Transcript Genetics

The Study of
Heredity
1. Genetics is the study of heredity.
2. Heredity is the study of how
characteristics, or traits, are
inherited .
Review:
3. Mitosis is asexual
______ reproduction
that results in ___
2 cells (diploid);
 Important for what three things?
repair, growth, & development
sexual
4. Meiosis is used only for ______
reproduction. This process
4 haploid cells!
produces ________
 Important in making what?
gametes – egg and sperm
5.
DNA’s ‘home’
6. DNA contains the ______
genetic
entire
material for the ______
organism.
• It is passed on from
generation to generation
_________
and from cell to ___.
cell
Based on this information, why do some of
us have characteristics of our
grandparents, aunts, uncles, cousins, etc.
7. Once upon a time, there live an ________
Austrian
Gregor ______.
Mendel He worked in
monk named ______
the monastery's garden, paying special
attention to ____
pea ______.
plants He studied how
genetic _____
traits were passed from generation
______
to generation. He did wonderful things in
Genetics, and that is why he is called the
Father of ________”!
Genetics
“______
Mendel loved his peas!
cross
8. Mendel _____-pollinated
pea plants.
{What does this mean?}

Pollination the male pollen grains are
transferred to the female and the ovule
is fertilized!
More info. on our man,
Mendel!
9. Mendel observed many
different traits that
showed up in his pea
plants.
 What is a “trait?”
 An “observable” inherited
characteristic containing
at least one pair of
genes
 Example: hair & eye color
10. Mendel’s 7 traits
11. Monohybrid = hybrid for ___
one trait
parent generation
 P = _____
 F = ____
filial generation:
1st filial generation (_______)
children
• F 1 = ______
2nd filial generation (__________)
grandchildren
• F2 = _______
3rd filial generation (_____
great
• F3 = _______
grandchildren
___________)
2
 Dihybrid = organism hybrid for __
traits
pure is defined as 2
12.Homozygous = ____
like symbols in a gene pair.
Ex: TT or tt
hybrid is defined as 2
13.Heterozygous = _____
unlike symbols in a gene pair.
Ex: Tt
In his first cross,
Mendel crossed true
breeding tall pea
plants
true for tall vs.
*Stop
andwith
do demo.
breeding
short(similar
pea to
short
corn plants
plants. pea plants).
Mendel’s
Cross of F1 generation
14. When Mendel crossed 1 of his
hybrid pea plants the next generation
“______________”
showed: 3 tall: 1 short pea plant (ratio).
How did that happen?
Tt x Tt
We now use “_____________”
Punnett Squares to help us
predict what the offspring may look like.
15. Mendel concluded from his experiments
organism has __
2 factors for
that each _______
trait
EACH _____!
 We now call them _____
genes which are found
on chromosomes
__________.
16.______
Alleles are different gene forms
trait of an organism.
for a ____
3
 Example: There are __alleles
for
human blood types (IA, IB, & i), but
a person only inherits 2 alleles for
blood type.
17.A parent can pass _1 gene from
each pair:
18. ________
Dominant genes are
recessive
“stronger” than ________
genes (weaker).
Dominant genes only require
19. ________
1 allele for a trait to be
__
present. Ex: TT or Tt = tall
plant
2
20.Recessive genes require __
alleles for a trait to be
tt = short plant
present. Ex: __
symbols which
21. Genotype refers to the _______
represent the genes. Ex: Tt or tt
 Identical twins have the same genotype.
phenotype refers to the “_______
physical
22.The ________
appearance” of a gene pair. Ex: Tall plant
or short plant
23.Complete Dominance: Dominant gene
is stronger (B) than the weaker
recessive gene (b). When together,
the dominant gene expresses the
phenotype (recessive gene trait is
“hidden” ). Ex: Bb
B
b
+
Bb
24.Incomplete Dominance: states that
2 alleles are ____
when __
equal in
blending of
strength; there is a _______
their phenotypes.
Ex: red + white = pink
+
Red, white, & pink!
Codominance
 Similar
to Incomplete Dominance
Codominance state that ____
both
25._________
phenotypes will show up together.
+
Ex: Black feathers + white feathers both show up!
Codominance
A joint & distinct expression of both
alleles in a heterozygote!
Ex: blood type {ABO blood groups}
The IA & IB behave dominantly over IO (i), but codominantly to each other.
Food production to produce better,
healthier plants & animals
 Genetic engineering
 Genetic disorders & diseases
 Cloning: pros & cons?
 Human Genome Project (worldwide effort):
• To map all 46 human chromosomes
• Completed in June of 2001 (13 years)





Genetics is the study of
heredity.
Gregor Mendel is the
“Father of genetics.”
Mitosis and meiosis are
types of cell reproduction.
Chromosomes contain genes
which have DNA (heredity).
Possible science fair experiment?
Punnett Square Practice