Transcription/translation

Question 1

Transcription

Answer 1

Instructions of the coding strand would be copied onto a messenger rna( MRNA), occurs in the cell nucleus

The gene of the DNA would unwind due tot the enzyme polymerase , H bonds would be brojen down

The bases of the nucleotides are now exposed, this would be a template strand

Free RNA nucleotides would line up against the bases , complementary bases bond

Sugar and phosphate groups of adjacent RNA nucleotides bond

This forms a single rna polynucleotide chain that would be complementary to the DNA strand

Now Carries codons ( base triplets)

Each codon on the mrna codes for a specific amino acid

Mrna can now break away from the chain, and leaves the nucleus carrying a copy of the instructions go make a protein

Mrna before copying dna, would be called pre- mrna

Question 2

Splicing

Answer 2

Non coding regions of DNA called introns, these do not code for any amino acid and are not expressed.

The coding or expressed regions of DNA are called exons and are seperated from the DNA length.

The exons and introns would be transcribed from the DNA, this would then be called pre- mRNA

Pre- mRNA would then undergo seperating and editing , where the RNA introns would be taken away, and exons left woule then join together to produce mRNA.

Endonuclease enzymes would be involved in the process of seperating and editing processes.

Some introns may become short.

Non-coding introns would be involved in gene regulation

Genes are able to be spliced in different ways to be able to code more than one protein.

Question 3

Translation

Answer 3

mRNA molecule binds to a ribosome so that two of its codons are exposed.

AUG is always the first codon thats exposed on the mRNA, tRNA, with corresponding codon UAC with an amino acid methinone attached , this forms H bonds to the AUG codon, atp is needed for this reaction to happen.

Second tRNA molecule, complementary to the second codon, brings the next amino acid coded for and binds to the second codon.

Now two amino acids now forms a peptide bond.

Ribosome moves along the mRNA, exposung tbe codons to the subunit.

tRNA, continues to bind to the codons , bringing anticodons , the first tRNA molecule leaves and brings another amino acid of the same type of the same type to the ribosome.

This carries on until an mRNA codon that doesn’t code for an amino acid is reached, acts as a stop codon.

The chain of amino acids leaves the ribosome and can be modified into its functioning form.