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A comprehensive set of multiple-choice questions and answers covering key concepts in cell biology and biochemistry. It is designed to help students prepare for a final exam in this subject. The questions cover a wide range of topics, including the structure and function of organelles, macromolecules, dna replication, and enzyme kinetics. Well-organized and provides detailed explanations for each answer, making it a valuable resource for students seeking to solidify their understanding of these fundamental biological processes.
Typology: Exams
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(a) transport of material to the Golgi
(b) clean-up, recycling, and disposal of macromolecules
(c) sorting of transport vesicles
(d) the storage of excess macromolecules
carry out certain biochemical reactions that generate harmful, highly reactive
oxygen species. These chemicals are both generated and broken down in the
same location.
(a) Nucleosomes
(b) Lysosomes
(c) Peroxisomes
(d) Endosomes
assemble selectively permeable boundaries around and inside cells?
(a) sugars
(b) fatty acids
(c) amino acids
(d) nucleotides
is true of DNA but not true of RNA?
(a) It contains uracil.
(b) It contains thymine.
(c) It is single-stranded.
(d) It has 5′-to-3′ directionality.
assemble RNA polymers, the number of possible sequence combinations that
can be created for an RNA molecule made of 100 nucleotides is.
(a) 100
4
(b) 4
100
(c) 4 × 100
(d) 100/
noncovalent interactions. These weak interactions also produce stable, highly
specific interactions between molecules. Which of the factors below is the most
significant in determining whether the interaction will be transient or stable?
(a) the size of each molecule
(b) the concentration of each molecule
(c) the rate of synthesis
(d) surface complementarity between molecules
concentrated NaOH stock solution. The molecular weight of NaOH is 40. How
many grams of solid NaOH will you need to weigh out to obtain a 500 mL
solution that has a concentration of 10 M?
(a) 800 g
(b) 200 g
(c) 400 g
(d) 160 g
Generally, the atom that is oxidized will experience which of the following with
respect to the electrons in its outer shell?
(a) a net gain
(b) a net loss
(c) no change
(d) an equal sharing
the bonds are split by the addition of in a process called.
(a) ATP, phosphorylation.
(b) water, hydrolysis.
(c) hydroxide, hydration.
(d) acetate, acetylation.
The maximum velocity ( V max
) of an enzymatic reaction is an important piece of
information regarding how the enzyme works. What series of measurements
can be taken in order to infer the maximum velocity of an enzyme-‐catalyzed
reaction?
(a) the rate of substrate consumption after the system reaches equilibrium, for
several reactant concentrations
(b) the rate of product consumption shortly after mixing the enzyme and substrate
(c) the rate of substrate consumption at high levels of enzyme concentration
(d) the rate of substrate consumption shortly after mixing the enzyme and
substrate, for several substrate concentrations
activated intermediate followed by a condensation step that completes the
process. Both amino acids are shown in the figure below.
In the condensation step, is displaced by.
(a) OH, NH
3
(b) ADP, NH 2
(c) ATP, NH 3
(d) phosphate, NH 3
(a) Peptide bonds are the only covalent bonds that can link together two amino acids
in proteins.
(b) The polypeptide backbone is free to rotate about each peptide bond.
(c) Nonpolar amino acids tend to be found in the interior of proteins.
(d) The sequence of the atoms in the polypeptide backbone varies between different
proteins.
(a) They assist polypeptide folding by helping the folding process follow the most
energetically favorable pathway.
(b) They can isolate proteins from other components of the cells until folding is
complete.
(c) They can interact with unfolded polypeptides in a way that changes the
final fold of the protein.
(d) They help streamline the protein-folding process by making it a more
efficient and reliable process inside the cell.
structural framework. Which of the following proteins do you expect to have
a coiled-‐coil domain?
(a) insulin
(b) collagen
(c) myoglobin
(d) porin
(a) A-T
(b) T-A
(c) G-C
(d) C-G
to power many of the cellular processes, increasing the pool of ADP. As the
relative amount of ADP molecules increases, they can bind to glycolytic
enzymes, which will lead to the production of more ATP. The best way to
describe this mechanism of regulation is.
(a) feedback inhibition.
(b) oxidative phosphorylation.
(c) allosteric activation.
(d) substrate-level phosphorylation.
lethal infection when injected into mice, and a second that is harmless_._ He
observed that pathogenic bacteria that have been killed by heating can no longer
cause an infection. But when these heat-‐killed bacteria are mixed with live,
harmless bacteria, this mixture is capable of infecting and killing a mouse. What
did Griffith conclude from this experiment?
(a) The infectious strain cannot killed by heating.
(b) The heat-killed pathogenic bacteria “transformed” the harmless strain into a lethal
one.
(c) The harmless strain somehow revived the heat-killed pathogenic bacteria.
(d) The mice had lost their immunity to infection with S. pneumoniae.
gametes, these specialized cells are haploid. What is the total number of
chromosomes found in each of the gametes (egg or sperm) in your body?
(a) 22
(b) 23
(c) 44
(d) 46
(a) Is the individual genetically female or male?
(b) Do any of the chromosomes contain pieces that belong to other chromosomes?
(c) Does the individual have an extra chromosome?
(d) Do any chromosomes contain point mutations?
very compact, DNA-‐binding proteins and protein complexes must be able to gain
access to the DNA molecule. Chromatin-‐remodeling complexes provide this
access by.
(a) recruiting other enzymes.
(b) modifying the N-terminal tails of core histones.
(c) using the energy of ATP hydrolysis to move nucleosomes.
(d) denaturing the DNA by interfering with hydrogen-bonding between base pairs.
the number, location, and combination of these modifications, these changes
may promote the formation of heterochromatin. What is the result of
heterochromatin formation?
(a) increase in gene expression
(b) gene silencing
(c) recruitment of remodeling complexes
(d) displacement of histone H
debris via centrifugation. These extracts provide the proteins required for DNA
replication. Your DNA template is a small, double-‐stranded circular piece of DNA
(a plasmid) with a single origin of replication and a single replication termination
site. The termination site is on the opposite side of the plasmid from the origin.
Which of the following statements is true with respect to this in vitro replication
system?
(a) There will be only one leading strand and one lagging strand produced using this
template.
(b) The leading and lagging strands compose one half of each newly synthesized
DNA strand.
(c) The DNA replication machinery can assemble at multiple places on this plasmid.
(d) One daughter DNA molecule will be slightly shorter than the other.
” mutant form of DNA polymerase in which the
3 ′-‐to-‐ 5 ′ exonuclease function has been destroyed but the ability to join
nucleotides together is unchanged. Which of the following properties do you
expect the mutant polymerase to have?
(a) It will polymerize in both the 5 ′-to-3′ direction and the 3 ′-to-5′ direction.
(b) It will polymerize more slowly than the normal Exo
polymerase.
(c) It will fall off the template more frequently than the normal Exo
polymerase.
(d) It will be more likely to generate mismatched base pairs.
one side of a replication fork? D
properly:
A. Holliday junction cut and ligated
B. strand invasion
C. DNA synthesis
D. DNA ligation
E. double-strand break
F. nucleases create uneven strands
Which of the following is the correct order of events during homologous
recombination?
(a) E, B, F, D, C, A
(b) B, E, F, D, C, A
(c) C, E, F, B, D, A
(d) E, F, B, C, D, A
figure below.
Which of the following statements is true?
(a) The two genes must be transcribed into RNA using the same strand of DNA.
(b) If gene A is transcribed in a cell, gene B cannot be transcribed.
(c) Gene A and gene B can be transcribed at different rates, producing different
amounts of RNA within the same cell.
(d) If gene A is transcribed in a cell, gene B must be transcribed.
ribonucleotide will attach in an RNA molecule is pointed to by arrow.
(a) 1.
(b) 3.
(c) 4.
(d) 5.
bacterial cell?
(a) a decrease in the amount of sigma factor
(b) a decrease in the amount of RNA polymerase
(c) a mutation that introduced a stop codon into the DNA that precedes the
gene’s coding sequence
(d) a mutation that introduced extensive sequence changes into the DNA that
precedes the gene’s transcription start site
several forms of mRNA in various cell types, three of which are shown in Figure B
below. The lines connecting the exons that are included in the mRNA indicate the
splicing. From your experiments, you know that protein translation begins in exon 1.
For all forms of the mRNA, the encoded protein sequence is the same in the regions of
the mRNA that correspond to exons 1 and 10. Exons 2 and 3 are alternative exons
used in different mRNA, as are exons 7 and 8. Which of the following statements
about exons 2 and 3 is the most accurate?
(a) Exons 2 and 3 must have the same
number of nucleotides.
(b) Exons 2 and 3 must contain an integral
number of codons (that is, the number of
nucleotides divided by 3 must be an
integer).
(c) Exons 2 and 3 must contain a number of
nucleotides that when divided by 3, leaves
the same remainder (that is, 0, 1, or 2).
(d) Exons 2 and 3 must have different
numbers of nucleotides.
(a) protein
(b) DNA
(c) RNA
(d) all came to be at the same time
DNA is altered irreversibly during development. Which of the following
statements about these experiments is true?
(a) Because the donor nucleus is taken from an adult animal, the chromosomes
from the nucleus must undergo recombination with the DNA in the egg for
successful development to occur.
(b) The embryo that develops from the nuclear transplant experiment is
genetically identical to the donor of the nucleus.
(c) The meiotic spindle of the egg must interact with the chromosomes of the
injected nuclei for successful nuclear transplantation to occur.
(d) Although nuclear transplantation has been successful in producing embryos in
some mammals with the use of foster mothers, evidence of DNA alterations
during differentiation has not been obtained for plants.
(a) Transcriptional regulators usually interact with the sugar–phosphate backbone
on the outside of the double helix to determine where to bind on the DNA
helix.
(b) Transcriptional regulators will form hydrogen bonds, ionic bonds, and
hydrophobic interactions with DNA.
(c) The DNA-binding motifs of transcriptional regulators usually bind in the major
groove of the DNA helix.
(d) The binding of transcriptional regulators generally does not disrupt the
hydrogen bonds that hold the double helix together.
Note: Questions 33 to 34 use the following information and the data in the figure
below.
You are interested in understanding the gene regulation of Lkp1, a protein that is
normally produced in liver and kidney cells in mice. Interestingly, you find that
the LKP1 gene is not expressed in heart cells. You isolate the DNA upstream of the
LKP1 gene, place it upstream of the gene for green fluorescent protein (GFP), and
insert this entire piece of recombinant DNA into mice. You find GFP expressed in
liver and kidney cells but not in heart cells, an expression pattern similar to the
normal expression of the LKP1 gene. Further experiments demonstrate that there
are three regions in the promoter, labeled A, B, and C in the figure below, that
contribute to this expression pattern. Assume that a single and unique
transcription factor binds each site such that protein X binds site A, protein Y
binds site B, and protein Z binds site C. You want to determine which region is
responsible for tissue-‐specific expression, and create mutations in the promoter
to determine the function of each of these regions. In the figure below, if the site is
missing, it is mutated such that it cannot bind its corresponding transcription
factor.
(a) factor X
(b) factor Y
(c) factor Z
(d) none of the above
(a) factors X and Y
(b) factors X and Z
(c) factors Y and Z
(d) factor X only
(a) do not code for proteins.
(b) act in the nucleus.
(c) are packaged with other proteins to form RISC.
(d) form base pairs with mRNA molecules.
(a) Pseudogenes code for microRNAs.
(b) Pseudogenes share significant nucleotide similarity with functional genes.
(c) Pseudogenes are no longer expressed in the cell.
(d) There are estimated to be approximately 20,000 pseudogenes in the human
genome.
(a) For protein-coding genes, homologous genes will show more similarity in
their amino acid sequences than in their nucleotide sequences.
(b) Fewer than 1% of human genes have homologs in the nematode and the fruit fly.
(c) Most homologous genes arose by gene duplication.
(d) A gene in humans that has homologs in plants and prokaryotes will show the
same level of similarity in nucleotide sequence when the human and prokaryotic
sequences are compared as when the human and chimpanzee sequences are
compared.
(a) About 50% of the human genome is made up of mobile genetic elements.
(b) More of the human genome comprises intron sequences than exon sequences.
(c) About 1.5% of the human genome codes for exons.
(d) Only the exons are conserved between the genomes of humans and other
mammals.
XhoI and SmaI, as indicated in the figure below.
If you were to cut this circular piece of DNA with both XhoI and SmaI, how many
fragments of DNA would you end up with?
(a) 1
(b) 2
(c) 3
(d) 4
heating it to 90°C because.
(a) heat disrupts the hydrogen bonds holding the sugar–phosphate backbone together.
(b) DNA is negatively charged.
(c) heat disrupts hydrogen-bonding between complementary nucleotides.
(d) DNA is positively charged.
discovered a brand-‐new virus that has recently been introduced into the human
population. She has just developed a new assay that allows her to detect the virus
by using PCR products made from the blood of infected patients. The assay uses
primers in the PCR assay that hybridize to sequences in the viral genome.
Your friend is distraught because of the result she obtained (see Figure below)
when she looked at PCR products made using the blood of three patients suffering
from the viral disease, using her own blood, and using a leaf from her petunia
plant.
You advise your friend not to panic, as you believe she is missing an important
control. Which one of the choices listed below is the best control for clarifying the
results of her assay? Explain your answer.
(a) a PCR assay using blood from a patient who is newly infected but does
not yet show symptoms
(b) a PCR assay using blood from a dog
(c) a PCR assay using blood from an uninfected person
(d) repeating the experiments she has already done with a new tube of polymerase
(a) They cannot be incorporated into DNA by DNA polymerase.
(b) They are incorporated into DNA particularly well by DNA polymerases from
thermophilic bacteria.
(c) Incorporation of a dideoxyribonucleoside triphosphate leads to the termination
of replication for that strand.
(d) Dideoxyribonucleoside triphosphates are more stable than deoxyribonucleoside
triphosphates.
(a) phospholipids
(b) glycolipids
(c) sterols
(d) triacylglycerides
(a) at the Golgi apparatus
(b) at the endoplasmic reticulum
(c) at the plasma membrane
(d) in the mitochondria
(e) on ribosomes
cells, illustrated in the figure below. Which type of defect described below is the
most likely to cause the redistribution of that protein around the entire cell,
shown in the figure below?
(a) a nonfunctional protein glycosylase
(b) the deletion of a junctional protein
(c) the truncation of a protein found in the extracellular matrix
(d) a nonfunctional flippase
(a) Gene amplification of a tumor suppressor gene is less dangerous than gene
amplification of a proto-oncogene.
(b) Cells with one functional copy of a tumor suppressor gene will usually
proliferate faster than normal cells.
(c) Inactivation of tumor suppressor genes leads to enhanced cell survival and
proliferation.
(d) Individuals with only one functional copy of a tumor suppressor gene are
more prone to cancer than individuals with two functional copies of a
tumor suppressor gene.
(a) a secondary tumor in a different part of the body that arises from a cell
from the primary tumor.
(b) a cell that is dividing in defiance of normal constraints.
(c) a part of the primary tumor that has invaded the surrounding tissue.
(d) the portion of the cancerous tumor that displays genetic instability.
adult cell into a cell with the properties of ES cells.
(a) chromosomes
(b) viruses
(c) hormones
(d) transcription factors
to
(a) the female who donated the egg.
(b) the adult who donated the cell for nuclear transplantation.
(c) both the female who donated the egg and the adult who donated the
cell for nuclear transplantation.
(d) the foster mother in which the embryo is placed.
(a) The DNA in the nucleus of cells produced for therapeutic cloning is
genetically identical to the donor genome, whereas in cells produced for
reproductive cloning it is not.
(b) Reproductive cloning requires a supply of fertilized donor egg cells,
whereas therapeutic cloning requires unfertilized egg cells.
(c) Therapeutic cloning requires nuclear transplantation, whereas reproductive
cloning does not.
(d) Embryos are placed into foster mothers during reproductive cloning but not
during therapeutic cloning.
(a) can only be produced in the laboratory.
(b) can give rise to all the tissues and cell types in the body.
(c) can only give rise to stem cells.
(d) is considered to be terminally differentiated.
in the body by a stock of.
(a) proliferating precursor cells.
(b) cells more apically located than the terminally differentiated cells.
(c) Wnt proteins.
(d) induced pluripotent cells.
(a) adherens junctions
(b) desmosomes
(c) tight junctions
(d) gap junctions
(a) allow small, water-soluble molecules to pass from cell to cell.
(b) interact with the intermediate filaments inside the cell.
(c) are formed from claudins and occludins.
(d) are found in cells in connective tissues.
to produce two three-carbon molecules (dihydroxyacetone phosphate and
glyceraldehyde 3-phosphate). Which enzyme catalyzes this reaction?
(a) aldolase
(b) phosphoglucose isomerase
(c) enolase
(d) triose phosphate isomerase
and metabolic pathways, which makes it a central hub in the regulation of
cellular metabolism. Which of the following molecules is not made from
pyruvate?
(a) oxaloacetate
(b) ethanol
(c) lactate
(d) NADH
membrane-dependent fashion.
A. True
B. False
purify the RNAs attached to it. Which of the following proteins do you expect the
RNA from the rough endoplasmic reticulum to encode?
(a) soluble secreted proteins
(b) ER membrane proteins
(c) plasma membrane proteins
(d) all of the above
cell recognition. Your friend discovered a transmembrane glycoprotein, GP1, on a
pathogenic yeast cell that is recognized by human immune cells. He decides to purify
large amounts of GP1 by expressing it in bacteria. To his purified protein he then adds
a branched 14-sugar oligosaccharide to the asparagine of the only Asn-X-Ser sequence
found on GP1 (Figure Q15-48). Unfortunately, immune cells do not seem to recognize
this synthesized glycoprotein. Which of the following statements is a likely
explanation for this problem?
Figure Q15-48
(a) The oligosaccharide should have been added to the serine instead of the
asparagine.
(b) The oligosaccharide should have been added one sugar at a time.
(c) The oligosaccharide needs to be further modified before it is mature.
(d) The oligosaccharide needs a disulfide bond.
(a) The membrane of a secretory vesicle will fuse with the plasma membrane
when it discharges its contents to the cell’s exterior.
(b) Vesicles for regulated exocytosis will not bud off the trans Golgi