3.4.2 DNA Ad Protien Syntheis

Question 1

Structure of mRNA

Answer 1

• single stranded
• linear
• no hydrogen bonds
• consists of many codons
• no amino acid binding site

Question 2

Structure of tRNA

Answer 2

• single stranded
• clover-leafed shape
• has hydrogen bonds
• has a single anticodon
• amino acid binding site

Question 3

Process of transcription

Answer 3

1. H2 bonds between DNA bases broken by DNA helicase & stands separate
2. Only one stand acts as a template strand
3. Free RNA nucleotides form H2 bonds with template stand by complimentary base pairing
4. U binds with A on DNA
5. RNA polymerase joins adjacent RNA nucleotides by forming phosphodiester bonds

Question 4

How is transcription different in Eukaryotes and Prokaryotes

Answer 4

EUK:
pre-mRNA - spliced to form mature mRNA, by removing the introns and re-joining the exons

PROK:
mRNA stand is translated directly

Question 5

Process of translation

Answer 5

1. mRNA leaves the nucleus and attaches to ribosomes
2. tRNA enters ribosome + their anticodons bind to complimentary mRNA codons
3. Each tRNA brings a specific a.a
4. A.a on adjacent tRNA’s are joined by peptide bonds, with the use of ATP
5. tRNA is released after the a.a is joined to polypeptide
6. The ribosome moves along the mRNA to from the polypeptide