BIOL-1703 Exam 2
An incoming aminoacyl-tRNA carrying the next amino acid in the chain will bind to the ______-site by forming base pairs with the exposed codon in the mRNA
A-site
During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level?
FADH2
Which of the following describe the sequence of electron carriers in the electron transport chain, starting with the last electronegative?
FMN, Fe.S, ubiquinone, cytochromes (Cyt)
Which of the following is NOT involved in post-transcriptional control?
Mediator
Which of the following changes is least likely to arise from a point mutation in a regulatory region of a gene?
a mutation that changes the sub cellular localization of a protein
Operons ________________.
contain a cluster of genes transcribed as a single mRNA
A protein acquires a DNA binding domain.
exon shuffling
If you were to observe the activity of the methylated DNA, you would expect it to
have turned off or slowed down the process of transcription
What type of bonding is responsible for maintaining the shape of the tRNA molecule?
hydrogen bonding between base pairs
Which of the following statements about what we have learned by comparing the modern-day human genome is true?
modern humans whose ancestors come from Europe or Asia share up to 4 percent of their genome with Neanderthals
During oxidative phosphorylation, H2O is formed. Where does the oxygen for the synthesis of the water come from?
molecular oxygen
In humans and in chimpanzees, 99% of the Alu retrotransposons are in corresponding positions. Which of the following statements below is the most likely explanation for this similarity?
most of the Alu sequences in the chimpanzee genome underwent duplication and divergence before humans and chimpanzees diverged
In humans and in chimpanzees, 99% of the Aluminums retrotransposons are in corresponding positions. Which of the following statements below is the most likely explanation for this similarity?
most of the Alu sequences in the chimpanzee genome underwent duplication and divergence before humans and chimpanzees diverged
Which of the following is not true of cell communication systems?
most signal receptors are bound to the outer membrane of the nuclear envelope
A protein normally expressed only in the liver is now expressed
mutation in a regulatory region
What is the function of topoisomerase?
relieving strain in the DNA ahead of the replication fork
Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight because their cells have an impaired ability to
repair thymine dimers
What is the name given to viruses that are single-stranded RNA that acts as a template for DNA synthesis?
retroviruses
Second-generation sequencing differs from Sanger sequencing because __________.
second-generation sequencing does not depend on chain-terminator ddNTPs
Which of the following help to hold the DNA strands apart while they are being replicated?
single-strand binding proteins
DNA polymerases are processive. Which piece of machinery account for this characteristic?
sliding clamp
Transcription of the structural genes in a inducible operon
starts when the pathway's substrate is present
Transcription of the structural genes in an inducible operon
starts when the pathway's substrate is present
The ATP made during glycolysis is generated by
substrate-level phosphorylation
What is the primary function of the Calvin cycle?
synthesize simple sugars from carbon dioxide
In the structural organization of many eukaryotic genes, individual exons may be related to which of the following?
the various domains of the polypeptide product
The modular nature of the Eve gene's regulatory region means that ______.
there are seven regulatory elements and each element is sufficient for driving expression in a single stripe
The modular nature of the Eve gene's regulatory region means that ___________.
there are seven regulatory elements and each element is sufficient for driving expression in a single stripe.
Which of the following statements is true concerning catabolic pathways?
they are usually coupled with anabolic pathways to which they supply energy in the form of ATP
Which is true of transcription factors?
they control which genes are turned on to form mRNA
The distinct characteristics of different cell types in a multicellular organism result mainly from the differential regulation of the _________________.
transcription of genes transcribed by RNA polymerase II
The distinct characteristics of different cell types in a multicellular organism result mainly from the differential regulation of the _________.
transcription of genes transcribed by RNA polymerase II.
Which of the following statements about transcriptional regulators is FALSE?
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
DNA can be introduced into bacteria by a mechanism called
transformation
DNA can be introduced into bacteria by a mechanism called ___________.
transformation
During gel electrophoresis, DNA fragments _____________.
travel through a matrix containing a microscopic network of pores
Bacterial mRNAs tend to be polycistronic whereas eukaryotic mRNAs do not (T/F)
true
Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with
two nuclei
A eukaryotic cell lacking telomerase would
undergo a reduction in chromosome length
Which of the following statements about how fruit flies can develop an eye in the middle of the leg is TRUE?
when the Ey gene is introduced into cells that would normally give rise to a leg, the transcription regulators used to control its expression in the leg are different from those that are normally used to control Ey expression in the eye
The extent of complementarity of a miRNA with it target mRNA determines _____________.
whether the mRNA will be immediately degraded or whether the mRNA will first be transported elsewhere in the cell before degradation
Starting with one molecule of glucose, the "net" products of glycolysis are
2'NADH, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O
The instructions specified by the DNA will ultimately specify the sequence of proteins. This process involves DNA, made up of ____ different nucleotides, which is then _________________ into RNA, which is then _________________ into proteins, made up of _____ different amino acids. In eukaryotic cells, DNA gets made into RNA in the __________, while proteins are produced from the RNA in the _____________. The segment of DNA called a _____ is the portion that is copied into RNA; this process is catalyzed by RNA __________.
4 transcribed translated 20 nucleus cytoplasm gene polymerase
Homologous recombination in which organisms use a "backup" copy of the DNA as a template to fix double-strand breaks without loss of genetic information. Which of the following is NOT necessary for homologous recombination to occur?
5' DNA strand overhangs
You have a piece of DNA that includes the following sequence: 5'-ATAGGCATTCGATCCGGATAGCAT-3' 3'-TATCCGTAAGCTAGGCCTATCGTA-5' Which of the following RNA molecules could have been transcribed from this piece of DNA?
5'-AUAGGCAUUCGAUCCGGAUAGCAU-3'
Below is the sequence from the 3′ end of an mRNA. 5′-CCGUUACCAGGCCUCAUUAUUGGUAACGGAAAAAAAAAAAAAA-3′ If you were told that this sequence contains the stop codon for the protein encoded by this mRNA, what is the anticodon on the tRNA in the P site of the ribosome when release factor binds to the A site?
5'-CCA-3'
Below is the sequence from the 3′ end of an mRNA. 5′-CCGUUACCAGGCCUCAUUAUUGGUAACGGAAAAAAAAAAAAAA-3′ If you were told that this sequence contains the stop codon for the protein encoded by this mRNA, what is the anticodon on the tRNA in the P site of the ribosome when release factor binds to the A site?
5'-CCA-3'
An incoming aminoacyl-tRNA carrying the next amino acid in the chain will bind to the __________________ site by forming base pairs with the exposed codon in the mRNA.
A
Which of the following is a major distinction between a transposon and a retrotransposon?
A transposon moves via a DNA intermediate and a retrotransposon via an RNA intermediate
Which enzyme catalyzes the elongation of a DNA strand in the 5' to 3' direction?
DNA polymerase
DNA ligase is an enzyme used when making recombinant DNA molecules in the lab. In what normal cellular process is DNA ligase involved?
DNA replication
Which of the following statements is NOT true? (a) Thymine dimers can cause the DNA replication machinery to stall (b) Thymine dimers are covalent links between thymidine on opposite DNA strands (c) Prolonged exposure to sunlight causes thymine dimers to form (d) Repair proteins recognize thymine dimers as a distortion in the DNA backbone
(b) Thymine dimers are covalent links between thymidine on opposite DNA strands
Which of the following statements below is the best explanation of why MyoD can cause fibroblasts to express muscle-specific genes?
During their developmental history, fibroblasts have accumulated some transcriptional regulators in common with differentiation muscle cells
The events listed below are all necessary for homologous recombination to occur 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 What is the correct order of events during homologous recombination?
E,F,B,C,D,A
The pufferfish, Fugu rubripes, has a genome that is one-tenth the size of mammalian genomes. Which of the following statements is not a possible reason for this size difference?
Fugu has lost many genes that are part of gene families
When glucose monomers are joined together by glycosidic linkages to form a cellulose polymer, the changes in free energy, total energy, and entropy are as follows:
+deltaG, +deltaH, -deltaS
A single transcription regulator, if expressed in the appropriate precursor cell, can trigger the formation of a specialized cell type or even an entire organ. (T/F)
True
Which of the following statements is false?
Unlike DNA, RNA uses a uracil base and a deoxyribose sugar
Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?
a deletion of 2 nucleotides
Which statement is not correct with regard to redox (oxidation-reduction) reactions?
a molecule is reduced if it loses electrons
You discover that the underlying cause of disease is a protein that is now less stable than the non-disease-causing version of the protein. This change is most likely to be due to ___________.
a mutation within a gene
What additional mark is there on eukaryotic DNA to indicate which strand needs to be repaired?
a nick in the new strand
What is a chromatid?
a replicated chromosome
Which of the following statements is true regarding enzyme cooperativity?
a substrate molecule bound to an active site affects the active site of several subunits
Which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of carbon (CO2) from one molecule of pyruvate?
acetyl CoA
The MPF protein complex turns itself off by
activating a process that destroys cyclin
How can one increase the rate of a chemical reaction?
add a catalyst
Which of the following generalities about genomes is true?
all vertebrate genomes contain roughly the same number of genes
The number of distinct protein species found in humans and other organisms can vastly exceed the number of genes. This is largely due to ______________.
alternative splicing
A series of enzymes catalyze the reaction X → Y → Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. Substance A functions as
an allosteric inhibitor
Which of the following organisms does not reproduce cells by mitosis and cytokinesis?
bacterium
Which of the following statements about gene families is false?
because gene duplication can occur when crossover events occur, genes are always duplicated onto homologous chromosomes
Testosterone functions inside a cell by
binding with a receptor protein that enters the nucleus and activates specific genes
The tryptophan operator ________.
binds to the tryptophan repressor when the repressor is bound to tryptophan
The tryptophan operator__________.
binds to the tryptophan repressor when the repressor is bound to tryptophan
How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?
by changing the structure of the enzyme
How are most eukaryotic transcription regulators able to affect transcription when their binding sites are far from the promoter?
by looping out the intervening DNA between their binding site and the promoter
Membrane receptors that attach phosphates to specific amino acids in proteins are
called receptor tyrosine-kinases
Alternative RNA splicing
can allow the production of proteins of different sizes from a single mRNA
alternative RNA splicing
can allow the production of proteins of different sizes from a single mRNA
mRNAs _____________.
can bind to specific sequences at intron-exon boundaries through complementary base-pairing
snRNAs ________________.
can bind to specific sequences at intron-exon boundaries through complementary base-pairing.
When 10,000 molecules of ATP are hydrolyzed to ADP and Pi in a test tube, about twice as much heat is liberated as when a cell hydrolyzes the same amount of ATP. Which of the following is the best explanation for this observation?
cells convert some of the energy of ATP hydrolysis into other forms of energy besides heat
All of the following occur during prophase of mitosis in animal cells except
chromosomes are duplicated
ATP generally energizes a cellular process by
coupling free energy released by ATP hydrolysis to free energy needed by other reactions
Where does glycolysis take place?
cytosol
The MyoD transcriptional regulator is normally found in differentiating muscle cells and participates in the transcription of genes that produce muscle-specific proteins, such as those needed in contractile tissue. Amazingly, expression of MyoD in fibroblasts causes these cells derived from skin connective tissue to produce proteins normally only seen in muscles. However, some other cell types do not transcribe muscle-specific genes when MyoD is expressed in them. Which of the following statements below is the best explanation of why MyoD can cause fibroblasts to express muscle specific genes?
during their developmental history, fibroblasts have accumulated some transcriptional regulators in common with differentiating muscle cells
DNA replication is considered semiconservative because ___________
each daughter DNA molecule consists of one strand from the parent DNA molecule and one new strand
Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy?
electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher affinity for electrons (such as O)
Sutherland discovered that epinephrine
elevates the cytosolic concentration of cyclic AMP.
To repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act?
endonuclease, DNA polymerase, DNA ligase
Genomic imprinting, DNA methylation, and histone acetylation are all examples of
epigenetic phenomena
During transcription in ____________ cells, transcriptional regulators that bind to DNA thousands of nucleotides away from agent's promoter can affect a gene's transcription. The __________ is a complex of proteins that links distantly bound transcription regulators with the proteins bound close to the transcriptional start site. Transcriptional activators can also interact with histone ________s, which. alter chromatin by modifying lysines in the tail of histone proteins to allow grater accessibility to the underlying DNA. Gene repressor proteins can reduce the efficiency of transcription initiation by attracting histone __________s. Sometimes, many continuous genes can become transcriptionally inactive as a result of chromatin remodeling, like the __________________ found in interphase chromosomes.
eukaryotic mediator acetylase deactylase heterochromatin
Which of the following processes is not thought to contribute to diversity in the genome of human individuals?
exon shuffling
Bacterial mRNAs have 5'-Caps whereas eukaryotic mRNAs do not
false
Which of the following organic molecules cannot be converted to an intermediate of glycolysis?
fatty acids
Which of the following statements about RNA splicing is false?
for a gene to function properly, every exon must be removed from the primary transcript in the same fashion on every mRNA molecule produce from the same gene
Which of the following statements about RNA splicing is FALSE?
for a gene to function properly, every exon must be removed from the primary transcript in the same fashion on every mRNA molecule produced from the same gene
Which of the following statements about homologous genes is true?
for protein-coding genes, homologous genes will show more similarity in their amino acid sequence than in their nucleotide sequences
Eukaryotic telomeres replicated differently than the rest of the chromosome. This is a consequence of which of the following?
gaps left at the 5' end of the lagging stand because of the need for a 3'end onto which nucleotides can attach
Consider the two eukaryotic genes that are next to each other on a chromosome, as shown below. Which of the following statements is true?
gene A and gene B can be transcribed into RNA using the same strand of DNA
Tandem copies of a gene are found in the genome
gene duplication
Which metabolic pathway is common to both cellular respiration and fermentation?
glycolysis
In the thylakoid membranes, what is the main role of the antenna pigment molecules?
harvest photons and transfer light energy to the reaction-center chlorophyll
A double stranded DNA molecule can be separated into single strands by heating it to 90 degrees because __________.
heat disrupts hydrogen-bonding between complementary nucleotides
Which of the following separates the NA strands during replication?
helicase
A copy of a bacterial gene is now found integrated on a human chromosome
horizontal gene transfer
You isolate a pathogenic strain of E. coli from a patient and discover that this E. coli strain is resistant to an antibiotic. Common laboratory strains of E. coli are not resistant to this antibiotic, nor are any other previously isolated pathogenic E. coli strains. However, such resistance has been observed in other bacteria in the hospital in which the patient was treated. This newly discovered antibiotic resistance in E. coli is most likely due to _______.
horizontal gene transfer
Which of the following statements about iPS cells is false?
iPS cells created from mouse cells can differentiate into almost any human cell type
Which of the following techniques is not appropriate if you want to examine the transciptome of a specific tissue?
in situ hybridization
Why are dideoxyribonucleoside triphosphates used during DNA sequencing?
incorporation of dideoxyribonucleoside triphosphate leads to the termination of replication for that strand
What part of the DNA replication process would be most directly affected in a strain of bacteria with a mutant primase?
initiation of DNA synthesis
Combinational control of gene expression ____________
involves groups of transcriptional regulators working together to determine the expression of a gene
Combinatorial control of gene expression
involves groups of transcriptional regulators working together to determine the expression of a gene
Combinatorial control of gene expression ____________.
involves groups of transcriptional regulators working together to determine the expression of a gene
Combinatorial control of gene expression _______________
involves groups of transcriptional regulators working together to determine the expression of a gene
Which of the following is true of a retrovirus but not of the Alu retrotransposon?
it encodes its own reverse transcriptase
Phosphofructokinase is an important control enzyme in the regulation of cellular respiration. Which of the following statements concerning phosphofructokinase is not true?
it is activated by AMP (derived from ATP)
Which of the following describes the function of an enzyme known as Dicer?
it trims small double-stranded RNAs into molecules that can block translation
You have discovered an "Exo" mutant form of DNA polymerase in which 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?
it will be more likely to generate mismatched base pairs
Muscle cells in oxygen deprivation convert pyruvate to ________, and in this step gain ________.
lactate; NADH+
You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). These two classes of DNA probably represent
leading strands and Okazaki fragments
Which of the following covalently connects segments of DNA?
ligase
Total nucleic acids are extracted from a culture of yeast cells and are then mixed with resin beads to which the polynucleotide 5′-TTTTTTTTTTTTTTTTTTTTTTTTT-3′ has been covalently attached. After a short incubation, the beads are then extracted from the mixture. When you analyze the cellular nucleic acids that have stuck to the beads, which of the following is most abundant?
mRNA
The ______ is a complex of proteins that links distantly bound transcription regulators with the proteins bound closer to the transcriptional start site.
mediator
In addition to the repair of DNA double-strand breaks, homologous recombination is a mechanism for generating genetic diversity by swapping segments of parental chromosomes. During which process does swapping occur?
meiosis
If cells in the process of dividing are subjected to colchicine, a drug that interferes with the formation of the spindle apparatus, at which stage will mitosis be arrested?
metaphase
Cytoskeletal elements play important roles in cell division. The mitotic spindle apparatus is made of _____ and pulls sister chromatids apart, whereas the contractile ring is made of ______ and required for the separation of daughter cells at the end of the mitotic phase of the cell cycle.
microtubules; actin microfilaments
Alternative exons can arise through the duplication and divergence of existing exons. What type of mutation below would be least tolerated during the evolution of a new exon?
mutation of the first nucleotide in the intron
A protein becomes much more unstable
mutation within a gene
A protein normally localized in the nucleus is now localized in the cytoplasm.
mutation within a gene
In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation?
no replication fork will be formed
In E. coli, these is a mutation in a gene called dnaB that alters the helices that normally acts at the origin. Which of the following would you expect as a result of this mutation?
no replication fork will be formed
Transcription is similar to DNA replication in that
nucleotide polymerization occurs only in the 5'-to-3' direction
The genes of a bacterial _____ are transcribed into a single mRNA. Many bacterial promoters contain a region known as a(n) ___________, to which a specific transcription regulator binds. Genes in which transcription is prevented are said to be ________. The interaction of small molecules, such as tryptophan, with ________ DNA-binding proteins, such as the tryptophan repressor, regulates bacterial genes. Genes that are being ___________ expressed are being transcribed all the time.
operon operator repressed allosteric constitutively
When a cell releases a signal molecule into the environment and a number of cells in the immediate vicinity respond, this type of signaling is
paracrine signaling
The ________ enzyme catalyzes the formation of a new peptide bond between the growing polypeptide chain and the newly arriving amino acid
peptidyl transferase
An inhibitor of phosphodiesterase activity would have which of the following effects?
prolong the effect of epinephrine by maintaining elevated cAMP levels in the cytoplasm
Which of the following describes a feature found in bacterial expression vectors but not in cloning vectors?
promoter DNA sequences
Which of the following is not a general mechanism that cells use to maintain stable patterns of gene expression as cells divide?
proper segregation of housekeeping proteins when cells divide
The correct sequence of steps in the M phase of the cell cycle is
prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis
Which of the following statements about pseudogenes is false?
pseudogenes code for microRNAs
Which of the following statements is true?
rRNA contains the catalytic activity that joins amino acids together
Which of the following would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins?
receptor tyrosine kinase activity
The sigma subunit of bacterial RNA polymerase ___________________.
recognizes transcription termination sites in the DNA
What is the function of topoiso...
relieving strain in the DNA ahead of the replication fork
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
saturation of the enzyme activity
In eukaryotes, but not in prokaryotes, ribosomes find the start site of translation by _____________.
scanning along the mRNA from the 5' end
Which of the following statements about the Ey transcriptional regulator is false?
the Ey transcription factor must bind to the promoter of every eye-specific gene in the fly
What do you predict would happen if you replaced the Lac operator DNA from the Lac operon with the DNA from the operator region from the tryptophan operon?
the Lac operon will not be transcribed when tryptophan levels are high
What do you predict would happen if you replace the Lac operator DNA from the Lac operon with the DNA from the operator region from the tryptophan operon?
the Lac operons will not be transcribed when tryptophan levels are high
A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because ________.
the activation energy barrier for this reaction cannot be surmounted
A particular cyclin called cyclin E forms a complex with a cyclin-dependent kinase called Cdk 2. This complex is important for the progression of the cell from G, into the past of the cell cycle. Which of the following statements is correct?
the amount of cyclin E is highest during G1.
You have a segment of DNA that contains the following sequence: 5′-GGACTAGACAATAGGGACCTAGAGATTCCGAAA-3′ 3′-CCTGATCTGTTATCCCTGGATCTCTAAGGCTTT-5′ You know that the RNA transcribed from this segment contains the following sequence: 5′-GGACUAGACAAUAGGGACCUAGAGAUUCCGAAA-3′ Which of the following choices best describes how transcription occurs?
the bottom strand is the the template strand; RNA polymerase moves along this strand from 3' to 5'
The figure below shows the nucleotide sequence from a protein-coding region of a gene in humans, chimpanzees, and gorillas and the protein sequence produced from this gene. The seventeen amino acids encoded by this DNA are numbered below. The two codons that are not conserved in all three species have been boxed. These two codons code for amino acids 3 and 15. Which of these statements is consistent with these sequence-comparison data?
the chimp DNA sequence has likely diverged at the DNA coding for amino acid 15 from the sequence found in the last common ancestor of humans and chimps.
You are studying a set of mouse genes whose expression increases when cells are exposed to hormonal cortisol, and you believe that the same cortisol-responsive transcriptional activator regulates all of these genes. Which of the following statements below should be true if your hypothesis is correct?
the cortisol-responsive genes share a DNA sequence in their regulatory regions that binds the cortisol-responsive transcriptional activator
The concentration of a particular protein X in a normal human cell rises gradually from a low point, immediately after cell division, to a high point, just before cell division, and then drops sharply. The level of its mRNA in the cell remains fairly constant throughout this time. Protein X is required for cell growth and survival, but the drop in its level just before cell division is essential for division to proceed. You have isolated a line of human cells that grow in size in culture but cannot divide, and on analyzing these mutants, you find that levels X in mRNA in the mutant cells are normal. Which of the following mutations in the gene for X could explain these results?
the deletion of a sequence that encodes sites at which ubiquitin can be attached to the protein
The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation is
the difference in H+ concentrations on opposite sides of the inner mitochondrial membrane
The owners of a local bakery ask for your help in improving a special yeast strain they use to make bread. They would like you to help them design experiments using RNA interference to turn off genes, to allow them to test their hypothesis that certain genes are important for the good flavors found in their bread. Of the components in the following lost, which is the most important to check for in this yeast strain if you'd like this project to succeed?
the presence of genes in the genome that code for RISC proteins
Nonhomologous end joining can result in all but which of the following?
the recovery of lost nucleotides on a damaged DNA strand
Which of the following does not occur before a eukaryotic mRNA is exported from the nucleus?
the ribosome binds to the mRNA
In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from
the storm to the thylakoid space
Which one of the following is the main reason that a typical eukaryotic gene is able to respond to a far greater variety of regulatory signals than a typical prokaryotic gene or operon?
the transcription of a eukaryotic gene can be influenced by proteins that bind far from the promoter
In the structural organization of many eukaryotic genes, individual eons may be related to which of the following?
the various domains of the polypeptide product
HIV is a human retrovirus that integrates into the host cell's genome and will eventually replicate, produce viral proteins, and ultimately escape the host cell. Which of the following proteins is not encoded in the HIV genome?
RNA polymerase
Which of the following is true for both prokaryotic and eukaryotic gene expression?
RNA polymerase binds to the promoter region to begin transcription
Ribozymes catalyze which of the following reactions?
RNA splicing
Which of the following functions do you not expect to find in the set of genes found in all organisms on Earth?
RNA splicing
Viral genomes ___________.
Composed of DNA or RNA, Single or Double stranded, (All answers above are true)
Which of the following statements about the human genome is false?
Only the exons are conserved between the genomes of humans and other mammals
What are the products of noncyclic photophosphorylation?
ATP and NADPH
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
ATP and NADPH
Allolactose induces the synthesis of the enzyme lactase. An E. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source. Which of the following occurs when the lactose enters the cell?
Allolactose binds to the repressor protein
Alu elements account for about 11% of the human genome. Which of the following is true about Alu sequences?
Alu elements represent the result of retrotransposition
Which of the following describes the lac operon in E. coli when lactose, but not glucose, is present in the culture medium?
CAP, but the lac repressor is not bound to the lac operon's regulatory DNA, and the lac operon is expressed
How does active CAP induce expression of the genes of the lactose operon?
It stimulates the binding of RNA polymerase to the promoter
The yeast genome was sequenced more than 15 years ago, yet the total number of genes continues to be refine. The sequencing of closely related yeast species was important for validating the identity of short (less than 100 nucleotides long) open reading frames (ORFs) that were otherwise difficult to predict. What is the main reason that these short ORFs are hard to find without the genomes of other yeast for comparison?
Many short stretches of DNA may lack a stop codon simply by chance, making it difficult to distinguish those DNA sequences that code for proteins from those that do not
You have purified DNA from your recently deceased goldfish. Which of the following restriction nucleases would you use if you wanted to end up with DNA fragments with an average size of 70 kilobase pairs (kb) after complete digestion of the DNA? The recognition sequence for each enzyme is indicated in the right-hand column.
Notl GCGGCCGC
The graph above shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?
Other pigments absorb light in addition to chlorophyll a
You are interested in studying the transcriptional regulation of the Gip1 promoter. The Gip1 promoter contains a binding site for the Jk8 protein that overlaps with the binding site for the Pa5 protein. Jk8 and Pa5 cannot bind DNA at the sane time, but both proteins are present at high levels in adult liver cells. Charts You know that Gip1 is only expressed in adult liver cells and not in the liver of embryos.... Given the data, use of which of the following mechanisms would make the most sense for regulating the Jk8 and Pa5 proteins.
Pa5 binds to the promoter of the gene that encodes Jk8 in embryonic liver cells
MicroRNAs are noncoding RNAs that are incorporated into a protein complex called __________________, which searches the __________________s in the cytoplasm for sequence complementary to that of the miRNA. When such a molecule is found, it is then targeted for __________________. RNAi is triggered by the presence of foreign __________________ molecules, which are digested by the __________________ enzyme into shorter fragments approximately 23 nucleotide pairs in length.
RISC mRNA destruction double-stranded dicer
Which of the following molecules is thought to have arisen first during evolution?
RNA
You are studying a disease that is caused by a virus, but when you purify the virus particles and analyze them you find they contain no trace of DNA. Which of the following molecules are likely to contain the genetic information of the virus?
RNA
Unlike DNA, which typically forms a helical structure, different molecules of RNA can fold into a variety of three-dimensional shapes. This is largely because ___________________.
RNA is single-stranded
Which of the following statements about the goblin gene family is true?
Some of the duplicated goblin genes that arose during vertebrate evolution acquired inactivating mutation and became pseudogenes in modern vertebrates
In eukaryotic cells, general transcription factors required for the activity of all promoters transcribed by RNA polymerase II. The assembly of the general transcription factors begins with the binding of the factor _____ to DNA, caused a marked local distortion in the DNA. This factor binds at the DNA sequence called the ____ box, which is typically located 25 nucleotides upstream from the transcription start site. Once RNA polymerase II has been brought to the promoter DNA, it must be released to begin making transcripts. This release process is facilitated by the addition of phosphate groups to the tail of RNA polymerase by the factor _____. It must be remembered that the general transcription factors and RNA polymerase are not sufficient to initiate transcription in the cell and are affected by proteins bound thousands of nucleotides away from the promoter. Proteins that link the distantly bound transcription regulators to RNA polymerase and the general transcription factors include the large complex proteins called the _________. The packing of DNA into chromatin also affects transcriptional initiation, and histone ____________ is an enzyme that can render the DNA less accessible to the general transcription factors.
TFIID TATA TFIIH Mediator Deacetylase
In eukaryotic cells, general transcription factors are required for the activity of all promoters transcribed by RNA polymerase II. The assembly of the general transcription factors begins with the binding of the factor _______ to DNA, causing a marked local distortion in the DNA. This factor bind at the DNA sequence called the _________ box, which is typically located 25 nucleotides upstream from the transcription start site. Once RNA polymerase I has been brought to the promoter DNA, it must be release to begin making transcripts. This release process if facilitated by the addition of phosphate groups to the tax of RNA polymerase by the factor _____. It must be rememberers that the general transcription factors and RNA polymerase are not sufficient to intitiate transcription in the cell and are affected by proteins bound thousands of nucleotides away from the promoter. Proteins that link the distantly bound transcription regulators to RNA polymerase and the general transcription factors include the large complex of proteins called the _________. The packing of DNA into chromatin also affects transcriptional initiation, and histone ____________ is an enzyme that can render the DNA less accessible to the general transcription factors
TFIID TATA TFIIH mediator deacetylase
Each of the following is a 'mutation' of the sentence THECATATETHERAT. Which of the following is analogous to a frameshift mutation?
THECATATTHERATS
Each of the following options is a 'mutation' of the sentence THECATATETHERAT. Which of the following is analogous to a frameshift mutation?
THECATATTHERATS
Sometimes, chemical damage to DNA can occur just before DNA replication begins, not giving the repair system enough time to correct the error before the DNA is duplicated. This gives rise to mutation. If the cytosine in the sequence TCAT is deaminated and not repaired, which of the following is the point mutation you would observe after this segment has undergone two rounds of DNA replication?
TTAT
The figure below shows the evolutionary history of the goblin gene family members. Given this information, which of the following statements is true?
The fetal B-goblins arose from a gene duplication that occurred 200 million years ago, which gave rise to a B-goblin express in the fetus and a B-gobling expresses in the adult.
The ribosome is important for catalyzing the formation of peptide bonds. Which of the following statements is true?
The catalytic site for peptide bond formation is formed primarily from an rRNA
The expression of the BRF1 gene in mice is normally quite low, but mutations in a gene called BRF2 lead to increased expressions in BRF1. You have a hunch that nucleosomes are involved in the regulation of BRF1 expression and so you investigate the position of nucleosomes over the TATA box of BRF1 in normal mice and in mice that lack either the BRF2 protein or part of histone H4 (HHF). The table new summarizes your results. A normal functional gene is indicated by a plus sign (+). Which of the following conclusions cannot be drawn from your data?
The specific pattern of nucleosome positioning over the BRF1 upstream region is required for BRF1 repression
All of the following statements are correct regarding the Calvin cycle except:
These reactions begin soon after sundown and end before sunrise