Gene Mutation

HideShow resource information
What is a gene mutation?
Any change to the quantity or structure of the DNA of an organism.
1 of 23
Which mutations are not passed on to future generations?
mutations that occur in somatic (body) cells.
2 of 23
Which mutations are passed on to future generations?
Mutations that occur in the gametes of an organism.
3 of 23
What is a substitution mutation?
When a mutation involves a nucleotide in the DNA molecule being replaces by a nucleotide that has a different base.
4 of 23
What are the three types of base substitution?
A nonsense mutation, a mis-sense mutation and a silent mutation.
5 of 23
What is a nonsense mutation?
A mutation that occurs if the base changes result in the formation of three stop codons that mark the end of a polypeptide chain. As a result the production of a polypeptide is stopped prematurely.
6 of 23
What is a mis-sense mutation?
A mutation which arises when the base change results in a different amino acid being coded for. The polypeptide produced will not be the same as the original one it would code for, and therefore results in a non-functioning enzyme.
7 of 23
What is a silent mutation?
A mutation that occurs when a substituted base, although different, still codes for the same amino acid before and so the mutation is unnoticed.
8 of 23
What happens in the deletion of bases mutation?
Bases are deleted which causes the code being shifted to the left by one nucleotide, which consequently may produce a different amino acid.
9 of 23
When can gene mutations occur spontaneously?
In DNA replication.
10 of 23
What is a mutagenic agent?
An outside factor that increases the chance of a mutation occuring.
11 of 23
What are two examples of mutagenic agents?
High energy radiation can disrupt the DNA molecule. Chemicals that later the DNA sequence of intefere with transcription.
12 of 23
What is one strength of a mutation occurring?
It produces genetic diversity necessary for natural selection and speciation.
13 of 23
What are 2 weaknesses of mutations?
1. Produces an organism less suited to its environment and so has low chance of survival. 2. Mutations in somatic cells can disrupt normal cellular activities.
14 of 23
What are the two genes that control cell division?
Proto-oncogenes and Tumour suppressor genes.
15 of 23
What do proto-onco genes do?
They stimulate cell division.
16 of 23
What do tumour suppressor genes do?
Slow down cell division.
17 of 23
What is the mutation of proto-oncogenes and in what 2 ways can it affect cell division?
Makes ONCO-GENES instead of proto-onco. These affect CD in 2 ways: 1. the receptor on CSM can be permanently activated so cell division is switched on always. 2. Oncogene codes for a growth factor that results in excessive cell division.
18 of 23
What is the overall effect of a mutation on the proto-oncogenes?
Cells divide too rapidly and a tumor or cancer develops.
19 of 23
What do tumour suppressor genes normally do?
They inhibit cell division. They maintain normal rates of cell division and prevents the formation of tumours.
20 of 23
What happens when a mutation occurs in tumour supressor genes?
The mutation deactivates the gene, consequently cell division increases. Most of mutated cells die, but any that survive are able to make clones and form tumours.
21 of 23
What are harmful tumors called?
Malignant tumous.
22 of 23
What are un-harmful tumors called?
Benign.
23 of 23

Other cards in this set

Card 2

Front

Which mutations are not passed on to future generations?

Back

mutations that occur in somatic (body) cells.

Card 3

Front

Which mutations are passed on to future generations?

Back

Preview of the front of card 3

Card 4

Front

What is a substitution mutation?

Back

Preview of the front of card 4

Card 5

Front

What are the three types of base substitution?

Back

Preview of the front of card 5
View more cards

Comments

RoisinP

Rudimentary

RoisinP

Spelling errors!

Similar Biology resources:

See all Biology resources »See all Human, animal and plant physiology resources »