with a diploid number of 8 (i.e. 2n=8)
Independent assortment of chromosomes occurs __.
B) during meiosis I only
Which is the first checkpoint in the cell cycle where a cell will be caused to exit the cycle if this point is not passed?
Two plants are crossed, resulting in offspring with 3:1 ratio for a particular trait. This probably indicates:
A) that the parents were both heterozygous for an autosomal recessive trait
What is the purpose of a testcross?
B) determine if an individual with a dominant phenotype is homozygous or heterozygous
A certain couple are both heterozygotes (carriers) for recessive autosomal allele for cystic fibrosis. If they have three children, what is the probability that all three will have cystic fibrosis
In snapdragons, heterozygotes have pink flowers, whereas the two homozygotes have red flowers or white flowers. When plants with red flowers are crossed with plants with pink flowers, what proportion of the offspring will have white flowers?
A red bull is crossed with a white cow and all of the offspring are roan, an intermediate color that is caused by the presence of both red hairs and white hairs. This is an example of genes that are __.
Black fur in mice (B) is dominant to brown fur(b). Short tails (T) is dominant to long tails (t). What fraction of the progeny of the cross BbTtxBBtt will have black fur and long tails?
A single genetic locus that controls more than one trait is said to be __.
Two true-breeding stocks of garden peas are crossed. Once parent had red, axial flowers and the other had white, terminal flowers; all F1 individuals had red, axial flowers. If 1000 F2 offspring resulted from the cross, approximately how many of them would you expect to have red, terminal flowers? (Assume independent assortment)
A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A woman with normal vision whose father is color-blind marries a color-blind male. What is the probability that this couple's son will be color-blind?
A particular biochemical pathway leading to fur color in a species of gerbil is shown. The first step of the pathway is catalyzed by an enzyme "A" for which there is a dominant wild-type allele, and a recessive mutant (non-functional allele). The second step of the pathway is catalyzed by an enzyme "B" for which there is also a dominant wild-type allele, and a recessive mutant (non-functional allele). Suppose two black, dihybrid gerbils are crossed. What phenotypic ratio would you expect to see in the progeny?
In trying to determine whether DNA or protein was the genetic material, Al Hershey and Martha Chase made use of which of the following facts?
B) Both DNA contains nitrogen and does not contain sulfur
Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. What percent of the nucleotides in this sample will be thymine?
Which of the following is true about all nucleic acid polymerases:
A) synthesis can only occur in the 5' to 3' direction
What is the function of topoisomerase?
C) Releiving strain in the DNA ahead of the replication fork
During the replication of DNA__.
B) both strands of a molecule act as templates
Once the DNA at the replication fork is unwound by helicases, what prevents the two strands from coming back together to reform a double helix?
D) Single-strand binding proteins bind the unwound DNA and prevent the double helix from reforming
A eukaryotic cell lacking telomerase would:
C) undergo a gradual reduction in chromosome length
Which of the following statements is false when comparing prokaryotes with eukaryotes?
C) Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not
Which one of the following statements is true?
B) Each amino acid in a protein is coded for by three bases in the DNA
What brings individual amino acids to the elongating polypeptide chain?
A particular triplet of bases in the coding sequence of DNA is 3' AGT 5'. The corresponding codon for the mRNA transcribed is __.
A) 5' UCA 3'
All of the following are transcribed from DNA except __.
What are the coding segments of a stretch of eukaryotic DNA called?
The structures called snRNPs are __.
D) part of a spliceosome
Which of the following is not involved in the process of translation?
Which of these statements represents a common misconception regarding point mutations?
A) They always produce a change in the amino acid sequence of a protein