Micro lecture 8

Question 1

Humans have similar synthesis of nucleotides steps that are found in bacteria. In this synthesis, there are a number of different pathways used. Name the chemical that is essential to these pathways.

Answer 1

Tetrahydrofolate (THF)

Question 2

Where do humans absorb folate?

Answer 2

Diet.

Question 3

True or False?

Bacteria synthesize THF.

Answer 3

True. Bacteria must synthesize Tetrahydrofolate (THF).

Question 4

state facts about the Synthesis of nucleotides

Answer 4

Number of different pathways used
Tetrahydrofolate (THF) = essential for many of these
Humans absorb folate from diet
Bacteria must synthesize THF

Question 5

state facts about trimethoprim-sulfamethoxazole

Answer 5

sulfamethoxazole – PABA

trimethoprim - dihydrofolate

Synergistic action on 2 steps towards tetrahydrofolate production

Often considered bactericidal

Toxic (skin reactions, bone marrow) so used to treat or prevent serious infections such as Pneumocystis pneumonia, Nocardia infections

Question 6

state facts about sulphonamides / sulfa drugs

Answer 6

Resistance :
Alteration of target enzymes
Changes in permeability
hyperproduction of PABA may overcome blockade