8.1 DNA And Alternation Of Proteins

Question 1

What is a gene mutation

Answer 1

Change is base sequence of DNA
Can arise spontaneously during DNA replication

Question 2

What is a mutagenic agent

Answer 2

Increases rate of mutation (UV)

Question 3

How can a gene lead to the production of a non-fictional protein

Answer 3

Changes in base triples in DNA so change in sequence of codons on mRNA

So changes of amino acids

So changes in position of H/ionic bonds

Changes in tertiary structure

Enzymes-active stie has changed shape

Question 4

Types of gene mutations

Answer 4

Sub-a base is release by a different base in DNA

Add-1 or more bases are added to DNA

deletion- 1 or more bases are lost from DNA

duplication - sequence of DNA bases are repeated

Inversion- sequence of DNA bases detaches, then rejoins DNA in reverse order

Translocation- sequence of DNA bases detaches and is inserted at different location on the same or different chromosome

Question 5

Why is a change in amino acid sequence not always bad

Answer 5

May not change tertiary structure

May give proteins selective advantage

Question 6

What is a frame shift

Answer 6

Change the number of bases by a number not divisible by 3

This shifts the way the genetic code is read so all the DNA triplets /mRNA codons downstream from the mutation change