Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Selective Toxicity > Insecticides > Flashcards

Insecticides Flashcards

1
Q

Organochlorines Examples

A

DDT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Organochlorines Target Site

A

Sodium Channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Organochlorines Action

A

Modulation of Sodium Channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Organochlorines Result

A

Sustained activation of sodium channels causing hyperactivity of the nervous system - prevents the cell from coming back to its resting potential.

Cell nerver recovers and remains active and functional causing spiking from one stimulus.

Neuron runs out of energy eventually, leading to the death of the insect.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Organochlorines LD50

A

250 mg/kg (rat) - takes a lot of this drug to have a negative effect on mammals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Pyrethroids Examples

A

Permethrin and Cypermethrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Pyrethroids Target site

A

Sodium Channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Pyrethroids mode of action

A

Modulation of sodium channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Pyrethroids result

A

Type 1 - repetitive discharge - multiple spikes from a single stimulus

Type 2 - no repetitive discharge, very slow after potential

Both lead to the sustained activation of sodium channels.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Pyrethroids LD50

A

1500 mg/kg - takes much more of this drug to harm mammals than with DDT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Positives of pyrethroids over organochlorines

A

Pyrethroids are much less stable compounds and mammals can metabolise them - don’t hang around destroying the environment and humans can digest them if they are ever ingested.

DDT doesn’t degrade so it accumulates in the environment and has negative impacts on the environment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Phenylpyrazoles examples

A

Fipronil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Phenylpyrazoles target site

A

GABA-gated and glutamate-gated chloride channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Phenylpyrazoles mode of action

A

Block the transmitter binding to the chloride channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Phenylpyrazoles result

A

Chloride influx into the cell causes hyperpolarizing the cell membrane potential keeping it in the resting state - this is lost when using Fipronil.

Loss of post-synaptic inhibition causes hyperexcitation of the CNS.

Can no longer inhibit the action potentials as the chloride ions are blocked to allow the membrane to return to normal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Positives of phenylpyrazoles?

A

Glutamate-gated chloride channels are only found in invertebrates so selective toxicity is enhanced.

Not found in mammals.

17
Q

Neonicotinoids target site

A

Acetylcholine receptors

18
Q

Neonicotinoids mode of action

A

Nicotinic acetylcholine receptor agonist.

19
Q

Neonicotinoids function

A

Mimic acetylcholine and binds to Ach receptors (agonists)

20
Q

Neonicotinoids result

A

Causes sustained excitation to neurons - hyperexcitation leads to the cell running out of energy and eventually, death.

They have sustained excitation as unlike with acetylcholine, they cannot by hydrolysed by acetylcholinesterases - hence why influx of sodium is sustained as it cannot be stopped.

21
Q

Organophosphates negatives

A

They are all derivates of phosphoric acid and they are really toxic.

22
Q

Organophosphates positives

A

Oxygen can be replaced by S, C and N to yield diffeent derivatives - means it can produce an incredibly wide range of insecticides.

23
Q

Organophosphates target site

A

Acetylcholinesterase

24
Q

Organophosphates mode of action

A

Inhibition via phosphorylation of AChE (phosphorylated AChE cannot hydrolyse acetylcholine)

25
Q

Organophosphates result

A

Sustained concentrations of acetylcholine at the synapse - excess neuroexcitation.

26
Q

Organophosphates hydrolysis

A

AChE can be dephosphorylated through hydrolysis - but this process can take days or weeks, which the insect doesn’t have with sustained excitation - classed as an ‘irreversible’ inhibitor.

27
Q

What are juvenoids?

A

Insect growth regulators (IGRs) - insects use juvenile hormone to control their development and moulting.

28
Q

Example of a juvenoid

A

Methoprene (a JH mimic)

29
Q

What does methoprene cause?

A

Early moulting
Sterlisation (can target reproductive organs so they can’t reproduce)
Early nymphal moulting
Morphogenic malformation

30
Q

Other non-neurotoxic insecticides?

A

Calcium channels - alter the muscles
Cuticle dehydrators - disrupt the lipids in the cuticle to removing ‘waterproofing’ (not toxic to humans)
Energy production inhibitors

Selective Toxicity (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions