Exam 3 review

Question 1

What was the conclusion of Avery’s experiment in 1944?

Answer 1

That DNAse destroyed the transforming principle.

Question 2

In Griffith’s Transformation experiment in 1928 what became transformed?

Answer 2

R-Bacteria were transformed to S-bacteria

Question 3

Transcription produces which of the following?
A. BI-directional DNA
B. Transfer RNA
C. amino acids
D. semi-conservative DNA
E. Proteins

Answer 3

B. Transfer RNA

Question 4

If DNA from a particular species contains 30% Adenine, how much Guanidine does it contain?

Answer 4

20%

Question 5

Which of the following is TRUE in a DNA double helix?
A. The two DNA strands are complementary
B. Purines pair with Purines
C. Thymine pairs with Cytosine
D. The sugars in the backbone are ribose
E. Two of these are true

Answer 5

A. The two DNA strands are complementary

Question 6

The fact that replication forks each contain a leading strand and a lagging strand means that the DNA replication is:
A. bi-directional
B. asymmetrical
C. processive
D. semi-conservative
E. error prone

Answer 6

B. asymmetrical

Question 7

For the single strand of DNA 5’-CCGGTTAA-3’ what would be the opposite strand?

Answer 7

5’-GGCCAATT-3’

Question 8

The region of DNA at which RNA polymerase binds to start transcription is the:

Answer 8

Promoter

Question 9

Which of the following is NOT TRUE of RNA molecules?
A. the molecules are single-stranded
B. Nucleotides include adenine, guanine, cytosine, and uracil
C. the sugar found in the nucleotides is ribose
D. They are very stable and last a long time.
E. Actually all of these are

Answer 9

D. They are very stable and last a long time.

Question 10

The genetic code is said to be ________ because more than one codon can specify an amino acid

Answer 10

degenerate

Question 11

Which molecules code for proteins?
A. tRNA
B. mRNA
C. rRNA
D. all of these
E. two of these

Answer 11

B. mRNA

Question 12

Which tRNA binding site is the entry point for tRNA’s in the ribosome?

Answer 12

The A site

Question 13

TRUE or FALSE The stop codons do not specify amino acids but the start codon does.

Answer 13

TRUE

Question 14

Which of the following is true regarding bacterial transcription?
A. RNA polymerase binds to the promoter and waits for sigma factor to start transcribing.
B. Sigma factor binds to the promoter and waits for the polymerase to start transcribing
C. Sigma factor must be released to enter elongation.
D. RNA polymerase starts from a primer made by the primase
E. RNA polymerase binds to DNA only with the sigma factor.

Answer 14

C. Sigma factor must be released to enter elongation.

Question 15

The main reason why DNA replication has to be asymmetrical is that
A. DNA polymerase proofreads
B. DNA polymerase is a 3’ to 5’ nucleotide polymerase
C. DNA polymerase requires a primer
D. DNA polymerase uses the 3’hydroxyl group from the nucleotide just added
E. two of these are correct.

Answer 15

D. DNA polymerase uses the 3’hydroxyl group from the nucleotide just added

Question 16

During replication the 2 strands of the DNA molecule are unwound from one another by enzymes called
A. ligases
B. unwindases
C. RNA polymerase
D. helicases
E. primases

Answer 16

D. helicases

Question 17

The strand of the DNA double helix from which RNA polymerase reads is called the 
A. transcription strand
B. sense strand
C. translation strand
D. template strand
E. copy strand

Answer 17

D. template strand

Question 18

TRUE or FALSE both the Lac and Trp operons are under negative control

Answer 18

TRUE

Question 19

When bound to the DNA, the repressor protein usually prevents attachment of the RNA polymerase to the 
A. operon
B. operator
C. promoter
D. regulator
E.activator

Answer 19

C. promoter

Question 20

–Promoter-Operato–GeneA–GeneB–

Answer 20

Negative transcriptional control

Question 21

An activator protein that cannot bind to the activator binding site if a particular substance is present in the bacterial cell

Answer 21

Negative transcriptional control, repressable gene

Question 22

The presence of a particular substance in the bacterial cell causes an operon to be transcribed

Answer 22

Inducible gene

Question 23

The tryptophan operon co-repressor is

Answer 23

Tryptophan

Question 24

Thymine Dimers are fixed by:
A. Base excision repair
B. Nucleotide excision repair
C. Mismatch repair
D. Proofreading
E. Actually, they aren't fixed

Answer 24

B. Nucleotide excision repair

Question 25

Mutations allowing for substitution of one purine for another or one pyrimidine for another is called a:
A. Transversion mutation
B. Transition mutation
C. Frameshift mutation
D. Silent mutation
E. Nonsense mutation

Answer 25

B. Transition mutation

Question 26

What type of mutation converts a codon for one amino acid, to a stop codon?

Answer 26

Nonsense Mutation

Question 27

Which type of mutation involves a single base substitution that changes a codon for one amino acid into a codon for another?

Answer 27

Missense mutation and point mutation

Question 28

When bacterial genes are transferred to another bacterium by a virus, it is called

Answer 28

Transduction

Question 29

Lysine auxotrophs:
A. Produce their own lysine, and can only grown on media without lysine
B. Produce their own lysine, and can only grow on media with Lysine added
C. Shut off the Lys operon instead of turning it on
D. Are unable to produce lysine, and can only grow on media without lysine
E. Are unable to produce lysine, and can only grow on media with lysine added.

Answer 29

E. Are unable to produce lysine, and can only grow on media with lysine added.

Question 30

Complementary DNA (cDNA)  molecules are produced using 
A. Restriction endonucleases
B. RNA Polymerase
C. DNA ligase
D. Reverse transcriptase
E. RNA Polymerase

Answer 30

D. Reverse transcriptase

Question 31

A DNA molecule used to carry a foreign gene into a host organism is called a: 
A. Plasmid
B. Vector
C. Probe
D. Blot
E. Phage

Answer 31

B. Vector

Question 32

Which of the following best describes the basis for separation of DNA fragments during agarose gel electrophoresis?
A. The fragments with the highest percentage of G and C will migrate fastest
B. The fragments with the highest percentage of A and T will migrate fastest
C. The largest fragments will migrate fastest
D. The smallest fragments will migrate fastest.
E. Small and large fragments will migrate at equal rates.

Answer 32

D. The smallest fragments will migrate fastest.

Question 33

The purpose of the Southern blotting technique is to:

Answer 33

Detect specific DNA fragments from a mixture of DNA molecules

Question 34

In the polymerase chain reaction (PCR), each cycle increases the DNA copy number how?

Answer 34

Exponentially