DNA
"The Blueprint of Life"
DNA stands for...
DeoxyriboNucleic Acid
DNA FACTS
• established by
James Watson
and Francis Crick
• Shape of a double
helix
• codes for your genes (traits)
• made of repeating subunits called
nucleotides
What is a nucleotide?
Has three parts:
PHOSPHATE
DEOXYRIBOSE (sugar)
BASE (A,T,G,C)
Base-Pair Rule
Adenine <==> Thymine
Guanine <==> Cytosine
The sides of the DNA
ladder are phosphate
& sugar
held together
by hydrogen bonds
Base Pair Rule
One side:
Other side:
A T A
T C A
T G C
G G G
How the Code Works
The combination of A,T,G,C determines what
traits you might have, for ex.
C A T C A T = purple hair
T A C T A C = yellow hair
Think of the bases of DNA like letters.
Letters form words....
Words form sentences....
*endless
combinations
DNA REPLICATION
the process by which DNA makes a copy of
itself (cell division)
SEMI-CONSERVATIVE - half of the old strand is saved
RNA - the messenger
*single strand
*ribose sugar
*contains no thymine, uracil instead
*can leave the nucleus
*follows base pair rule
DNA: A T A G C G
RNA:
RNA carries the
"message" to the
ribosomes, where
proteins are made
DNA --> RNA --> Protein
Proteins are the building
blocks of the organism (traits)
Transcription - process where RNA is
made from DNA, occurs in the nucleus
of the cell
Translation - process where proteins
are made from RNA, occurs in the
cytoplasm
Let's Review What We Know About DNA
1. DNA stands for:
2. What is the shape of DNA? _______________
3. Who established the structure of DNA? ____________
4. Adenine always pairs with _______________
5. The sides of the DNA ladder are deoxyribose and _____
6. Guanine always pairs with _____________
7. What is the complimentary sequence: A A T G C A
8. The two sides of DNA are held together by _______
bonds.
9. DNA is composed of repeating subunits called
______________________
10. What are the 4 bases that make up the rungs of the DNA
ladder? _______________________________________