introduction let’s read – page 687 paragraph one what of this to do we agree with? what...
TRANSCRIPT
20.4 - MUTATIONS AND GENETIC VARIATION
Introduction
Let’s Read – page 687 paragraph one
What of this to do we agree with?
What don’t we agree with and why?
Mutations are changes in a sequence of DNA
They may be harmful, neutral or beneficial (there are incredibly few beneficial mutations)
Broad Types of Mutations
Point mutations – change a single base pair
Gene mutations – change the amino acid that was coded for – usually involve more than one base pair
Brief to Do:
Fill in the worksheet called “Types of Mutations”
The types and pictures can be found on page 687
The descriptions can be found on page 688
You have 20 minutes
Other Mutation Vocabulary
A frameshift mutation causes the reading frame of codons to change Result: completely different
amino acids are coded for How many base pairs need to
be inserted or deleted to cause a frameshift mutation?
Translocation is the movement of a group of base pairs from one part of the genome to another 2 pieces of DNA from different
chromosomes break and switch places
RESULT – ”fusion” proteins produced have altered function if any function at all
Some leukemia is associated with translocation
An inversion – a piece of chromosome has turned itself around RESULT : a gene may be
disrupted
Causes of Genetic Mutations A spontaneous mutation is caused
when the DNA is being replicated (ex. By DNA polymerase I)
Mutagenic agents can cause induced mutations
Examples of mutagenic agents are UV radiation,
cosmic rays, X-rays and some chemicals
To Do:
With a partner or on your own do the case study on page 689 called “Gene Mutations and Cancer”
Hand in your answers together #1-6
Part 2
Inferring Relationships from DNA Sequences As a class read page 690 and
691
Vocab Phylogeny – proposed evolutionary
history of a species or group of organisms SINEs – (short interspersed elements) –
repeated DNA sequences 300 bp long that alternate with lengths of DNA sequences found in the genome of higher organisms
LINEs – (long interspersed elements) - repeated DNA sequences 5000 - 70000 bp long that alternate with lengths of DNA sequences found in the genome of higher organisms
Any other notes?
Mitochonridial DNA (mtDNA) -
To Do:
Watch “Animals the Defy Evolution” Make any necessary flashcards
Next Day to do:
1) Protein Synthesis Review Wksht
2) p. 694 #1-73) p. 702 #1-7, 214) P. 705 #1-15 5) Go to the computer lab and do
“Science Gizmo” – RNA to Protein worksheet