Chapter 4 Translation and Protein Structure

The two types of secondary structure interactions are referred to as:

α-helix and β-sheet.

The unfolding of a protein by heat or chemical treatment is referred to as:

denaturation.

A mutation is defined as a change in the sequence of a DNA molecule. Sometimes mutations cause no obvious changes, but at other times mutations can have profound effects on the synthesis or the function of a protein. The nucleotide sequences of the DNA molecules in the figure below are the same except for a single point mutation highlighted in yellow. Transcribe and translate each of the sequences, then answer the questions below. (In each instance, the circled base pair is the start point of transcription.) Which of the mutations above would be least likely to cause a change in the function of the protein?

mutation III

Amino acid sequences evolve through:

mutation and selection.

The genetic code is:

redundant.

The three-dimensional structure of a functional protein composed of a single polypeptide chain is referred to as the ____________ structure.

tertiary

When the peptide bond is created between amino acid 1 and amino acid 2:

the carboxyl group of amino acid 1 is joined to the amino group of amino acid 2.

In a ribbon model of a polypeptide, broad arrows indicate:

β-sheets.

How many different types of aminoacyl tRNA synthetases are there?

20

Use the double-stranded DNA molecule below to answer the following question. The first pair of nucleotides (circled) is the start point of transcription. Which of the following is the correct mRNA produced from the transcription of this DNA molecule?

5'-AUGAUCGGAUCGAUCCAU-3

The codons in mRNA specify the amino acids that are used to make a protein. Mark the following statement concerning translation TRUE or FALSE. "Because there are four RNA nucleotides and each codon is three nucleotides long, there are 64 possible codons, each of which directs the ribosome to incorporate a specific amino acid into a growing polypeptide chain."

False

The codons in mRNA specify the amino acids that are used to make a protein. Mark the following statement concerning translation TRUE or FALSE. "The limitations of the genetic code are such that a single amino acid may be specified by no more than four codons."

False

Secondary structure is characterized by which one of the following types of interactions?

Hydrogen bonding within the peptide backbone

Which one of the following is not a component of an amino acid?

Triphosphate group

The codons in mRNA specify the amino acids that are used to make a protein. Mark the following statement concerning translation TRUE or FALSE. "Sixty-one of the 64 possible codons specify amino acids, whereas the other three are stop codons. Each of the 61 codons specifies just one amino acid."

True

Use the double-stranded DNA molecule below to answer the following question. The first pair of nucleotides (circled) is the start point of transcription. Which of the following is the correct polypeptide assembled by the translation of the mRNA produced by the transcription of this DNA molecule?

amino end - Met-Ile-Gly-Ser-Ile-His - carboxyl end