Chapter 13

Question 1

The genetic code

Answer 1

• Consist of three ribonucleotide letters

* written in linear form

Question 2

Unambiguous

Answer 2

Each triplet specifies only one amino acid

Question 3

Degenerate

Answer 3

A given amino acid can be specified by more than one triplet codon

Question 4

Commaless

Answer 4

Once translation begins, codons are read with no break

Question 5

Nonoverlapping

Answer 5

Any single ribonucleotide within mRNA is part of one triplet

Reads three nucleotides at a time in continuous manner

Question 6

Colinear

Answer 6

Sequence of codons in a gene is colinear

Question 7

Nearly universal

Answer 7

A single coding dictionary is used by viruses, prokaryote, archaea, and eukaryotes

Question 8

mRNA

Answer 8

Serves as intermediate in transferring genetic information form DNA to proteins

Question 9

The triplet code

Answer 9

Provides 64 codons to specify 20 amino acids.

Question 10

Reading frame

Answer 10

Contiguous sequence of nucleotides. Insertions or deletions shift reading frame and change codons downstream.

Question 11

Polynucleotide phosphorylase

Answer 11

Enzyme that catalyze production of synthetic mRNAs

Question 12

RNA homopolymers

Answer 12

RNA nucleotides with only one type of ribonucleotide.

Question 13

RNA heteropolymers

Answer 13

Two or more different ribonucleotides were used to decipher relative proportion of each type of ribonucleotide diphosphate in synthetic mRNA

Question 14

Triplet binding assay

Answer 14

Developed by Nirenberg and leder

Determines specific codon assignments

Question 15

Chemically synthesized long RNAs

Answer 15

Short repeating sequences enzymatically joined short sequences together making long RNAs

Question 16

Splicing

Answer 16

Removes introns

Question 17

Introns

Answer 17

Regions of initial RNA transcript not expressed in amino acid sequence of protein.

Question 18

Prokaryotes do not have introns

True or false

Answer 18

True

Question 19

Heteroduplexes

Answer 19

Introns present in DNA but not mRNA loop out

Question 20

RNA polymerase II

Answer 20

Responsible for transcription of wide range of genes in eukaryotes

Activity is dependent on cis-acting elements

Question 21

Wobble hypothesis

Answer 21

The initial ribonucleotides of triplet codes are often more critical than the third.

Question 22

Nonsense mutations

Answer 22

Mutations that produce a stop codon internally in gene

Translation is terminated & partial polypeptide is produced

Question 23

Phage MS2

Answer 23

Bacteriophage that infects E. Coli

Question 24

Transcription

Answer 24

RNA synthesized on DNA template

Serves as intermediate molecule between DNA and proteins

Question 25

RNA polymerase

Answer 25

Enzyme directs synthesis of RNA using DNA template

Question 26

Chain elongation

Answer 26

Ribosomes are added to RNA chain

Question 27

Transcription in eukaryotes occurs in

Answer 27

The nucleus--unlike prokaryotes

Question 28

Eukaryotes possess three forms of RNA polymerase

Answer 28

RNA poly I,II,III