DNA Replication, Transcription and Translation

Turning genes into proteins

DNA Replication

DNA replication

– Takes place in the nucleus

– Requires 2 enzymes

Purpose- to make copies of DNA

How is DNA replication related to mitosis?

Complimentary Base Pairing

• The 2 sides of DNA are not exactly the same, they are complimentary.

• If on one side of the DNA strand there is the nucleotide Cytosine, the opposite side will have Guanine, Adenine always pairs with Thymine.

• Remember Chargaff’s rule!

DNA Replication

DNA is replicated through…

1) The unwinding of DNA’s double helix.

2) Separation of strands by helicase

3) Formation of new complementary strands by DNA polymerase.

Step 2- enzyme DNA polymerase adds complimentary base pairs to the original

parent strand.

Step 1- an enzyme, helicase, opens up the original DNA molecule.

helicase

There are now 2 new DNA molecules each with an original parent strand.

Replication Review

• Where does replication take place?

• What are the enzymes involved and what do they do during replication?

• What is a gene?

• Approximately how many genes do you have?

• How is DNA replication related to mitosis?

• Explain complimentary base pairing. Which scientist helped to prove this? (hint: there is a rule named after him)