“The Genetic Code”
DNA Discovery and History
Chargaff’s Rule:
Fred Griffith:
Oswald Avery:
Rosalind Franklin:
Watson and Crick:
Human Genome Project:
The Double Helix: DNA
DNA is located in the ___________, tightly wound to make __________, which can all be found on
________________
Function of DNA
1. ____________________________________
2. ____________________________________
DNA stands for _______________________________________________________
DNA is a complex molecule made up of units called ______________________ (joined in chains)
Nucleotides are molecules made up of 3 parts:
1. ____________________________ - ____________________________
2. ____________________________
3. ____________________________
DNA has 4 nitrogenous bases (thus 4 different nucleotides)
1. ___________________________
And they can only pair in certain ways:
2. ___________________________
3. __________________________
4. __________________________
All DNA molecules contain _______________________.
DNA is built like a twisted ladder, called a _________________________
It is made up of ____________ chains of ________________________ joined together by weak
_______________________ bonds.
Human Cells contain about 6.6 billion ______________________ in its DNA
= 2.0 x 1013M
= 66 round trips to the Sun
The order of the bases makes up the __________________________
Differences in the order of bases are what makes _____________________________________________
_____________________________________________________________________________________
DNA Replication
Each strand of double helix has all the information needed to make copies; _____________________
Prokaryotes: DNA replication occurs at one point and proceeds in both directions until completely copied.
Eukaryotes: Replication occurs at hundreds of places and proceeds in both directions until completely copied
Sites where separation and replication occur are called ____________________________ and an enzyme
_____________________ joins individual nucleotides and proofreads the base pairings as they are being paired
Steps Involved:
1.
DNA __________ and ______________, the weak H bonds _______________________
2. Bases of the unzipped nucleotides are exposed to __________________________ also found in the
_______________________
3. New nucleotides ______________________________________
4. DNA polymerase, an _____________, proofreads and joins the base pairs
5. Resulting in ___________________ as the original DNA strand, making it ____ new, complete strands
Enzymes involved:
DNA Helicase:
DNA Polymerase:
DNA Ligase:
Protein Synthesis
DNA is the _______________________________ or the making of proteins. Proteins are made up of
___________________________.
Amino Acids
There are __________ known amino acids.
3 bases in a row act as a code for ____________________, called a ______________
There are _________ possible codons, only 20 _________________ - some - _______________
have more than one codon.
Example:
Codon
Amino Acid
GCC, or GCA
________________________
CAC
________________________
GTT, or GC___
________________________
Universal Code: ____________________________________________________________________________
__________________________________________________________________________________________
Question: Protein synthesis occurs in the ribosomes. Since the DNA code is in the nucleus, how does the
code get to the ribosomes?????
RNA
__________________________, is found in the ________________, ____________________, and
___________________________
RNA
DNA
Sugar:
________________________
_________________________
A pairs with:
________________________
_________________________
Appearance:
________________________
_________________________
Found in:
________________________
_________________________
RNA Bases:
Adenine pairs with ___________________________
Guanine pairs with ___________________________
Protein Synthesis: _________________________________________________________________
Process for Making Proteins:
1. DNA ____________________________________
2. RNA nucleotides ___________________________ - called Messenger RNA ( _________ )
3. mRNA breaks away from the _______ and moves to the ____________________ and then to the
_________________
4. Transfer RNA ( _______ ) is found in the ____________________
a. tRNA brings ________________________ to mRNA.
b. One end of tRNA ____________________ while the other end has __________________
(tRNA is the ___________ )
5. Amino Acids attach to _______________ to form _________________
DNA Sequence
mRNA Sequence
tRNA codon
amino acid
A
G
C
T
T
A
T
C
C
__________________
Transcription = the DNA code is transcripted to RNA message
RNA Polymerase = ___________________________ and links nucleotides together
Occurs in the _______________________ of the cell
At the end of a gene, RNA polymerase encounters a DNA sequence called a ______________________
and it detaches from the DNA and releases the RNA molecule
Translation = RNA code is translated to code for and make
proteins
Occurs in the ___________________________
Mutations