Protein synthesis

Question 1

describe transcription

Answer 1

a. it is the synthesis of mRNA / transcription of DNA to RNA, which carries genetic information from DNA to ribosome, where it can synthesize proteins

b. RNA is synthesized by the linking of RNA nucleotides together to form a single-stranded RNA molecule, which serves as a copy of the DNA sequence.

c. RNA molecule is synthesized by RNA polymerase, which reads the DNA template strand

d. During transcription, the DNA double helix is unwound and separated into two strands, with one strand serving as the template for RNA synthesis.

e. The RNA molecule is synthesized in the 5’ to 3’ direction, with the RNA polymerase adding new nucleotides to the 3’ end of the growing RNA strand.

f. RNA synthesis involves the complementary base pairing of RNA nucleotides with the template DNA strand,

g. RNA contains uracil (U) instead of thymine (T), which pairs with adenine (A) in the DNA template strand during transcription.

h. Transcription starts at a specific DNA sequence called a promoter, which signals the RNA polymerase to bind to the DNA and initiate transcription. It ends at the terminator region, where the RNA polymerase and new mRNA strand detach

i. Transcription is regulated by various factors, including transcription factors, DNA binding proteins, and nucleosomes, which can either promote or inhibit the binding of RNA polymerase to the DNA and the initiation of transcription.

j. the mRNA can move from the nucleus to the ribosome to be translated after transcription

Question 2

Explain how polypeptides are produced by the process of translation.

Answer 2

a. The genetic information stored in the mRNA molecule is used to synthesize a polypeptide chain.

b. The mRNA molecule binds to the ribosome, a molecular machine that facilitates the translation of the mRNA into a polypeptide chain.

c. It is binded at the start codon, which has three base pairs (AUG)

f. tRNA carrying first amino acid/methionine binds to
P site of the large ribosomal subunit

g. anticodon (on tRNA) binds to codon (on mRNA);

h. complementary base pairing (between codon and anticodon);

i. a. new tRNA for next codon binds to A site/amino acyl site;

j. peptide bond forms between amino acids (on tRNAs) at P and A sites;

k. ribosome moves along mRNA to next codon/by three bases/in 5’ to 3’ direction;

l. tRNA released from E/exit site, a new tRNA is introduced at the A site

m. process/cycle repeats to elongate the polypeptide/until stop codon is reached;

n. release of polypeptide and mRNA/disassembly of ribosome complex at stop codon;