module 7 lec 7

Question 1

What can mutations in a gene’s coding sequence do?

Answer 1

They can alter the gene product (protein).

Question 2

What is a silent mutation?

Answer 2

A silent mutation changes a codon, but doesn’t alter the amino acid or protein.

Question 3

What is a missense mutation?

Answer 3

A missense mutation changes a codon, resulting in a different amino acid and potentially altering protein function.

Question 4

What is a nonsense mutation?

Answer 4

A nonsense mutation changes a codon to a stop codon, truncating the protein.

Question 5

What is a frameshift mutation

Answer 5

A frameshift mutation adds or deletes nucleotides, shifting the reading frame and changing the protein sequence.

Question 6

Can mutations outside the gene’s coding sequence affect gene expression?

Answer 6

Yes, they can alter gene expression without changing the protein itself.

Question 7

What are regulatory mutations?

Answer 7

Regulatory mutations occur in promoter or enhancer regions, affecting gene transcription

Question 8

How can mutations in the promoter affect gene expression?

Answer 8

Mutations in the promoter can decrease or increase transcription by altering the binding of transcription factors.

Question 9

What is the effect of mutations in splice sites?

Answer 9

Splice site mutations can lead to improper RNA splicing, producing abnormal mRNA and protein.

Question 10

What happens when mutations occur in the terminator sequence?

Answer 10

Mutations in the terminator can affect transcription termination, leading to incomplete mRNA.

Question 11

Can mutations outside the gene’s coding region affect gene function?

Answer 11

Yes, they can affect transcription, mRNA splicing, or translation.

Question 12

How can mutations outside the coding region affect transcription?

Answer 12

Mutations in promoters or enhancers can reduce or block transcription.

Question 13

How do mutations outside the coding region affect mRNA splicing?

Answer 13

Mutations in splice sites can cause improper splicing, leading to abnormal mRNA.

Question 14

Can mutations outside the coding region affect translation?

Answer 14

Yes, mutations in ribosome binding sites or terminators can disrupt translation.

Question 15

What is the typical result of mutations outside the coding region?

Answer 15

They are usually lethal, disrupting essential gene expression processes.

Question 16

What is a nonsense-suppressing mutation?

Answer 16

A nonsense-suppressing mutation allows amino acid addition at a stop codon, enabling the production of a full-length polypeptide.

Question 17

How does a nonsense-suppressing mutation work?

Answer 17

It bypasses a stop codon by introducing a new codon that allows continued translation, preventing premature termination.

Question 18

What effect does a nonsense-suppressing mutation have on protein synthesis?

Answer 18

It can result in a full-length polypeptide despite the presence of an original stop codon.

Question 19

Can nonsense-suppressing mutations compensate for other mutations?

Answer 19

Yes, they can compensate for nonsense mutations that would otherwise stop translation prematurely.

Question 20

What is a loss-of-function mutation?

Answer 20

A loss-of-function mutation results in reduced or absent function of a gene product, affecting the amino acid sequence or protein amount.

Question 21

Can loss-of-function mutations occur outside the coding region?

Answer 21

Yes, they can affect regulatory regions, impacting transcription or splicing.

Question 22

Are loss-of-function mutations usually recessive or dominant?

Answer 22

Loss-of-function mutations are typically recessive, but can be dominant in some cases.

Question 23

What is haploinsufficiency in the context of loss-of-function mutations?

Answer 23

Haploinsufficiency occurs when one functional copy of a gene is not enough to produce a normal phenotype, often seen in dominant mutations.

Question 24

What is a dominant negative mutation?

Answer 24

A dominant negative mutation occurs when a mutated gene product interferes with the function of the normal allele, leading to a dominant phenotype.

Question 25

What are the types of loss-of-function mutations?

Answer 25

The types include null (amorphic) and leaky (hypomorphic) mutations.

Question 26

What is a null (amorphic) mutation?

Answer 26

A null mutation completely abolishes the gene’s function, producing no functional protein.

Question 27

What is a leaky (hypomorphic) mutation?

Answer 27

A leaky mutation results in partial loss of gene function, producing reduced amounts of functional protein.

Question 28

What is a gain-of-function mutation?

Answer 28

A gain-of-function mutation results in a protein with new or enhanced activity, often leading to a new phenotype.

Question 29

Are gain-of-function mutations typically dominant or recessive?

Answer 29

Gain-of-function mutations are almost always dominant.

Question 30

What is a hypermorphic mutation?

Answer 30

A hypermorphic mutation enhances the function of a protein, leading to increased activity or expression.

Question 31

What is a neomorphic mutation?

Answer 31

A neomorphic mutation creates a new protein function or causes the protein to perform an activity in the wrong place or at the wrong time.

Question 32

What is the result of a neomorphic mutation?

Answer 32

A neomorphic mutation can lead to a new phenotype by producing proteins with novel functions or incorrect localization.