Unit 2 AP Bio - The Central Dogma, Enzymes, Gene Expression, and Genetic Engineering

N--C--C--N--C--C A B C D E Which bond is closed to the N-terminus of the molecule? a) A b) B c) C d) D e) E

A

In an analysis of the nucleotide composition of DNA, which of the following will be found? a) A=C b) T=G c) A=G and C=T d) A+C = G+T e) G+C = T+A

D

A eukaryotic gene has "sticky ends" produced by the restriction endonucleus EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight at are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics. Bacteria that do not take up any plasmid would grow on which media? a) The nutrient broth only b) The nutrient broth and the tetracycline broth c) The nutrient broth and the ampicillin broth d) The tetracycline broth and the ampicillin broth e) All four broths

A

A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell would result in a) Continuous transcription of the structure gene controlled by that regulator b) Complete inhibition of transcription of the structural gene controlled by that regulator c) Irreversible binding of the repressor to the operator d) Inactivation of RNA polymerase by alteration of its active sit e) Continuous translation of the mRNA because of alteration of its structure

A

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) 3' UGA 5' c) 5' TCA 3' d) 3' ACU 5' e) Either UCA or TCA, depending on wobble in the first base.

A

For this pair of items, choose the option that best describes their relationship. I. The number of purines in the DNA strand 5' -AAGAGGAGAAA- 3' II. The Number of pyrimidines in the DNA strand 5' -AAGAGGAGAAA- 3' a) Item I is greater than item II b) Item I is less than item II c) Item I is exactly or very approximately equal to item II d) Item I may stand in more than one of the above relations to item II e) None of the above

A

The genetic code is essentially the same for all organisms. From this, one can logically assume all of the following except a) a gene from an organism could theoretically be expressed by any other organism b) All organisms have a common ancestor c) DNA was the first genetic material d) The same codons in different organisms usually translate into the same amino acids e) Different organisms have the same number of different types of amino acids

A

The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called a) RNA interference b) RNA obstruction c) RNA blocking d) RNA targeting e) RNA disposal

A

What does the operon model attempt to explain? a) The coordinated control of gene expression in bacteria b) Bacterial resistance to antibiotics c) How genes move between homologous regions of DNA d) The mechanism of viral attachment to host cells e) Horizontal transmission of plant viruses

A

Which of the following best describes the flow of information in eukaryotic cells? a) DNA > RNA > Proteins b) RNA > Proteins > DNA c) Proteins > DNA > RNA d) RNA > DNA > Proteins e) DNA > Proteins > RNA

A

Which of the following is most likely to have a small protein called ubiquitin attached to it? a) A cycling that usually acts in G1, not that the cell is in G2 b) A cell surface protein that requires transport from the ER c) An mRNA that is leaving the nucleus to be translated d) A regulatory protein that requires sugar residues to be attached e) An mRNA produced by an egg cell that will be trained until after fertilization

A

Which of the following is true for both prokaryotic and eukaryotic gene expression? a) After transcription, a 3' poly-A tail and a 5' cap are added to mRNA b) Translation of mRNA can begin before transcription is complete c) RNA polymerase binds to the promoter region to begin transcription d) mRNA is synthesized in the 3' > 5' direction e) The mRNA transcript is the exact complement of the gene from which it was copied

A

If one strand of a DNA molecule has the sequence of bases 5' ATTGCA 3', the other complementary strand would have the sequence a) 5' TAACGT 3' b) 3' TAACGT 5' c) 5' UAACGU 3' d) 3' UAACGU 5' e) 5' UGCAAU 3'

B

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? a) No proofreading will occur b) No replication will be formed c) The DNA will supercoil d) Replication will occur via RNA polymerase alone e) Replication will require a DNA template from other source.

B

The R group or side chain of the amino acid serine is -CH2 -OH. The R group or side chain US and alanine is -CH3. Where would you expect to find these amino acids in a globular protein and aqueous solution? a) Serine would be in the interior, and alanine would be on the exterior of the globular protein b) Alanine will be in the interior, and serine will be on the exterior of the globular protein c) Both serine and alanine would be in the interior of the globular protein d) Both serine and alanine would be on the exterior of the globular protein e) Both serine and alanine would be in the interior and on the exterior of the globular protein

B

The segment of DNA shown above has restrictions sites I and II, which create restrictions fragments A, B and C. Which of the gels produced by electrophoresis shown below best represents the separation and identity of these fragments? a) A, B, C - equal length apart b) C, A, B c) B, A, C d) C, A, B - equal length apart e) B, A, C - equal length apart

B

Which mutation would be most likely to have a catastrophic effect on the function of a protein? a) A base substitution b) A base deletion near the start of a gene c) A base deletion near the end of the coding sequence, but not in the terminator codon d) Deletion of three bases near the start of the coding sequence, but not in the initiator codon. e) A base insertion near the end of the coding sequence, but not in the terminator codon.

B

Which of the following experimental procedures is most likely to hasten mRNA degradation in a eukaryotic cell? a) Enzymatic shortening of the poly-A tail b) Removal of the 5' cap c) Methylation of C nucleotides d) Methylation of histones e) Removal of one or more eons

B

Which of the following statements is/are true regarding the chemical reaction illustrated to right? a) It is a hydrolysis reaction b) It results in a peptide bond c) It joins two fatty acids together d) A and B only e) A, B, and C

B

A eukaryotic gene has "sticky ends" produced by the restriction endonucleus EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight at are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics. Bacteria that contains the plasmid, but not the eukaryotic gene, would grow a) In the nutrient broth plus ampicillin, but not in the broth containing tetracycline b) Only in the broth containing both antibiotics c) In the broth containing tetracycline, but not in the broth containing ampicillin d) In all four types of broth e) In the nutrient broth without antibiotics only

C

A mutation in this section of DNA could influence the binding of RNA polymerase to the DNA: a) Operon b) Inducer c) Promoter d) Repressor e) Corepressor

C

A 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 peptide? a) 3' UUU-CCC-AAA-GGG-UUU-CCC b) 3' AUG-AAA-GGG-TTT-CCC-AAA-GGG c) 5' TTT-CCC-AAA-GGG-TTT-CCC d) 5' GGG-AAA-TTT-AAA-CCC-ACT-GGG e) 5' ACT-TAC-CAT-AAA-CAT-TAC-UGA

C

A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because a) The starch solution has less free energy then the sugar solution b) The hydrolysis of starch to sugar is endergonic c) The activation energy barrier for this reaction cannot be surmounted d) Starch cannot be hydrolyzed in the presence of some much water e) Starch hydrolysis is non spontaneous

C

Altering patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways? a) Organizing gene expression so that gene are expressed in a given order b) Allowing each gene to be expressed an equal number of times c) Allowing the organism to adjust to changes in environmental conditions d) Allowing young organisms to respond differently from more mature organisms e) Allowing environmental change to alter the prokaryote's genome

C

During splicing, which molecular component of the spliceosome catalyzes the excision reaction? a) Protein b) DNA c) RNA d) Lipid e) Sugar

C

For a repressible operon to be transcribed, which of the following must occur? a) A Corepressor must be present b) RNA polymerase and the active pressor must be present c) RNA polymerase must bind to the promoter, and the pressor must be inactive d) RNA polymerase cannot be present, and the repressor must be inactive e) RNA polymerase must not occupy the promoter, and the repressor must be inactive

C

Gene expression might be altered at the level of post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following? a) Eukaryotic mRNAs get 5' caps and 3' tails b) Prokaryotic genes are expressed as mRNA, which is more stable in the cell c) Eukaryotic eons may be spliced in alternative patterns d) Prokaryotes use ribosomes of different structure and size e) Eukaryotic coded polypeptides often require cleaving of signal sequences before localization

C

If a DNA sample were composed of 10% thymine, what would be the percentage of guanine? a) 10% b) 20% c) 40% d) 80% e) Impossible to tell from the information given

C

N--C--C--N--C--C A B C D E Which bond is a peptide bond? a) A b) B c) C d) D e) E

C

What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium? I. Transform bacteria with recombinant DNA molecule II. Cut the plasmid DNA using restriction enzymes III. Extract plasmid DNA from bacterial cells IV. Hydrogen-bond the plasma DNA to non-plasmid DNA fragments V. Use ligase to seal plasma DNA to non-plasma DNA a) I, II, IV, III, V b) II, III, V, IV, I c) III, II, IV, V, I d) III, IV, V, I, II e) IV, V, I, II, III

C

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? a) Synthesize RNA nucleotides to make a primer b) Catalyze the lengthening of telomeres c) Join Okazaki fragments together d) Unwind the parental double helix e) Stabilize the unwounded parental DNA

C

Which enzyme was used to produce the molecule in the image to the right? a) Ligase b) Transcriptase c) A restriction enzyme d) RNA polymerase e) DNA polymerase

C

In an experimental situation, a student researcher inserts a mRNA molecule into a eukaryotic cell after he has removed its 5' cap and poly-A tail. Which of the following would you expect him to find? a) The mRNA could not exit the nucleus to be translated b) The cell recognizes the absence of the tail and polyadenylates the DNA c) The molecule is digested by restriction enzymes in the nucleus d) The molecule is digested by exonuclease since it is no longer protected at the 5' end e) The molecule attached to a ribosome and is translated, but more slowly

D

Muscle cells and nerve cells in one species of animal owe their differences in structure to a) Having different genes b) Having different chromosomes c) Using different genetic codes d) Having different genes expressed e) Having unique ribosomes

D

This can inhibit transcription by blocking the binding of positively acting transcription factors to the DNA a) Enhancer b) Promoter c) Activator d) Repressor e) Terminator

D

Two potential devices that eukaryotic cells use to regulate transcription are a) DNA methylation and histone amplification b) DNA amplification and histone methylation c) DNA acetylation and methylation d) DNA methylation and stone acetylation e) DNA acetylation and histone amplification

D

What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3' a) met-arg-glu-arg-glu-arg b) met-glu-arg-arg-gln-leu c) met-ser-leu-ser-leu-ser d) met-ser-ser-leu-ser-leu e) met-let-phe-arg-glu-glu

D

When ATP releases some energy, it also releases inorganic phosphate. What purpose does this serve (if any) in the cell? a) It is released as an excretory race b) It can only be sued to regenerate more ATP c) It can be added to water and excreted as a liquid d) It can be added to other molecules in order to activate them e) It can enter the nucleus to effect gene expression

D

When DNA replicates, each strand of the original DNA molecules is used as a template for the synthesis of a second, complimentary strand. Which of the following figures most accurately illustrate enzyme-mediated synthesis of new DNA at a replication fork? a) 5' > 3' 3' > 5' b) 5' - - > 3' 3' > 5' c) 5' > 3' 3' > 5' d) 5' < - - 3' 3' > 5'

D

A eukaryotic gene has "sticky ends" produced by the restriction endonucleus EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight at are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics. Bacteria containing a plasmid into which the eukaryotic gene has integrated would grow in a) The nutrient broth only b) The nutrient broth and the tetracycline broth only c) The nutrient broth, and ampicillin broth, and the tetracycline broth d) All four types of broth e) The ampicillin broth and the nutrient broth

E

For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogen. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why won't this experiment work? a) There is no radioactive isotopes of nitrogen b) Radioactive nitrogen has a half life of 100,000 years, and the material would be too dangerous for too long c) Avery et al. have already concluded that this experiment showed inconclusive results d) Although there are some nitrogens in a nucleotide, labeled phosphates actually have 16 extra neutrons; therefore, they are more radioactive e) Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins

E

N--C--C--N--C--C A B C D E Which bond is closed to the carboxyl end of the molecule? a) A b) B c) C d) D e) E

E

The DNA of telomeres has been found to be highly conserved throughout the evolution of eukaryotes. What does this most probably reflect? a) The inactivity of this DNA b) The low frequency of mutations occurring in this DNA c) That new evolution of telomeres continues d) That mutations in telomeres are relatively advantageous e) That the crucial function of telomeres must be maintained

E

The tryptophan person is a repressible operon that a) Permanently turned on b) Turned on only when tryptophan is present in the growth medium c) Turned off only when glucose is present in the growth medium d) Turned on only when glucose is present in the growth medium e) Turned off whenever tryptophan is added to the growth medium

E

Which term most precisely describes the cellular process of breaking down large molecules into smaller ones? a) Catalysis b) Metabolism c) Anabolism d) Dehydration e) Catabolism

E