Biochemistry Practice Test 9

1. About what proportion of mitochondrial proteins are encoded by nuclear DNA?

More than 95%

1.5%

50%

2. Which of the following promotes branch migration at higher rates than does Rec-A?

Rec-B

Rec-C

Rec-D

Ruv-A and Ruv-B

3. 70S prokaryotic ribosome is the complex of ____________

30S + 40S

20S + 30S

20S + 60S

30S + 50S

4. Which of the following histones shows more sequence similarity among eukaryotic species?

H2B

H2A

5. In the first committed step of pyrimidine biosynthesis, the reaction is catalyzed by ____________

Aspartate transcarbamoylase

Dihyhroorotase

Cytidylate synthase

Adenylate kinase

6. Lignin is derived from ____________

Arginine

Phenylalanine

Valine

Tryptophan

7. Which of the following is not a major class of chromatin proteins?

Cohesins

Topoisomerases

SMC proteins

Histones

8. CTP is formed from UTP by the action of ____________

Aspartate transcarbamoylase

Dihyhroorotase

Adenylate kinase

Cytidylate synthase

9. Which of the following is true about DNA polymerase?

It can synthesize DNA in the 5’ to 3’ direction

It can synthesize mRNA in the 3’ to 5’ direction

It can synthesize DNA in the 3’ to 5’ direction

It can synthesize mRNA in the 5’ to 3’ direction

10. What is the reaction in DNA replication catalyzed by DNA ligase?

Base pairing of the template and the newly formed DNA strand

Formation of a phosphodiester bond between the 3’-OH of one Okazaki fragment and the 5’-phosphate of the next on the lagging strand

Addition of new nucleotide to the lagging strand

Addition of new nucleotides to the leading strand