Biology Chapter Fourteen

In which direction does RNA polymerase move along the DNA?

3' to 5' along the template strand

Which of the following processes only occurs in eukaryotic gene expression?

A poly-A tail is added to the 3' end of an mRNA and a cap is added to the 5' end.

Which of the following statements describes one of the functions of GTP in translation?

GTP provides the energy for the formation of the initiation complex, using initiation factors.

Which of the following statements correctly defines the process of gene expression?

Gene expression is the process by which DNA directs the synthesis of proteins.

Which of the following statements correctly describes the function of a signal peptide?

It assists in the translocation of polypeptides across the ER membrane.

What is the function of the release factor in translation?

It binds to the stop codon in the A site in place of a tRNA.

Which of the following statements correctly describes alternative RNA splicing?

It can allow the production of different protein products from a single mRNA.

Which of the following is a function of a poly-A tail in mRNA?

It helps protect the mRNA from degradation by hydrolytic enzymes.

In what way could a point mutation in DNA make a difference in the function of protein?

It might substitute a different amino acid in the protein, which could change its function.

What must happen to a newly made polypeptide before it can be secreted from a cell?

Its signal sequence must target it to the ER, after which it goes to the Golgi.

Which of the following DNA mutations is likely to have the most negative effect on the protein it specifies?

a base-pair deletion

Which of the following mutations is most likely to cause a phenotypic change?

a single nucleotide deletion in an exon coding for an active site

Which of the following descriptions of nucleotide triplets best represents a codon?

a triplet in the same reading frame as an upstream AUG

What is a ribozyme?

an RNA with enzymatic activity

When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following sets of structures would you be able to isolate from the cell?

an assembled ribosome with a polypeptide attached to the tRNA in the P site

Accuracy in the translation of mRNA into the sequence of amino acids in a polypeptide depends on specificity in which of the following?

bonding of the anticodon to the codon and the attachment of amino acids to tRNAs

Which of the following types of mutations could result in a frame shift mutation?

either insertion or deletion of a base

Transcription in eukaryotes requires which of the following in addition to RNA polymerase?

several transcription factors

Which of the following events in translation is the first to occur in eukaryotes?

the small subunit of the ribosome recognizing and attaching to the 5' cap of mRNA