Week 7 Flashcards
What do antioxidants do in foods?
Antioxidants slow or delay the oxidation of foods, especially lipids.
What is autoxidation of fats and oils?
Autoxidation is a free radical chain reaction that makes fats rancid.
How do BHA and BHT work as antioxidants?
They act as hydrogen donors to inhibit oxidation.
What is the concern with nitrates/nitrites in curing salts?
They can form carcinogenic nitrosamines, potentially causing cell damage or mutations.
What role does sulfur dioxide play in wine-making?
It serves as an antimicrobial preservative, preventing microbial growth.
How is benzoic acid used in foods?
It acts as a microbial preservative at low pH.
What is the difference between acute and chronic toxicity?
Acute kills quickly; chronic kills slowly over time.
How do organophosphates affect pests?
They inhibit enzymes in the nervous system, causing paralysis.
Why is malathion toxic to aquatic organisms?
It oxidizes to form malaoxon, which is highly toxic.
What type of insecticide is diazinon?
A non-systemic organophosphate used for pest control in homes.
How does Bacillus thuringiensis work in genetically modified crops?
The bacteria’s protein crystal kills specific insect pests.
What does sulfur do as a fungicide?
It prevents fungal spores from germinating.
What is a potential downside of using copper as a fungicide?
It may harm the host plant despite killing fungi and bacteria.
What is a benefit of using methyl bromide as a fumigant?
It leaves no residue after aeration.
What are chlorophenoxy acid esters used for?
They mimic plant hormones to act as herbicides.
How does glyphosate kill weeds?
It inhibits aromatic amino acid synthesis.
How does paraquat function as a herbicide?
It inhibits photosynthesis by disrupting electron transfer.
Name four common contaminant metals.
Arsenic, cadmium, lead, and mercury.
How is mercury transformed in lakes?
It undergoes bacterial processes to form toxic, soluble compounds.
What are pyrethrins and where are they derived from?
Natural insecticides from chrysanthemum plants.
What is nicotine’s effect as a pesticide?
It acts as a fast-acting nerve toxin.
What is limonene, and why is it used?
A citrus peel extract that kills pests with low human toxicity.
What does botulinum toxin do to the nervous system?
It prevents neurotransmitter release, causing paralysis.
Where is tetrodotoxin found, and how does it work?
Found in puffer fish; it blocks sodium channels in neurons.
