Name:________________________________ Date:____________ Period:______
DNA Structure Review
1. The structure of DNA is made up subunits shown on the diagram by an X. This
subunit is called a ________________.
2. The rings labeled A, T, G, and C represent ______________________.
3. The pentagon shaped structures in the molecule are sugars which in DNA are ______________.
4. The shape of DNA is described as a ______________________________.
5. Before a cell goes through either mitosis (an identical cell formed) or meiosis (a gamete cell such
as an egg or sperm formed) the process of ____________________ must be carried out by the
DNA in the nucleus.
6. There are two types of nitrogen bases purines (double-ringed) such as ________________ and
pyrimidines (single-ringed) such as ______________________. In 1950, Erwin Chargaff and
colleagues examined the chemical composition of DNA and demonstrated that the amount of
adenine always equals that of thymine, and the amount of guanine always equals that of cytosine.
This observation became known as Chargaff's rule. Therefore because of these base-pairing
relationships the amount of ________________ is equal to the amount of
____________________ in DNA. Describe the base-pairing rules that are used to form
complementary strands of DNA
7. A segment of a DNA strand has the following bases: 5’ TAC GAT 3’. What is the complementary
strand of DNA?
8. During DNA replication, a DNA strand that has the bases 3’ CTAGGT 5’ produces a strand with
the bases:
9. The three basic steps for DNA replication are listed below. Write the name of enzyme
responsible for each step
a.
Unwinding -
b. Adding nucleotides complementary to a parent strand –
c. Attaching fragments together 10. DNA replication is called semi-conservative because the new strands that are produced consist
of one ________ strand and one __________ strand. The strand that is leading strand is
replicated ___________________. The complementary strand requires RNA primers to
provide a 5’ end and produces fragments called _________________ fragments.
11. DNA replication occurs in the ____________________, another process that occurs in the
nucleus is ___________________ which produces _______________________ that leaves
the nucleus and enters the ________________. The final step of the central dogma is the
production of proteins that involve specific amino acid carrying delivery trucks
_______________ that bind to ribosomes – protein factories based on a ________ sequence.