Name: _____________________________________________________ Pd.: ________ Date: ______________________
Homework – DNA Replication
1. The process by which DNA is copied during the cell cycle is called ______________________________________.
2. The diagram at the left represents the cell cycle. During what stage of
the cell cycle is DNA copied?
3. Why must DNA replicate itself before the cell divides?
_________________________________________________________
_________________________________________________________
4. How many chromosomes are in a human somatic cell? _____________
5. After mitosis, how many chromosomes are in each of the daughter
cells? ________________________
6. The process of replication
is shown in the series of
diagrams at the left. In
the first diagram, what
unzips the DNA molecule?
______________________
7. What kind of bonds are
being broken as the DNA
strands are unzipped?
______________________
8.
In the second diagram,
what bonds the free
floating nucleotides
together to form the new
strands of DNA?
______________________
9. In the last diagram, two
identical molecules of DNA
result. DNA replication is
called _________________
because one old strand is
conserved, and one
complementary new strand
is made.
10. DNA replication takes about eight hours in human cells.
The chromosomes have many origins of replication as
shown in the diagram. The DNA is unzipped at many
points along each chromosome and replication proceeds in
both directions. If there were only one origin, the process
would take about a hundred times longer. In human cells,
about _________ nucleotides are added every second to a
new strand of DNA at an origin of replication.
11. The process that makes an exact copy of a cell's DNA is called
a. conservation.
b. preservation.
c.
replication.
d. synthesis.
12. What are the main functions of DNA polymerase?
a. breaks hydrogen bonds and exposes bases
b. holds DNA strands apart and attracts bases
c.
zips and unzips the double-stranded DNA
d. binds nucleotides and corrects base pair errors
13. Which of the following events occurs directly after a DNA molecule is unzipped?
a. Mismatched nucleotide bases are identified and replaced.
b. Free-floating nucleotides pair up with exposed bases.
c.
Identical double-stranded DNA molecules are formed.
d. Enzymes break hydrogen bonds between base pairs.
14. When new DNA molecules are formed, almost all errors are detected and fixed by
a. the correct nucleotide.
b. the sugar-phosphate backbone.
c.
DNA polymerase.
d. one DNA strand.
15. Replicate the following strand of DNA: A T T C G G C A T C C T C G C G G A