FLC gene expression, protein synthesis and antibiotics

Question 1

Steps in DNA replication

Answer 1

-Parent DNA double helix ‘melts’ into 2 strands of DNA
-New strands formed by complementary base pairing
-Semi conservative process as you have one original strand and one new strand

Question 2

What are genes?

Answer 2

Genes are stretches of DNA that contain information for
making RNA, mostly protein-encoding mRNA

Question 3

Steps in transcription

Answer 3

-Transcription produces single-stranded RNA that is complementary to one strand of DNA
1.DNA strands ‘melt’ into 2 strands
2.RNA strand created which is complementary to DNA strand

Question 4

What is the structure of RNA

Answer 4

-single stranded
-Ribose instead of deoxyribose
-Uracil instead of thymine

Question 5

What are the different mRNA processing in eucaryores?

Answer 5

-5’ capping
-RNA splicing
-3’ Polyadenylation

Question 6

What portion of the mRNA is translated into protein?

Answer 6

Only the central portion of mRNA
is translated into protein

Question 7

What regions of the mature mRNA are coded in the gene’s exons?

Answer 7

These regions are coded in the gene’s exons

Question 8

What is mRNA decoded in sets of?

Answer 8

mRNA is Decoded in Sets of Three Nucleotides:
The Genetic Code

Question 9

What do tRNA molecules do?

Answer 9

tRNA Molecules Match Amino Acids to Codons in mRNA

Question 10

How does an amino acid bind to tRNA and using what enzyme?

Answer 10

-Aminoacyl tRNA synthetase(tryptophanyl tRNA synthetase) catalyses the linkage of amino acid to tRNA with the use of ATP.

Question 11

What is the specificity of amino acyl tRNA synthetase often referred to as?

Answer 11

The specificity of amino acyl tRNA synthetases is often referred to as the
“second genetic code”

Question 12

How is a peptide bind between amino acids formed

Answer 12

Condensation

Question 13

What are the steps in elongation: incorporation of an amino acid into a protein?

Answer 13

1. Peptidyl tRNA attached to C-terminus of the growing polypeptide chain
   2.tRNA molecule is then freed from its peptidyl linkage
   3.New peptidyl tRNA molecule attached to C-terminus of the growing polypeptide chain

Question 14

What reading frames is used in mRNA and what is the frame determined by?

Answer 14

Only one frame is used for each mRNA, determined by the location of the
AUG start codon

Question 15

Prokaryotic ribsome

Answer 15

50S and 30S

Question 16

Eukaryotic ribosome

Answer 16

60S and 40S

Question 17

What is the cellular target in bacteria for streptomycin and what effect does it have on protein synthesis?

Answer 17

-Streptomycin
-Target small ribosomal subunit
-Inhibit initiation of misreading genetic code

Question 18

What is the cellular target in bacteria for tetracyclines and what effect does it have on protein synthesis?

Answer 18

-Tetracyclines
-Target small ribosomal subunit
-Inhibition of aminoacyl tRNA binding to ribosome

Question 19

What is the cellular target in bacteria for Chloramphenicol and what effect does it have on protein synthesis?

Answer 19

-Chloramphenicol
-Target large ribosomal subunit
-Inhibit peptidyl transferase activity

Question 20

What is the cellular target in bacteria for Erythromycin and what effect does it have on protein synthesis?

Answer 20

-Erythromycin
-Target large ribosomal subunit
-Inhibit translocation

Question 21

What is the cellular target in bacteria for Neomycins and what effect does it have on protein synthesis?

Answer 21

-Neomycins
-Target multiple sites
-Has several effects

Question 22

What is the mechanism of action of streptomycin?

Answer 22

Inteferes with codon recognition

Question 23

What is the mechanism of action of Chloramphenicol?

Answer 23

Binds to 50S and blocks peptide bond formation

Question 24

What is the mechanism of action of Tetracycline?

Answer 24

Binds to 30S and interferes with tRNA binding