Lecture 16 - Genetic Changes and protein functions

Question 1

What is the central purpose of translation?

Answer 1

The central purpose of translation is to make a polypeptide chain using the message encoded by mRNA

Question 2

Where does translation occur, what is the key structure involved?

Answer 2

Translation occurs in the cytoplasm, and ribosome, made of protein and mRNA, carry it out

Question 3

What are codons, and how are they important for translation?

Answer 3

Codons are sets of three RNA nucleotides that correspond to specific amino acids. Codons direct the order in which amino acids are assembled during protein synthesis

Question 4

Why is codon redundancy beneficial?

Answer 4

Codon redundancy allows multiple codons to code for the same amino acid, reduces the impact of mutations

Question 5

How does tRNA contribute to translation?

Answer 5

tRNA molecule carry amino acids to the ribosome and have anticodon that pair with the mRNA codons, ensuring the correct sequence of amino acids in the peptide chain

Question 6

What are the three stages of Translation?

Answer 6

1. Initiation - the ribosome, mRNA, and the first tRNA assemble.
2. Elongation - the ribosome moves along the mRNA, adding amino acids
3. Termination - A stop codon ends the process and the peptide chain is released

Question 7

What is genetic variation?

Answer 7

Genetic Variation refers to differences in DNA sequence between individuals, contributing to diversity within a species.

Question 8

What is a genetic variant, and what are alleles?

Answer 8

A genetic variant is a specific difference in the DNA sequence, and different forms of those variants at the same location in the DNA are called alleles.

Question 9

Describe SNPs and InDels as types of genetic variants ?

Answer 9

• SNP (single nucleotide polymorphism): A change in one nucleotide
• InDel (Insertion/Deletion): the addition or removal of one or more nucleotides

Question 10

What are coding and non-coding variants

Answer 10

• Coding variants occur within the exons of a gene and can affect the amino acid sequenc.
• Non-coding variants occur in regulatory regions and may affect gene expression without altering the protein sequence

Question 11

What are potential consequence of coding variants?

Answer 11

• coding for the same amino acid (synonymous)
• Code for a different amino acid (mis sense)
• Code for a stop codon, truncating the protein (nonsense)

Question 12

What happens in a frameshift mutation cause by an InDel?

Answer 12

A frameshift mutation changes the reading frame of the genetic code, usually leading to significant changes in the protein and often serious consequence

Question 13

How can missense variants affect protein function?

Answer 13

The consequence depends on where the variant occurs in the protein, the similarity between the amino acids, and the whether the variants affects critical structures like enzyme active sites

Question 14

What is the importance of genetic variation in survival and adaptation?

Answer 14

Genetic variation allows species to adapt to environmental changes, survive and differentiate individuals within a population

Question 15

Why is Translation called the universal genetic code?

Answer 15

The genetic code is universal because all organism use the same codons to encode the same amino acids, which ensures consistency in protein synthesis across life forms

Question 16

What is a nonsense mutation?

Answer 16

changes codons to a stop codon, prematurely ending translation and producing shortened, often non functional protein

Question 17

What are the consequence of a pathogenic mis sense variant in the haemoglobin beta chain

Answer 17

Missense variants in the haemoglobin beta chain, such as HBB E6V (sickle cell anaemia), can lead to altered haemoglobin function, causing red blood cells to become misshapen and impairing oxygen transport