BMS 127 Ch. 7 Microbial Genetics

Question 0

Which of the following is a true statement concerning prokaryotic chromosomes?

a. They typically have two or three origins of replication.
b. They contain single-stranded DNA
c. They are located in the cytosol
d. They are associated in linear pairs

Answer 0

c. They are located in the cytosol

Question 1

Which of the following is most likely the number of base pairs in a bacterial chromosome?

a. 4,000,000
b. 4000
c. 400
d. 40

Answer 1

a. 4,000,000

Question 2

What is a plasmid?

Answer 2

Extrachromosomal DNA

Question 3

What the function of a histone?

Answer 3

to form ionic bonds with eukaryotic DNA and stabilizes

Question 4

Nucleotides used in the replication of DNA

a. carry energy.
b. are found in four forms, each with a deoxyribose sugar, a phosphate, and a base
c. are present in the cytosol of cells as triphosphate nucleotides
d. all of the above

Answer 4

d. all of the above

Question 5

What molecule functions as a “proofreader” for a newly replicated strand of DNA?

Answer 5

DNA Polymerase III

Question 6

What is the addition of -CH3 to a cytosine nucleotide after DNA replication called?

Answer 6

methylation

Question 7

In translation, what is the biding site through which tRNA molecules leave?

Answer 7

E site

Question 8

What does the Ames test use to reveal potential mutagens?

Answer 8

auxotrophs and liver extract

Question 9

What method of DNA repair involves enzymes that recognize and correct nucleotide errors in unmethylated strands of DNA?

Answer 9

mismatch repair

Question 10

Which of the following is NOT a mechanism of natural genetic transfer and recombination?

a. transduction
b. transformation
c. transcription
d. conjugation

Answer 10

c. transcription

Question 11

Cells that have the ability to take up DNA from their environment are said to be ________.

Answer 11

competent

Question 12

Conjugation requires a ________ extending from the surface of a cell.

Answer 12

sex pilus

Question 13

What genes are “jumping genes”?

Answer 13

transposons

Question 14

Although cells P and Q are totally unrelated, cell Q receives DNA from cell P and incorporates this new DNA into its chromosome. This is a process called ________.

Answer 14

horizontal gene transfer

Question 15

Which of the following is part of each molecule of mRNA?

a. palindrome
b. codon
c. anticodon
d. base pair

Answer 15

b. codon

Question 16

A nucleotide is composed of

a. a five carbon sugar
b. phosphate
c. a nitrogenous base
d. all of the above

Answer 16

d. all of the above

Question 17

In DNA, adenine forms ________ hydrogen bonds with _________.

Answer 17

two; thymine

Question 18

What is a sequence of nucleotides formed during replication of the lagging DNA strand?

Answer 18

an Okazaki fragment

Question 19

Which of the following is not part of an operon?

a. operator
b. promoter
c. origin
d. gene

Answer 19

c. origin

Question 20

Repressible operons are important in regulating prokaryotic _________.

Answer 20

RNA transcription

Question 21

What does transcription produce?

Answer 21

RNA molecules

Question 22

What does ligase play a major role in?

Answer 22

lagging strand replication

Question 23

Before mutations can affect a population permanently, they must be

a. lasting
b. inheritable
c. beneficial
d. all of the above

Answer 23

d. all of the above

Question 24

The three steps in RNA transcription are ________, ________ and _______.

Answer 24

initiation; enlongation; termination

Question 25

A triplet of mRNA nucleotides that specifies a particular amino acid is called a ________.

Answer 25

codon

Question 26

Three effects of point mutations are ______, _______ and ________.

Answer 26

silence; missense; and nonsense

Question 27

Insertions and deletions in the genetic code are also called _______ mutations.

Answer 27

frameshift

Question 28

An operon consists of _______, ______ and _________ and is associated with a regulatory gene.

Answer 28

promoter; operator; series of genes

Question 29

In general, __________ operons are inactive until the substrate of their genes’ polypeptides is present.

Answer 29

inducible

Question 30

A daughter DNA molecule is composed of one original strand and one new strand because DNA replication is ____________.

Answer 30

semiconservative

Question 31

A gene for antibiotic resistance can move horizontally among bacterial cells by ________, __________ and ____________.

Answer 31

transformation; transduction; bacterial conjugation

Question 32

____________ are nucleotide sequences containing palindromes and genes for proteins the cut DNA strands.

Answer 32

Transposons

Question 33

_______ _______ is a recombination event that occurs during gamete formation in eukaryotes.

Answer 33

Crossing over

Question 34

______RNA carries amino acids.

Answer 34

Transfer

Question 35

______ RNA and _______ RNA are antisense; that is, they are complementary to another nucleic acid molecule.

Answer 35

Short interference; micro