Transcript Genetics Notes

Genetics Notes
I. Heredity is the passing of ___________
traits
from _________
parents
to __________.
offspring
A. Hereditary information is contained in ________
genes
which are segments
of the _____
DNA molecule located in the __________________.
chromosome
B. Each gene carries a ________
single ________
unit
of information. A single
inherited trait of an individual can be determined by ______
one or
________
many pairs of _________.
genes
A human cell contains ___________
thousands
of different genes.
C. The different forms a gene may have for a trait are its __________.
alleles
D. _______________
Genetics
is the study of how alleles affect generations of
offspring.
II. _________
Gregor ___________
Mendel
is considered to be the father of genetics because
he observed ______
pea _________
plants
using the ____________
scientific
_____________
method
and discovered 2 types of factors. His genetics describes the basis of how
_______
traits are passed from one generation to the next in ______
all
organisms.
A. Mendel cross-pollinated purebred ______
tall
pea plants with purebred
tall
_______
short pea plants. The offspring were all __________.
Cross-pollination: Pollen
from one flower is put on the
pistil of another flower. The
______
sperm in the pollen joins with
the _____
egg in the ovary and they
form a ________
seed
(zygote).
B. Mendel concluded that the tall factor was _____________
dominant
over the short
factor, which must therefore be _____________.
recessive
C. Mendel cross-pollinated the tall
offspring and found that their offspring
3 tall plants
grew in a ratio of ___
to ___
1 short plant, a ratio of ___:___.
3 1
D. Summary of Mendel’s Inheritance
1. _______
Traits are controlled by alleles on __________________.
chromosomes
2. An allele may be _____________
dominant
or ________________.
recessive
3. When a pair of __________________
chromosomes
separates during meiosis,
the different _____________
alleles
for a trait move into separate _____________.
gametes
III. Geneticists use the ___________
Punnett
___________
Square to predict the genetic
make-up (_________________)
genotype
of an organism. A capital letter indicates a
_______________
dominant
trait and a lower case letter indicates a ______________
recessive
trait.
A. The genotype for the purebred (_______________)
homozygous
tall pea plants was ____.
TT
B. The genotype for the purebred (_______________)
homozygous
short pea plants was ____.
tt
C. Draw a Punnett Square to determine the possible genotypes for the offspring
of cross-pollinated tall and short pea plants (as in Mendel’s experiment).
T
T
t
Tt
Tt
t
Tt
Tt
genotype
T
t
tall
tall
T
TT
Tt
tall
tall
tall
tall
t
Tt
tt
tall
short
phenotype
genotype
phenotype
D. The _____________
phenotype
is the physical trait that shows up for a particular
genotype. In the first set of offspring, the ratio of tall plants to short
plants was ___:___.
4 0 When those offspring were crossed, the ratio of tall
plants to short plants of their offspring was ___:___.
3 1
E. A plant with a genotype of 2 of the same alleles (TT or tt) is called
___________________.
homozygous
A plant with a genotype with 2 different alleles
heterozygous
(Tt) is called ____________________.
IV. Other topics in Genetics (other ways to inherit traits)
A. Incomplete Dominance - when _____
both alleles are expressed in the offspring.
Ex: Flower color in 4 o’clocks - When _____
red and _________
white
flowering
plants were cross-pollinated, _______
pink flowers were produced. Both
____________
alleles
(red and white) were expressed.
Make a Punnett Square for a red flower crossed with a white flower, and
also show the phenotype. Do the same for their offspring. CR = red, CW = white
CR CR
CR CW
CW CRCW CRCW
pink
pink
R R
CR C C CRCW
red
CW CRCW CRCW
pink
pink
CW CRCW CWCW
pink white
phenotype
genotype
genotype
pink
phenotype
B. Multiple Alleles - Some ________
traits
are determined by more than 2 alleles.
Ex: Blood type in humans - Humans can have ___,
A ___,
B or ___
O alleles for
blood type. The ___
A and ___
B alleles are dominant over the ___
O allele,
codominant
but are ______________
when together. If one parent has the A and
O alleles and the other has B and O alleles, what can their offspring
have? Draw a Punnett Square for this cross.
A
O
B AB BO
AB
B
O AO OO
A
O
genotype
phenotype
C. Polygenic inheritance - occurs when a group of _______
gene _______
pairs act
together to produce a single trait. Many _____________
variations
appear in a species.
Examples:
1. Eye color - ________,_________,
blue
brown
__________,
green
_________,
hazel
________
mixed
2. Height (in humans) _______,
______,
tall
short _______
medium
3. Body build
4. Hair and skin color
D. Sex determination - Male gametes carry ___
X or ___
Y chromosomes while
female gametes contain only ___
X chromosomes. All males have an ___
X
X chromosomes.
and a ___
Y chromosomes while all females have 2 ___
1. Draw a Punnett Square to determine the possible sexes of offspring
from the union of an egg and a sperm. What is the probability of having
a girl? ____%
50
or ____
1/2 A boy? ____%
50
or ____
1/2
X Y
What is the probability of
girl
boy
X XX XY
having 3 girls and no boys?
X XX XY
genotype
girl
boy
1/2 x ____
1/2 x ____
1/2 = ____
1/8
____
phenotype
X chromosome carries a recessive gene for
E. Sex-linked Disorders - The ___
a trait that is not present on the ___
Y chromosome. The trait will always be
expressed in males since the allele for that trait is not found on the ___
Y
chromosome and cannot mask (cover) it. The female must have both
genes to
recessive _______
express the trait.
1.
2.
Color blindness – (See picture on page 119 in old text book).
Hemophilia - ______________________________________
Blood does not clot properly. A small scrape
__________________________________________________
can cause the person to bleed to death.
trait
F. Pedigrees – diagrams that show the occurrence of a ___________
in a
family.
C = normal
= female
= male
color vision
c = colorblindness
= female carrier
= male carrier
(normal phenotype)
= affected female
c
= affected male
Xc Y
C C
XX
XY
1st generation
(parents)
XC XCXc XCY
C
XY
2nd generation
(children)
C c
C
XX
XY
c
XY
3rd generation
(grandchildren)
C
XY
C
XY
XC XCXc XCY
genotype
normal
girl
normal
boy
normal normal
boy
girl
phenotype
0
____%
of females are affected.
____%
0
of males are affected.
G. Homozygous Recessive Disorders - the person must have ___
2 genes in order
to have the trait.
1. Sickle-Cell Anemia - blood cells can’t deliver
enough __________
oxygen
because they are __________.
misshapen
Because of the shape, the cells get __________
tangled
up as they flow through the arteries and veins
and it is very ____________.
painful
A benefit of this gene
_____________
mutation
is that some people with sicklecell anemia show a resistance to _____________
malaria
(a disease caused by a _______________
protist
and
transmitted by a __________).
mosquito
2. Cystic Fibrosis - thick _______
mucus is
produced in the ___________
lungs
and
___________
digestive __________,
system
which
restricts ___________
oxygen
intake and
food
____________
absorption.
Genetics Notes
I. Heredity is the passing of ___________ from _________ to __________.
A. Hereditary information is contained in ________ which are segments
of the _____ molecule located in the __________________.
B. Each gene carries a ________ ________ of information. A single
inherited trait of an individual can be determined by ______ or
________ pairs of _________. A human cell contains ___________
of different genes.
C. The different forms a gene may have for a trait are its __________.
D. _______________ is the study of how alleles affect generations of
offspring.
II. _________ ___________ is considered to be the father of genetics because
he observed ______ _________ using the ____________ _____________
and discovered 2 types of factors. His genetics describes the basis of how
_______ are passed from one generation to the next in ______ organisms.
A. Mendel cross-pollinated purebred ______ pea plants with purebred
_______ pea plants. The offspring were all __________.
Cross-pollination: Pollen
from one flower is put on the
pistil of another flower. The
______ in the pollen joins with
the _____ in the ovary and they
form a ________ (zygote).
B. Mendel concluded that the tall factor was _____________ over the short
factor, which must therefore be _____________.
C. Mendel cross-pollinated the tall
offspring and found that their offspring
grew in a ratio of ___ tall plants
to ___ short plant, a ratio of ___:___.
D. Summary of Mendel’s Inheritance
1. _______ are controlled by alleles on __________________.
2. An allele may be _____________ or ________________.
3. When a pair of __________________ separates during meiosis,
the different _____________ for a trait move into separate _____________.
III. Geneticists use the ___________ ___________ to predict the genetic
make-up (_________________) of an organism. A capital letter indicates a
_______________ trait and a lower case letter indicates a ______________ trait.
A. The genotype for the purebred (_______________) tall pea plants was ____.
B. The genotype for the purebred (_______________) short pea plants was ____.
C. Draw a Punnett Square to determine the possible genotypes for the offspring
of cross-pollinated tall and short pea plants (as in Mendel’s experiment).
D. The _____________ is the physical trait that shows up for a particular
genotype. In the first set of offspring, the ratio of tall plants to short
plants was ___:___. When those offspring were crossed, the ratio of tall
plants to short plants of their offspring was ___:___.
E. A plant with a genotype of 2 of the same alleles (TT or tt) is called
___________________. A plant with a genotype with 2 different alleles
(Tt) is called ____________________.
IV. Other topics in Genetics (other ways to inherit traits)
A. Incomplete Dominance - when _____ alleles are expressed in the offspring.
Ex: Flower color in 4 o’clocks - When _____ and _________ flowering
plants were cross-pollinated, _______ flowers were produced. Both
____________ (red and white) were expressed.
Make a Punnett Square for a red flower crossed with a white flower, and
also show the phenotype. Do the same for their offspring.
genotype
phenotype
genotype
phenotype
B. Multiple Alleles - Some ________ are determined by more than 2 alleles.
Ex: Blood type in humans - Humans can have ___, ___, or ___ alleles for
blood type. The ___ and ___ alleles are dominant over the ___ allele,
but are ______________ when together. If one parent has the A and
O alleles and the other has B and O alleles, what can their offspring
have? Draw a Punnett Square for this cross.
C. Polygenic inheritance - occurs when a group of _______ _______ act
together to produce a single trait. Many _____________ appear in a species.
Examples:
1. Eye color - ________,_________,
__________, ______________
2. Height (in humans) _______, ______, _______
3. Body build
4. Hair and skin color
D. Sex determination - Male gametes carry ___ or ___ chromosomes while
female gametes contain only ___ chromosomes. All males have an ___
and a ___ chromosomes while all females have 2 ___ chromosomes.
1. Draw a Punnett Square to determine the possible sexes of offspring
from the union of an egg and a sperm. What is the probability of having
a girl? ____% or ____ A boy? ____% or ____
What is the probability of
having 3 girls and no boys?
____ x ____ x ____ = ____
E. Sex-linked Disorders - The ___ chromosome carries a recessive gene for
a trait that is not present on the ___ chromosome. The trait will always be
expressed in males since the allele for that trait is not found on the ___
chromosome and cannot mask (cover) it. The female must have both
recessive _______ to express the trait.
1.
2.
Color blindness – (See picture on page 119 in old text book).
Hemophilia - ______________________________________
__________________________________________________
F. Pedigrees – diagrams that show the occurrence of a ___________ in a
family.
= female
= male
= female carrier
(normal phenotype)
= affected female
= male carrier
= affected male
1st generation
(parents)
2nd generation
(children)
3rd generation
(grandchildren)
genotype
phenotype
____% of females are affected.
____% of males are affected.
G. Homozygous Recessive Disorders - the person must have ___ genes in order
to have the trait.
1. Sickle-Cell Anemia - blood cells can’t deliver
enough __________ because they are __________.
Because of the shape, the cells get __________
up as they flow through the arteries and veins
and it is very ____________. A benefit of this gene
_____________ is that some people with sicklecell anemia show a resistance to _____________
(a disease caused by a _______________ and
transmitted by a __________).
2. Cystic Fibrosis - thick _______ is
produced in the ___________ and
___________ __________, which
restricts ___________ intake and
____________ absorption.