Week 7 Flashcards

1
Q

What do antioxidants do in foods?

A

Antioxidants slow or delay the oxidation of foods, especially lipids.

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2
Q

What is autoxidation of fats and oils?

A

Autoxidation is a free radical chain reaction that makes fats rancid.

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3
Q

How do BHA and BHT work as antioxidants?

A

They act as hydrogen donors to inhibit oxidation.

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4
Q

What is the concern with nitrates/nitrites in curing salts?

A

They can form carcinogenic nitrosamines, potentially causing cell damage or mutations.

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5
Q

What role does sulfur dioxide play in wine-making?

A

It serves as an antimicrobial preservative, preventing microbial growth.

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6
Q

How is benzoic acid used in foods?

A

It acts as a microbial preservative at low pH.

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7
Q

What is the difference between acute and chronic toxicity?

A

Acute kills quickly; chronic kills slowly over time.

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8
Q

How do organophosphates affect pests?

A

They inhibit enzymes in the nervous system, causing paralysis.

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9
Q

Why is malathion toxic to aquatic organisms?

A

It oxidizes to form malaoxon, which is highly toxic.

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10
Q

What type of insecticide is diazinon?

A

A non-systemic organophosphate used for pest control in homes.

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11
Q

How does Bacillus thuringiensis work in genetically modified crops?

A

The bacteria’s protein crystal kills specific insect pests.

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12
Q

What does sulfur do as a fungicide?

A

It prevents fungal spores from germinating.

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13
Q

What is a potential downside of using copper as a fungicide?

A

It may harm the host plant despite killing fungi and bacteria.

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14
Q

What is a benefit of using methyl bromide as a fumigant?

A

It leaves no residue after aeration.

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15
Q

What are chlorophenoxy acid esters used for?

A

They mimic plant hormones to act as herbicides.

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16
Q

How does glyphosate kill weeds?

A

It inhibits aromatic amino acid synthesis.

17
Q

How does paraquat function as a herbicide?

A

It inhibits photosynthesis by disrupting electron transfer.

18
Q

Name four common contaminant metals.

A

Arsenic, cadmium, lead, and mercury.

19
Q

How is mercury transformed in lakes?

A

It undergoes bacterial processes to form toxic, soluble compounds.

20
Q

What are pyrethrins and where are they derived from?

A

Natural insecticides from chrysanthemum plants.

21
Q

What is nicotine’s effect as a pesticide?

A

It acts as a fast-acting nerve toxin.

22
Q

What is limonene, and why is it used?

A

A citrus peel extract that kills pests with low human toxicity.

23
Q

What does botulinum toxin do to the nervous system?

A

It prevents neurotransmitter release, causing paralysis.

24
Q

Where is tetrodotoxin found, and how does it work?

A

Found in puffer fish; it blocks sodium channels in neurons.

25
Q

What is a characteristic effect of saxitoxin?

A

It causes paralysis and can lead to respiratory failure.

26
Q

What effect does caffeine have on the body?

A

It blocks adenosine receptors, acting as a stimulant.

27
Q

Why is solanine toxic, and where is it found?

A

Found in green potatoes, it disrupts cell membranes and mitochondrial function.

28
Q

What do lectins in legumes do?

A

They bind to carbohydrates and can agglutinate red blood cells.

29
Q

How are chemical contaminants in food detected?

A

By using mass spectrometry to detect trace amounts.

30
Q

How does carbohydrate concentration affect food viscosity?

A

High concentration increases viscosity due to hydrogen bonding.