From DNA To Proteins - Translation

Question 1

Genetic Code Table

Answer 1

A table containing codons that can be used to translate a genetic code into a sequence of amino acids.

Question 2

Polypeptide

Answer 2

Chain of amino acids linked by peptide bonds; also called a protein.

Question 3

Protein Structure

Answer 3

The arrangement of the chains of amino acids in proteins. It has several levels of organization (primary, secondary, tertiary, and quaternary).

Question 4

Peptide Bond

Answer 4

Chemical bond that connects amino acids in a protein.

Question 5

Amino Acid

Answer 5

Repeating unit of proteins; each consists of a central carbon atom bonded to an amino group, a hydrogen atom, a carboxyl group, and an R group.

Question 6

Nonoverlapping Genetic Code

Answer 6

Refers to the fact that, generally, each nucleotide is part of only one codon and encodes only one amino acid in a protein.

Question 7

Sense Codon

Answer 7

Codon that specifies an amino acid in a protein.

Question 8

Universal Genetic Code

Answer 8

Refers to the fact that particular codons specify the same amino acids in almost all organisms.

Question 9

Codon

Answer 9

Sequence of three nucleotides that encodes one amino acid in a protein.

Question 10

Degenerate Genetic Code

Answer 10

Refers to the fact that the genetic code contains more codons than are needed to specify all 20 common amino acids.

Question 11

Kozak Sequence

Answer 11

A sequence that functions as the protein translation initiation site in most eukaryotic mRNA transcripts.

Question 12

Initiation (Start Codon)

Answer 12

The first codon of the mRNA to specify an amino acid (fMet in bacterial cells; Met in eukaryotic cells); most often AUG.

Question 13

Isoaccepting tRNAs

Answer 13

Different tRNAs that accept the same amino acid but have different anticodons.

Question 14

Synonymous Codons

Answer 14

Different codons that specify the same amino acid.

Question 15

Initiation Of Translation

Answer 15

The process in which initiator tRNA, small and large ribosomal subunits are assembled by eukaryotic initiation factors into a ribosome at the initiation codon of mRNA.

Question 16

Termination Of Translation

Answer 16

The stage of translation when a stop codon in the mRNA enters the A site. Stop codons are recognized by proteins called release factors, which fit neatly into the P site (though they aren’t tRNAs).

Question 17

Nonsense Codon

Answer 17

Codon in mRNA that signals the end of translation. Also called a stop codon.

Question 18

Stop (Termination) Codon

Answer 18

Codon in mRNA that signals the end of translation. The three common stop codons are UAA, UAG, and UGA.

Question 19

Elongation Of Translation

Answer 19

The stage of translation in which the nascent polypeptide chain extends by one amino acid during one elongation cycle.

Question 20

Wobble

Answer 20

Base pairing between codon and anticodon in which there is nonstandard pairing, usually at the third 3’ position of the codon; allows more than one codon to pair with the same anticodon.

Question 21

tRNA charging

Answer 21

Chemical reaction in which an aminoacyl-tRNA synthetase attaches an amino acid to its corresponding tRNA.

Question 22

Reading Frame

Answer 22

Particular way in which a nucleotide sequence is read in groups of three nucleotides (codons) in translation; begins with a start codon and ends with a stop codon.

Question 23

Initiation Factors

Answer 23

Proteins that bind to the small subunit of the ribosome during the initiation of translation.

Question 24

Ribosome

Answer 24

An intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell.

Question 25

Aminoacyl-tRNA Synthetase

Answer 25

Enzyme that attaches an amino acid to a tRNA. Each of these recognizes a particular amino acid.

Question 26

Small Ribosomal Subunit

Answer 26

The smaller of the two subunits of a functional ribosome.

Question 27

Aminoacyl (A) Site

Answer 27

One of the three sites in a ribosome occupied by a tRNA during translation. All charged tRNAs (with the exception of the initiator tRNA) first enter this site.

Question 28

Large Ribosomal Subunit

Answer 28

The larger of the two subunits of a functional ribosome.

Question 29

Peptidyl (P) Site

Answer 29

One of the three sites in a ribosome occupied by a tRNA during translation. In the elongation stage, tRNAs move from the aminoacyl (A) site into this site.

Question 30

Exit (E) Site

Answer 30

One of the three sites in a ribosome occupied by a tRNA during translation. In the elongation stage, the tRNA moves from the peptidyl (P) site to this site, from which it then leaves the ribosome.

Question 31

Elongation Factors

Answer 31

Proteins that function at the ribosome, during protein synthesis, to facilitate translational elongation from the formation of the first to the last peptide bond of a growing polypeptide.

Question 32

Polyribosome

Answer 32

Messenger RNA molecule with several ribosomes attached to it.

Question 33

Release Factor

Answer 33

Protein required for the termination of translation; binds to a ribosome when a stop codon is reached and stimulates the release of the polypeptide chain, the tRNA, and the mRNA from the ribosome.

Question 34

Translocation

Answer 34

Movement of a ribosome along mRNA during translation.