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Which of the following descriptions of nucleotide triplets best represents a codon?
A. a triplet in the same reading frame as an upstream AUG
B. a triplet at the opposite end of tRNA from the attachment site of the amino acid
C. a triplet separated spatially from other triplets
D. a triplet that has no corresponding amino acid
A. a triplet in the same reading frame as an upstream AUG
Which of the following statements best describes the termination of transcription in bacteria?
A. RNA polymerase transcribes through an intron, which causes the polymerase to let go of the transcript.
B. RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase.
C. Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the chromosome.
D. RNA polymerase transcribes through
D. RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.
Which of the following statements correctly compares transcription in prokaryotes and eukaryotes?
A. RNA polymerase in both prokaryotes and eukaryotes produce the same RNA molecules.
B. Bacteria have one type of RNA polymerase, whereas eukaryotes have at least three.
C. Prokaryotes have at least three types of RNA polymerases, whereas eukaryotes only have one.
D. Both eukaryotes and prokaryotes recognize a polyadenylation signal in order to terminate transcription.
B. Bacteria have one type of RNA polymerase, whereas eukaryotes have at least three.
Which of the following statements correctly defines the process of gene expression?
A. Gene expression is the process by which proteins direct the synthesis of RNA.
B. Gene expression is the process by which proteins direct the synthesis of DNA.
C. Gene expression is the process by which DNA directs the synthesis of proteins.
D. Gene expression is the process by which RNA direct the synthesis of DNA.
C. Gene expression is the process by which DNA directs the synthesis of proteins.
In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA known as pre-mRNA?
A. RNA polymerase I
B. RNA polymerase III
C. ligase
D. RNA polymerase II
D. RNA polymerase II
A particular triplet of bases in the template strand of DNA is 5'-AGT-3'. The corresponding codon for the mRNA transcribed is
A. 3'-UCA-5'.
B. 5'-TCA-3'.
C. 3'-UGA-5'.
D. 3'-ACU-5'.
A. 3'-UCA-5'.
The nitrogenous base adenine is found in all members of which of the following groups of molecules?
A. glucose, ATP, and DNA
B. proteins, triglycerides, and testosterone
C. proteins, ATP, and DNA
D. ATP, RNA, and DNA
D. ATP, RNA, and DNA
The genetic code is essentially the same for all organisms. Based on this information, one can logically assume which of the following statements to be correct?
A. The same codons in different organisms translate into different amino acids
B. Gene expression differs considerably in different organisms
C. DNA was the first genetic material
D. A gene from an organism can theoretically be expressed by any other organism
D. A gene from an organism can theoretically be expressed by any other organism
Garrod hypothesized that inherited diseases such as alkaptonuria, the inability to metabolize the chemical alkapton, occur because
A. many metabolic enzymes use DNA as a cofactor, and affected individuals have mutations that prevent their enzymes from interacting efficiently with DNA.
B. genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.
C. certain metabolic reactions are carried out by ribozymes, and affected
B. genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.
Which of the following processes only occurs in eukaryotic gene expression?
A. RNA polymerase binds to the promoter.
B. A poly-A tail is added to the 3' end of an mRNA, and a cap is added to the 5' end.
C. mRNA, tRNA, and rRNA are transcribed.
D. Transcription can begin as soon as translation has assembled the first few amino acids in the polypeptide.
B. A poly-A tail is added to the 3' end of an mRNA, and a cap is added to the 5' end.
A eukaryotic mutation upstream of a particular gene has been identified that changes the sequence of the TATA box to GATA. How would you predict that this mutation would affect the transcription of this gene?
A. Transcription factors would bind to the start point in the promoter region.
B. Transcription would proceed normally.
C. Transcription factors would bind in the middle of the gene sequence and transcribe the gene from that point.
D. Transcription factor binding would be reduced or eliminated, and transcription of the gene would decrease dramatically.
D. Transcription factor binding would be reduced or eliminated, and transcription of the gene would decrease dramatically.
Transcription in eukaryotes requires which of the following in addition to RNA polymerase?
A. the protein product of the promoter
B. ribosomes and tRNA
C. start and stop codons
D. several transcription factors
D. several transcription factors
In which direction does RNA polymerase move along the DNA?
A. 3' to 5' along the template strand
B. 5' to 3' along whichever strand it's on
C. 5' to 3' along the template strand
D. 5' to 3' along the double-stranded DNA
A. 3' to 5' along the template strand
Which of the following is a function of a poly-A tail in mRNA?
A. It adds the modified guanine to the 3' end of the mRNA.
B. It is a sequence that codes for the binding of RNA polymerase to the DNA.
C. It indicates the site of translational termination.
D. It helps protect the mRNA from degradation by hydrolytic enzymes.
D. It helps protect the mRNA from degradation by hydrolytic enzymes.
Which of the following statements best describes the function of the TATA box in eukaryotic promoters?
A. It is the recognition site for a specific transcription factor.
B. It signals the end of the nucleotide sequence of the gene.
C. It is the recognition site for ribosomal binding.
D. It sets the reading frame of the mRNA.
A. It is the recognition site for a specific transcription factor.
How do small RNAs in the spliceosome initiate the splicing of the pre-mRNA?
A. by base pairing to the exons on each side of the intron
B. by base pairing to sites on both the intron and nearby exons
C. by binding to the 3'end of the pre-mRNA and removing the poly-A tail
D. by base pairing to specific sites along the intron
D. by base pairing to specific sites along the intron
What is a ribozyme?
A. an enzyme that synthesizes RNA as part of the transcription process
B. an enzyme that uses RNA as a substrate
C. an RNA with enzymatic activity
D. an enzyme that catalyzes the association between the large and small ribosomal subunits
C. an RNA with enzymatic activity
A part of the promoter called the TATA box, is said to be highly conserved in many different organisms through evolution. Which of the following correctly describes why this is the case?
A. The sequence evolves very rapidly.
B. The sequence does not mutate.
C. The sequence is found in many but not all promoters.
D. Any mutation in the sequence is selected against.
D. Any mutation in the sequence is selected against.
A eukaryotic transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. Which of the following statements best explains this fact?
A. There is redundancy in the genetic code.
B. Many nucleotides are needed to code for each amino acid.
C. There are termination exons near the beginning of the mRNA.
D. Many noncoding stretches of nucleotides are present in eukaryotic DNA.
D. Many noncoding stretches of nucleotides are present in eukaryotic DNA.
Which of the following statements correctly describes alternative RNA splicing?
A. It is a mechanism that can increase the rate of transcription.
B. It allows the production of similar proteins from different RNAs.
C. It can allow the production of different protein products from a single mRNA.
D. It increases the rate of transcription.
C. It can allow the production of different protein products from a single mRNA.
Which of the following statements correctly defines the process of gene expression?
A. Gene expression is the process by which proteins are produced under the instructions of DNA.
B. More than one correct answer.
C. Gene expression is the process by which which DNA is produced under the instructions of proteins.
D. Gene expression is the process by which RNA is produced under the instructions of proteins.
E. Gene expression is the process by which RNA is produced under the instructions of DNA.
B. More than one correct answer.
A particular triplet of bases in the template strand of DNA is 5'-ACT-3'. The corresponding codon for the mRNA transcribed is
A. 5'-TCA-3'.
B. 3'-UCA-5'.
C. More than one correct answer.
D. 3'-ACU-5'.
E. 3'-UGA-5'.
E. 3'-UGA-5'.
Which of the following descriptions of nucleotide triplets best represents a codon?
A. six ribonucleotides in the same reading frame that comes before the ribonucleotides AUG
B. three ribonucleotides in the same reading frame that comes before the ribonucleotides AUG
C. a triplet at the opposite end of tRNA from the attachment site of the amino acid
D. More than one correct answer.
E. a triplet that has no corresponding amino acid
B. three ribonucleotides in the same reading frame that comes before the ribonucleotides AUG
In eukaryotes there are several different types of RNA polymerase. What is the name of the enzyme that synthesizes mRNA in eukaryotes?
A. ligase
B. RNA polymerase I
C. RNA polymerase II
D. RNA polymerase III
C. RNA polymerase II
A part of the promoter, called the TATA box, is said to be highly conserved in many different organisms through evolution. Which of the following correctly describes why this is the case?
A. If an organism gets a mutation in this sequence they are highly likely not to survive.
B. The sequence evolves very rapidly.
C. The sequence is found in many but not all promoters.
D. The sequence does not mutate.
E. More than one correct answer.
A. If an organism gets a mutation in this sequence they are highly likely not to survive.
We all know UGA, and I am not talking about the team that beat Old Miss. in the Saturday football game. This UGA are codons in mRNA. What does this UGA do?
A. It signals the end of the gene.
B. More than one correct answer.
C. It sets the reading frame of the mRNA.
D. It is the recognition site for ribosomal binding.
E. It is the recognition site for a specific transcription factor.
A. It signals the end of the gene.
A eukaryotic mutation upstream of a particular gene has been identified that changes the sequence of the TATA box to GATA. How would you predict that this mutation would affect the transcription of this gene?
A. More than one correct answer.
B. The transcription factors would bind to the start point in the promoter region.
C. The binding of the transcription factor binding would be reduced or eliminated, and transcription of the gene would decrease dramatically.
D. Transcription and protein synthesis would likely decrease dramatically.
E. Transcription factors would bind in the middle of the gene sequence and transcribe the gene from that point.
A. More than one correct answer.
In which direction does RNA polymerase lay down nucleotides when transcribing a gene?
A. The direction can 5' to 3' or 3' to 5' depending on which side of the DNA is the template strand
B. 5' to 3' direction
C. 3' to 5' direction
D. It depends on if the organism is prokaryotic or eukaryotic. The direction can 5' to 3' or 3' to 5' in prokaryotes.
E. More than one correct answer.
B. 5' to 3' direction
Which of the following is a function of a poly-A tail in mRNA?
A. It is a sequence that codes for the binding of RNA polymerase to the DNA.
B. It helps to get the mRNA out of the nucleus.
C. It adds the modified guanine to the 3' end of the mRNA.
D. It helps protect the mRNA from degradation by hydrolytic enzymes.
E. More than one correct answer.
More than one correct answer.
What is a ribozyme?
A. an RNA that can be used as a substrate
B. more than one of the other options is correct
C. More than one correct answer.
D. an enzyme that synthesizes RNA as part of the transcription process
E. an RNA with enzymatic activity
E. an RNA with enzymatic activity
Which of the following responses correctly lists the order of events in a generalized viral replicative cycle?
A. Host enzymes replicate the viral genome, enzymes transcribe the viral genome into mRNA, the virus enters the cell.
B. The virus enters the cell, enzymes transcribe the viral genome into mRNA, host enzymes replicate the viral genome.
C. Enzymes transcribe the viral genome into mRNA, the virus enters the cell, host enzymes replicate the viral genome.
D. The virus enters the cell, host enzymes replicate the viral genome, enzymes transcribe the viral genome into mRNA.
D. The virus enters the cell, host enzymes replicate the viral genome, enzymes transcribe the viral genome into mRNA.
How do antiviral drugs help to treat viral infections?
A. They remove all viral proteins from the host.
B. They interfere with viral replication.
C. They remove all viral mRNAs from the host.
D. They remove all viruses from the infected host.
B.They interfere with viral replication.
Some people who have had a herpesvirus-mediated cold sore or genital sore may have flare-ups for the rest of their life. Why does this occur?
A. co-infection with an unrelated virus that causes the same symptoms
B. copies of the herpesvirus genome remaining as mini-chromosomes in some host cell nuclei
C. re-infection by the same herpesvirus strain
D. re-infection by a closely related herpesvirus of a different strain
B. copies of the herpesvirus genome remaining as mini-chromosomes in some host cell nuclei
Why do RNA viruses tend to have unusually high rates of mutation?
A. Replication of their genomes does not involve correcting errors in genome replication.
B. RNA viruses can incorporate a variety of nonstandard bases.
C. RNA nucleotides are more unstable than DNA nucleotides.
D. RNA viruses replicate faster.
A. Replication of their genomes does not involve correcting errors in genome replication.
Which of the following statements correctly describes one characteristic of the lytic cycle of viral replication?
A. A large number of phages are released at a time.
B. The viral genome replicates without destroying the host.
C. Many bacterial cells containing viral DNA are produced.
D. Viral DNA is incorporated into the host genome.
A. A large number of phages are released at a time.
What is the function of reverse transcriptase in retroviruses?
A. It hydrolyzes the host cell's DNA.
B. It uses viral RNA as a template for DNA synthesis.
C. It uses viral RNA as a template for making complementary RNA strands.
D. It converts host cell RNA into viral DNA.
B. It uses viral RNA as a template for DNA synthesis.
Which of the following nucleic acids make(s) up viral genomes?
A. DNA only
B. double-stranded RNA only
C. single-stranded RNA only
D. DNA or RNA
D. DNA or RNA
Which of the following processes can be effective in preventing the onset of viral infection in humans?
A. taking vitamins
B. applying antiseptics
C. taking antibiotics
D. getting vaccinated
D. getting vaccinated
Which of the following statements
A. They can reproduce by dividing.
B. They cannot reproduce without a host cell.
C. They have a genome similar to prokaryotic and eukaryotic cells.
D. They can carry out their own metabolic activities.
B. They cannot reproduce without a host cell.
Which of the following statements correctly describes the lysogenic cycle of lambda (λ) phage?
A. After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses.
B. The phage genome replicates along with the host genome.
C. Most of the prophage genes are activated by the product of a particular prophage gene.
D. Certain environmental triggers can cause the phage to exit the host genome, switching from the lytic to the lysogenic.
B. The phage genome replicates along with the host genome.
What is metagenomics?
A. the sequencing of only the most highly conserved genes in a lineage
B. genomics as applied to a species that most typifies the average phenotype of its genus
C. the sequence of one or two representative genes from several species
D. sequencing DNA from a group of species from the same ecosystem
D. sequencing DNA from a group of species from the same ecosystem
What is proteomics?
A. the study of how a single gene activates many proteins
B. the totality of the functional possibilities of a single protein
C. the study of the full protein set encoded by a genome
D. the linkage of each gene to a particular protein
C. the study of the full protein set encoded by a genome
What is bioinformatics?
A. a procedure that uses software to order DNA sequences in a variety of comparable ways
B. a technique using three-dimensional images of genes to predict how and when they will be expressed
C. software programs available from NIH to design and synthesize genes
D. the application of computational methods to the storage and analysis of biological data
D. the application of computational methods to the storage and analysis of biological data
A microarray known as a GeneChip, with most of the human protein-coding genetic sequences, has been developed to aid in the study of human cancer by comparing gene sequences and patterns of gene expression in cancer cells with those in normal cells. What kind of information might be gleaned from this GeneChip to aid in cancer prevention?
A. data that could alert patients to what kind of cancer they were likely to acquire
B. information about whether or not a patient has this type of cancer prior to treatment
C. evidence that might suggest how best to treat a person's cancer with chemotherapy
D. information about which parent might have provided a patient with cancer-causing genes
A. data that could alert patients to what kind of cancer they were likely to acquire
What characteristic of short tandem repeat DNA makes it useful for DNA fingerprinting?
A. The sequence variation is acted upon differently by natural selection in different environments.
B. The number of repeats varies widely from person to person or animal to animal.
C. Every racial and ethnic group has inherited different short tandem repeats.
D. The sequence of DNA that is repeated varies significantly from individual to individual.
B. The number of repeats varies widely from person to person or animal to animal.
In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. Why is this the case?
A. Nonidentical genes produce different versions of globins during development.
B. The attachment of methyl groups to cytosine following birth changes the type of hemoglobin produced.
C. Pseudogenes interfere with gene expression in adults.
D. Identical genes generate many copies of the ribosomes needed for fetal globin production.
A. Nonidentical genes produce different versions of globins during development.
Humans have 23 pairs of chromosomes. By contrast, chimpanzees have 24 pairs of chromosomes and lack any pair resembling the long human chromosome 2 pair; instead, chimpanzees have two pairs of medium-sized chromosomes, each of which resembles parts of human chromosome pair 2. What is the most likely explanation for these differences and similarities in the human and chimpanzee genomes?
A. At some point in evolution, human ancestors and chimpanzee ancestors were able to mate and produce fertile offspring, making a new species.
B. The common ancestor of humans and chimpanzees had 23 pairs of chromosomes, but when chimpanzees evolved, one of the chromosomes broke in half.
C. The common ancestor of humans and chimpanzees had 24 pairs of chromosomes, and at some point in the human lineage, two chromosomes fused end to end, providing some selective advantage.
D. Chromosome breakage resulted in additional centromeres being
C. The common ancestor of humans and chimpanzees had 24 pairs of chromosomes, and at some point in the human lineage, two chromosomes fused end to end, providing some selective advantage.
Unequal crossing over during prophase I can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin, called hemoglobin Lepore, exists in the human population. Hemoglobin Lepore has a deleted series of amino acids. If this mutated form was caused by unequal crossing over, what would be an expected consequence?
A. There should also be persons whose hemoglobin contains two copies of the series of amino acids that is deleted in hemoglobin Lepore.
B. Each of the genes in the hemoglobin gene family must show the same deletion.
C. The deleted region must be located in a different area of the individual's genome.
D. The deleted gene must have undergone exon shuffling.
A. There should also be persons whose hemoglobin contains two copies of the series of amino acids that is deleted in hemoglobin Lepore.
Genetic variation among humans is relatively small when compared to other species. Where in the human genome does most of the diversity occur?
A. in sequences that code for tRNA
B. in the mitochondrial DNA
C. in single nucleotide-polymorphisms
D. in the homeotic genes
C. in single nucleotide-polymorphisms
Fragments of DNA have been extracted from the remnants of extinct woolly mammoths, amplified, and sequenced. How might these fragments be used now?
A. They may be used to clone live woolly mammoths.
B. They may be introduced into relatives, such as elephants, to recreate certain mammoth traits.
C. They may help us to understand the evolutionary relationships among members of related organisms.
D. They may help study the relationships among woolly mammoths and other wool producers.
C. They may help us to understand the evolutionary relationships among members of related organisms.
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