NFS284: Protein 1 Flashcards
1
Q
62% of protein in diet comes from…
A
meat poultry fish eggs dairy
2
Q
Unlike Canada, most of the world gets proteins from…
A
plants
3
Q
Relationship between economy and animal foods in diet?
A
better economy = more animal foods in diet
4
Q
Define: proteins
A
large, complex molecules composed of AA
5
Q
elements in protein
A
C
H
O
N
6
Q
Proteins is the primary source of ___ in our diets
A
N
7
Q
AA have which groups?
A
alpha C amino group acid group H R group
8
Q
Define: conditionally essential
A
In some situations, these compounds become essential
9
Q
List all the essential AA
A
- His
- Iso
- Leu
- Lys
- Met
- Phe
- Thr
- Trp
- Val
HI M F W L V K T
hi my friend will like very kinky things
10
Q
How are non-essential AA produced in the body?
A
transamination
11
Q
how are peptide bonds formed?
A
OH from acid end joins with H on amino end
12
Q
secondary structure of proteins
A
alpha helix
beta sheet
13
Q
Process of protein digestion & absorption
A
- Mouth
- Stomach
- small intestines
- transport proteins at small intestines
- liver
14
Q
What happens to proteins at the mouth?
A
mechanical digestion
grind into smaller particles
15
Q
Protein digestion begins at…
A
the stomach
16
Q
what happens to proteins at the stomach?
A
- HCl denatures protein structure
- Pepsinogen + HCl -> pepsin
- pepsin breaks protein into polypeptides & AA
17
Q
what happens to proteins at the small intestines?
A
Pancreatic enzymes (trypsin, chymotrypsin) cut peptide chains -> di- and tripeptides
18
Q
what are pancreatic enzymes that break down proteins called?
A
protease
19
Q
what happens to proteins at the transport proteins (small intestines)?
A
- absorbed into villi as di-/tripeptide
2. Broken down into AA and absorbed
20
Q
AA are used as precursors to…
A
NT
21
Q
use of protein in the body
A
- energy production
- make glucose / FA
- make N-containing molecules
22
Q
The whole process of protein synthesis is referred to as…
A
expression
23
Q
Common mutations are referred to as…
A
polymorphism
24
Q
Uncommon mutations are referred to as…
A
genetic disorder
25
changes in DNA may lead to...
- altered gene expression
| - altered protein structure
26
examples of genetic disorders
- Phenylketonuria
- cystic fibrosis
- sickle cell anemia
27
Phenylketonuria (PKU)
Cannot metabolize Phe, so no Tyr produced
| Phenylketones are produced, which are toxic to the brain
28
treatment for PKU
avoid Phe in diet
29
Sickle cell anemia results in...
- abnormal blood clotting
- stroke
- severe pain
- anemia
30
What AA is changed in those with sickle cell?
E -> V
31
what does "A-250G" mean?
G has been replaced by A at position 250 on DNA
32
caffeine is metabolized by __ in the liver
cytochrome P450 1A2 enzyme (CYP1A2)
33
Do people with A or C at position 734 metabolize coffee faster?
A
34
Relationship between caffeine and risk of MI
Increase intake will increase risk for MI (but only in slow metabolising population)
35
What did the Finnish Diabetes Prevention Study show?
Weight loss in people with a certain gene is much more effective at reducing risk of diabetes than those with the other polymorph
(risk for both groups decreased, but one more than the other)
36
Energy production from protein
1. Deamination gets rid of N group
| 2. Becomes pyruvate / acetyl coa / goes in TCA
37
Process of deamination
Happens in the liver
1. NH2 + H -> NH3
2. NH3 is toxic
3. CO2 + 2NH3 -> urea (condensation)
4. Urea goes to kidney to be excreted
38
Functions of proteins (8)
1. cell growth, repair, maintenance
2. enzymes
3. transport
4. antibodies
5. contractile proteins
6. hormones
7. fluid electrolyte balance
8. pH balance
39
what is the first thing that is compromised when we have low protein intake?
production of antibodies
40
How does proteins act as transport?
membrane transporters
binding proteins
lipoproteins
41
Proteins are mainly used to make __ hormones
peptide
42
3 example of peptide hormones
insulin
glucagon
thyroxine
43
3 examples of other hormones proteins make
E
NE
Serotonin
44
Peptide hormones are made from __, while other hormones made by proteins are made from ___
peptide chains
| single AA
45
NE and E are made from which AA?
Tyr
46
Serotonin is made from which AA?
Try
47
Give example of how protein influences electrolyte balance
Na/K channel is a protein
48
PEM
protein-energy malnutrition
49
PEM is caused by...
inadequate intake of protein and energy
50
2 types of PEM
1. Marasmus
| 2. Kwashiorkor
51
Marasmus
chronic inadequate food intake (inadequate everything, and protein is included in that category)
52
Kwashiorkor
Severe acute malnutrition (too little protein in diet)
53
Symptom difference between marasmus and kwashiorkor
Kwashiorkor has edema & enlarged fatty liver
54
why might fatty liver be a result of not enough protein?
Can't make transporters to move fat out of liver
55
People at high risk for PEM in Canada
- Poverty
- rural areas
- elderly living alone
- homeless
- eating disorders
- drug/alcohol addiction
- AIDS/cancer (painful to eat)
56
Chronic excess protein can result in...
- increased risk of CVD and cancer
- bone health issues
- hydration and kidney function issues
57
Animal protein is associated with...
high cholesterol
58
effect of eating vegetable protein instead of fat
- decrease cholesterol
- decrease LDL
- decrease TG
(no effect on HDL and VLDL)
59
__ g of soy protein a day is associated with __ % cholesterol lowering (___ mmol/L)
30
9
0.5
60
Sources of soy protein
- soy milk
- tofu
- isolated soy protein
- TVP (textured vegetable protein)
- meat analogue
61
Why does excess protein cause bone health issues?
Protein excreted in urine, so Ca++ also lost in urine
62
Why does excess protein cause hydration & kidney function issues?
Excess protein is excreted, so incr. workload on kidneys.
Excretion of protein brings water out as well -> dehydration
63
Protein quality is dependent on...
1. amount of essential AA
| 2. protein digestibility (better digestibility is good)
64
Protein requirements depend on...
- activity level
- age
- health status
65
a sedentary adult requires __ g of protein per kg of lean body weight
0.8
66
Who needs more protein than normal?
- children
- teens
- pregnant / lactating women
- athletes
- vegetarians
67
define: N balance
difference between N intake and N excretion
68
100g of protein contains __g of N
16
69
1 g of N = __ g protein
6.25
70
____ studies are the basis of DRI for protein
N balance
71
effect on N balance: low energy intake
must increase N intake (right shift)
72
effect on N balance: trauma / illness / low gravity
down shift (negative N balance)
73
effect on N balance: growth / pregnancy / body building
extend line until positive N (want positive N balance)
74
Negative N balance
intake < output
| Body protein mass decreases
75
Positive N balance
intake > output
| Body protein mass increases
76
Are plant proteins more/less digestible than animal proteins?
Less, except soy. Soy is about the same.
77
2 measures of protein quality (equations)
1. chemical/AA score
| 2. protein digestibility-corrected AA score (PDCAAS)
78
Formula: AA score
[(mg of limiting AA / g of test protein) / (mg of limiting AA / g of reference protein)] * 100
(test / reference) * 100
79
formula: PDCAAS
AA score * digestibility factor
80
How to determine which is limiting AA?
AA score is lowest for that AA
81
What does PDCAAS tell you?
amount of essential AA mg / g of protein
82
What is the reference protein calculated from?
needs of preschool children
83
How is digestibility factor measured?
in rats
84
Which foods have the best protein quality?
animal & soy
plant proteins are usually worse quality
85
Incomplete protein
does not contain all essential AA in sufficient amounts
86
Incomplete proteins are also known as...
low quality protein
87
Complete proteins
contains sufficient amounts of all essential AA
88
How many essential AA are there?
9
89
Complete proteins are also known as...
high quality proteins
90
What is mutual complementation?
consuming 2 incomplete proteins which together make a complete protein
91
example of complementary proteins
rice + beans
rice high in Met + Cys
beans high in Lys
oatmeal & milk
pasta & vegetables & parmesan cheese
92
complementary proteins
foods that when together supply all 9 essential AA
93
types of vegetarianism
1. partial: no meat
2. lacto-ovo: no fish and meat
3. vegan: no animal products
94
reasons for becoming a vegetarian
- health benefits
- ecological reasons
- religious reasons
- ethical reasons
- concerns over food safety
95
Health benefits of vegetarianism
- lower fat & kcal
- lower BP
- lower risk for CVD
- lower risk for come cancers
- less digestive problems (e.g. constipation)
96
Challenges of vegetarianism
- protein
- iron
- zinc
- calcium
- vit D
- vit B12*
97
Where can vegetarians get proteins
complementary proteins
98
Where can vegetarians get iron
```
whole grains
leafy veggies
beans
nuts
seeds
```
99
Where can vegetarians get zinc
whole grains
beans
nuts
seeds
100
Where can vegetarians get calcium
fortified soy
green veggies
beans
almonds
101
Where can vegetarians get vit D
fortified
sunlight
supplements
fish
102
Where can vegetarians get vit B12
fortified cereals
yeast soy
meat analogues
103
Which vit can only be found in meat products?
vit B12
