Download 7th grade Ch. 5 section 2 and 3 Notes

Genetic Disorders
Ch. 5 section 2
Causes
• Genetic Disorder: an abnormal
condition that a person inherits through
genes or chromosomes.
• Some are caused by mutations in DNA.
• Others by the changes in structure or
Number of chromosomes.
Cystic Fibrosis
• The body produces abnormally thick
mucus in the lungs and the intestines.
• Mucus makes it hard to breath.
• The recessive allele is a result of a
mutation in which 3 bases are removed.
Sickle Cell Disease
• Affects the hemoglobin in red blood
cells that carry oxygen.
• When oxygen levels are low the red
blood cell has a sickle shape.
• Blot clots are common with this disease.
Hemophilia
• Disorder where a person’s blood clots
very slowly.
• Occurs more in males than females.
• People bleed a lot just from a small cut.
Downs Syndrome
• A person’s cells carry an extra copy of
chromosome 21.
• Instead of a pair of chromosomes they
have 3 in the 21st set.
• People with DS have a degree of
mental retardation and heart defect are
also common.
Pedigrees
• An important tool that geneticists use to
trace inheritance of traits in humans.
• Chart or “family tree” that track which
family member has a particular trait.
Karyotypes
• Picture of all the chromosomes in a cell.
• Can help reveal if a person has the
correct number of chromosomes in his
or her cells.
Dealing with genetic disorders
• People with disorders face serious
challenges.
• Medical care and treatments can help
people with some of these disorders.
• Most genetic disorders do not prevent
people from living active and productive
lives.
CH. 5 section 3
• Selective Breeding: selecting organisms
with desired traits to be parents of the
next generation.
• Inbreeding: crossing 2 individuals that
have similar characteristics. (usually
very similar)
• Hybridization: cross 2 genetically
different individuals.
Cloning
• Can be used to produce offspring with
desired traits.
• Clone: organism that has the exact
same genes as the organism in which it
was produced by.
• Researchers have cloned sheep and
pigs.
Genetic Engineering
• Genes from one organism are
transferred into the DNA of another.
• One type of Bacteria is genetically
engineered to produce insulin that is
used for people with Diabetes.
Gene Therapy
• Involves inserting copies of a gene
directly into a person’s cells.
Concerns
• Long term effects are still in question.
• could cause health problems or
environmental problems.
Human Genome project
• Genome: all the DNA in one cell of an
organism.
• Goal is to identify the DNA sequence of
every gene in the human genome.
• Humans contain at least 30,000 genes.
• Average gene has about 3,000 bases.