Download Chromosome vs. Gene Mutations

Aim: How can we compare
chromosome mutations & gene
mutations?
Gene
Chromosome
Chromosome Mutation:
Causes a
change in
chromosome
number or
structure.
Nondisjunction- occurs when homologous chromosomes or sister chromatids
fail to separate during meiosis.
Trisomy Vs Monosomy:
Trisomy 21
3 Copies of a
Chromosome
Down Syndrome
Monosomy X
1 copy of a
homologous pair
Turner Syndrome
Down Syndrome
Turner’s Syndrome
What causes nondisjunction to occur?
Trisomy 21
No one really
knows for sure,
but the older the
age of the mother
the greater the
chance of having
a child with Down
Syndrome.
Chromosome Damage:
Part of a chromosome
is repeated.
Part of a chromosome
is missing.
Reversing a fragment
of the chromosome.
Rearrangement of
parts between nonhomologous pairs of
chromosomes.
Gene Mutations:
• Are due to a change in a single
gene.
• Can involve changes in several
nucleotides
Genetic Diseases caused by gene
mutations:
Cystic Fibrosis
Faulty gene produces a
defective protein that does not allow for
the proper removal of mucous lining
the cells of the lung and GI tract.
Gene Mutations:
Tay-Sachs Disease
Faulty gene produces a defective
enzyme which cannot help remove fat
from nerve cells.
Sickle-Cell Anemia:
One base is substituted for another and
this causes the production of a
distorted hemoglobin molecule (protein)
which cannot function properly.
What do these three gene
mutations have in common?
They all affect the shape of proteins!! If
we change the shape of proteins
(enzymes) they will not function properly
and this will affect our phenotype.