extra biochem Q's (midterm) Flashcards
Which of the following histone proteins doesn’t participate in forming an octamer protein complex?
a. H1
b. H2A
c. H2B
d. H3
e. H4
a. H1
Which of the following is the function of H1 histone protein?
a. 10-bp linker nucleotide stabilization
b. 30-bp linker nucleotide stabilization
c. 50-bp linker nucleotide stabilization
b. 30-bp linker nucleotide stabilization
Which of the following required cooling?
a. denaturation
b. melting temperature
c. renaturation
c. renaturation
In which of the following is half of the DNA denatured?
a. denaturation
b. melting temperature
c. renaturation
b. melting temperature
Which of the following has a higher melting temperature?
a. G-C rich DNA
b. A-T rich DNA
a. G-C rich DNA
because the G-C bond has 3 hydrogen bonds unlike the A-T which have two
What’s true about prokaryotic gene?
a. they don’t have a promoter region
b. they don’t have introns
b. they don’t have introns
What percent of the human genome is repetitive sequences?
a. 33%
b. 47%
c. 53%
b. 47%
Which best describes Alu elements?
a. promote gene inactivation
b. promote gene activation
a. promote gene inactivation
they do this by inserting themselves in or near genes
Where do Alu elements belong?
a. LINEs
b. SINEs
c. LTR
d. Satelight DNA
b. SINEs
Which of the following does the DnaA protein bind to so it can separate the DNA?
a. replication fork
b. satellite region
c. origin of replication
c. origin of replication
What best describes the origin of replication?
a. recognized by helicase
b. has A-T rich sequences
c. needs cool temperature to open
b. has A-T rich sequences
Which of the following is the function of single stranded binding proteins?
a. protects DNA from nuclease degradation
b. helps keep the two DNA strands separate
c. both
d. neither
c. both
What is FALSE about helicase?
a. binds to origin of replication
b. breaks hydrogen bonds
c. uses ATP for energy
a. binds to origin of replication
it binds to the replication fork created by DNA A
Which of the following relaxes the supercoiled DNA?
a. helicase
b. topoisomerase
c. DNA polymerase III
d. primase
b. topoisomerase
Which of the following is a holoenzyme?
a. helicase
b. topoisomerase
c. DNA polymerase III
d. primase
c. DNA polymerase III
Which of the following is the acceptor site of RNA primer?
a. 5-OH
b. 3-OH
c. 3’-OH
d. 5’-OH
c. 3’-OH
Which characterizes the lagging strand?
a. goes in the 3->5 direction
b. needs one RNA primer
c. synthesized in the direction towards the replication fork
d. synthesized in the direction opposite to the replication fork
d. synthesized in the direction opposite to the replication fork
(its made in the 5’->3’ direction by using many RNA primers)
Which of the following DNA polymerase III subunit proofreads?
a. α subunit
b. θ subunit
c. ε subunit
c. ε subunit
proofreads in the 3’->5’ direction
Which of the following fills in the DNA gap made by the RNA primer in the prokaryotic cell?
a. DNA polymerase I
b. DNA ligase
c. polymerase ε
d. exonuclease
a. DNA polymerase I
Which of the following fills in the DNA gap made by the RNA primer in the eukaryotic cell?
a. DNA polymerase I
b. DNA ligase
c. polymerase ε
d. exonuclease
c. polymerase ε
What’s true about telomerase?
a. acts as RNA primer
b. acts as a reverse transcriptase
c. active in all cells
b. acts as a reverse transcriptase
What exonuclease activity does the prokaryotic DNA Polymerase I have?
a. 5’->3’
b. 3’->5’
c. both
c. both
What exonuclease activity does the prokaryotic DNA Polymerase III have?
a. 5’->3’
b. 3’->5’
c. both
b. 3’->5’
Didanosine is an analog of
a. Guanosine
b. Adenosine
c. Thymidine
d. Adenine
b. Adenosine