Post Spring Break Review

When does DNA replication take place?

• Whenever new genes are needed

• During the S phase of the cell cycle

• In the middle of mitosis or meiosis

• Immediately before cytokinesis begins

Answer explanation

The DNA must be replicated before cell division takes place so that the daughter cells each receive all the necessary information

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IST-1

Match the following enzymes to their roles in DNA replication.

• Unwinds the parent DNA strands

• Ligase

• Synthesizes the new strands of DNA

• DNA polymerase

• Fills in the gaps in the new DNA strands

• Helicase

• Adds a small RNA "primer"

• Primase

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IST-1

Which of the following would lead to an increase in the rate of transcription?

• methylation of DNA, particularly the cytosine bases

• acetylation of histone proteins

• binding of the operator in an operon

• negative feedback from accumulating product

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IST-2

After eukaryotic transcription takes place, mRNA undergoes several modifications before leaving the nucleus to take part in translation. Some sections of mRNA are cut out, and the remaining sections are spliced together to create the finished mRNA molecule. Which of the following mRNA sections are spliced together in the finished mRNA molecule?

• introns

• exons

• operons

• ribozymes

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IST-2

The human genome appears to have only about as many genes as the simple nematode worm, C. elegans. Which of the following best explains how the more complex humans can have relatively few genes?

• Human genes have unusually long introns involved in the regulation of gene expression

• More than one polypeptide can be produced from a gene by alternative gene splicing

• The human genome has a high proportion of noncoding DNA

• The human genome has a large number of SNPs (single nucleotide polymorphisms) which increases genetic variability

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IST-2

Which of the following are pyrimidines?

• adenine and cytosine

• adenine and guanine

• adenine and thymine

• cytosine and guanine

• cytosine and thymine

During transcription, what is the relationship between DNA and RNA?

• DNA is the template, RNA reads DNA in 3' -> 5' direction

• DNA is the template, RNA reads DNA in 5' -> 3' direction

• RNA is the template, DNA reads RNA in 3' -> 5' direction

• RNA is the template, DNA reads RNA in 5' -> 3' direction

What is the sequence of nucleotides on mRNA read in triplets called?

• anticodon

• codon

• triplet box

• wobble

Identify which molecules bind to the promoter region

• Ligase

• Topoisomerase

• DNA polymerase

• RNA polymerase

How does the DNA in a prokaryote differ from a eukaryote?

• Prokaryote has circular DNA, Eukaryotes has linear DNA

• Prokaryote has single stranded DNA, Eukaryotes has double stranded DNA

• Prokaryote has linear DNA, Eukaryotes has circular DNA

• Prokaryote has double stranded DNA, Eukaryotes has single stranded DNA