Deck 7: The Human Genome

Question 1

There are more than 25,000 copies of DNA sequences homologous to zinc finger protein genes in the human genome.Many of these are contained within actively transcribed genes.These transcribed zinc finger protein DNA sequences are included in which category of human genomic DNA?

A)Interspersed elements: 45% of the entire genome.
B)Constitutive heterochromatin: 6% of the entire genome.
C)Centromeric DNA: 1% of the entire genome.
D)Non-conserved DNA: 44% of the entire genome.
E)Highly conserved DNA: 5% of the entire genome.

Answer 1

Highly conserved DNA: 5% of the entire genome.

Question 2

The 5' cap and the 3' poly-A tail are added in the production of mature eukaryotic mRNA.The 5' cap and the 3' poly-A tail have which respective functions?

A)Transcript stability and transcriptional termination.
B)Translation initiation and transcript stability.
C)Transcriptional initiation and termination.
D)Translation initiation and termination.
E)The functions have not been determined.

Answer 2

Translation initiation and transcript stability.

Question 3

There are about 28,000 copies of zinc finger domains in the human genome, most of them as constituents of transcribed genes.This is a result of what process?

A)Evolutionary conservation, exon duplication, and exon shuffling.
B)Evolutionary conversion of leucine zipper, helix-turn-helix, and helix-loop-helix domains into zinc finger domains.
C)Retrotransposition of mobile sequences.
D)Evolutionary selection for proteins that interfere with nucleosome packing.
E)Genes that "jump" with the help of a transposase.

Answer 3

Evolutionary conservation, exon duplication, and exon shuffling.

Question 4

LINE-1 sequences and Alu sequences can occasionally cause problems by jumping into an important gene.They can also lead to:

A)Chromosome breakage.
B)Retroviral infections, by serving as "landing pads" for retroviral cDNAs.
C)The transfer of genes from the nucleus to the mitochondria, thereby maintaining the mitochondrial genome on the evolutionary time scale.
D)Faulty crossing over between misaligned chromosomes in meiosis, leading to deletions and duplications.
E)Occasional expansions of the tandemly arranged sequences.

Question 5

Estimates of the gene number in the human genome are being revised continuously.Currently, it is believed that humans have approximately _____ times the number of genes in the bacterium E.coli.

A)2.
B)7.
C)12.
D)25.
E)50.

Question 6

The closest equivalent to the σ subunit of bacterial RNA polymerase in eukaryotes is:

A)Initiation factor eIF-2.
B)A set of "general" transcription factors.
C)RNA polymerase I.
D)Histone H1.
E)RNase H.

Question 7

A geneticist introduces into the human germline the genes for a super-spliceosome that is able to remove every intron without fail.In which way would people with this genetic innovation differ from the rest of the species?

A)They would have only one kind of histone.
B)They would produce fewer unique proteins.
C)They would transcribe fewer genes.
D)They would produce mRNA transcripts without cap and poly-A tail.
E)Their proteins would no longer be modified post-translationally.

Question 8

Eukaryotes and prokaryotes share which of the following characteristics during transcription?

A)A σ subunit that binds to the promoter.
B)A template that is read in the 3'-to-5' direction.
C)A primase to initiate RNA synthesis.
D)Cotranscriptional attachment of a cap to the 5' end of the RNA.
E)Proofreading through a 3'-exonuclease activity.

Question 9

The closest equivalent to bacterial DNA polymerase III in eukaryotes is:

A)DNA polymerase α.
B)DNA polymerase β.
C)DNA polymerase γ.
D)DNA polymerase δ.
E)DNA polymerase ε.

Question 10

A genetic engineer announces the birth of a baby with an artificial chromosome that carries an extra copy of the gene for telomerase.The gene is engineered with an inducible promoter that causes transcription in response to the insect hormone ecdysone.Why should people with this artificial chromosome want to take ecdysone pills?

A)To reduce the cancer risk.
B)To be resistant to viral infections.
C)To delay aging.
D)To get a high.
E)To cure cancer.

Question 11

Cycloheximide inhibits the peptidyl transferase reaction in eukaryotes.It does so by binding to:

A)The 50S ribosomal subunit.
B)Elongation factor Tu.
C)The 60S ribosomal subunit.
D)The 30S ribosomal subunit.
E)Elongation factor eEF-2.

Question 12

A patient is shown to have a deletion of 500 base pairs within the 3.7-kilobase pair sequence between the promoter of the L-type pyruvate kinase (PK) gene and an erythroid cell-specific enhancer element for the PK gene.What is the most likely outcome of the mutation in erythroid cells?

A)PK will be produced at a higher rate.
B)Transcriptional initiation becomes impossible.
C)There will be no change in the rate of enzyme synthesis.
D)There will be faulty splicing of the transcript.
E)The rate of transcription initiation by transcription factor IIH will be reduced.

Question 13

One important feature of LINE-1 sequences is:

A)There are fewer than 100 known copies in the human genome.
B)The full-length sequence encodes a protein with reverse transcriptase activity.
C)The sequences are arranged in tandem, sometimes hundreds of units in length.
D)They are also known as minisatellites.
E)A full-length LINE-1 sequence is about 300 base pairs long.

Question 14

In a scientific article, you read that the transcriptional regulator satanin recruits a histone deacetylase to the promoter of the gene for transcendentin, the major structural protein of the human soul.The most likely effect of this will be:

A)Altered splicing of the transcendentin messenger RNA (mRNA), resulting in the production of a structurally altered protein.
B)The destabilization of nucleosomes in the region of the transcendentin gene.
C)Reduced transcription of the transcendentin gene.
D)Recruitment of the TATA-binding protein to the promoter of the transcendentin gene.
E)Stimulation of the protein kinase activity of transcription factor H.