Download DNA Presentation

What do Genes look
like?
What are Genes?
•
Genes are located on the chromosomes and code
for traits that are passed from parent to offspring.
What is DNA?
•
DNA is the molecule that makes up chromosomes
and therefore genes. DNA is short for
Deoxyribonucleic Acid.
What are functions of
genes?
•
The gene must be able to supply instructions for
cell processes and for building cell structures. It
must be able to be copied each time the cell
divides.
What are Nucleotides?
•
Nucleotides are the 4 subunits that make up DNA.
A nucleotide is made up of a sugar, a phosphate,
and a base.
•
Nucleotides are composed of 4 different bases,
adenine, thymine, cytosine, and guanine. The
bases are identified by their first letter.
DNA Nucleotide
Phosphate
Group
O
O=P-O
O
5
CH2
O
N
C1
C4
Sugar
(deoxyribose)
C3
C2
Nitrogenous base
(A, G, C, or T)
Genetic Diversity…
• Different
arrangements of
NUCLEOTIDES in a
nucleic acid (DNA)
provides the key to
DIVERSITY among
living organisms.
What is Chargaff’s Rule?
•
There are equal amounts of thymine and adenine,
and equal amounts of cytosine and guanine
T
A
G
C
Who was Rosalind Franklin?
•
Create X-Ray images that revealed the shape of
the DNA molecule.
Who were Watson and
Crick?
•
Used the X-Ray images developed by Franklin to
create a model of DNA. They created the double
helix model to predict how DNA is copied.
What does DNA look Like?
•
Shaped like a twisted ladder
called a double helix.
DNA Double Helix
5
O
3
3
P
5
O
O
C
G
1
P
5
3
2
4
4
2
3
P
1
T
5
A
P
3
O
O
P
5
O
3
5
P
What is Base Pairing
•
Cytosine pairs up with Guanine and Thymine pairs
with Adenine.
Base-Pair Rule
Adenine <==> Thymine
Guanine <==> Cytosine
The sides of the DNA
ladder are phosphate
& sugar
held together by
hydrogen bonds
How does DNA Get Copied
•
DNA has 2 complementary strands. Each base
pairs up with another complementary base on the
other strand. The DNA molecule untwists, unzips
or splits down the middle, and then an enzyme
pairs new bases up and creates 2 identical
strands.
What is incomplete
Dominance?
•
When one allele is not dominant over the other and
both alleles are expressed. Example: Red flowers
and White flowers creating pink flowers.
Codominance
•
Both allele contribute to the
phenotype.
•
This is described as a solid
color parents with offspring
that are striped or spotted.
Gene and trait influence
•
One gene can control multiple traits such as eye
color and fur in a white tiger.
•
One traits has multiple genes that influence it. Eye
color has multiple genes that effect the amount of
pigment that results in different shades.
Environmental Impact
•
Traits can be effected by the environment. Diet,
nutrients, water, etc... can influence how traits are
shown.
heredity?
ow is
ender
etermined?
2.What is
Meiosis?
x: Female
y: Male
Nucleotide: sugar,
phosphate, and a
base.
P
S
(A)
Base
DNA is made
up four
Nucleotide
Bases
Adenine
(A)
Guanine
(G)
Thymine
(T)
Cytosine
(C)
4. How
Genetics
and
Heredity
does
DNA
work?
3 base
codes
(Codon)
amino ac
how
gene
chan
3. What are
characteristics
of genes?
What is
Genetic
Influence?
Incomplete
Dominance
1 gene can
influence
many traits
hum
cau
chan
Environmental
influences
Many genes
can influence
1 trait
sel
bre
dity, dominant traits, recessive traits, genes, alleles, genotype, phenotype, probability, sex cells, homologo
es, DNA, Nucleotide, adenine, thymine, guanine, cytosine, Codon, ribosome, mutation, mutagen, pedigree