Question

Flag this Question

Question 491 pts

A neutral missense mutation is a mutation that

Group of answer choices

Gives rise to another codon, which nonetheless specifies the same amino acid

Gives rise to another codon, which specifies a chemically similar amino acid (so that protein function remains unaffected)

Gives rise to another codon, which is not translated

Flag this Question

Question 501 pts

Consider the following codon for lysine: 5’-AAA-3’. The DNA is mutated in such a way that this codon becomes 5’-UAA-3’. Such a mutation could be characterized as

Group of answer choices

Transition; missense

Transition; nonsense

Transversion; missense

Transversion; nonsense

Flag this Question

Question 511 pts

Which of the following wobble pairs makes a larger contribution to spontaneous mismatch mutations in DNA?

Group of answer choices

AT

CC

GC

GT

Flag this Question

Answer 1

Answer::

(491)Give rise to another amino acids which specifies chemically similar amino acid( so that protein function remain unaffected)

(501) Transversion,nonsense mutation

(511) GT

Explanation:::

#As we know genome are not a static entity,it is dynamic in nature and a sudden heritable change in the genetic material give rise to alternative form of any gene termed as mutation.Mutation can be spontaneous or induced.Spontaneous mutation occur without involvement of mutagens ,it occur because of replication error, spontaneous lesions and transposition of transposable elements during the normal growth of cells.

Normally DNA replication to gives DNA then transcribe to RNA and it translates into proteins ( amino acids).when mutation occur in the DNA sequence it affects the RNA sequences and amino acids also.

DNA--RNA---proteins

Some genetic codon coded for same amino acids because we have 20 amino acids and 64 genetic codon...so when there is mutation occur in the sequence but after translation it will give same amino acid ,it termed as silent mutation...but in some cases the mutation occur in the amino acid sequence gives rise to different amino acid sequence but the chemical nature will be same as it does not affects the functioning of protein ...it termed as Neutral missense mutation.For example..the change of AAA( lysine) to AGA ( arginine), both amino acid are chemically basic in nature so after mutation as proteins function are equivalent.

##Normally DNA has 4 base sequences A,G,C,T in which purine contain adenine(A) , guanine(G) and pyrimidine has cytosine (C)and thymine(T).In mutations when purine bases replace with purines means A--G or Pyrimidines bases replace with Pyrimidines means C--T ,it is called transition...whereas when Purine bases replace with pyrimidines such as A--T or G---C is called Transversion. In the given question A is replaced with T means purine bases replace with Pyrimidines..so it is Transversion....and in genetic codon three sequence UAA,UAG,UGA are known as stop codon/ termination codon responsible for shortening the protein length by stopping the translation.In a mutation ,if amino acid sequence coded any of three sequence then it is called nonsense mutation.In this sequence we get UAA after mutation so it is nonsense mutation.

## When A pair with T and G paired with C it is called Watson crick pairings but sometimes it is not paired as naturally occur due to mutation then G pairs with T because of their stable keto enol formation or A pair with C imino to enol state which is not stable.Wobble pairing is normally occur in the last(3rd position) sequence of amino acid which doesn't affect the nature of amino acid because 1st two pair are the same as required.

So, mostly GT transition is responsible for DNA mismatch mutation due to keto enol formation.