Biology 1305 Chapter 17 (Mutations)

What are mutations?

Changes in the genetic information of a cell.

What are point mutations?

Changes in just one nucleotide pair of a gene.

How can mutations of one or a few nucleotides affect proteins?

They can affect protein structure and function.

What is the quaternary structure of hemoglobin composed of?

Two alpha subunits and two beta subunits.

What is sickle-cell disease caused by?

A mutation in the β-globin gene leading to sickle-cell hemoglobin.

What are small-scale mutations?

Mutations that involve single nucleotide-pair substitutions or nucleotide-pair insertions or deletions.

What is a silent mutation?

A nucleotide-pair substitution that does not change the amino acid sequence.

What is a missense mutation?

A mutation that changes one amino acid in a protein sequence.

What is a nonsense mutation?

A mutation that changes an amino acid codon into a stop codon.

What happens during a nucleotide-pair deletion?

It results in the loss of one or more nucleotides, potentially altering the reading frame.

What is the effect of a nucleotide-pair substitution on protein synthesis?

It can lead to silent, missense, or nonsense mutations depending on the nature of the substitution.

What is the role of mRNA in protein synthesis?

mRNA carries the genetic code from DNA to the ribosome for protein synthesis.

What does the term 'wild-type' refer to?

The typical form of a gene or organism as it occurs in nature.

How does a missense mutation differ from a silent mutation?

A missense mutation results in a different amino acid, while a silent mutation does not change the amino acid sequence.

What is the significance of the heme group in hemoglobin?

It binds oxygen, allowing hemoglobin to transport it in the blood.

What is the consequence of a nonsense mutation in a protein?

It leads to premature termination of protein synthesis, resulting in a truncated protein.