DNA transcription

What is bp

Base pairs

What is kDa

KiloDaltons- 1000 atomic mass units

What unit does S stand for

Svedberg unit- refers to mass and shape of cellular organelles

How does RNA differ from DNA

1. DNA is double stranded, RNA is single

2. DNA has base thymine but RNA has uracil

3. RNA has many types

What are some types of RNA

mRNA

rRNA

tRNA

What is mRNA

Messenger RNA- long linear transcript

Spliced to mature form in proximity to nuclear membrane

Has a 5’ CAP and a 3’ Poly A tail

What is a 5’ CAP

A specially altered nucleotide on the 5’ end. Helps ribosomes to recognise and bind to mRNA

What is a 3’ poly A tail

String of adenine nucleotides added to 3’ end.

Protects mRNA from degradation

Helps export mRNA into cytoplasm

Involved in binding proteins to initiate translation

Why is a 5’ CAP and a 3’ poly A tail important

They are added to pre-mRNA during the processing near nuclear membrane

Both protect the transcript and help it to get exported from nucleus and translated into protein by ribosomes

What is rRNA

Ribosomal RNA, non coding, key part of ribosomes

What is tRNA

Transfer RNA- carries amino acids to ribosomes, checks that amino acids are incorporated in the correct position

What is the structure of tRNA

Clover-like shape with a 3’ and 5’ end

Contain an anti-codon

Where does amino acids attach on tRNA

At the 3’ end

What are the three stop codons

UAA

UAG

UGA

What are the 3 features of the DNA code

1. Degenerate- more than one codon codes for a specific amino acid

2. Almost universal- almost all organisms use the same code

3. Non-overlapping- codons do not overlap, each nucleotide is read only once