Insect control

Question 1

How does DEET work?

Answer 1

Interferes with the receptors in mosquitos (and other biting insects) antannae that detect L-lactic acid and carbon dioxide

Also blocks the olfactory receptors to 1-octan-3-ol present in human sweat and breath

Question 2

How does the CRISPR-Cas9 system work as a gene drive?

Answer 2

• ability to change organisms DNA
• allow genetic material to be added or removed or altered at a particular genome location
• CRISPR-Cas9 adapted from naturally occuring genome editing system in bacteria which they use as an immune defense
• How researchers used this…

Created small piece of RNA with short “guide” sequence that binds to specific target sequence in cells DNA

Guide RNA also attaches to Cas9 enzyme

Which when introduced into cells, guide RNA is recognised as the intended DNA sequence and Cas9 cuts DNA at target location

Once DNA is cut, researchers use own cells DNA repair machinery to add or deltere pieces of genetic material

Ethican concerns: altering human genome

Question 3

For the following insecticides, what do they act on?

DDT

Chlorinated alicyclics

Phenol pyrazole

Organophosphates and carbamates

Neonicinoids

Ryanoids

Pyrethroids

Answer 3

DDT: Blocks Na+

Chlorinated alicyclics: Blocks GABA Cl- complex

Phenol pyrazole: Blocks Glutamate gated Cl- channels and GABA Cl- complex

Organophosphates and carbamates: Blocks Acetylcholinesterase

Neonicinoids: Nicotinic acetylcholine receptor agonist

Ryanoids: Rayanodine receptor binds

Pyrethroids: Blocks Na+