Download powerpoint human disorders - Social Circle City Schools

Human Heredity
Do Now
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Read the statements below. Determine if they
are true or false. Record answer.
1. The father determines the gender of the
child.
2. Individuals may transmit characteristics to
their offspring which they themselves do not
show.
3. Identical twins always are of the same
gender.
Discuss
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1. Which questions did we miss?
Why?
2. Why is it helpful to understand human
heredity?
Vocab
Carrier
nondisjunction
Pedigree
telomere
Incomplete dominance
Codominance
karyotype
Multiple alleles
polygenic trait
Epistatis
sex- linked trait
Sex chromosome
autosome
Team 1 vs Team 2
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Pictonary
Each team will draw a word meaning on the
board
If your team gets the word in 45 seconds you
win a point.
Flip flop between teams.
Human Chromosomes
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Humans have 46 chromosomes- 23
pairs
Genotype of Female is XX
 Genotype of Male is XY
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karyotype: picture of chromosomes
Most genetic disorders are
caused by RECESSIVE alleles.
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Cystic fibrosis- large accumulation of
muscus due to lack of protein.
Phenylketonuria (PKU)- lack enzyme that
converts phenylalanine to tyrosine.
Tay-Sachs- lack of enzyme that breaks
down fat in the CNS
Albinism- lack of pigment in skin.
Cystic Fibrosis
*Caused by a defect in a protein that results
in an overproduction of muscus.
*Favors bacterial infections because mucos clogs
the body like the pancreas, lungs and digestive
system.
*1 in 20 white Americans are carriers.
Cystic Fibrosis cont…
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1 in every 2000 children born to white
Americans has this disorder.
Without treatments, most children die before
age 5.
With treatments, can live into 20’s+
Treatment includes diet, meds, replacement
enzymes and physical therapy
Cystic Fibrosis
Tay-Sachs- DON’T WRITE
*Lack enzyme breaks down fat in the CNS- fat
collects on the brain.
*No treatment or cure. Most will die before the
age of 6.
• Found on chromosome #15 predominant in
Eastern European Jewish decent.
Tay- Sachs cont…
Albinism
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*Absence of pigment melanin in hair, eyes and
skin.
*Affects eyesight
Albinism
Celiac Disease
*Gluten cannot be
broken downprotein in wheat,
rye and barley.
*Small intestine
responds by
attacking itself.
Disorders caused by dominant
alleles:
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Huntington’s
*Disease- effects
nervous system.
1/10,000 people in
U.S between ages
30-50 yrs old.
*Gradual loss of
brain functions
Dwarfism/ Achondroplasia
*Genetic disorder due
to lack of growth
hormone
• Little people is the
PC term.
• Many different forms
not just height.
• 75% are born to
people of average
height.
Polydactyl- more than 5 digits on
hand or foot
Top 10 Genetic Disorders.
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top 10
Caused by changes in DNA
(mutations):
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Sickle-cell Anemia: amino acid is
changed in hemoglobin to give cells a
sickle shape. Blocks the flow of red
blood cells.
Sex-Linked Disordersmost commonly found in males
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Mostly on X chromosome (recessive) and
since males have only one X
chromosome they will express the
disorder more often.
Examples:
Colorblindness
 Hemophilia
 Muscular Dystrophy
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DON’T WRITE
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Some genes are located on the X chromosome.
Females receive two alleles for these genes, but males
only receive one.
If the parent is a male, the genotype is automatically
known. A colorblind male has to be b, since he only
has one allele and colorblindness is recessive. A
normal male must then be B
Females can be heterozygous for the colorblindness
trait - they are called carriers. A female can be BB normal, Bb - carrier, or bb - colorblind
The following shows a cross between a normal
man and a woman who is a carrier
colorblindess test
a Y-linked trait
Chromosomal Disorders
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Nondisjunction: chromosomes fail to
separate properly during meiosis
(formation of gametes)
Chromosomal Disorders
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Down Syndrome- extra chromosome on #21 (results
in total of 47 chrom)
Turner’s- only 1 sex chromosome and alters
female development
Klinefelter’s- males with an extra X
chromosome. Alters testosterone
development. May cause infertility
Down Syndrome- Extra
chromosome on #21.
Total of 47 chromosomes
Turner’s
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Only 1 X
Klinefelter”s
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Extra X
Karyotype
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A karyotype is an image of whole
chromosomes stained during metaphase.
Show identical genes on homologous
chromosomes.
Pairs are arranged by decreasing size.
Down Syndrome Karyotype
Klinefelter’s Karyotype
Turner’s Karyotype
Karyotype activity
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You and a partner will assemble the Karyotype
of your human in the envelope.
1. match up chromosomes
2. arrange by size
3. label # 1-23 pairs and each individual
chromosome
4. match up with known karyotypes and
identify your human
5. If they have a disorder list symptoms.
Pedigree
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A pedigree is a family history study.
If a trait is expressed the shape is darkened
If not shaded trait not expressed
Half shaded carrier but not expressed
Pedigree—graphic representation of genetic
inheritance.
- Male= square
- Female= circle
- Shaded= has the disorder
- Half shaded= carrier of disorder.
Activity
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Pick one of the case studies or page 300