Cundliffe 3 splicing genes

Question 1

Prokaryotic genes are..

Answer 1

not processed

Question 2

Eukaryotic are

Answer 2

Capping -> splicing -> tailing.

Question 3

Post translation possibilities

Answer 3

• Attract ribosomes
• methylated base (ring of N)
• catatonic charge ring +/ve
• age of DNA = length => degraded

Question 4

Exon:

Answer 4

= coding seqence for gene

• exons left mature mMRNA
• RNA pol II cant’s tell difference between DNA hence spliceosomes

Question 5

SPLICEOSOMES

Answer 5

RiboNucleoProtein (RNP) rince ribosomes complex of tRNA
[snRNAs + protein] => snRNPs
=> non-coding RNA => splicing U1-U6

Question 6

B-Globin gene process of splicing

Answer 6

1 gene + RNA pol II
2 Primary transcript + splicing (w/ splicosomes
3 spliced mRNA

Question 7

ALTERNATIVE SPLICING:

Answer 7

Tissue specific variation of proteins in mammalian cells

Exon order maintained => more than 1 mature strand
Gene => 7 different RNA => 7 proteins => need less genes

Question 8

Mistakes in splicing cause disease

e.g.

Answer 8

Breast cancer (BRCA1), Duchenne muscular dystrophy (DMD), Neurofibromatosis (NF-1), Thalassaemias (see Stryer table 29.4)

Question 9

Genetic Code:

Answer 9

relationship between DNA/ mRNA base sequence and amino acid sequence of encoded protein.
- there are 4 bases in DNA /RNA & 20 amino acids in proteins , 3 per Codon

Question 10

How big is a Codon?

Answer 10

64 possible base triplets for 20 AA’s => specificity 
unused triplets (61 sense, 3 non-sense) 
Synonym AA’s have multiple codons ie. Leu =6

Question 11

Point mutation:

Answer 11

Changes a single amino acid in encoded protein, hence code is non-overlapping => would create more than 1 protein from one codon other wise.

Question 12

sickle cell anaemia is caused by…

Answer 12

Haemoglobin S (HbS) => sickle cell from mutated form => implications in molecular medicine & define genetic disease.

Question 13

Deciphering the code

Answer 13

Degeneracy/ Redundancy in 3’ codon position

Artificial mRNA translated in vitro via E.coli

Question 14

“mRNA” 			
Poly U		 
UUU	      
Poly A 		
AAA

Answer 14

Product	
=> 	poly PHE
 encodes	PHE
=> 	poly LYS
encodes 	LYS

Question 15

STOP codon:

Answer 15

UAG, UAA, UGA

Question 16

START codon:

Answer 16

AUG (almost all proteins start with MET)

Question 17

Transfer RNAs:

Answer 17

: genetic ‘adaptors’ translate code
mRNA -> Protein
Clover leaf structure, 76 nucleotides long. Carry amino a. to ribosomes for p.synth – ribosomes make any protein dependant on mRNA.

Question 18

Variable arm:

Answer 18

‘cognate’/ dedicated to 1 amino a.

Question 19

DHU loop:

Answer 19

dehyudro U

Question 20

T ψ C:

Answer 20

ubiquitous –post transcription add T to RiboT & cut methyl grp