Lec 33: The Genetic Code

Question 1

What is RNA for?

Answer 1

RNA is the intermediate between DNA and proteins

Question 2

Explain the relationship between DNA, RNA and proteins

Answer 2

DNA —-> RNA (RNA syntheses, transcription)
RNA –> proteins (Protein synthesis, translation)

Question 3

In a bacterial cell describe the locations of RNA and protein synthesis

Answer 3

DNA —> mRNA (Transcripiton)
Add a ribsome and polypeptide

to mRNA to make a new protein (Translation)

All just within the cytosol

Question 4

In a Eukaryotic cell what is the location of RNA and protein synthesis?

Answer 4

DNA —> pre- mRNA (Transcripiton)
pre mRNA to mRNA (RNA processing)
All happens in the nuclear envelope
Then we leave to the cytoplasm

Add a ribosome and polypeptide
to mRNA to make a new protein (Translation)

Question 5

What is a gene?

Answer 5

A gene is a DNA region responsible for the production of an RNA molecule

Question 6

What do Messenger RNAs do?

Answer 6

Encode proteins

Question 7

How can 4 nucleotides make 20 amino acids?

Answer 7

3 nucleotides = 1 codon = 1 amino acids

Question 8

How are amino acids abbreviated?

Answer 8

Written with three letters

Question 9

What is the one start codon?

Answer 9

AUG = start = methionine = MET

Question 10

What are the three stop codons?

Answer 10

UAA, UAG, UGA = stop = Ter = X

Question 11

Can multiple condons specify one amino acid?

Answer 11

Yes UUU and UUC = Phenylalanine = Phe = F

Question 12

NEED TO MEMORIZE: Stop =

Answer 12

Stop = TER (UAA, UAG, UGA)