Practice Exam 4 Biology
E
1) 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) aminoacyl synthetase D) start and stop codons E) several transcription factors (TFs)
A
10) A synthetic peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this synthetic peptide in a laboratory? (No need to account for the start and stop codons for this case.) A) 5' -TTT-CCC-AAA-GGG-TTT-CCC-3' B) 5' -GGG-AAA-TTT-AAA-CCC-ACT-GGG-3' C) 3' -UUU-CCC-AAA-GGG-UUU-CCC-5' D) 3' -AUG-AAA-GGG-TTT-CCC-AAA-GGG-5' E) 5' -ACT-TAC- CAT-AAA-CAT-TAC-UGA-3'
E
11) Which of the following best describes siRNA? A) a double -stranded RNA that is formed by cleavage of hairpin loops in a larger precursor B) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits C) a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns D) a molecule, known as Dicer, that can degrade other mRNA sequences E) a short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA
C
12) The trp operon is a repressible operon that is A) permanently turned on. B) turned on only when tryptophan is present in the growth medium. C) turned off whenever tryptophan is added to the growth medium. D) turned on only when glucose is present in the growth medium. E) turned off only when glucose is present in the growth medium.
C
13) The role of a metabolite that controls a repressible operon is to A) bind to the repressor protein and inactivate it. B) bind to the promoter region and decrease the affinity of RNA polymerase for the promoter. C) bind to the repressor protein and activate it. D) bind to the operator region and block the attachment of RNA polymerase to the promoter. E) increase the production o f inactive repressor proteins.
C
14) A lack of which molecule would result in the cell's inability to "turn off" genes? A) ubiquitin B) operon C) corepressor D) inducer E) promoter
C
15) Mutations in which of the following genes lead to transformations in the identity of entire body parts? A) Inducers B) Segmentation genes C) Homeotic genes D) Morphogens E) Egg-polarity genes
B
16)The fact that plants can be cloned from somatic cells demonstrates that A) differentiated cells contain masked mRNA. B) differentiated cells retain all the genes of the zygote. C) differentiation does not occur in plants. D) genes are lost during differentiation. E) the differentiated state is normally very unstable.
E
17) In 1997, Dolly the sheep was cloned. Which of the following processes was used? A) Separation o f an early-stage sheep blastula into separate cells, one of which was incubated in a surrogate B) Use of mitochondrial DNA from adult female cells of another ewe C) Isolation of stem cells from a lamb embryo and production of a zygote equivalent D)Replication and dedifferentiation of adult stem cells from sheep bone marrow E) Fusion of an adult cell's nucleus with an enucleated sheep egg, followed by incubation in a surrogate
A
18) The bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, which of the following would occur? A) Anterior structures would form in both sides of the embryo. B) The embryo would grow to an unusually large size. C) The embryo would develop normally. D) The embryo would grow extra wings and legs. E) The embryo would probably show no anterior development and die.
A
19) Embryonic lethal mutations result in A) phenotypes that are never born/hatched. B) failure to express maternal effect genes. C) phenotypes that prevent fertilization. D) homeotic phenotype changes. E) death during pupation.
A
2) During splicing, which molecular component of the spliceosome catalyzes the excision reaction? A) RNA B) DNA C) protein D) sugar E) lipid
B
20) Which of the following responses correctly lists the order of events in a generalized viral replicative cycle? A)enzymes transcribe the viral genome into mRNA, the virus enters the cell, host enzymes replicate the viral genome B)the virus enters the cell, host enzymes replicate the viral genome, enzymes transcribe the viral genome into mRNA C)host enzymes replicate the viral genome, enzymes transcribe the viral genome into mRNA, the virus enters the cell D)the virus enters the cell, enzymes transcribe the viral genome into mRNA, host enzymes replicate the viral genome
D
21) What is the function of reverse transcriptase in retroviruses? A)It translates viral RNA into proteins. B) It hydrolyzes the host cell's DNA. C) It uses viral RNA as a template for making complementary RNA strands. D) It uses viral RNA as a template for DNA synthesis. E) It converts host cell RNA into viral DNA.
B
22) What is proteomics? A) The study of how amino acids are ordered in a protein B) The study of the full protein set encoded by a genome C) The study of how a single gene activates many proteins D) The linkage of each gene to a particular protein E) The totality of the functional possibilities of a single protein
C
23) What is bioinformatics? A) Software programs available from NIH to design and synthesize genes B) A procedure that uses software to order DNA sequences in a variety of comparable ways C) The application of computational methods to the storage and analysis of biological data D) A technique using 3 -D images of genes to predict how and when they will be expressed E) A series of search programs that allow a student to identify which labs around the world are trying to sequence the genome of a given species
D
3) 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 enzyme that synthesizes RNA primers during DNA repli cation D) an RNA with enzymatic activity E) an enzyme that catalyzes the association between the large and small ribosomal subunits
B
4) Alternative RNA splicing A) is due to the presence or absence of particular small RNAs in a spliceosome. B) can allow the production of proteins of different sizes from a single mRNA. C) is a mechanism for increasing the rate of transcription. D) can allow the production of similar proteins from different RNAs. E) increases the rate of transcription.
D
5) Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the A) shape of the A and P sites of ribosomes. B) bonding of the anticodon to the codon. C) binding of ribosomes to mRNA. D) bonding of the anticodon to the codon and the attachment of amino acids to tRNAs. E) attachment of amino acids to tRNAs.
A
6) The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following? A) A gene from an organism can theoretically be expressed by any other organism. B) Different organisms have different numbers of different types of amino acids. C) DNA was the first genetic material. D) The same codons in different organisms translate in to the different amino acids. E) All organisms have experienced convergent evolution.
C
7) Gene expression might be altered at the level of post -transcriptional processing in eukaryotes rather than prokaryotes because of which of the following? A) Prokaryotes use ribosomes of different structure and size. B) Eukaryotic mRNAs get 5' caps and 3' tails. C) Eukaryotic exons may be spliced in alternative patterns. D) Eukaryotic coded polypeptides often require cleaving of signal sequences before localization. E) Prokaryotic genes are expressed as mRNA, which is more stable in the cell.
D
8) Which of the following is the first event to take place in translation in eukaryotes? A) Base pairing of activated methionine -tRNA to AUG of the messenger RNA B) Elongation of the polypeptide C) Covalent bonding between the first two amino acids D) The small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA E) Binding of the larger ribosomal subunit to smaller ribosomal subunits
E
9) A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell would result in A) irreversible binding of the repressor to the operator. B) complete inhibition of transcription of the operon gene s controlled by that regulator. C) inactivation of RNA polymerase by alteration of its active site. D) continuous translation of the mRNA because of alteration of its structure. E) continuous transcription of the operon gene s controlled by that regulator.