1. REPLICATION

2. 1.
Before a cell divides,
the bonds between the
complementary
bases
break in short sections
of the double-stranded
DNA molecules, and the
complementary strands
separate
from
one
another (UNWINDING/
UNZIPPING)

3. • Each split in the
molecule is called a
REPLICATION FORK
2. At the forks, each
separated strand serves
as a template for the
synthesis of a new
complementary strand

4. 3. In a process
directed by enzymes,
free nucleotide units
that are present in
the nucleus link to
complementary
bases on each of the
DNA strands

5. The sugars and
phosphates of the
new nucleotides
bond together to
form the backbones
of both new strands
4.

6. • The process of DNA
replication begins
with one doublestranded DNA
molecule and ends
with 2 double
stranded DNA
molecules

7. • Each double strand
contains one strand
from the parent
molecule + a new
complementary strand
assembled from free
nucleotides

8. • Each of the new
double stranded
molecules is identical
to the other and is
also identical to the
original parent
molecule

9. PROTEIN
SYNTHESIS

10. TRANSCRIPTION

11. 1.Protein synthesis
begins once the
double-stranded
DNA molecule
unzips
2.Double helix
uncoils

12. 3. Nucleotides from the
mRNA find the
appropriate pair by
using the single
stranded DNA as
blueprint
* Soon mRNA
nucleotides are joined
into a long chain

13. 4. Once the chain has
been fused, the mRNA
molecule moves away
from the parent DNA
strand
* The 2 strands of the
original DNA rejoins

14. • THE PROCESS OF
TRANSCRIPTION IS
COMPLETE
• ss mRNA molecule
moves through the
nuclear membrane &
carries the nitrogen base
code to the ribosomes in
the cytoplasm

15. TRANSLATION

16. 1. mRNA attaches itself
to the ribosome
much like a ribbon
2. An initiator codon
turns on the protein
synthesis

17. tRNA picks up
amino acids that are
circulating within the
cytoplasm and
shuttles them to the
mRNA
3.

18. 4. The
amino acid is held
in place against one
end of the clover-leafshaped molecule
* The other end of the
tRNA molecule has a
plug-shaped structure
with 3 nitrogen bases
exposed (ANTICODON)

19. • Each kind of tRNA
molecule has a specific
anticodon
5. The mRNA moves
along the ribosome
much like a typewriter
ribbon

20. 6. A new codon of mRNA
is then exposed for
fitting with another
tRNA anticodon
7. The amino acid carried
by the tRNA molecules
are fused into longchain proteins on the
ribosome

21. 8. The sequencing of
the amino acid is
determined by the
message carried
from the nucleus by
the mRNA molecule

22. 9. Once the protein
molecule has been
built, a terminator
codon turns the
synthesis off and the
process of translation is
complete