Transcript DNA and Mutations

DNA and Mutations
What is DNA?
• DNA
(Deoxyribonucleic
acid) is found in
all living things.
• It is the carrier of
genetic
information
• DNA affects how an organism looks, behaves,
and how it’s body functions.
• You found some of those traits earlier in this
unit!
• Sections of DNA are called genes
• Many genes stacked together form our
chromosomes
• You have 46 chromosomes, 23 from mom, 23
from dad.
• Genes can come in multiple forms-usually
dominant or recessive
• The genes for blood type have 3 different
versions (3 different alleles)
– A, B, and o
• These genes tell the blood cell what type of
protein to have on the cell membrane surface
• The phenotype (physical appearance) is
controlled by the genotype (genes) of the
organism.
• But what if there is a change to the genotype?
• A small change in the genes can cause a big
change in the appearance and traits of the
organism!
Objectives
• Define mutation
• Identify causes of mutations
• Describe effects of mutations
What is a Mutation?
• Any permanent change to DNA is called a
mutation.
What is a mutation?
• The DNA can be changed in several ways
What is a mutation?
• A mutation can happen to a small section of
DNA or to a chromosome
What causes a mutation?
• Mutations are a natural process that has been
occurring for millions of years, changing DNA a
little at a time.
What causes a mutation?
• Many times a mutation occurs naturally
during mitosis.
• That mutated cell often doesn’t survive to
divide again.
• Other causes of mutations can be
environmental
– Radiation (x-rays/gamma rays), UV light, chemicals
(cigarettes) , or viruses (HPV) can cause mutations
in the DNA
Normal DNA
and DNA
being hit by
x-rays and
radiation
What are the effects of mutations?
• Are mutations bad?
• Can I get superpowers from a mutation?
What are the effects of mutations?
• Most of the time, there is NO effect!
• The cell may fix the mistake or destroy itself
and the mutation does not get passed on.
What are the effects of mutations?
• Or the
mutation may
have occurred
in a section of
DNA that does
not affect the
organism’s
genes.
https://www.youtube.com/watch?v=uX7Okcqe8eU
Effects
• Sometimes the mutation can be harmful to
the organism.
Harmful mutation in humans
• Sickle Cell- red blood cells cannot carry oxygen
as well due to their shape.
• Uncontrolled growth of a mutated cell can
lead to cancerous tumors
Effects
• Sometimes the mutation can be helpful to the
organism-which banana would you prefer?
Effects
• Watermelon anyone?
Effects
• Double muscled (Belgian Blue) cattle with
myostatin mutations
Effects
• Some gardeners will purposely expose seeds
to radiation to cause mutations in their plants
Blue eyes are a mutation
• Even bacteria can benefit from having
mutated DNA- they can avoid being killed by
an antibiotic
Review and Summary
• Mutations are a change in DNA
• They occur naturally but can also be caused by
environmental factors
• Most of the time, there is no effect to a
mutation, but other times, the mutation can
harmful or helpful to the organism.
https://www.youtube.com/watch?v=GieZ3pk9YVo&nohtml5=False