Lecture 21

Question 1

What is malaria and what are its methods of control? (3)

Answer 1

Malaria is a disease caused by a protozoan parasite transmitted by mosquitos causing fever, chills, anemia

Methods of control: killing parasite, killing vector, decreasing contact bw humans and vector

Question 2

What causes pathogen drug resistance? (2)

Answer 2

Genetic variation in parasite sensitive to drug (some don’t respond at all -> will excel when other strains die off)

Drug pressure forcing parasite to adapt and become less sensitive/more resistant

Question 3

Describe 2 ways of eradicating mosquitos in relation to their life cycle

Answer 3

Larval stage: reduce small bodies of water so eggs have nowhere to develop

Adult stage: spray with insecticide to kill aggressive mosquitos

Question 4

What was the conclusion to the selection pressure study where insecticide was sprayed and frequency of resistant alleles over time was recorded to measure selection pressure?

Quickly describe the results

Answer 4

Mosquitos will migrate in an effort to survive while they adapt to new selection pressure but when the selection pressure is removed they will die off because having increased resistant comes at a cost fitness

When the insecticide was first introduced frequency of resistant alleles increased and migrated outside the area sprayed but when treatment was removed frequency rapidly decreased

Question 5

Define antibiotics

Answer 5

Molecules that kill bacteria by disrupting many biochemical process

Question 6

What are plasmids?

Answer 6

Extrachromosomal loops of DNA that transfer resistance genes among cells

Question 7

What is HGT?

Answer 7

Horizontal Gene Transfer

Question 8

What two processes can exacerbate antibiotic resistance?

Answer 8

Use of antibiotics for non-bacteria infections

Use of antibiotics in agriculture

Question 9

Methods of HIV transmission (6)

Answer 9

Sexual 
Intravenous drug use 
Perinatal
Blood transfusion 
Other direct blood contact 
Breast milk

Question 10

Life cycle of HIV process

Answer 10

HIVA is a dsRNA retrovirus -> infects hosts of CD4+ helper T Cells -> viral enzyme (reverse transcriptase) turns RNA to DNA -> embeds its genome into host DNA -> viral genes transcribed and translated by host machinery -> new virus buds out of host cell

Question 11

What is AZT?

Answer 11

Azidothymidine is a drug that mimics nucleotides and can be picked up by reverse transcriptase to stop replication from occurring (inactivates HIV)

Question 12

What is combination therapy?

Answer 12

A solution where one constructs a treatment that needs multiple mutations to occur (makes it difficult for pathogen to evolve) (ex. By HAART)