Download Mutations PPT

MONSTROUS
MUTATIONS!!!
What is a mutation?
• Mutations are
changes in DNA!
• However, these
simple changes or
mistakes can cause
big changes in
phenotypes of
organisms!
Mutations in reproductive cells…
• If a mutation happened during the
creation of the reproductive cells…
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There could be non-functioning cells
New traits might be produced
Proteins may not work correctly
Embryo may not survive 
• There can be positive effects though!
– Faster or stronger cells!
Mutations in body cells…
• If mutation is caused by radiation and it is a
non-reproductive cell, the mutation may not
be passed on to the offspring.
• However, the mutation could cause problems
for the individual.
• Damage to the gene could impair the function
of the cell.
– Muscle cell may lose its ability to make the protein
necessary for contraction
– Skin cell may lose its elasticity.
Mutations in body cells…
• When the cells
divide, the new cells
will have the same
mutation!
• Aging may be caused
by a buildup of these
mutated cells!
• Cancer is also caused
by a mutation in the
cell’s rate of
division.
Point Mutations
• A point mutation changes a single base pair in
the DNA sequence.
• What could this cause?
– Change in amino acid sequence
– EX: THE DOG BIT THE CAT.
THE DOG BIT THE CAR.
This is a BIG difference!
• In general, point mutations are less harmful
than other mutations because it only changes
one base in the sequence.
Frameshift Mutations
• A frameshift
mutation occurs
when a single base is
added or deleted
from the DNA
sequence.
• This is a problem
because it shifts the
reading of codons by
one base and thus a
totally different
protein is produced!
Chromosomal Mutations
• Chromosomal mutations are changes at
the chromosomal level.
• Some of these changes may be caused
by:
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Chromosome parts breaking off
Lost parts of chromosomes
Parts that rejoin incorrectly
Parts that rejoin backwards or even the
wrong chromosome part
Effects of Chromosomal
Mutations:
• Occurs most often in plants!
• Few chromosomal mutations are passed
on to the next generation because the
zygote usually dies.
• If the zygote lives and grows up, usually
it is sterile and cannot produce
offspring or pass on the mutated genes.
Causes of Mutations
• Some mutations just happen! Similar to a silly
mistake on a math problem. These are called
SPONTANEOUS mutations!
• Many mutations are caused by environmental
factors, such as, radiation.
• MUTAGENS are agents that can cause errors
in DNA.
– EX: high energy radiation, chemicals, high
temperatures.