Ch.4 Quiz

How many water molecules would be produced in making a polypeptide that is 14 amino acids long?

13

An mRNA molecule has a sequence 5'- CAGAUCUAAUGCUUAUCGGAU-3'. When translated in a laboratory setting in which translation can be initiated anywhere along the molecule, how many reading frames are possible?

3

A double-stranded DNA molecule is being transcribed, only part of which is shown below. If the molecule is translated from left to right, one of the nucleotides shown in bold would be the first transcribed in this small molecule. 5'-ATGATCGGATCGATCCAT-3' 3'-TACTAGCCTAGCTAGGTA-5' Which of the following is the correct mRNA produced from the transcription of this DNA molecule?

5'-AUGAUCGGAUCGAUCCAU-3'

True or false: Because there are three different possible reading frames in a messenger RNA molecule, most mRNAs can be translated in a cell into three different proteins.

False

The function of a protein is dependent upon the shape into which the chain of amino acids folds. Many noncovalent interactions are responsible for maintaining the protein's shape. Assume you have isolated a protein from an organism in its proper shape, and you have treated it with an enzyme that selectively targets and breaks only the peptide bonds in the proteins. Would the protein retain its shape under these conditions?

No; while the noncovalent bonds determine the shape of a protein, the peptide bonds are required to hold the amino acids together.

Imagine that a primary RNA transcript from your favorite eukaryotic gene was processed incorrectly, such that it has no 5' cap. What would be the result?

The initiation complex would fail to form properly, and translation would not occur.

In what order does a charged tRNA move through the sites of a ribosome?

The tRNA binds with the A site, then is moved to the P site, then the E site as the ribosome shifts.

True or false: Multiple ribosomes can be translating protein from a single mRNA simultaneously in a eukaryote, but the mRNAs being translated are monocistronic.

True

True or false: The energy to carry out the movement of a ribosome comes from GTP.

True

If the RNA transcript resulting from the DNA sequence above is present in the mRNA and translated codon by codon from one end to the other, which of the following polypeptides would correspond to this part of the mRNA? a. NH2 - Met-Ile-Gly-Ser-Ile-His -COOH b. NH2 - Tyr-Leu-Ala-Arg-Lue-Val -COOH c. COOH- Met-Ile-Gly-Ser-Ile-His - NH2 d. COOH- Tyr-Leu-Ala-Arg-Lue-Val - NH2

a. NH2 - Met-Ile-Gly-Ser-Ile-His -COOH

At physiological pH, the ionized state of the amino (NH2) group in the R group of lysine is: a. NH-. b. NH4++. c. NH3+. d. NH2.

a. NH3+.

A consecutive sequence of codons following a start codon is called a: a. reading frame b. genetic code c. gene d. peptide e. template strand

a. reading frame.

Which one of the following types of proteins interacts directly with a stop codon? a. release factor b. initiation factor c. sigma factor d. transcription factor e. elongation factor

a. release factor

Which of the following brings amino acids to the ribosome for use in translation? a. tRNA b. rRNA c. mRNA

a. tRNA

The interactions between amino acids are major factors in determining the shape of a protein. These interactions can be affected by the environment surrounding a protein. Which of the following would have an effect on the shape of a protein? a. the pH of the environment b. All of the other answer options are correct. c. the temperature of the environment d. the concentrations of ions present in the environment e. whether the other molecules in the environment are predominantly hydrophilic or hydrophobic

b. All of the other answer options are correct.

At physiological pH, the ionized state of the carboxyl (COOH) group in the R group of aspartic acid is: a. CO-O-. b. COO-. c. COOH. d. COOH+.

b. COO-.

Which one of the following amino acids is MOST likely to participate in hydrogen bonding with water? a. phenylalanine b. alanine c. asparagine d. valine e. leucine

c. asparagine

Assuming that transcription and translation both proceed from left to right, which is the correct orientation of the DNA template, the RNA transcript, and the protein product? a. DNA template 3'- ......... -5' RNA transcript 5'- ......... -3' Protein product HOOC- ....... ..-NH2 b. DNA template 5'- ......... -3' RNA transcript 5'- ......... -3' Protein product H2N- ....... -COOH c. DNA template 5'- ......... -3' RNA transcript 3'- ......... -5' Protein product HOOC- ....... ..-NH2 d. DNA template 3'- ......... -5' RNA transcript 5'- ......... -3' Protein product H2N- ....... -COOH

d. DNA template 3'- ......... -5' RNA transcript 5'- ......... -3' Protein product H2N- ....... -COOH

During elongation of translation, the growing polypeptide is transferred from the tRNA in the _____ site of the ribosome to the tRNA in the _____ site as a peptide bond is formed between the growing polypeptide and the newest tRNA. a. P; E b. A; P c. E; A d. P; A e. A; E f. E; P

d. P; A

Which of the following codons is capable of terminating translation? a. UAG and UAA b. UGA c. UAG d. UAA e. All of these choices are correct.

e. All of these choices are correct.

Which of the following is a critical region of a tRNA molecule? a. anticodon loop and ribosome binding site b.stop codon and Shine-Dalgarno sequence c. amino acid attachment site and start codon d. ribosome binding site and 5′ cap e. amino acid attachment site and anticodon loop

e. amino acid attachment site and anticodon loop

When a charged tRNA is about to bind to the vacant A site of a ribosome, where is the growing polypeptide?

in the P site

Transcripts of rRNA genes are concentrated in the:

nucleolus

Ribosomes in prokaryotes and eukaryotes are:

similar in structure and translate using the same genetic code.

In which of the following ribosomal sites does the anticodon of a tRNA pair completely with the mRNA codon?

the A site and the P site

In eukaryotes, the AUG codon that starts translation is:

the AUG nearest the 5' cap on the mRNA.

Which cellular processes occurs in the nucleus of a eukaryote?

transcription and RNA processing

Two major types of protein secondary structures are referred to as:

α (alpha) helix and β (beta) sheet.