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• Chapter 14 Vocabulary
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• Tutoring – Troy Central – Tomorrow - Wednesday!!
• Sections 14.1 and 14.2 from Workbook
• Quiz – Friday ( Section 14.1)
• Homework:
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• 1.5 Pages in length
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The Human
Genome
Chapter 14
Section 14-1: Human Heredity
Section 14.1
Key Concepts:
How is sex determined?
How do small changes in DNA Cause genetic disorders?
I. Human Chromosomes
A.
Karyotype:
A picture of chromosomes taken during mitosis and cut
out and arranged into homologous pairs.
Section 14-1: Human Heredity
I. Chromosomes
sets of homologous
B. Diploid Cell: Two
________
chromosomes
46 chromosomes
Human diploid cell has ____
23 pairs
arranged in ____
The 46 chromosomes contain
6 billion nucleotide pairs
I. Chromosomes
C. Mendelian genetics requires that organisms
inherit a single copy of gene from each parent
the gametes
D. In humans, _______________
(reproductive cells
of egg and sperm) contain a single copy of each gene
(one set of genetic information).
Section 14-1: Human Heredity
I. Chromosomes
• Gametes are formed in the __________
(sperm)
testes
ovaries
and __________(egg)
by meiosis.
• Each gamete contains 23 chromosomes (one set)
haploid number
or __________________
(n) of chromosomes.
Fertilization
• ________________
requires the egg and the
zygote
sperm to join and produce a ______________
(fertilized egg) that contains 46 chromosomes (two
diploid number
sets) or _____________________
(2n).
Section 14-1: Human Heredity
II. Human Traits
• Humans have 46 total chromosomes
autosomes follow regular Mendelian
• 44 _____________
genetics
sex chromosomes (X and Y) are sex-linked
• 2 _________________
Section 14-1: Human Heredity
II. Human Traits
A. Pedigree Chart: A pedigree chart shows the
_________________
within a family and can be
relationship
genetic inheritance problems
useful to help with __________________________
within families. It is another __________________
way to predict the
outcome of a particular cross and the genotype
_________
of the family members.
Section 14-1: Human Heredity
Pedigree
Section 14-1
A circle represents
a female.
A horizontal line connecting
a male and female
represents a marriage.
A half-shaded circle
or square indicates
that a person is a
carrier of the trait.
A completely
shaded circle or
square indicates
that a person
expresses the
trait.
A square represents
a male.
A vertical line and a
bracket connect the
parents to their children.
A circle or square
that is not shaded
indicates that a
person neither
expresses the trait
nor is a carrier of
the trait.
Section 14-1: Human Heredity
II. Human Traits
Phenotypes are determined by genotype as well as
________________________________.
environmentally influenced
________________________________
on gene
Environmental influences
expression are not inherited, but genes are.
Section 14-1: Human Heredity
III. Human Genes
The __________________:
Complete set of genetic
human genome
information
• Composed of about 30,000 genes
Section 14-1: Human Heredity
III. Human Genes
Blood Group Genes
• Human Blood
• variety of genetically determined blood groups
• Many different types of blood groups
• ones associated with these groups are best
known
• ABO blood
• Rh blood
.
Section 14-1: Human Heredity
III. Human Genes
A. Blood Group Genes
• Rh blood groups :controlled by single gene with
Two alleles
________________.
• Antigen in blood
• discovered in Rhesus monkeys.
Rhesus Monkey
Section 14-1: Human Heredity
III. Human Genes
• Rh blood groups :controlled by single gene with
Two alleles
________________.
• Antigen in blood
• discovered in Rhesus monkeys.
• The arrangement of the alleles determines
two
only _______
possible types
positive
• _____________
(+) contains antigen
negative (-) doesn’t contain antigen
• ___________
dominant
• Positive is ______________
over negative.
• Rh-positive -two genotypes: Rh+/Rh+ or Rh+/Rh• Rh-negative -one genotype: Rh-/Rh-
Section 14-1: Human Heredity
III. Human Genes
ABO Blood Groups:
• Discovered in 1900 by Karl Landsteiner.
• He realized that all blood is classified into four
A ____,
types: ____,
AB and _____
O due to
B ____,
the presence of or absence of specific
__________
antigens in the blood.
codominant
• Alleles IA and IB are __________________
recessive
• io is ________________
to both IA and IB
Section 14-1: Human Heredity
III. Human Genes
chemical markers
Antigens are ______________________
used by
the immune system. When an unrecognized
antigen is present an immune response takes place
clump or agglutinate
and the cells ____________________________.
Section 14-1: Human Heredity
Section 14-1
Phenotype
(Blood Type
Genotype
Antigen on
Red Blood Cell
Blood Type and Antigen
Interactions
Safe Transfusions
To
From
Bell Work: 2-2
• Turn in Signed syllabus pages on top of overhead.
• Take out 14.1 Outline and Stamp Sheet so I can stamp it
• You have 20 Minutes
• Draw/ Color Create-A-Kid using phenotypes
• Worksheet # 3; 4-6
• If you finish early, work on homework
• Outline 14.2 (1 Page; minimum)
Announcements: 2-2
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• Quiz – Friday ( Section 14.1)
• Homework:
• Chapter 14.2 Outline (1 page; minimum)
• Finish Create-A-Kid packet
Section 14-1: Human Heredity
III. Human Genes
B. Recessive Alleles: Trait controlled by a
recessive allele. This results in the
disorder being present
only if both alleles are recessive
___________________________.
•
Examples include: PKU (Phenylketonuria),
Tay Sachs disease and Cystic Fibrosis,
Albinism, and Galactosemia (See chart on
page 345)
Section 14-1: Human Heredity
III. Human Genes
C. Dominant Alleles: Traits controlled by a
dominant allele. This results in the
disorder being present when
only one allele is present
__________________________.
• Examples include: Achondroplasia
(dwarfism), Hypercholesterolemia, and
Huntington’s Disease
Section 14-1: Human Heredity
Autosomal Disorders
Section 14-1
Autosomol
Disorders
caused by
Recessive
alleles
Dominant alleles
Codominant
alleles
include
include
include
Huntington’s
disease
Sickle cell
disease
Galactosemia
Albinism
Cystic
fibrosis
Phenylketonuria
Tay-Sachs
disease
Achondroplasia
Hypercholesterolemia
Section 14-1: Human Heredity
III. Human Genes
C. Dominant Alleles
Huntington Disease:
It is controlled by a _________________________.
single dominant allele
The gene is located on Chromosome #4.
Genetic degenerative disease that shows no
symptoms until a person is in their
____________________.
It progresses with
thirties or forties
gradual degeneration of their nervous system
leading to loss of muscle control and mental
function until death occurs.
Section 14-1: Human Heredity
III. Human Genes
C. Dominant Alleles
Question? Would you want to know now if you
could potentially get Huntington’s disease when you
are older? Would you want to know if you could
pass the gene on to your offspring before you have
children?
Bell Work: 2-3
• Take out lecture outline and
worksheet # 3
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• Put Stamp sheet with 14.2 Outline so
I can stamp it
Announcements: 2-3
• Turn in Extra Credit work from Friday
• Quiz – Rescheduled to Monday( Section 14.1)
• Homework:
• Worksheet # 1
• Study for the Quiz
Section 14-1: Human Heredity
III. Human Genes
D. Codominant Alleles
two alleles that share dominance
controlled by ______________________________.
Sickle Cell Anemia is such a disorder. (This will be
discussed in detail later)
Section 14-1: Human Heredity
IV. From Gene to Molecule
The link between ______________________
genetics and phenotype
is not easily determined but for several diseases we
have been able to make the connection.
For both _____________
Cystic fibrosis and ________________
Sickle cell disease
single gene
a small change in the DNA of a _____________
affects the ______________________,
causing a
structure of a protein
serious genetic disorder.
Section 14-1: Human Heredity
IV. From Gene to Molecule
A. Cystic Fibrosis: (See figure 14-8 p. 347)
Cystic Fibrosis a.k.a. “CF” is a common genetic
disease. It is most common in people of
Northern European decent.
Recessive disease
It is a _______________________
of a gene
found on the # 7 chromosome and affects
the______________________________
digestive and respiratory systems
Section 14-1: Human Heredity
IV. From Gene to Molecule
A.. Cystic Fibrosis
deletion of 3 bases in
• Caused by the____________________
the middle of a sequence for a protein and
abnormal
• Causes the protein to be ______________
• Doesn’t allow Chloride ions to transport across
the membrane, as they should.
• Causes the cells in a person’s airways to be
unable totransport chloride ions and become
clogged with mucus
__________________.
Section 14-1: Human Heredity
Chromosome # 7
CFTR
gene
The most common allele
that causes cystic fibrosis is
missing 3 DNA bases. As
a result, the amino acid
phenylalanine is missing
from the CFTR protein.
Normal CFTR is a chloride
ion channel in cell
membranes. Abnormal
CFTR cannot be transported
to the cell membrane.
The cells in the person’s airways
are unable to transport chloride
ions. As a result, the airways
become clogged with a thick
mucus.
Section 14-1: Human Heredity
IV. From Gene to Molecule
B. Sickle Cell Anemia
• The patient’s blood cells were found to be
like a sickle
irregularly shaped, ____________________
• how the disease got its name.
• In normal red blood cells the
hemoglobin
molecule carries ___________
oxygen
____________________
and distributes it around the body.
• In sickle cell disease, the red blood cells are sickle–
shaped, causing the blood hemoglobin to no longer
disrupts the normal
carry oxygen as well and _____________________
functioning of the bodies cells, tissues and organs
Section 14-1: Human Heredity
IV. From Gene to Molecule
B. Sickle Cell Anemia
This person is deprived of oxygen and the result is physical
weakness, and damage to the brain, heart, spleen. It may be
fatal.
single base
The cause: A _________________
in the DNA that codes for
Hemoglobin polypeptides is changed. This substitutes Valine for
glutamic acid.
This change makes the hemoglobin less soluble in blood. This will
cause the hemoglobin to come out of the blood and
_______________.
This crystallization causes the
crystallize
________________
of the blood cells and the medical
sickle shape
consequences.
Section 14-1: Human Heredity
IV. From Gene to Molecule
B. Sickle Cell Anemia
The genetics: The allele for sickle cell (HS) is
codominant with the allele for normal
___________
hemoglobin (HA).
Heterozygotes (HS HA) are said to be ____
____
Sickle
cell
__________
carriers and have some effects of the disorder
because they have both normal and sickle cell
blood hemoglobin.
Section 14-1: Human Heredity
IV. From Gene to Molecule
B. Sickle Cell Anemia
The distribution: Sickle Cell anemia is most prevalent in
people of __________________.
African descent
10% of African Americans and 40% of populations in Africa
and Asia carry the gene for Sickle cell anemia.
Why? The carriers for the disease have a
___________________,
resistance to Malaria a dangerous disease caused by a
blood parasite found in tropical areas of the world.
Section 14-1: Human Heredity
IV. From Gene to Molecule
B. Sickle Cell Anemia
mutation that has
Sickle Cell Anemia is a __________
provided an ____________
in Malaria prone areas
advantage
and in these areas it is _______________________
favored by natural selection
and therefore Sickle Cell Anemia persists.
HS
HA
HS
HS HS
HS HA
HA
HS HA
HA HA
Section 14-2: Human Chromosomes
Section 14-2: Human Chromosomes
Key concepts:
Why are sex-linked disorders more common in
males than in females?
What is nondisjunction, and what problems does it
cause?
Section 14-2: Human Chromosomes
I. Human Genes and Chromosomes
6 billion base pairs
• Human diploid cell contains ______________________
of DNA. All neatly packed into the 46 chromosomes.
Small part
__________________
of the DNA actually functions as
genes.
• Genes are located on the chromosomes and each gene
specific place
occupies a ______________________
on a
chromosome.
Section 14-2: Human Chromosomes
I. Human Genes and Chromosomes
several forms
• Genes may exist in ____________________
(alleles)
one of the alleles
• Each chromosome contains ______
for each of its genes
smallest
• Chromosome #21 and 22 are the ____________
of the human autosomes. These were the first
two chromosomes whose sequences had been
determined.
Section 14-2: Human Chromosomes
I. Human Genes and Chromosomes
• Both also contain genes for some genetic
Leukemia
and
disorders like ________________________
Amyotrophic
Lateral Sclerosis (ALS)
___________________________
• We also discovered that there are many
non-coding, repeating
_________________________
segments of DNA
• Human chromosomes also have_____________
Linked genes
that can cross over just as they saw in the fruit
fly.
Section 14-2: Human Chromosomes
II. Sex-linked Genes
Sex Chromosomes
1. _______________________
are the ones that
differ
__________
in males and females
same in male
2. Chromosomes that are the ________
and females =autosomes
_______________
XX and Males = ____
3. In humans: females = ____
XY
4. The Y chromosome is smaller than the X
Section 14-2: Human Chromosomes
II. Sex-Linked Genes
A. Sex Determination
1. Female _________
gametes carry an X chromosome
2. _________
gametes can carry either an X or Y
Male
(meiosis segregates the chromosomes; _______
of
50%
the sperm carry X and ______
50% of the sperm carry
Y)
3. In humans, _____________________
males determine the sex of an
offspring
X
Y
Female: XX
X XX
XY
male: XY
X XX
XY
Section 14-2: Human Chromosomes
II. Sex-Linked Genes
A. Sex Determination
4. In some animals such as birds,
butterflies, and some fish, the female
determines the sex because she has
the __________
chromosomes.
differing
Section 14-2: Human Chromosomes
II. Sex-Linked Genes
B. Sex-linked Genes
1. In addition to determining the sex of an
individual, the sex chromosomes carry
affect other traits.
genes that ____________________
Section 14-2: Human Chromosomes
II. Sex-Linked Genes
B. Sex-linked Genes
Sex-linked Genetic Disorders
May be on the X or Y chromosome, but
usually on the X because the Y has very few genes.
Most often expressed in ____________because
males
they only have one X chromosome and thus all the
alleles are expressed even if they are recessive.
Section 14-2: Human Chromosomes
II. Sex-Linked Genes
B. Sex-linked Genes
Colorblindness is a recessive disorder in which
people can’t distinguish between certain colors.
Red-green
____________________
colorblindness is most
common.
XC and Xc are ________________
for normal and
the alleles
colorblind vision.
Section 14-2: Human Chromosomes
II. Sex-Linked Genes
B. Sex-linked Genes -
XC XC and XC Xc are
Color Blindness
both normal vision females.
carrier for colorblindness and can pass
XC Xc is a _______________________
the gene on to her sons.
Xc Xc is a colorblind female.
XC Y is a
normal male and
Xc Y is a colorblind male.
http://www.toledo-bend.com/colorblind/Ishihara.html
Section 14-2: Human Chromosomes
Colorblindness
Father
(normal vision)
Colorblind
Normal
vision
Male
Female
Daughter
(normal vision)
Son
(normal vision)
Daughter
(carrier)
Son
(colorblind)
Mother
(carrier)
Section 14-2: Human Chromosomes
Colorblindness
Father
(normal vision)
Colorblind
Normal
vision
Male
Female
Daughter
(normal vision)
Son
(normal vision)
Daughter
(carrier)
Son
(colorblind)
Mother
(carrier)
Section 14-2: Human Chromosomes
II. Sex-Linked Genes
B. Sex-linked Genes
Hemophilia
Hemophilia is a __________________________
recessive sex-linked disorder in
which one is unable to clot their blood.
Also known as “bleeders disease”.
Hemophilia is caused by a defect in a gene and the
protein for normal blood clotting is missing.
Section 14-2: Human Chromosomes
Figure 21.12
Page 394
Section 14-2: Human Chromosomes
Royal Family and Hemophilia
I
II
III
Albert Victoria
IV
V
VI
Figure 21.13
Page 394
Slide 18
WORKSHEET 3: # 7-9
Agenda: 2-6
• Quiz – Today!
• Finish Lecture
• Start Karyotype Analysis
• Finish for Homework
Announcements: 2-6
• Tutoring – Troy Central – Wednesday!!
• Sections 14.1 and 14.2 from Workbook
• Exam – Thursday
• Homework:
• Karyotype Analysis
Section 14-2: Human Chromosomes
II. Sex-Linked Genes
B. Sex-linked Genes
Muscular Dystrophy
Muscular Dystrophy is another sex-linked recessive disease.
Here the affected individual inherits a degenerative
muscle
__________disorder.
muscle protein is defective.
The gene that codes for a _____________
They rarely live past early adulthood.
replace
Treatments are being explored that ___________
the
defective gene.
Section 14-2: Human Chromosomes
III. X-Chromosomes Inactivation
Males survive with only one X chromosome so, what do females do
shut one off it becomes inactive. This creates a
with 2? They ___________;
dense region in the nucleus known as a ______________.
Barr body
This is seen in coat color in cats. The cells will randomly shut off
the coat color allele in one X chromosome and turn them off in
the other X chromosome in other cells and this leads to some
areas that are spotted orange and some spotted black, creating a
calico
tricolor cat, ________.
This only happens in __________
females
because males only have one X chromosome.
Section 14-2: Human Chromosomes
IV. Chromosomal Disorders
Whole/sets of chromosome mutations
1. _______________
Nondisjunction = failure of homologous
chromosomes to separate normally during meiosis
This results in a disorder of __________________
chromosome number
2. Examples of disorders include Down’s Syndrome,
Klinefelter’s, and Turner’s Syndrome
Section 14-2: Human Chromosomes
Nondisjunction
Homologous
chromosomes
fail to separate
Meiosis I:
Nondisjunction
Go to
Section:
Meiosis II
Section 14-2: Human Chromosomes
Nondisjunction
Homologous
chromosomes
fail to separate
Meiosis I:
Nondisjunction
Go to
Section:
Meiosis II
Section 14-2: Human Chromosomes
Nondisjunction
Homologous
chromosomes
fail to separate
Meiosis I:
Nondisjunction
Go to
Section:
Meiosis II
Nondisjunction
n+1
n+1
n-1
n-1
chromosome
alignments at
metaphase I
nondisjunction
at anaphase I
alignments at
metaphase II
anaphase II
gametes
Figure 21.19
Page 398
Slide 23
Section 14-2: Human Chromosomes
IV. Chromosomal Disorders
2. Examples of disorders include Down’s Syndrome,
Klinefelter’s, and Turner’s Syndrome
Nondisjunction disorders: Disorders in which the failure of
chromosome
separationduring one of the stages of
_____________________
meiosis causes a gamete to have
_______________________________.
too
few or too many chromosomes
Nondisjunction can occur in
___________________________.
autosomes
or sex chromosomes
Section 14-2: Human Chromosomes
IV. Chromosomal Disorders
Down’s Syndrome: Down’s syndrome is an example of
nondisjunction
of an autosome specifically chromosome 21.
____________________________,
extra copy of chromosome 21
In Down’s syndrome there is an ___________
(trisomy 21).
karyotype (display of all the chromosomes in a cell
Doing a _____________
nucleus) and looking at the chromosomes under a microscope
detect the extra chromosome.
mental retardation
Characteristics of Down’s syndrome include _________________,
physically challenged, facial irregularities, and often heart defects.
Section 14-2: Human Chromosomes
incidence per 1,000 births
Incidence of Down’s Syndrome and mother’s age
20
15
10
5
0
20
25
30
35
40
45
mother's age
Fig. 21.20a,b
Page 399
Sl i de 24
Section 14-2: Human Chromosomes
IV. Chromosomal Disorders
Turners Syndrome: Nondisjunction of the sex
chromosomes in which a chromosome is missing.
45 XO
They have the chromosome makeup of _________
where “O” represents the missing chromosome.
This individual is female in appearance but does
not develop the female sex organs during puberty
sterile.
and is ________.
Section 14-2: Human Chromosomes
IV. Chromosomal Disorders
Klinefelter’s Syndrome: Nondisjunction of the sex
extra X chromosome is
chromosomes in which an _____________________
present.
47XXY
They have the chromosome makeup of ________.
They
male
are ___________
in appearance and are also sterile. May
also be 48 XXXY or 49 XXXXY
No nondisjunctions of the sex chromosomes have ever
produced and survived without an ______________.
X chromosome This is
because the X chromosome carries many genes
essential for life.
Section 14-2: Human Chromosomes
IV. Chromosomal Disorders
Klinefelters Syndrom - XXY condition
•Results mainly from nondisjunction in
mother (67%)
•Phenotype is tall males
–Sterile or nearly so
–Feminized traits (sparse facial hair,
somewhat enlarged breasts)
–Treated with testosterone injections
Section 14-2: Human Chromosomes
Nondisjunction of Sex Chromosomes
XX
x
Y
XX
x
X
O
x
Y
x
X
gamete
XX
XXY
(Klinefelter syndrome)
or
nondisjunction
XXX
(“metafemale”)
XX
gamete
O
YO
(not viable)
or
O
meiosis and
possibilities
gamete formation at fertilization
XO
(Turner syndrome)
genotype
(phenotype)
Figure 21.21
Page 399
Slide 25
Section 14-2: Human Chromosomes
IV. Chromosomal Disorders
The impact of the sex chromosome nondisjunction has led us to
understand the importance of the _____________________
Y chromosome in
determination of sex of an individual.
This has recently been determined to be true because the Y
chromosome has been found to have a gene that turns on
____________________________
male sexual developmentin the embryo even if many X
chromosomes are present.
The End 