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What is a mutation?
Any heritable change in the genetic material of an organism.
What is the cause of mutation?
Mutations are spontaneous. They occur due to errors in cellular processes (ie. errors in DNA replication)
On average, only __ nucleotide in every ____ is mistakenly substituted for another.
What is a pint mutation?
- It's a single nucleotide base pair change in the DNA that results in a changed mRNA
- (A change of one base for another)
What's a silent mutation?
Change in nucleotide that DOESN'T change amino acid specifies by codon.
What's a missense mutation?
It's a change in nucleotide that DOES cahnge amino acid specified by codon
What's a nonsense mutation?
A change in nucleotide that results in an early stop codon
What's a frameshift mutation?
Addition or deletion of a nucleotide
Which type of mutation causes Sickle Cell anemia?
- Missense mutation
- produced by a single amino acid change
- (glu is replaced by val)
- Results in misfolding of the hemaglobin
What's the cause of Cystic Fibrosis?
-Small deletion mutation
-Deletion of 3 nucleotides, which results in a lost of a single amino acid
What are the 2 categories of mutations?
- 1. Small Scale
- 2. Large Scale
Which mutations are part of small scale mutations?
Nucleotide substitution or point mutations:
- 1. Silent mutations
- 2. Missense mutation
- 3. Nonsense mutation
Which mutations are part of Large Scale mutations?
- Chromosomal mutations
- 1. Insertion
- 2. Deletion
Where do Germ-line mutations occur?
in reproductive cells
Where do somatic mutations occur?
in nonreprodcutive cells
Which of the following mutations are transmitted to progeny and play a role in evolution:
How are mutations random?
They occur without regard to the needs of an organism.
What did Darwin suggested in regards to mutations?
He suggested that mutations happen randomly and are selected for under different conditions.
Describe the nuclotide excision repair system
- 1. An enzyme detects an irregularity in DNA structure
- 2. Nuclease cuts damaged DNA strand and removes nucleotide
- 3. DNA polymerase fills in missing nucleotides
- DNA ligase closes gap joining both nucleotides.
Describe the Mismatch Repair System
When DNA polymerase doesn't fix a mistake, a mismatch repair mechanism activates.
- 1. A repair enzyme breaks the backbone downstream
- 2. Anotherenzyme removes successive nucleotides, including the mismatched base.
- 3. DNA polymerase comes in and adds the missingbases, using the intact strand as a template.
Which enzyme proofreads each nuclotide against the template?
What's a mutagen?
is a physical or chemical agent that changes the genetic material, usually DNA, of an organism and thus increases the frequency of mutations
Provide examples of mutagens
- 1. X-rays
- 2. UV light
- 3. Chemicals