Transcript Genetic Disorders - Sarah E. Goode STEM Academy

Heredity and Genetics
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Certain traits, such as eye and hair
color, come from both parents.
chromosomes
genes
DNA
genetic disorders
amniocentesis
chorionic villi sampling
gene therapy
Heredity
Heredity is the passing of physical traits
from parents to their children.
All the characteristics you have, such as your
eye color, the amount of curl in your hair, and
your height, are determined by your genetic
code.
Heredity
Family members often share similar physical traits.
Heredity
Most of the cells in the human body contain 46
chromosomes that are arranged in 23 pairs.
Chromosomes
Thread-like structures found within
the nucleus of a cell that carry the
codes for inherited traits
Heredity
Genes are sections of chromosomes that occur in
pairs. One gene from each pair is inherited from
each parent.
Genes
The basic units of heredity
DNA
All living things are made of DNA, or
deoxyribonucleic acid.
DNA
The chemical unit that makes up
chromosomes
DNA
DNA like this double helix, looks
like a long twisted ladder.
Genetics and Fetal Development
Chromosomes from a sperm and an egg
unite to carry the hereditary traits from
parents.
Passing on traits from parent to child involves
genetics.
Genetics and Fetal Development
Most human cells have 46 chromosomes, or 23
pairs.
However, egg and sperm cells have half that
number—23 chromosomes.
Genetics and Fetal Development
When a sperm and egg unite during fertilization,
the resulting zygote will have 46 chromosomes:
23 from the mother’s egg and
23 from the father’s sperm.
Dominant and Recessive Genes
Some genes are dominant, while others are
recessive.
The traits of recessive genes usually appear only
when the dominant genes are not present.
Dominant and Recessive Genes
Because females have only X chromosomes, their
egg cells contain only an X chromosome.
Sperm contain either an X or a Y chromosome.
Thus, the sperm from the male determines the
gender of a child.
Genetic Disorders
Genetic disorders are caused by defects in
genes.
Most genetic disorders cannot be cured, but
some can be treated.
Genetic Disorders
A person can inherit genes that contain a mutation,
or abnormality.
The mutation may have little or no effect. It also
may result in a birth defect or may increase the
person’s likelihood of developing a disease.
Genetic Disorders
Some genetic disorders are apparent at birth.
Genetic disorders
Disorders caused partly or
completely by a defect in
genes
Genetic Disorders
Amniocentesis is used to test for genetic
disorders.
Amniocentesis
A procedure in which a syringe is inserted
through a pregnant female’s abdominal wall to
remove a sample of the amniotic fluid
surrounding the developing fetus
Genetic Disorders
Common Human Genetic Disorders
Sickle Cell Anemia
Red blood cells have a sickle shape and clump together;
may result in severe joint and abdominal pain, weakness,
kidney disease, restricted blood flow
Tay-Sachs Disease
Destruction of nervous system; blindness; paralysis; death
during early childhood
Cystic Fibrosis
Mucus clogs many organs, including lungs, liver, and
pancreas; nutritional problems; serious respiratory
infections and congestion
Down Syndrome
Varying degrees of mental retardation, short stature, round
face with eyelids that cover inner corners of the eyes
Hemophilia
Failure of blood to clot
Genetic Disorders
Chorionic villi sampling is used to test for
genetic disorders.
Chorionic villi sampling
A procedure in which a small piece
of membrane is removed from the
chorion, a layer of tissue that
develops into the placenta
Battling Genetic Diseases
Research is ongoing to correct genetic
disorders.
Research into the human genome has given
scientists a greater understanding of how
genetic diseases progress.
Battling Genetic Diseases
Gene therapy is an experimental treatment for
correcting genetic disorders.
Gene therapy
The process of inserting normal
genes into human cells to correct
genetic disorders
Genetic Counseling
Genetic counselors can guide families of children
with genetic disorders on treatment options.
Genetic Counseling
Though genetic engineering, some vaccines that
can prevent disease have been produced.
After You Read
Reviewing Facts and Vocabulary
1. Define the terms chromosomes and
genes.
Chromosomes are found within the nucleus
of a cell and carry the codes for inherited
traits. The chromosomes contain genes,
which are the basic units of heredity.
After You Read
Reviewing Facts and Vocabulary
2. How many chromosomes are found in
most human cells? How many are found
in egg and sperm cells?
Most human body cells have 46
chromosomes, but egg and sperm cells
have 23 chromosomes.
After You Read
Reviewing Facts and Vocabulary
3. Identify the difference between the
chromosomes of a male and the
chromosomes of a female.
Males have an X and a Y chromosome.
Females have two X chromosomes.