CHAPTER 9—FROM DNA TO PROTEIN

There are how many different types of amino acids?

20 different amino acids

The genetic code is made up of units consisting of how many nucleotides?

3 nucleotides

How many different RNA codons are listed on the Genetic Code chart?

64 different RNA codons

The two steps of transCription followed by transLation.

describe the flow of genetic information

Of all the different codons that exist, three of them

do not specify a particular amino acid and provide instructions such as STOP.

DNA & RNA are alike in a. pentose sugar. b. nitrogenous bases. c. number of strands. d. function in genetics. e. none of these.

e. None of these

Ricin is

e. a substance found in castor bean seeds & a protein that inactivates ribosomes.

During the termination stage a. a STOP codon enters the ribosome. b. release factors bind the ribosome. c. ribosomal subunits separate. d. mRNA detaches from the ribosome and the polypeptide chain. e. all of these occur.

e. all of these occur during the termination stage

A gene mutation a. is a change in the nucleotide sequence of DNA. b. may arise spontaneously. c. can occur in any organism. d. may be caused by environmental agents. e. is described by all of these.

e. is described by all of these

Which stage of transLation is shown in the figure

elongation

A frameshift mutation results in a/an

error in mRNA splicing

The portion of the DNA mol that is not translated and is a non-coding portion of DNA is called

exons

The portion of the DNA molecule that is transLated is composed of

exons

. Before messenger RNA is mature,

a cap and a tail are provided

Frameshift mutations may involve

addition or deletion of one or more base pairs

A polysome is

an mRNA molecule with several ribosomes attached

The relationship between strands of RNA & DNA is

complementary

Ribosomal subunits

converge only when mRNA is to be translated

Which of the following carries amino acids to the ribosomes?

tRNA

A single mutation involving the second letter of codon AUA would convert it to this codon.

AAA

This codon is complementary to the Anti-codon UUU

AAA

If the 4th base from the left (C) in RNA were deleted, what would the new 4th codon be?

AGA

. If the fourth base from the left (C) in RNA were deleted, what would the new 3rd codon be?

AGG

This codon specifies an amino acid and indicates the beginning of a coding region.

AUG

Which of the following statements is true? a. Gene mutations occur independently of each other. b. Gene mutations are relatively rare. c. Ionizing radiation causes chromosome damage & free radical formation. d. Mutations are random; that is, it's impossible to predict exactly when a specific gene will mutate, but an expected frequency can be assigned. e. All of these are true

All are true

What molecules carry protein-assembly instructions from the nucleus to the cytoplasm.

Messenger RNA

All of the different kinds of RNA are transCribed in the

Nucleus

Which event occurs during the elongation stage? a. Peptide bonds form.

Peptide bonds form, & anticodons bind to complementary codons.

The helix structure on the right of the figure represents

RNA

Which of the following dominates in the process of transCription?

RNA polymerase

The form of RNA that carries the code from DNA to the site of protein assembly is called

Transfer RNA

A DNA codon of ATT would be complementary to this RNA codon.

UAA

This codon terminates a coding region.

UAA

If the DNA triplets are ATGCGT, the mRNA codons are

UACGCA

The anticodon AAA would pair with this codon.

UUU

This codon specifies the amino acid phenylalanine.

UUU

What amino acid is carried by the 2nd anti-codon in the figure?

Valine

Four of the five answers listed below are components of a nucleotide EXCEPT? a. pentose sugar b. amino acid c. pyrimidine d. phosphate group e. purine

b. amino acid

Ricin is toxic because it

inactivates ribosomes

When a gene transCription occurs, which of the following is produced?

messenger RNA

The 1st amino acid of a new polypeptide chain is

methionine

The sequence of amino acids specified by the mRNA codons AUGCGUCCA is

methionine ---> arginine ----> proline.

The structure in the figure depicts which of the following?

multiple ribosomes on a strand of mRNA

What stage of translation occurs when ribosomal subunits & tRNAs converge around a mRNA transcript?

peptide bond formation

Which event of transLation is shown in the figure?

peptide bond formation?

TransCription starts at a region of DNA called a(n)

promoter

In this depiction of transCription: the ____ strand is ____ because it ____.

the lower strand is RNA because it contains uracil.

If the DNA nucleotides read ATGCGTGAC, the amino acid sequence of the resulting polypeptide would be

tyrosine ---> alanine ----> leucine.