Protein production

Question 1

folding and cross linkage

Answer 1

• into secondary and tertiary structures

- via cross linking of amino acids in the chain with the help of molecular chaperones

Question 2

cleavage or addition of molecules/groups

Answer 2

• removal of a section of a protein resulting in its activation

Question 3

assembly into polymeric proteins

Answer 3

• complex proteins have multiple polypeptide chains forming a quaternary structure

Question 4

Splicing

Answer 4

• performed by spliceosomes

- controlled by snRNA, which has > 7 protein subunits that form the core of the spliceosome

Question 5

snRNA dual function

Answer 5

• recognising the portion of the nucleotide sequence that needs to be spliced
• catalysing the chemistry of the splicing

Question 6

alternative splicing

Answer 6

• different introns can be removed meaning the same gene can code for different proteins

Question 7

Poly-adenylation

Answer 7

• addition of the poly (A) tail to the 3’ end of the mRNA strand
• tail is composed of many adenosine units with the purpose of ensuring that the message in the mature RNA is intact

Question 8

Capping

Answer 8

modified guanine nucleotide is added to the end of the molecule:

• a phosphate enzyme cleaves the phosphate from the 5’ end of the RNA
• a guanyltransferase enzyme adds GMP in reverse linkage
• a methyl transferase enzyme adds a methyl group to guanosine

Question 9

purpose of the cap

Answer 9

Assists in:

• regulating nuclear transport
• transcription
• ensuring the mature mRNA is not degraded by ribonucleases