MOLECULAR AND CELLULAR
BIOLOGY TEST BANK 6 EXAM 1
WITH QUESTIONS AND WELL
IDENTIFIED ANSWERS[GRADED A+]
The process of DNA replication requires
... [Show More] that each of the parental DNA
strands be used as a _____ to produce a duplicate of the opposing
strand - ANS-(c) template
DNA replication is considered semiconservative because - ANS-(c)
each daughter DNA molecule consists of one strand from the parents
DNA molecules and one new strand
(d) true, but not correct - new DNA strands must be copied from a DNA
template
The classic experiments conducted by Meselson and Stahl
demonstrated that DNA replication is accomplished by employing a
mechanism - ANS-(b) semiconservative
If the genome of the bacterium E. coli requires about 20 minutes to
replicate itself, how can the genome of the fruit fly Drosophila be
relocated in only 3 minutes? - ANS-(d) Drosophila DNA contains more
origins of replication than E. coli DNA
6-6 - ANS-
(A) When DNA is being replicated inside a cell, local heating occurs,
allowing the two strands to separate
(B) DNA replication origins are typically rich in G-C base pairs
(C) Meselson and Stahl ruled out the dispersive model for DNA
replication
(D) DNA replication is a bidirectional process that is initiated at
multiple locations along chromosomes in eukaryotic cells - ANS-(A)
FALSE - the two strands do need to separate for replication to occur
but this is accomplished by the binding of initiator proteins at the
origin of replication
(B) FALSE - DNA replication origins are typically rich in A-T base pairs,
which are held together by only two hydrogen bonds (instead of three
for C-G base pairs), making it easier to separate the strands at these
sites
(C) TRUE
(D) TRUE
How many replication forks are formed when an origin of replication is
opened? - ANS-(b) 2
(A) On a DNA strand that is being synthesized, which end is growing -
the 3' end, the 5' end, or both ends?
(B) On a DNA strand that is being used as a template, where is the
copying occurring relative to the replication origin - 3' of the origin, 5',
or both? - ANS-(A) The 3' end - DNA polymerase can add nucleotides
only to the 3'-OH end of a nucleic acid chain
(B) Both, as a result of the bidirectional nature of chromosomal
replication
How does the total number of replication origins in bacterial cells
compare with the number of origins in human cells? - ANS-(d) 1 verses
10,000
Which of the following statements correctly explains what it means for
DNA replication to be bidirectional? - ANS-(d) the replication forks
formed at the origin move in opposite directions
Initiator proteins bind to replication origins and disrupt hydrogen
bonds between the two DNA strands being copied. Which of the
factors below does not contribute to the relative ease of strand
separation by initiator proteins? - ANS-(b) the reaction can occur at
room temperature
The chromatin structure in eukaryotic cells is much more complicated
than that observed in prokaryotic cells. This is thought to [Show Less]