Midterm 2 Flashcards
1
Q
What is photosynthesis?
A
- Most important reaction in our body
- Plants take up CO2 + H2O and they produce O2
- What agriculture is based upon
2
Q
Explain the change in the amount of farmers
A
- 50 years ago= 70% involved / Now = 2%
• As population grew, there was need for more and more food - PROBLEM – in the 1800s conventional agriculture was unable to fulfill needs
• Today we have great technology that allows us to mass produce food
-Modern fertilizers, pesticides and techniques to meet food needs
3
Q
What is organic?
A
Growing crops without the use of synthetic fertilizers, synthetic pesticides and relying on natural means to control insects
- Fertilizer = manure
- BUT not enough manure in world to sustain crops that are needed
- Organic farming is difficult on a large scale
4
Q
What 3 major nutrients are needed in manure for crops to go?
A
- Nitrogen (one of the most important)
- Phosphorous
- Potassium
-Others in small amounts
TODAY we use this technology to make fertilizers - different kinds of plants require different ratios
5
Q
What did Fritz Haber discover in the end of 19th century?
A
He found a way to combine N + H to make NH3 (ammonia)
N2 + 3H2 –> 2NH3
6
Q
What is ammonium nitrate?
A
Ammonia is sometimes umped directly into the soil as a fertilizer but most of the time it recombines with nitric acid to form ammonium nitrate (most widely used fertilizers in the world)
- slowly decomposes to yield nitrous oxide or laughing gas
7
Q
What is nitrous oxide?
A
A greenhouse gas
- Contributes to global warming
8
Q
What is soilless gardening called?
A
Hydroponics
- Grow a large variety of crops in greenhouses without any soil at all
- Need a good ratio of nutrients
- Can be grown under many climatic conditions because its in a greenhouse
9
Q
What is significant about the largest hydroponic farm in Montreal?
A
- Do NOT need to use pesticides
- Use predatory insects (i.e. ladybug)
10
Q
What is apple scab?
A
Fungus growth on apples
- Cosmetic problem; they do not compromise health
- BUT people won’t buy these apples even though there’s nothing wrong with them
- Farmers resort to agrochemicals to eliminate the scab
11
Q
What is botrytis fruit rot?
A
Growth on strawberries
12
Q
What do weeds do?
A
Suck nutrients from soil –> less nutrients left for crops you want
13
Q
What are examples of animals clambering all over crops?
A
- Corn borer invades corn
- Tunnels of rats and mice in wheat
- Apple orchard roots are surrounded by nematodes
14
Q
What happens when you burn sulphur?
A
SO2 (sulphur dioxide) is formed
- Kills many insects and many fungi (dangerous to inhale)
15
Q
What is a tobacco plant?
A
- Tobacco plant produces nicotine
- Tobacco plant evolved so that it could protect itself against predators
- Nicotine is a natural insect pesticide
- Burn nicotine = carcinogenic
16
Q
How are synthetic pesticides made?
A
Buy the combination of substances
17
Q
What is copper acetoarsenate?
A
arsenic trioxide + copper acetate
- Called Paris Green” because its used to rid sewers of Paris of mice and rats
- Used in paints = BAD (Arsenic could dissolve off)
- The first “synthetic” pesticide
18
Q
What is DDT?
A
Most famous synthetic pesticide (middle of 20th C)
- Very effective against flees, mites, ants (anything that crawled)
- Helped shape outcome of WWII (allied soldiers were sprayed with DDT to keep them free of lice and insects that could transmit typhoid fever)
- The WHO estimates that 25 million lives were saved because of the use of DDT
- Has estrogen-like properties
19
Q
Who is Paul Miller?
A
Physician who introduced DDT and received a Nobel prize
20
Q
What was the problem with DDT?
A
Problem with DDT was that it was too efficient
- Farmers overused DDT
- FIRST problem = eggshells that were laid by birds broke too frequently
- Fewer hatching and decline of eagle and offspring
• Rachel Carson: DDT gets into food chain and its not biodegradable –> builds up in the food chain
- No evidence that is caused harm to humans but there was an environmental problem
- Banned in 1969 in Canada and 1972 in the US
21
Q
What did DDT have to do with malaria?
A
• In 2006, the WHO suggests DDT be used to control malaria in Africa
- DDT to kill mosquito that transmits malaria
- Spraying powered version on inside of homes, NOT randomly everywhere
- Has been shown to cut down malaria
22
Q
What were the effects of DDT among rats?
A
Rats exposed to traces of DDT develop fewer liver tumours than unexposed rats (DDT caused animal to generate detoxicating enzymes in rats)
23
Q
What is melathion?
A
Interferes with a very important enzyme system in our body
• Can kill us in high amounts, but can kill mosquitos that carry disease
24
Q
How does the Pesticide Management Regulatory Agency makes decisions about safety of chemicals in pesticides ?
A
• Organic pesticides are NOT differentiated in any way from synthetic pesticides in terms of approval process
- If a pesticide is “registered” it means it can be used in certain applications
- Before its registered, there’s a lot of information that has to be transmitted to Health Canada
- Pesticide has very specific instructions
- Is it a guarantee that its safe? No!
- *All that PMR says is that when used under proper conditions, the benefits outweigh the risks
25
What is the nocebo effect?
if you believe something does you harm, you can get physical symptoms
26
What is the lethal dose of the pesticide monocrotophos?
1.2g
27
How is exposure to insecticides linked to Parkinson’s?
- Parkinson’s is higher in agricultural areas
| - May have a connection to specific pesticides
28
What is Paraquat?
- A pesticide that caused caused problem among drug users in California in 1980
- Young drug users showed up in ER virtually paralyzed
- Looked like they were suffering of end-stage Parkinson’s disease
- Problem: contaminant in China White (a drug), the side product destroyed part of brain that causes dopamine and low dopamine causes Parkinson’s
- Paraquat has a chemical similarity to this contaminant
29
What is Rotenone?
extracted from roots of Derris plants
| - Natural compound that has been linked to Parkinson’s because of chemical similarity to paraquat and China white
30
What is the link between household pesticides and leukemia?
- The use of professional pest control services (indoor) at any time from 1 year of birth to 3 years after was associated with a significantly increased risk of childhood leukemia
- No risk with outdoor pesticides including herbicides!
31
What is the difference between long-term lasting and short-term?
Long term: more than 6 months
| Short term: less than 3 months
32
What is atrazine?
Widely used weed killer, has been shown to disrupt development in tadpoles
- Question affect on humans
33
Is pesticide exposure linked to increased endometriosis risk (uterus)?
Yes, but not PROVEN
34
What presents a barrier to current risk assessment of pesticides on humans?
The lack of human biomonitoring data for environmentally relevant pesticides presents
35
The WHO estimates how many pesticide poisonings per year?
3 million poisonings and 220 000 deaths
36
Why do pesticides now have lower toxicity?
Because they consist of enzymes that do not interact with humans
- NOW you can make more potent herbicides (use less to get greater effect, a few teaspoons for acres of land)
37
What are neonicotinoids linked with?
colony collapse disorder (banned in Europe)
38
How many suspected or known carcinogens does a cup of coffee have?
About 10mg
39
How many natural pesticides do we consume a day?
about 1.5g of natural pesticides a day which is 10 000 times more than synthetic pesticide residues in the body
40
What percentage of pesticides in the environment are natural?
99.99%
41
Why does the human body handle synthetic and natural toxins the same way?
Detoxicating systems do not recognize the difference between natural and synthetic insecticides
42
Why is it not possible to get rid of pesticides completely and transition towards an exclusively organic culture?
1) nature provides us with natural pesticides
| 2) we cannot produce all the food in the world that is needed by an organic way
43
Is organic pesticide-free?
No
44
What is Bacillus thuringinesis?
- Very effective at killing pests
- NOT toxic to humans (no analogous pathways)
- Insecticidal gene in the bacteria can be used in crops to ward of insects
= GMO (NOT organic)
- Most widely used in corn
45
How many pesticides can apples have?
Up to 36
| - There are 36 approved pesticides, but farmers don't use all 36
46
What is Integrated Pest Management?
Famers use this to check which insects and fungi are present and target the insecticide only to those species
47
What percentage of fresh and processed foods are residue free?
80% of fresh foods are residue free
| 90% of processed foods are residue free
48
What do nutrients depend on?
- Variety type
- Soil quality
- Fertilizers
- Crop rotations
- Maturity at harvest
- Transportation
- Temperature
49
What is the environmental impact quotient?
Looks at all parameters that we are concerned about when using pesticides
50
What is grapefruit a hybrid of?
Orange and pomelo
51
What is tricticale a hybrid of?
wheat and rye (all caused by cross pollination)
52
What is gene splicing?
Specifically mutate genes
- Genes are fragments of DNA that code for specific proteins
- Its possible to snip DNA in one organism and insert it in another = recombinant DNA technology
53
What is chymosin?
An enzyme used in making of cheese
- Traditionally came from stomach of calves (+ rennet) to make cheese
- Possible to extract from the cells of calves
- Clone gene into yeast --> produce chymosin without calves involvement
* *Introduced in 1990 and is the FIRST product of genetic engineering in our food supply
54
What was the first real food product of genetic modification introduced?
Tomato in 1994
55
Why were tomatoes the first real food product of genetic modification introduced?
- Climate does not allow for good tasting tomatoes all year round
- Instead, tomatoes are picked green down south, then shipped to the north where they are gassed with ethylene to ripen
56
What is polygalacturonase?
Enzyme that breaks down pectin in tomatoes and is responsible for its texture, so it remains stronger faster
57
What factors do we have to consider when introducing any new food?
- Biochemical, toxicological, nutritional, allergenicity data
- Estimate of dietary exposure
- Anticipated pattern of use
- Potential harm to non-target species
- Potential to spread genetic material to other species
- Potential of plant becoming a weed
- Impact on biodiversity
58
What are Brazil nuts?
- Very rich in methionine (critical AA for animal feed)
- Soya beans are poor in methionine (main animal feed) so they found the gene that coded for Met in brazil nuts and put it in soya beans
59
What are the 4 most common GMO crops grown?
- Maize (corn)
- Cotton
- Soybean (soy)
- Canola (rapeseed)
60
What is the % of GMO crops grown by developing nations versus industrial nations?
Industrialized countries = 49%
| Developing countries = 51%
61
What is canola crop used for?
Used mostly to produce oil
62
What has the canola genome has been modified to provide?
Provide tolerance to glyphosate based herbicides (roundup resistant)
- The modified plants are able to withstand application of the herbicide while weeds competing for nutrients in the soil are destroyed
63
What are the benefits of being roundup resistant?
- A lot less tillage (plowing) which is energy intenstive
- A lot less fuel
- A lot less herbicide
- Better yield
64
What is glyphosate?
A weed killer and one of safest herbicides out there
- Use has been increasingly dramatically because it works
- It is linked to “roundup ready” produce (GMOs)
- You can kill weeds without destroying crops
- It less toxic than aspirin, salt and caffeine
65
Explain how glyphosate resistance can occur
- When gene is inserted into crop, not every single plant takes up that gene and some will survive spraying of herbicide
- These resistant plants will give rise to offspring that are also resistant
= INCREASE OVERALL RESISTANCE
66
How do you avoid carcinogen production?
By using Bt toxin
67
Why is the Colorado Potato Beetle is devastating insect for potato plant?
Bt technology not widely used because of public misperception that it makes potato dangerous
68
Why does GM corn has NO effect on the monarch butterfly?
The pollen from Bt-corn doesn't affect caterpillars
69
What does fusarium ear rot lead to?
Fumonisins (carcinogens)
70
Does eating GMO corn cause tumours?
No
71
What is golden rice?
Gene from daffodil inserted in genome of rice and codes for beta carotene (precursor of vitamin A)
- helps with vitamin A deficiency
72
What is the amount of beta carotene in rice?
A bowl of 100-150g of cooked golden rice (50g dry weight) can provide about 60% of recommended nutrient intake of vitamin A for 6-8year old children
73
Why do 2 billion people suffer from iron deficiency anemia?
- Deficiency due to high intake of rice (little natural iron content)
SOLUTION – insert gene in rice from a variety of BEAN that encodes for the production of ferritin, an iron storage protein
74
What is Indole-3-Carbinol?
Substance found to slow down the rate of tumour growth in animals
- found in cabbage
75
What are Low Linolenic Acid Soybeans?
Soy oil made from these beans doesn’t contain trans fats but it can still be used for frying
- Withstand high temperature well
- Less prone to oxidation
- Less need for hydrogenation
76
What virus is the papaya susceptible to?
Papaya ring spot virus
77
What is significant about the GM arctic apple?
Does not go brown as easily
- Only uses genes from apples that naturally don’t turn brown
- NO foreign gene
78
What is significant about GMO potatoes?
- Fewer black spots and produce less acrylamide
| - Genes derived from endogenous potato genes
79
What is the Precautionary Principle?
You must have proof of no harm before you introduce any product of some novel technology
- A demand that science cannot meet
- Cannot prove that something will never cause harm in anyone
- Can only make good educated guesses
80
When is labelling required for GMO products?
Any GM food that is nutritionally or compositionally different from its traditional counterpart
- BUT if it isn’t, then GMO labelling does not give any information
81
What is dicamba?
Herbicide, very effective
| - No evidence that dicamba causes cancer
82
What are some problems associated with dicamba?
- Resembles auxin, a plant hormone that causes growth
- Plants mistake dicamba for auxin and they grow out of control and there aren’t enough nutrients to sustain the plant
- Dicamba cannot be controlled, it can spread very easily onto neighboring fields that could be growing non-resistant plants, destroying the crop
- Farmers are suing Monsanto over dicamba devastation
83
What is 2,4-D?
Herbicide that has been used for a long time
| - Resistant crops to this as well
84
What is agent orange?
Chemical used in Vietnam sprayed from airplanes
• Mixtures of herbicides 2,4-D and 2,4,5-T
• Idea was to defoliate trees to prevent enemies from hiding
• 2,4,5-T gave rise to a highly toxic substance that is a carcinogen
• Not been made since 60s, it does not exist anymore
85
Explain the different uses of ammonium nitrate
Ammonium nitrate can be used as a weapon of war (explosive), however, people make the decision whether to use it for fertilizers or war
86
Why are homeopathic remedies for glyphosate "symptoms" inadequate?
They are too diluted to the point where they won't work
87
What is the difference between a risk and a hazard?
```
Hazard = innate property of some substance to do damage under some condition
Risk = measure of whether or not that damage is done under realistic conditions
Risk = Hazard x Exposure
```
88
Why has Glyphosate been placed in the carcinogen category?
Because in large doses in some test animals under some conditions it can trigger cancer
89
What is the accepted daily intake of glyphosate?
about 0.5 mg/kg body weight
90
If someone was consuming food with glyphosate on daily basis, their urine would contain how much glyphosate?
4 mg/L
91
Urine measurements show that people produce how much glyphosate in their urine?
anywhere from 1-3 micrograms / L (1/1300th of acceptable daily intake)
92
What does proposition 65 in CA say?
Says that any substance that in any dose in any animal can cause cancer must be labelled with a warning.
- Leads to overwhelming amount of cancer warning signs, even when the evidence is not clear
93
France wants to replace glyphosate with pelargonic acid- what is it?
Not a highly effective alternative
94
Do GMOs have benefits for celiac patients?
Yes
95
What are some benefits of GMOs in foods?
- Higher percentage of nutrients
| - Better crop yield, therefore more food
