Download Genetics notes

DO NOW:
NOW : List From Largest to
Smallest
Genetics
Chapter 12
DNA
Nucleus
Largest to Smallest
Nucleus
Chromosome
Gene
DNA
Scientist’s Questioned…..
• What was responsible for transferring
genetic material?
•
•
What is Genetics?
The study of how genes are passed from
generation to generation (HEREDITY
(HEREDITY).
).
The study of how genes give an organism
its traits.
Gene
Chromosome
______________________________
Already knew that chromosomes were
made of proteins & DNA.
Was it the protein or the DNA?
Chromosomes
- Contain DNA and proteins.
- have the genetic information that is
passed down to family members
• DNA
- the instructions for each trait (a blue print).
• Gene
- segments or parts on a chromosome
1
Gene
Functions::
Functions
1. Controls the making of proteins called
protein synthesis.
synthesis.
2. Directs the order of amino acids.
3. Determines the traits (characteristics) &
function of a cell.
Name Some Traits
Hair color
Eye color
Height
Weight
The Gene Chromosome
Model
A cell
Chromosomes- 23 pairs
The chromosome is
made up of genes
Chromosomes
Genes
The genes consist of
DNA which is made up
of four chemical letters
2
Different genes are activated
(turned on) in different cells. So
each cell has a specific protein that
makes it special!
Nucleotides
- sub
sub--units that make up DNA
1 Nucleotide is made of:
1 5-carbon ring
1 phosphate
1 nitrogen base
5 Carbon
Sugar
S
S
S
Nucleotide connects by a
bond to Sform a DNA strand
S
Four Types of Nucleotide
making up DNA
S
S
S
S
S
S
S
S
S
S
S
S
1 DNA Stand
1 DNA Strand
A Double Helix
(2 Strands = 1 DNA)
2 Types of Nucleic Acids
DNA:: Deoxyribonucleic acid
DNA
- in nucleus
Hydrogen
bond
RNA:: Ribonucleic acid
RNA
- in cytoplasm
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DNA
DNA
RNA
• DOUBLE Stranded Helix • SINGLE Stranded
• Deoxyribose sugar
• Ribose sugar
• Nitrogen bases:
• Nitrogen bases:
DNA acts as a TEMPLATE
TEMPLATE..
Meaning it acts as a pattern so it can be
COPIED..
COPIED
DNA is copied (replicated) before mitotic &
meiotic cell division.
A, U, C, G
A, T, C, G
• 1 type of DNA
(u- uracil, no- thymine)
• Connected by weak
bonds
• 3 RNA Types
3 Types of RNA
mRNA = messenger RNA
(copies DNA, carries the instructions for protein
assembly)
tRNA = transfer RNA
(transfers/carries amino acid)
rRNA = ribosomal RNA
(makes ribosomes in cytoplasm, site for
protein synthesis)
? Questions ?
1. What is the shape of a DNA molecule?
Double Helix
2. Name the 3 chemical groups that make up a
nucleotide?
Sugar, phosphate group, 1 nitrogen base
3. Name 3 ways that the chemical make-up of
RNA differs from DNA.
RNA- sugar (ribose), nitrogen base- uracil not
thymine, single strand of nucleotides
DNA (Chromosome) Replication:
Complimentary Strand
Complimentary Pairs
What Does This Mean?
DNA Replication - the copying of DNA to
have a complete set of DNA molecules.
A ------------------- T
A Good Match or Fit!!!!
G ------------------- C
http://www.dnai.org/lesson/go/19436
http://fig.cox.miami.edu/~cmallery/150/gene/mol_gen.htm
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DNA Replication
OLD
NEW
Template
Old Strand
New Strand
New Strand
Old Strand
http://www.sumanasinc.com/webcontent/animations/content/meselson.html
What is the Role of
DNA Polymerase?
Critical Thinking
Copy
this base sequence for the DNA
strand:
TGGCAATCTG
What would be its base sequence for the
complimentary strand?
ACCGTTAGAC
Joins
the DNA strands together
during DNA replication.
It
proofreads the DNA strand to make
sure it is a perfect fit for the
complimentary base!
• Genes are found within the
What is a Triplet Code?
Code
On the chromosome in the nucleus
_______________________.
• After DNA replication, the 2
strands are referred to as the
Old
New
_____
and _______
strands
A
codon.. This is every 3 bases on
codon
mRNA.
Each
set of 3 bases = 1 amino acid.
acid.
• Which strand is referred to as
the template? The Old strand
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Pairing –Up Rule for RNA
A Sequence of Nucleotides
A (DNA) ---------------- U (mRNA) NO THYMINE
What is the sequence of the mRNA molecule
transcribed from this gene.
GAC-AAG-TCC-ACA-ATC
C (DNA) ---------------- G (mRNA)
CUG-UUC-AGG-UGU-UAG
OR
GAC-AAG-UCC-ACA-AUC
1. Substitue all “T”’s for “U”.
CUG-UUC-AGG-UGU-UAG
2. Translate all
http://biology.unm.edu/ccouncil/Biology_124/Summaries/T&T.html
Protein Synthesis
Process 1: Transcription (copy)
1. 1 side of the DNA strand is copied by
mRNA in the nucleus
nucleus..
Process 2: Translation
1.
mRNA has the instructions to code for the order of
specific amino acids to make a polypeptide chain
(protein).
2. tRNA carries the anticodon (3 nitrogen bases) & 1 kind of
amino acid. tRNA binds with mRNA.
3. A protein is made (a polypeptide chain).
4. tRNA leaves to pick up another amino acid.
2. mRNA travels to a ribosome in the
cytoplasm (rRNA is found here)
http://www.dnai.org/lesson/go/19436
5. A STOP codon is reached on the mRNA.
6. The ribosome releases mRNA & an amino acid chain (a
protein).
Summary Review
Transcription:: DNA is copied into mRNA.
Transcription
Translation: mRNA matches with tRNA
Translation:
who carries the amino acid that codes for
mRNA.
Use Genetic Code Chart to find out the
amino acid that the mRNA codes for.
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Process 1:
Transcription DNA
unwinds (Nucleus)
Diagram Summary of
Protein Synthesis
Process 2: Translation Protein
Synthesis (in the ribosome) of the
Cytoplasm
DNA -transcription
RNA -translation to make
a polypeptide chain
http://www.dnai.org/lesson/go/19436
(Protein)
Reading the Genetic Code Chart
is to Determine
the Sequence of Amino Acids
for a SPECIFIC PROTEIN
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Genetic Problems
DNA Gene:
Gene: AAAAAA-GTTGTT-ATGATG-CGTCGT-TGTTGT-CTT
Translate
mRNA:
into mRNA
UUU--CAA
UUU
CAA--UAC
UAC--GCA
GCA--ACAACA-GAA
Find amino acid sequence
(chart)
Amino acid:
acid: PHE
PHE--GLN
GLN--TYRTYR-ALA
ALA--THR
THR--GLU
Genetic Problems
DNA Gene:
Gene: TACTAC-CAT
CAT--GTTGTT-TCT
TCT--GTG
Translate
mRNA:
(chart)
Amino acid:
acid: MET
MET--VAL
VAL--GLNGLN-ARG
ARG--HIS
• Protein synthesis takes place
.
The Process for
Protein Synthesis
AUG--GUAAUG
GUA-CAA
CAA--AGAAGA-CAC
Find amino acid sequence
Review Questions
into mRNA
Outside the NUCLEUS or in the ribosome
located in the cytoplasm
The
first & second process called?
Transcription & Translation
• What is the 1st step that takes place in
the nucleus during transcription?
•What helps DNA direct the
synthesis of proteins?
RNA
DNA unwinds or separates
• Which type of RNA meets with a DNA
strand in the nucleus to transcribe the
codons?
mRNA
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Where
Does mRNA travel to?
How
Cytoplasm, specifically to a ribosome
• Which RNA transports the anticodon
Three nitrogen bases at a time.
• What do every three codons represent?
specific for the mRNA’s codon?
tRNA
• What is located on tRNA besides the
is the sequence of codons read?
A different amino acid
• What term is used to refer to the
completion of protein synthesis?
anticodon?
Translation
A specific amino acid
The
end result of translation is a protein.
What is the structure of a protein
called? A polypeptide chain or a polymer
of amino acids
• What holds each amino acid together?
A peptide bond
• What happens to tRNA after its’
anticodon connects with mRNA’s codon?
Leaves to go back to the cytoplasm & pick up
another specific amino acid
Genetic Problems
DNA Gene:
Gene: AAAAAA-GTTGTT-ATGATG-CGTCGT-TGTTGT-CTT
Translate
mRNA:
into mRNA
UUU--CAA
UUU
CAA--UAC
UAC--GCA
GCA--ACAACA-GAA
Find amino acid sequence
(chart)
Amino acid:
acid: PHE
PHE--GLN
GLN--TYRTYR-ALA
ALA--THR
THR--GLU
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Do Now:
Now: Fill in the Schematic
Diagram for Protein Synthesis
?
?
?
A Schematic Diagram
Sequence Goes to
copied
cytoplasm
?
Gene of DNA
in nucleus
?
Word Bank:
rRNA
tRNA
Replication
rRNA
mRNA
tRNA
Gene of DNA in Nucleus
Protein
DNA
Every Protein has a SPECIFIC
SEQUENCE (order) of amino acids
SHAPE
FUNCTION
Protein
What Does Gene Expression
Mean?
Important!!!!!!!!!!!!
Different genes are activated
(turned on) in different cells. So
each cell has a specific protein that
makes it special!
mRNA
Carries over
amino acid
Means a gene is ON so its making a
synthesis).
protein (protein
(protein synthesis).
When gene is OFF, gene is not being
expressed and no protein is made (no
protein synthesis).
What would cause this rabbit’s
color to change?
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Gene Expression
& the Environment
Gene Expression
& the Environment
Himalayan rabbit
-
Changes in Temp. causes change in gene expression.
Cold temp. (below 33 C) turns on the gene that
controls black pigment.
-
Painted Turtle
The sex of the turtle during development is
determined by the incubation temperature.
Low temp produce males. High temp
produce females.
-
-
Do Different Species Have Similar
Genes & Proteins?
Let’s take a look……………
Human DNA (hemoglobin)
AGC--CCG
AGC
CCG--GTAGTA-CAG
mRNA:: UCG
mRNA
UCG--GGCGGC-CAU
CAU--GUC
a.a
a.a::
SER-GLY
SERGLY--HIS
HIS--VAL
Do Different Species Have Similar
Genes & Proteins?
2. DNA Gene (gorilla)
AGA--CTCAGA
CTC-CGT
CGT--CAT
1.
mRNA: UCU
mRNA:
UCU--GAG
GAG--GCAGCA-GUA
a.a
a.a::
SER-GLUSERGLU-ALAALA-VAL
Do Different Species Have Similar
Genes & Proteins?
3. DNA Gene (chimpanzee)
AGT--CCT
AGT
CCT--GTGGTG-TCC
mRNA: UCA
mRNA:
UCA--GGAGGA-CAC
CAC--AGG
a.a
a.a::
SER-GLY
SERGLY-- HIS
HIS-- ARG
Which species is more closely
related to humans? Why?
The chimpanzee has 3 of the same amino
acids as humans with the exception of one
– ARG.
The gorilla has 2 of the same & 2 different.
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Genetic Mutations
Albino Koala
(San Diego)
Albino
Peacock
Colombia
June 15,
2005
Snowflake
The world’s only captive Albino Gorilla, died 2003 from skin
cancer. Lived past 40 years at the Barcelona zoo in Spain.
Albino
alligator
Louisiana
April 2,
2008
June 5, 1998
Albino
No Skin Pigmentation
Both parents carry the recessive gene for
albinism.
However, the parents themselves were of
normal color (grey/black).
What is a MUTATION ?
A permanent change in the structure or
amount of genetic material.
2 Causes of MUTATIONS
1. Natural random errors (spontaneous)- happens
during DNA replication with DNA polymerase.
2. Mutagenic (mutagens) – chemicals & radiation
damage DNA.
Ex: x-rays, UV light, radiation, toxic chemicals
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Inherited
Sporadic
Some MUTATIONS Are….
HELPFUL
NEUTRAL
HARMFUL
Total loss of
gene function
Genetic variations
result in new traits
A change
Defective proteins
=
=
=
Nonfunctional proteins
Better working proteins Unchanged protein
Total loss of
gene function
2 Types of MUTATIONS
GENE
MUTATIONS
A change in 1 or more
bases within a DNA,
It affects a gene
on a chromosome.
What does a Gene do?
It sequences the order of amino acids for
a specific protein.
A change in the sequence of a base will
change how mRNA will transcribe for a
specific protein. A different protein could
be made.
CHROMOSOME
MUTATIONS
Change in the
NUMBER or STRUCTURE
of chromosome.
Gene MUTATIONS
TYPES
Substitution
Addition
Deletion
Definition
1 base replaces
another
Adds an extra
base
Missing base
ATACGAGCC
Gene MUTATIONS
(Normal Gene)
ATACGAGCC
ACACGAGCC
AT ACGAGCC
ATCACGAGCC
ATACGAGCC
Inversion
Alter amino acid SEQUENCE
Alter protein SHAPE
Alter protein FUNCTION
ATACGAGCC
ATAC_AGCC
Flips bases
Ex: enzyme function
ATAAGCGCC
13
CHROMOSOME MUTATIONS
Chromosomal Mutations
involves more than one gene
on the chromosome.
TYPES
Usually
Effects
Translocation
Inversion
are drastic
FLIPPED Genes
(reverses the order)
Addition/
Usually
Definition
2 different
chromosomes
change parts with
each other
LETHAL!!!!!!
LETHAL
!!!!!!
ADDED Genes
ABCDEFGHIJ ( Normal Gene)
ABCDEFGXYZ
TUVWHIJ
FROM
TUVWXYZ
FROM
ABCDEFGHIJ
ABCDEFGHIJ
ABCFEDGHIJ
ABCDEFGHIJ
ABCABCDEFGHIJ
Duplication
ABCDEFGHIJ
MISSING Genes
Deletion
Non--disjunction
Non
Chromosome Mutations
Deletion
Addition/
Duplication
Inversion
ABCDEFJ
Chromosomes fail
to separate equally
during MEIOSIS
(gamete cell division).
Sperm or egg gets
less or more
chromosomes.
47
chromosomes
Inherited MUTATIONS
Turner Syndrome
When
mutation is passed down to
offspring.
Mutation
is in the sex cell (sperm,
egg)
Happens
during MEIOSIS
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Turner Syndrome
Klinefelter Syndrome
• The presence of only 1 sex
chromosome in the cells (X,0)
• Physically- female has
underdeveloped sex
characteristics, webbed neck,
low-set ears, swollen hands &
feet, shorter height, heart
defects & kidney problems, &
infertile.
• Has 2 X’s, one Y.
• Male with underdeveloped sex organs,
enlarged breasts, tall stature, long legs, short
trunk, infertile, learning disabilities.
Two Ways Humans Can Alter
Genetic MakeMake-up of Organisms
1. Selective Breeding (artificial selection)
Genetic Engineering
~ Hybridization
~ Inbreeding
2. Bioengineering
*** Both are similar because humans use these
methods to develop new traits for better crops,
food, & animals.
Scientists Manipulate (change)
DNA
Humans mate specific plants or animals to
produce better traits, new varieties (type).
Goal:: To produce desirable traits.
1. Selective Breeding
1. Plants
Make better & more crops &
flowers.
Ex: disease resistant corn
crops to produce a lot of corn.
2. Animals
Make better herds (livestock)
Ex: make Pure breed dogs, cats, race
horses
Ex: Produce more beef, more pork.
15
Applied Genetics
Drought Resistant Corn
Polyploidy- cells have multiple, complete sets of
Polyploidychromosomes to obtain desirable traits in plants.
Chinese hibiscus
(East Asia)
The dog in your backyard could be a result
of selective breeding.
Labrador retriever
Goldendoodle?
Bt Corn &
European Corn
Borer
Labradoodles?
Poodle
2 Types of Selective Breeding
1. Hybridization
- 2 organisms of diff. breeds, but
within same species. Ex: dogs
or
- crossing 2 organisms of different
(dissimilar) species. Ex: Mule (horse
& donkey)
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Goal of Hybridization
Wolf Dog
Hybrid Animals
Mule
1. Increase genetic diversity
2. Make a new breed
3. Develop new traits (stronger, size,
color)
4. Breed out unwanted traits
5. Agriculture (healthier, longer surviving
plants)
Male donkey +
female horse
Zorse
Horse +Zebra
Wolf + Dog
Pheasant
2 similar
pheasants
2. Inbreeding
Mating of closely related individuals
to maintain desirable traits.
-
Ex: cats, farm animals (horses, sheep,
cattle)
How can decreasing variation be
good?
Can reduce variables in an experiment.
Investigate certain traits you want to study
(aggression).
Good for studying disease (resistance,
cancer).
Goal of Inbreeding
1. Increases desirable traits (milk yield,
rate of growth)
2. Decreases variation in a population (lab
animals: mice, rats, rabbits).
3. Increases risk for abnormal genes (Ex:
seizures)
Natural Occurrance of Inbreeding
17
Questions?
Why do the Cheetah, the Giant Panda, & the
Wolf inbreed?
Factors (health weaknesses,
environmental changes, & certain innate
behaviors) have lead to geographic
isolation resulting in inbreeding.
Name 2 methods that humans use to
develop new traits for better crops, animals,
& food.
Selective breeding & Bioengineering
Hybridization
Inbreeding
Result in less favorable genes that will put
them at risk for extinction.
Figure 17.5 A tobacco plant expressing a firefly gene
Bioengineering
Also called: recombinant DNA or gene splicing.
splicing.
DNA (genes) from 1 species is inserted into
another species DNA to produce rare
substances that are wanted.
Goal: To correct genetic disorders by
Goal:
transferring normal genes to cells that do not
have the gene.
http://www.sumanasinc.com/webcontent/animation
s/content/plasmidcloning.html
Transgenic bacteria
Bacteria with foreign genes in it.
Example::
Example
- A bacteria is injected with the human
gene for a rare protein (interferon, insulin,
or clotting substances) to be made.
- Results in more of the desired
substances (proteins) to be made.
Interferon- is an antiviral chemical that
helps humans fight off viruses.
What is a Plasmid
Plasmid?
?
A roundround-shaped DNA molecule found
inside a bacteria that have genes on it.
What Tool Do Scientists Use to Insert
Genes On a Plasmid?
Restriction Enzymes
(cuts the DNA within a specific
sequence)
18
Restriction Enzymes
Restriction Enzymes
Recognition
sequences
Section 13-2
Recognition
sequences
Section 13-2
Sticky end
Recognition sequences are the
places on the DNA where an
enzyme will cut it
Steps
For Gene Splicing
Figure 13-9 Making Recombinant DNA
Section 13-3
Gene for
human growth
Recombinant
hormone
DNA
Gene for human
growth hormone
Human Cell
Sticky
ends
1.
DNA
recombination DNA
Cut the desired DNA into pieces using
restriction enzymes (a protein).
insertion
2. Next, plasmids are removed from bacterial
cells.
Bacterial Cell
Bacterial
chromosome
Plasmid
Bacterial cell for
containing gene
for human
growth hormone
3. Plasmids are placed in a solution containing
foreign DNA (test tube).
4. Restriction enzyme is added to break
open the plasmid.
Questions?
5. Foreign DNA attaches to the opening of
the plasmid to become 1.
6. Plasmid ring closes.
______________ or __________________
A Type of Bioengineering would be
Gene splicing
Recombinant DNA
7. Insert the DNA pieces into a host cell (ex:
virus, bacteria).
8. Bacteria replicates.
Draw diagram.
http://www.sumanasinc.com/webcontent/animations/content/plasmidcloning.htm
l
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CLONING
An organism with EXACTLY the SAME
number of genes.
Benefits::
~ Produce better livestock (cows, pigs, sheep)
~ Produce better crops (wheat, corn, rice)
Examples::
Identical twins
Asexual reproduction (ameba, bacteria, some plants)
Dolly the sheep (1996-2003). Courtesy of Roslin Institute, Edinburgh.
PROCEDURE FOR CLONING
1. Remove nucleus
from egg cell
(discard nucleus)
4. Electric Shock
to begin cell
division into
embryo
2. Remove
nucleus from
cell of organism
3. Insert
nucleus from
body cell into
egg cell
5. Implant embryo
into uterus
6. Embryo
develops into
clone
NUCLEAR TRANSFER
Removing an egg's nucleus during nuclear transfer.
Courtesy of Roslin Institute, Edinburgh.
Ethical, legal and social issues.
Ethical issues - consider the potential moral outcomes of
cloning technologies.
Legal issues - how should it be regulated by the
government.
Social issues –impact on society as a whole.
Some questions to ponder.
•Who has the right to have children, no matter how they are created?
•Is human cloning "playing with nature?“
in vitro fertilization or hormone treatments?
•Does cloning to create stem cells, also called therapeutic cloning,
justify destroying a human embryo?
•If a clone originates from an existing person, who is the parent?
•What are some of the social challenges a cloned child might face?
•Do the benefits of human cloning outweigh the costs of human dignity?
•Should cloning research be regulated? How, and by whom?
20
Gel Electrophoresis
A techniques to separate DNA fragments
by length (size) in an electrical field using
a gel.
DNA is ((-) charged due to the phosphate
located on DNA strands.
DNA fragments will move towards the
POSITIVE POLE!
Smaller fragments
move faster than
larger fragments
because of a lower
molecular weight.
Procedure:: Gel Electrophoresis
Procedure
1.
2.
3.
4.
Uses
1. Compare relatedness of individuals of
some or different species.
2. Paternity or maternity testing
3. Place suspects at a crime scene or not.
Restriction enzymes cut DNA into
different length pieces.
DNA fragments are put into wells in gel.
Electrical current causes fragments to
travel towards the + pole.
Smaller fragments are faster & travel
further in gel
Larger fragments more slower.
Interpretation
Identical DNA Band Pattern = Same Individual
Similar DNA Band Pattern = Related Individual
Different Band Pattern = Not Closely Related
21
Genetic Disorders
Words To Know!
Alleles
– An area of DNA on a chromosome.
- The different forms of a gene for a
specific trait.
- Humans have 2 alleles
Allele
for each trait.
- Allows for
genetic variation..
Dominant-- the trait expressed (XX, Xx)
Dominant
Recessive-- the trait that’s hidden (xx)
Recessive
Allele
Cystic Fibrosis
Recessive disorder (inherited from 2 defective
genes)
System Affected:
Affected: lung & digestive system
Chloride channel
defect- diffusion of
salt & water in the
cell membrane
doesn’t work.
Disease:
Disease:
- thick mucus in lungs = difficulty breathing
- blocked pancreas = difficulty breaking down to
digest food (fats)
Symptoms:: difficulty breathing, constipation,
Symptoms
lung infections
TX: inhaler, percussion therapy
22
Sickle Cell Anemia
Sickle Cell Anemia
Recessive disorder
System Affected:
Affected: RBC is Sickle-shaped (defect in
hemoglobin)
Disease:
- blocked blood vessels
- decrease oxygen
Symptoms
Symptoms::
- fatigue, PAIN
Normal codon is GA
GAA = glutamic acid
Abnormal codon is GU
GUA = valine
DEFECTIVE GENE
TYPE=
Substitution
CHANGES AMINO ACID SEQUENCE
CHANGES PROTEIN SHAPE
Tx: fluids, rest
CHANGES FUNCTION
Phenylketonuria (PKU)
Tay--Sachs
Tay
Recessive disorder (inherited 2 defective genes)
System Affected:
Affected: high levels of phenylalanine in
blood due to the missing enzyme (protein) called
Phenylalanine.
Recessive disorder
System Affected:
Affected: Nervous System due to lack of
enzyme needed to break down LIPIDS
Disease::
Disease
- unable to break down lipids, important for
normal brain function.
Symptoms
Symptoms:: build up of lipids in brain tissue =
brain damage, blindness, muscle paralysis.
Disease:
Disease:
- unable to break down amino acids so it breaks
down into chemicals that damage the brain.
Symptoms:
- mental retardation
Tx: none, early death
Tx: special diet (low protein)
Nerve Cell
damage
Down’s Syndrome
Nondisjunction (chromosomes do not separate
during meiosis)
24 (egg) + 23 (sperm) = 47 chromosomes
Systems Affected:
Affected: Brain, heart, kidney
Disease::
Disease
- extra chromosome # on chrom. 21
Systems
Systems:: mental disabilities
physical problems,
heart, kidney
http://www.momsonthemove.com/show_detail.asp?id=9
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