Deck 13: Translation: From Nucleic Acids to Amino Acids

Question 1

The majority of genes in mammals encode proteins

Answer 1

False

Question 2

Which of the following statements about transcription and translation are true? Please select all that apply.

A) Translation in bacteria begins before mRNA transcription is completed
B) rRNA is involved in translation
C) Transcription is more conserved between species than translation
D) mRNA is transported out of the nucleus in eukaryotes

Answer 2

Translation in bacteria begins before mRNA transcription is completed
rRNA is involved in translation
mRNA is transported out of the nucleus in eukaryotes

Question 3

Put the following events in translation in order.

-tRNA is charged with amino acid

A) 1 (first)
B) 2
C) 3
D) 4

Answer 3

1 (first)

Question 4

Put the following events in translation in order.

-tRNA interacts with mRNA

A) 1 (first)
B) 2
C) 3
D) 4

Question 5

Put the following events in translation in order.

-Peptide bond forms

A) 1 (first)
B) 2
C) 3
D) 4

Question 6

Put the following events in translation in order.

-tRNA leaves the ribosome4

A) 1 (first)
B) 2
C) 3
D) 4

Question 7

Match the missing words in the following phrase. [A] on [B], which is held within a tunnel in the [C], base-pairs with [D] on tRNA. The 5' of the anticodon corresponds to the [E] of the codon and the 3' of the anticodon correspond to the [F] of the codon.

Question 8

There are 4 different bases and 64 possible codons in the genome, 20 different amino acids, and a large but variable number of tRNA genes (400-500 in mammals). How many aminoacyl synthetase genes are there?

A) 4
B) 64
C) 20
D) The same number as there are tRNA genes

Question 9

Match the site in the ribosome to its function.

-Charged tRNA enters the ribosome

A) (A) site
B) (P) site
C) (E) site

Question 10

Match the site in the ribosome to its function.

-tRNA holds the growing amino acid chain

A) (A) site
B) (P) site
C) (E) site

Question 11

Match the site in the ribosome to its function.

-Uncharged tRNA leaves the ribosome

A) (A) site
B) (P) site
C) (E) site

Question 12

Which of the following are characteristics of translation initiation? Please select all that apply.

A) The initiator codon arrives at the A site
B) The first translated codon is for methionine
C) tRNA used for initiation is not used for elongation
D) Translation starts at the 5' UTR of the mRNA

Question 13

Which of the following is not true of translation termination?

A) Stop codons bind to special tRNA molecules
B) There are three possible stop codons
C) Release factor proteins free the polypeptide from the ribosome
D) Mutations in tRNA molecules can affect translation termination

Question 14

During which stage of translation is translational regulation most likely to occur?

A) Termination
B) Elongation
C) Initiation

Question 15

Iron response proteins (IRPs) are involved in regulating iron levels in the cell through translational regulation. Which of the following statements regarding IRP regulation is untrue?

A) IRP binds to iron
B) Ferritin is produced when there is too much iron in the cell
C) IRP binding prevents transferrin translation
D) Transferrin is produced when there is too little iron in the cell
E) IRP binds to 3' and 5' UTRs

Question 16

The regulation that determines the anterior and posterior ends of a developing Drosophila embryo is primarily ______

A) maternal vs paternal translation
B) transcriptional
C) temporal
D) spatial

Question 17

Match the missing words in the following phrase. In developing Drosophila embryos, [A] mRNA is evenly distributed through the embryo whereas [B] mRNA is confined to the posterior pole. Nanos protein binds to hunchback mRNA and represses its transcription. This produces a gradient of Nanos protein in the embryo, with more at the [C] end, and a corresponding gradient of Hunchback protein, with more at the [D] end.

Question 18

Fill in the blank. Position 3 in the codon is the least likely to influence which amino acid is encoded and has the weakest base-pair interaction; i.e., the position can _______

Question 19

AUU, AUC, and AUA all encode isoleucine, but AUA is used only ~10% of the time. Why is this thought to be the case?

A) A and G are both purines
B) U and C are both pyrimidines
C) U and C are both purines
D) A and G are both pyrimidines

Question 20

Biochemically similar amino acids are likely to have similar codons. This reduces the chance that a mutation will cause an amino acid to be substituted with a different amino acid.

Question 21

What is an evolutionarily accepted mutation?

A) A mutation that is very rarely observed
B) A mutation that leads to a change in the amino acid code
C) A mutation that leads to replacement of an amino acid with a biochemically similar amino acid
D) A mutation that does not have adverse impact on the function of a protein

Question 22

What is the term used for a mutation that overcomes the effect of another mutation?

A) Nonsense mutation
B) Nonsense suppressor
C) Suppressor mutation
D) Amber mutation

Question 23

Position-specific weight matrix tables show relatively few substitutions for cysteine and tryptophan compared with other proteins. Which of the following are possible explanations for this? Please select all that apply.

A) Cysteine and tryptophan are more likely to have essential roles in the mature protein than other amino acids
B) Cysteine and tryptophan are larger than other amino acids.
C) Cysteine and tryptophan have unusual structures
D) The codons for cysteine and tryptophan are similar to a stop codon

Question 24

Fill in the blank. Descent from a common ancestor is defined as ______

Question 25

What is a BLOSUM matrix used for?

A) To assess the probability that amino acid changes in a protein occurred by chance
B) To show all the amino acid changes that have occurred over evolutionary time
C) The test the probability that a base change will result in a change to an amino acid
D) To show the probability of a base change resulting in no change to an amino acid

Question 26

With a few exceptions, the genetic code is universal. What are the implications of this? Please select all that apply.

A) All living organisms can be traced to a common ancestor
B) Finite genetic differences between organisms underlie their relatedness
C) A gene from one organism can be translated by another organism and the same protein produced.
D) Transcriptional and translational regulation are universal

Question 27

The majority of polypeptides are post-translationally modified.

Question 28

Which of the following is not a post-translational modification?

A) Ubiquitylation
B) Methylation
C) Proteolytic cleavage
D) Addition of a 5' cap

Question 29

Fill in the blank. _____ enzymes carry out post-translational phosphorylation of peptides.

Question 30

Match the levels of protein structure to their descriptions.

-Peptide amino acid sequence

A) Primary structure
B) Secondary structure
C) Tertiary structure
D) Quaternary structure

Question 31

Match the levels of protein structure to their descriptions.

-Regional folding

A) Primary structure
B) Secondary structure
C) Tertiary structure
D) Quaternary structure

Question 32

Match the levels of protein structure to their descriptions.

-Three-dimensional structure of complete polypeptide

A) Primary structure
B) Secondary structure
C) Tertiary structure
D) Quaternary structure

Question 33

Match the levels of protein structure to their descriptions.

-Combination of multiple subunits and other molecules

A) Primary structure
B) Secondary structure
C) Tertiary structure
D) Quaternary structure