topic 4 Flashcards

1
Q

what are the 3 macronutrients? what are their calories? how many calories does fiber have?

A

fats (9cal/g), carbohydrates (4cal/g), and proteins (4cal/g), fiber (2 ca/g)

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2
Q

What elements are the macronutrients made up of?

A

Fats and carbohydrates: C, H, O
Proteins: C, H, O, N

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3
Q

What are carbohydrates? What is their general formula?

A
  • they are composed of carbon (carbo) and water (hydrate) and thus has a general formula of Cm(H2O)n.
  • they give us energy during their consumption (in addition to creating water and CO2)
  • carbohydrates + O2 = energy + H2O + CO2
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4
Q

what is glucose oxidation? What happens when the opposite occurs?

A

glucose oxidation = when carbs are consumed (carbs +o2)

opposite is when glucose produced during consumption is converted back into water and carbon dioxide

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5
Q

Describe sucrose

A
  • disaccharide made up of glucose and fructose
  • otherwise known as table sugar
  • Broken down by invertase
  • Makes up most of brown sugar (sucrose + molasses)
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6
Q

What is the bad news for sucrose?

A
  • It causes glycation: unnatural binding of molecules (Maillard reaction) where there is engagement of protein units that have an NH2 group at one end with carbohydrate units, such that when you heat it, water is quickly given off and leads to browning.
  • Advanced Glycation End (AGE) products: 2 protein chains connected to what was a sugar unit, this can cause cataracts (causes clouded lenses and you see blurry, due to protein folding in eye lens which creates clumps) and makes skin not as supple.
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7
Q

Describe glucose

A
  • C6 monosaccharide
  • it is sometimes called dextrose
  • It makes up cellulose and starch
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8
Q

What characteristic of the carbohydrate structure defines the type of carb that will be built?

A

Whether the H atoms are up or down is what defines what type of carbohydrate is produced and what kind of features it has

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9
Q

What is the difference between cellulose and starch?

A

the OH bonds between the glucose molecules, in cellulose the bond is diagonal (OH bond up up) making it indigestible for humans and in starch the OH bond is down and up (digestible)

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10
Q

What makes a food digestible?

A

whether the enzymes matches up with the reactant (food) molecule in shape. If it is, the enzyme fits in with the reactant food and is able to make products.

Otherwise, there is a mismatch and the food is not digestible

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11
Q

Describe fructose

A
  • monosaccharide,
  • usually an individual sweetener because very sweet.
  • Honey is very sweet due to its high (39%) fructose content.
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12
Q

Describe maltose

A
  • disaccharide,
  • sweetening agent derived from partial hydrolysis of starch,
  • maltose = glucose + glucose,
  • broken down by maltase which breaks it down into glucose and subsequently converts it into energy through complete oxidation.
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13
Q

Break it down, what is the good news about fructose?

A
  • low glycemic index, so it doesn’t cause blood sugar to rise as much as sucrose, so good substitute.
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14
Q

Break it down, what is the bad news about fructose?

A
  • too much at once isn’t good and modern diet is ~ 10% fructose
  • When it enters bloodstream, insulin regulates it but fructose is processed in the liver and if there’s too much it makes fat and too much fat in blood is a risk for heart disease
  • Fructose circumvents appetite signaling, so body doesn’t know when it is satiated.
  • Some evidence suggests that excess fructose causes insulin resistance which can lead to type II diabetes.
  • High fructose drinks have been associated with the risk of gout as excess fructose causes uric acid increase which creates inflamed joints (gout). This does not apply to diet soft drinks. Study says contribution to development of gout is modest.
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15
Q

Describe lactose

A
  • disaccharide,
  • lactose = galactose + glucose, has diagonal bond so not digestible (like cellulose), which is why a lot of people are lactose intolerant
  • broken down by lactase (aka Lactaid).
  • lactose intolerant people tend to have high H concentrations in breath when they consume lactose.
  • Northern hemisphere populations tend to have less intolerance frequency.
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16
Q

order these by sweetness: sucrose, honey, glucose, fructose

A

fructose > honey (39% fructose) > sucrose > glucose

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17
Q

True or false: diet soda is full of fructose

A

False, diet soda has 0g of fructose.

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18
Q

What is Beano?

A

enzyme that prevents gas from beans, called alpha-galactosidase which breaks down the sugar from beans that creates gas.

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19
Q

What is amylose and what breaks it down?

A

a starch which is broken down by amylase, an enzyme produced by the pancreatic and salivary glands, so chewing food helps breaking down carbs. It can also break down amylopectin, a starch like molecule that is easier to digest.

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20
Q

How is High Fructose Corn Syrup (HFCS) made?

A
  1. Start off with corn starch: glucose polymer
  2. This polymer is broken down into single units by 3 enzymes
    * alpha-amylase,
    * glucoamylase,
    * glucose-isomerase
  3. glucose isomerase which converts glucose into high % fructose (up to 90%, super sweet)
  4. Final result, made into pure glucose aka corn syrup with high fructose content.
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21
Q

True or false: obesity has been linked with HFCS

A

True, obesity increased with increase of HFCS.

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22
Q

How much of sugar cane is sucrose? Who is the biggest producer?

A

15%, Brazil

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23
Q

Why is sugar bad for your teeth?

A

when sugar and S. Mutans, a bacteria in the mouth, come together, they produce lactic acid which eats away teeth and creates cavities. Though gene removal could reduce this effect.

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24
Q

True or false: candy is 50% fructose

A

False, candy is 98% sucrose

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25
Q

What is invertase?

A

An enzyme that makes sugar (sucrose) into 50/50 glucose and fructose

26
Q

What does fat do?

A
  • stores energy,
  • insulates,
  • buoyancy,
  • padding,
  • hormone production
27
Q

What is the difference between a saturated fat and an unsaturated fat?

A

Saturated fat = fat where all possible H atoms that can be there are there

Unsaturated fat = fewer H atoms, has double bonds (decreases H atoms by 2), often liquid

28
Q

What is a polyunsaturated fat?

A

saturated fat with more than 1 double bond

29
Q

Where can you get saturated fat and what can excess do to you?

A

Can be found in meats
Too much can cause build up in arteries

30
Q

True or false: Margarine often has water

A

True

31
Q

What is the difference between an unsaturated fatty acid chain and trans fats?

A

unsaturated fatty acid chain: c=c has 2 oxygens on top and 2 H on bottom

trans fats: c=c has 1 hydrogen on top and 1 hydrogen on bottom in a diagonal matter

32
Q

How is margarine made?

A

To make margarine, it is usually necessary to hydrogenate (add H2) many of the double bonds in unsaturated fats to single bonds (so it is less liquid and more spreadable). This causes partial reorganization of the bonding to give rise to some trans double bonds (hydrogens in diagonal).

Process: catalyst surface associates with fat’s double bond (C=C) where H2 is embedded and H2 is transferred to C=C one at a time making CIS, BUT possible rotation can occur thus forming a trans double bond so we make trans fat (less healthy).

33
Q

T or F: Natural trans fats increase cholesterol levels

A

False, no evidence has shown this

34
Q

Why is filet mignon more tender than other meats?

A

Because it has less fat

35
Q

Where does cholesterol exists?

A

In food, as cholesterol,
or more commonly in our bodies where it is made

36
Q

So do cholesterol causing foods really exists?

A

Not really, some foods do already have pre-existing cholesterol, but 80% of it is made by our bodies

37
Q

What is methionine

A

Raising chickens requires more methionine, an amino acid in food used as feed supplement. Molecule methyl mercaptan is part of this process, v foul smelling, it is a gas

38
Q

What are some fat substitutes?

A
  • carbohydrate based: gums, seaweed, cellulose derivatives
  • protein-based: microparticulates (eggs, milk)
  • fat-based: modified fats, more saturated fat chains are added to harden the vegetable oil so it it’s not necessary to hydrogenate
39
Q

Synthetic fats have x cals

A

0 cal/g

40
Q

Describe sucrose fats

A

short chain fats, not digested and not really a fat, more for texture, non caloric, suitable for frying, absorbs vitamins A,D,E,K (fat-soluble vitamins), causes loose stools.

41
Q

What does protein do in our bodies?

A
  • important for growth,
  • necessary for tissue maintenance,
  • needed for enzymatic processes
42
Q

Protein deficiency leads to….

A

Kwashiorkor (is reversible)

43
Q

What happens when an egg turns white? This process is…

A

this is the protein denaturing – water is driven off, so protein becomes visible. Protein denaturing is irreversible

44
Q

The building blocks of proteins are…and they are defined by…

A

amino acids, the R-groups

45
Q

What are peptide/amide bonds?

A

the bond that holds the oxygen double bond to nitrogen

46
Q

What does protein folding mean for a protein?

A

Different degrees of folding define a proteins capacities and function in the body

47
Q

What is tryptophan, what does it do, and why was it banned by the FDA in 1991?

A

An amino acids used because precursor to serotonin, a neurotransmitter, which induces sleep. Though in 1991, the FDA banned it due to an impurity which contaminated the samples. They were linked to eosinophilia myalgia syndrome and people died. However, this restriction was loosened in 2001 after they realized it was because of the impurity and not the tryptophan

47
Q

Why are amino acids called that way?

A

Because they contain nitrogen (amino from ammonia H-N-H) and an acid (CO2H)

47
Q

How are proteins built? What defines the type of protein that is built?

A

water splits out from the a.a. and the CO and NH groups connect to form chain. This is an energy favourable reaction. These chains can be very long, and order of the amino acids defines the type of protein.

47
Q

What is the opposite of protein building? How does it happen?

A

Hydrolysis reaction: proteins (peptides) are broken apart by the addition of water. This is why we end up being thirsty after we eat.

48
Q

what are the essential amino acids?

A

-Methionine
- Arginine (necessary for young people),
- Tryptophan,
- Threonine,
- Valine,
- isoleucine,
-leucine,
- proline,
- histidine,
- lysine.

49
Q

What is so important about the essential a.a.?

A

These need to be in the right proportions to make the appropriate body proteins. Foods don’t always have them in the right proportions. They can’t be synthesized by the body

50
Q

Name the complete and incomplete proteins

A

Complete proteins: eggs, meat, fish, milk, soy, they have a balance of the necessary a.a.

Incomplete proteins: wheat, corn, rice, efficient in some a.a. but deficient in others, not right proportions

51
Q

Vegetarian foods are rich in….

A

in lysine (usually deficient in what, rice, corn)

52
Q

Vegans often lack this amino acid

A

Vegans do not consume any animal products or animal derived products so they are sometimes deficient in arginine.

53
Q

Brown rice is low in…

A

lysine

54
Q

black, white, kidney, adzuki, pinto beans are high in…so we add it to…

A

lysine, so bread sometimes had added bean protein concentrate to compensate for low lysine in wheat.

55
Q

Red meat (processed and total red meat) has been positively associated with…

A

all-cause mortality in a linear fashion

56
Q

what is the recommended red meat serving size?

A

3 oz.

57
Q

What would be a good alternative to red meat?

A

Insects

58
Q

How many barrels of oil’s worth does it cost to raise 1 cow?

A

5-6 barrels