Download Mutation

Ms. Hu
Living Environment Name: _______________ Class: ______ Date: ____________ Pg#_____
Aim: Mutations the significance of changes the in the genetic code
Do Now: What do you know about mutations? Do you think they are good or bad or the organism?
Mini Lesson Notes: Video Clip http://www.copernicusproject.ucr.edu/ssi/HSBiologyResources.htm
Mutations is a ______________________ (error) in a _________ (genetic information) or a change in a
chromosome in a living thing. Mutation is a change in the DNA ____________________________, which
means, a change in the ____________________ (sequence) of nitrogen bases in the DNA (Ex. TACGCTA
changed to TAACGCTA) causes a change in which amino acid (examples hormones, enzymes) to be produced,
there will be _____________________(differences) among the organisms.
Living things with mutations get new, changed, or different characteristics. For example: hemophilia is
a disease caused by a mutation; when a person with hemophilia gets a cut, it does not stop bleedings,
Example: DNA sequence order of nitrogen bases is TACGCTA. Let’s make four kind of mutations or changes
in the DNA sequence.
Mutation: Change in the Nitrogen Bases of DNA
Base Sequence
Type of Mutation
TACGCTA
Original Sequence
TAACGCTA
Addition
(
T_CGCTA
Deletion
(
TAGBCTA
Substitution (
CATGCTA
Reversal of order of bases (
)
)
)
)
Mutations can causes change in the gene sequence that can cause a different amino acid to be made into
protein to make it defective (does not work anymore).
An example of a mutation (substitution of a nitrogen base) is sickle cell disease (sickle cell anemia). A red
blood cell is normally round, but in sickle cell disease a red blood cell is sickle shaped and cannot do its
function (work).
Normal red blood cell
Sickle-shaped red blood cell
A mutated gene can be passed on to every cell that develops from the cell with the mutated gene. If one cell
with an altered gene divides and forms two cells, then both cells will have the mutated gene. Changes in
mRNA or tRNA affect the protein formed but are not passed on when cells divide.
Only mutations in the sex cells (male sperm or female eggs) will be passed on to the offspring (child). A
mutation in a stomach cell or liver cell will not be passed on to the child.
Mutations can be caused by: cells being exposed to too much radiation, (such as x rays or ultraviolet rays from
the sun) and also by certain chemicals (mutangenic agents); mutations increases the risk of getting cancer.
Sickle cell disease is caused by a mutation, a wrong base substituted fro the correct base in the DNA base
sequence. Mutations are RANDOM (happen by chance) and can occur any place in the DNA.
Work Period:
1. A change in the base subunit sequence during DNA replication can result in
a. Variation within the organism
b. Rapid evolution of an organism
c. Synthesis of antigens to protect the cell d. Recombination of genes within the cell
2.
What is the definition of a mutation?
3. What changes in the DNA causes hemophilia? What is the effect of having a defective gene?
4. Given the following original sequence of DNA. Please either give an example of a mutation or define the
type of mutation that is caused
Base Sequence
Type of Mutation
Original base sequence
CAT GTA ACT TAC
CAT ATG ACT TAC
Deletion
CAT CTA ACT TAC
CAT GTA ACA TTA C
CAT GTA ACT TAC
5. Will changes in RNA cause mutations to be passed onto future generations?
6. Where must a mutation occur if it is to be passed onto the offspring?
7. Name two causes of genetic mutations.
Closing: What is a mutation?
Homework: Try eight questions for homework: 39, 40, 41, 44, 45, 46, 47, and 49