quiz 12

The following enzymes are involved in DNA replication on the lagging strand. In order for normal DNA replication to occur, these enzymes must work in the following order: ligase primase helicase polymerase

4 2 1 3

Indicate the polarity of the DNA molecule at each letter: A = B = C = D =

5' 3' 5' 3'

Which of the following mutations would likely be most dangerous to a cell? A) Deletion of three nucleotides B) Deletion of one nucleotide C) Substitution of one nucleotide for another

B

Which of the following DNA strands is the template strand for this molecule of mRNA? 5'AUUCGGCAUUCC 3' A) 5'TAAGCCGTAAGG 3' B) 5'GGAAUGCCGAAU 3' C) 5'GGAATGCCGAAT 3' D) 5'AUUCGGCAUUCC 3'

C

A DNA sequence reads 3' AGGCTTA 5'. Therefore, the complementary DNA strand must read _________________________. A) 3' AGGCTTA 5' B) 3' TCCGAAT 5' C) 3' TAAGCCT 5' D) 3' UAAGCCU 5'

C

The genetic code is said to be "redundant" because _____________________________________. A) one anticodon can attach to several amino acids B) there is more than one start codon C) one amino acid can have more than one codon D) one codon can signify more than one amino acid

C

Which characteristic of the genetic code lowers the likelihood of a mutation causing a mutant phenotype? A) Universality B) Un-ambiguity C) Non-overlapping D) Redundancy

D

A molecule of DNA is comprised of 38% A, 22% T, 24%G, 16% C. What can you conclude about this molecule from this information? A) It is single-stranded B) It is double-stranded C) It is non-coding DNA D) It is from a bacterium

A

According to the base-pairing rules in DNA, which of the following must be true of a molecule of DNA? A) The amount of C = the amount of G B) The amount of C > the amount of G C) The amount of C = the amount of T D) The amount of C < the amount of T

A

During the process of transcription: A) DNA polymerase adds nucleotides to the newly synthesized strand. B) one DNA strand serves as a template. C) a supply of the nucleotides ACGT is required. D) two new RNA molecules are produced.

B

All of the following are directly required for protein synthesis EXCEPT _____________________. A) DNA polymerase B) tRNA C) ribosomes D) RNA polymerase

A

An actively dividing bacterial culture is grown in a medium containing radioactive adenine (A*). After all the adenine is labeled, the bacteria are transferred to a medium containing nonradioactive adenine (A). Following one round of DNA replication in the nonradioactive medium, the DNA is analyzed. Which of the following sequences could represent this DNA? A) A* A* T T G A* T C T T A A C T A G B) A* A T T G A* T C T T A* A* C T A G C) A A T T G A T C T T A A C T A G D) A* A* T T G A* T C T T A* A* C T A* G

A

Here are four individual strands of DNA: 1- 5'AATTCCGGCCTAACTT3' 2- 5'AAGTTAGGCCGGAATT3' 3- 5'TTAAGGCCGGATTGAA3' 4- 5'TTCAATCCGGCCTTAA3' Which strands would pair with one another? A) 1 and 2, 3 and 4 B) 1 and 4, 2 and 3 C) 1 and 3, 2 and 4 D) 1 and 3 only

A

Here is the amino acids sequence for a short piece of a protein: Pro-Thr-Gln-Lys-Asn-Ser Which of the following is the DNA TEMPLATE strand used to produce the mRNA that encodes this protein sequence? A) 5'AGAATTTTTTTGAGTAGG 3' B) 5'GGATGAGTTTTTTTATCA 3' C) 5'CCUACUCAAAAAAAUUCC 3' D) 5'UUUUUAUCAUUGAGUAGG 3'

A

In eukaryotes, DNA replication takes place: A) in the nucleus during interphase. B) in the cytoplasm during mitosis. C) in the nucleus during mitosis. D) in the cytoplasm during interphase.

A

In eukaryotes, transcription takes place in the ______________________________. A) nucleus B) cell membrane C) ribosomes D) cytoplasm

A

Rifamycin is an antibiotic used to treat the bacterium that causes tuberculosis. It works by binding to the bacterium's RNA polymerase 𝛽β subunit. This kills the bacterium by inhibiting A) transcription. B) translation. C) DNA replication. D) cell division.

A

Which of the following sequences of DNA was produced using this strand as a template? 5' ACAGTCGAGCCTCGT 3' A) 3' TGTCAGCTCGGAGCA 5' B) 3' ACGAGGCTCGACTGT 5' C) 3' ACAGTCGAGCCTCGT 5' D) 3' UGUCAGCUCGGAGCA 5'

A

You are studying a protein and have sequenced the DNA that encodes it. There is also a mutant version of the protein that does not function correctly. When you transcribe the DNA to obtain the mRNA sequence, you find that at one position, there has been a mutation from 5'UGC 3' to 5'UGA 3'. Using the genetic code, you determine that this mutant protein A) is too short. B) has the amino acid Trp in place of the amino acid Cys. C) is too long. D) has the amino acid Ser in place of the amino acid Arg.

A

Based on your knowledge of mutations and protein synthesis - which of the following is true of how a mutation can result in yellow coat color in Labrador Retrievers? Select all that apply. A) A mutation occurred in the MC1R gene. B) A mutation occurred in the MC1R mRNA. C) A mutation in the DNA results in an alteration of the mRNA. D) The normal MC1R allele results in either black or brown fur color in Labrador Retrievers. E) The mutant MC1R allele results in yellow coat color in Labrador Retrievers. F) The mutant MC1R allele results in a stop codon replacing an amino acid codon. G) The shortened MC1R gene product that results from the mutant allele is nonfunctional. H) Because yellow Labrador Retrievers have this mutation - they are less healthy then black or brown-coated Labrador Retrievers. Mutations are bad for the organisms that inherit them.

A & C & D & E & F & G

DNA is replicated: A) during mitosis, producing sister chromatids. B) during interphase, producing sister chromatids. C) during interphase, producing homologous chromosomes. D) during mitosis, producing homologous chromosomes.

B

During DNA replication along the lagging strand of DNA, Okazaki fragments are produced. This is because DNA polymerase A) can only add new nucleotides to the 5' end of the newly synthesized DNA. B) can only add new nucleotides to the 3' end of the newly synthesized DNA. C) is only active along the leading (continuously synthesized) strand. Primase produces the Okazaki fragments. D) is the enzyme involved in producing the mRNA molecule.

B

Tetracycline is an antibiotic that kills bacteria by blocking the A-binding site on the bacterial ribosome. This kills the bacterium by inhibiting A) transcription. B) translation. C) DNA replication. D) cell division.

B

The gene KRTHAP1 codes for the production of hair keratin in humans and other primates. It is this gene that is thought to be responsible for humans having relatively little body hair compared to other primates. A portion of the template strand of the chimp gene: 3' ACGACCGCT 5' A portion of the template strand of the human gene: 3' ACGACTGCT 5' What type of mutation occurred in humans to result in our relative hairlessness? A) Silent B) Nonsense - protein is shorter C) Nonsense - protein is longer D) Missense

B

The genetic disease sickle cell anemia is due to a mutation in the 𝛽β- globin gene (a component of hemoglobin). Normal 𝛽β-globin allele (template strand): 3' T G A G G A C T C C T C 5' Sickle 𝛽β-globin allele (template strand): 3' T G A G G A C A C C T C 5' Which of the following statements best summarizes the sickle cell mutation? A) The mutation results in a Leu being replaced by a His B) The mutation results in a Glu being replaced by a Val C) The mutation results in a stop codon appearing in the mRNA too early D) This is a silent mutation

B

The process of DNA replication is semiconservative. This means that a replicated chromosome is composed of: A) two DNA molecules (sister chromatids). One molecule is composed of two newly synthesized strands of DNA, while the template molecule is composed of the two parental strands of DNA. B) two DNA molecules (sister chromatids), each with one newly synthesized strand of DNA and one parental strand of DNA. C) two DNA molecules (sister chromatids). Each DNA molecule contains segments of both newly synthesized and parental DNA randomly mixed throughout the molecule. D) one DNA molecule and one RNA molecule (sister chromatids).

B

These examples demonstrate the ability of genes from one species to be expressed in a different species. This is possible because of which property of the genetic code? A) Redundancy B) Universality C) Unambiguousness D) All of the above.

B

What enzyme is responsible for unwinding the DNA to initiate replication? A) Primase B) Helicase C) DNA polymerase D) Ligase

B

What type of mutation has occurred? Original DNA: 3' AGCCGCATA 5' Mutated DNA: 3' AGCCGCATC 5' A) A single amino acid replacement B) A shortened protein C) All amino acids in the protein change D) There is no change in the protein (silent mutation).

B

What type of mutation is responsible for the disease sickle-cell anemia? A) Silent B) Missense C) Nonsense D) Synonymous

B

The melanocyte-stimulating hormone receptor gene (MC1R) codes for one of the key proteins involved in regulating mammalian skin and hair color. The normal allele for MC1R in Labrador retrievers and other dogs has this as part of its sequence on the CODING DNA strand: 5'AGCCAGGAACTTCGAAAG 3' What is the sequence of the transcribed mRNA? A) 5' AGCCAGGACTTCGAAAG 3' B) 5' CTTTCGAAGTTCCTGGCT 3' C) 5' AGCCAGGAACUUCGAAAG 3' D) 5' CUUUCGAAGUUCCUGGCU 3'

C

What is meant when DNA is described as being an "antiparallel" molecule? A) One strand is positively charged and the other is negatively charged. B) he twisting nature of DNA creates nonparallel strands. C) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. D) One strand contains only purines and the other contains only pyrimidines. E) Base pairings create unequal spacing between the two DNA strands.

C

You are working in a molecular biology lab and isolate a previously unknown virus. Analysis of its genome reveals that it is composed of a double stranded DNA molecule containing 14% T (thymine). Based on this information, what would you predict the %C (cytosine) to be? A) 14% B) 28% C) 36% D) 72% E) Cannot be determined from the information given.

C

A mutation in the DNA sequence of a gene that codes for a protein: A) is always harmful to the organism, impairing the function of the protein. B) cannot be repaired. C) is a very common occurrence, happening in about one out of every 100 nucleotides. D) is only heritable if it occurs in a gamete producing cell.

D

Given this DNA template strand: 5' ATTTGCGATAGGCA 3' What is the mRNA strand that is produced? A) 5' AUUUGCGAUAGGCA 3' B) 3' ATTTGCGATAGGCA 5' C) 5' UAAACGCUAUCCGU 3' D) 3' UAAACGCUAUCCGU 5'

D

Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base? A) Radioactive thymine would pair with nonradioactive guanine. B) All four bases of the DNA would be radioactive. C) One of the daughter cells, but not the other, would have radioactive DNA. D) DNA in both daughter cells would be radioactive. E) Neither of the two daughter cells would be radioactive.

D

The coding strand of a DNA molecule that encodes an mRNA molecule: A) has the same nucleotide sequence as the template DNA strand. B) has the complementary nucleotide sequence to the mRNA molecule (with Ts instead of Us). C) has the same nucleotide sequence as the template DNA strand except for the 3'/5' polarity. D) has the same nucelotide sequence as the mRNA molecule (with Ts instead of Us).

D

The leading and the lagging strands of DNA differ in that A) the leading strand is synthesized at twice the rate of the lagging strand. B) the lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together. C) the leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end. D) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.

D

This is the normal messenger RNA for (MC1R) in dogs is: 5'AGCCAGGAACUUCGAAAG 3' Yellow Labrador Retrievers produce this mRNA transcript: 5'AGCCAGGAACUUUGAAAG 3' What is the normal sequence of the polypeptide that is produced, and what type of mutation is seen in yellow labs? A) Glu - Ser - Phe - Lys - Asp - Arg/ protein is too short B) Ser - Gln - Glu - Leu - Arg - Lys / protein is too long C) Glu - Ser - Phe - Lys - Asp - Arg/ protein is too long D) Ser - Gln - Glu - Leu - Arg - Lys / protein is too short

D

Which of the following sets of tRNA anticodons would associate with the following mRNA during translation? 5'-AAU CCA UUU-3' A) 5'-TTA GGT AAA-3' B) 5'-UUA GGU AAA-3' C) 5'-AAA TGG ATT-3' D) 5'-AAA UGG AUU-3'

D