DNA
Mr. Skirbst
DNA Code
Number from 1 – 26. Assign each letter of the
alphabet a number (1 = A through 26 = Z)
DNA Code
Number from 1 – 26. Assign each letter of the
alphabet a number (1 = A through 26 = Z)
Decode the following message:
19, 3, 9, 5, 14, 3, 5
9, 19
3, 15, 15, 12
DNA
is short for
Deoxyribonucleic
acid
DNA
Deoxyribonucleic acid
- stores & passes on genetic
info from one generation to
the next
Structure of DNA
The structure of DNA was
developed by Watson & Crick
Structure of DNA
DNA is in the shape of a
“twisted ladder”
(double helix)
Structure of DNA
There are “steps” made from
four nitrogen base pairs
Double Helix Structure
Nitrogen Bases of DNA
A – adenine
Nitrogen Bases of DNA
A – adenine
T – thymine
Nitrogen Bases of DNA
A – adenine
T – thymine
G – guanine
Nitrogen Bases of DNA
A – adenine
T – thymine
G – guanine
C – cytosine
Nitrogen Bases of DNA
A – adenine
T – thymine
G – guanine
C – cytosine
Nitrogen Bases of DNA
A – adenine
T – thymine
G – guanine
C – cytosine
Nitrogen Bases of DNA
A – adenine
T – thymine
G – guanine
C – cytosine
Nitrogen Bases of DNA
Replication of DNA
Replication of DNA
Duplication of DNA
1. DNA “unzips”
Replication of DNA
Duplication of DNA
1. DNA “unzips”
2. “free” N bases pair up
Replication of DNA
Duplication of DNA
1. DNA “unzips”
2. “free” N bases pair up
3. 2 new DNA molecules form
Chromosomes & DNA
Chromosomes
Chromosomes & DNA
Chromosomes are:
- rod-shaped structures in
nucleus where genes are
found
Chromosomes & DNA
Chromosome Theory
Chromosomes & DNA
Chromosome Theory states:
- genes are carried from parent
to offspring on chromosomes
(ex. Humans have 23 pairs
Fruit flies have 4 pairs)
Chromosomes & DNA
Meiosis is the:
- production of SEX CELLS with
½ normal # of chromosomes
(through two divisions)
Meiosis
male
Meiosis
female
1 egg
3 Polar Bodies (disintegrate)
Goober
Chromosomes (4 pairs)
4 legs
2 eyes
1 tail
fur
Goober
Goobet
Goober
Goobet
Goobies
Chromosomes (4 pairs)
4 legs
2 eyes
1 tail
fur
Chromosomes (4 pairs)
4 legs
2 eyes
1 tail
fur
Goober
What would happen if all chromosomes from
both parents were combined?
What would happen if some of the
chromosomes were missing?
What would happen if all chromosomes from
both parents were combined?
mutations
Meiosis
Why is meiosis important?
Meiosis
Why is meiosis important?
To prevent mutations…….
Meiosis
Why is meiosis important?