4a. Biochemistry - Proteins, Enzymes Flashcards
(119 cards)
1
Q
What are the building blocks for proteins?
A
Amino acids
2
Q
What four elements do amino acids contain?
A
Carbon
Hydrogen
Oxygen
Nitrogen
3
Q
Which element distinguishes proteins from fats and carbs?
A
Nitrogen
4
Q
How many different amino acids does the body need to create the proteins needed to function?
A
20
5
Q
Which functional groups make up amino acids?
A
Carboxyl
Amino
Side chain of R that determines characteristics
6
Q
What are the bonds that join amino acids together?
A
Peptide bonds
7
Q
How do amino acids join together?
A
Dehydration synthesis
8
Q
What are 2 amino acids joined together called?
A
Dipeptide
9
Q
What are 3 amino acids joined together called?
A
Tripeptide
10
Q
What type of peptide is aspartame?
A
Dipeptide
Neurotoxin
11
Q
What type of peptide is glutathione?
A
Tripeptide
Antioxidant
12
Q
Which three amino acids make up glutathione?
A
Cysteine
Glutamate
Glycine
13
Q
Why do we need to ensure a good supply of cysteine in our diets?
A
We don’t have enough in the body which can impair glutathione production
14
Q
Which foods are a good source of cysteine?
A
Legumes
Eggs
Sunflower seeds
15
Q
What are the two types of amino acids?
A
Acidic side chains
Basic side chains
16
Q
What do amino acids with acidic side chains do?
A
Release hydrogen ions
17
Q
What do amino acids with basic side chains do?
A
Bind to hydrogen ions
18
Q
What determines whether or not the amino acids release H+ or bind to hydrogen?
A
The pH of the surrounding fluid
19
Q
What effect does the pH of the surrounding fluid do to a protein?
A
Effects its 3D structure and function
i.e. ceviche - raw fish - starts off soft, then goes hard when lemon juice squeezed on it
20
Q
What characteristic do non-polar amino acids have?
A
Hydrophobic
21
Q
How does a non-polar, hydrophobic amino acid react in a watery environment?
A
It folds to be on the inside of the protein structure, away from water
22
Q
Example of a non-polar, amino acid
A
Tryptophan
23
Q
What characteristic do polar amino acids have?
A
Hydrophilic
24
Q
How does a polar, hydrophilic amino acid react in a watery environment?
A
It folds to be on the outside of the protein structure, interacting with the polar water molecules
25
Example of a polar, hydrophilic amino acid
Tyrosine
26
Examples of functions of proteins
```
Fluid balance in blood e.g. albumin
Alternative energy source
Clotting mechanisms e.g. clotting factors
Enzyme production
Storage molecule e.g. ferritin
```
27
What is the 3D structure of a protein key to?
Its function
28
What is the process whereby a protein's structure changes?
Denaturing
29
How can proteins become denatured?
Heat - cooking (e.g. egg whites)
| Heavy metals e.g. lead, mercury
30
What is needed to digest proteins?
Enzymes
31
How are proteins digested?
Mouth - mechanically broken down
| Stomach - pepsin enzyme breaks down peptide bonds between the amino acids
32
What is pepsin?
Enzyme
| Released by gastric cells
33
What is the inactive form of pepsin called?
Pepsinogen
34
What activates pepsinogen into pepsin?
HCl
35
What is required for pepsin to function properly?
Fluid pH of 2
| Adequate stomach acid
36
What happens when protein-rich chyme enters the small intestine?
Hormone CCK is released
| Triggers release of pancreatic enzymes
37
What are the pancreatic enzymes?
Trypsin
| Chymotrypsin
38
What happens to proteins once the pancreatic enzymes are released?
Broken down further into tripeptides, dipeptides and single amino acids by pancreatic juices and brush border enzymes
Absorbed into blood
39
What are nucleic acids?
Largest molecules in the body
| Used to store genetic information
40
What are the most common nucleic acids?
```
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
```
41
What are the building blocks of nucleic acids called?
Nucleotides
42
What do nucleotides consist of?
Phosphate group
Sugar
Nitrogenous base
43
What are the functions of nucleic acids?
DNA - template for protein synthesis
| RNA - copies specific sub-sections of DNA (genes) and translates it into proteins
44
What do the nucleotides in DNA contain?
5-carbon sugar deoxyribose
45
DNA contains which four nucleotide bases?
Adenine
Cytosine
Guanine
Thymine
46
Which nucleotide bases are purines?
Adenine
| Guanine
47
Which nucleotide base pairs with adenine?
Thymine
48
Which nucleotide base pairs with cytosine?
Guanine
49
What is the structure of DNA?
Two strands wound together like a twisted ladder
| Double helix
50
What are the 'sides of the DNA ladder' formed from?
Sugar-phosphate bonds which are covalent bonds
51
What are the 'rungs of the DNA ladder' made from?
Hydrogen bonds
52
What is the structure of RNA?
Single strand of nucleotides containing ribose
53
When DNA is condensed down, what does it form?
Chromosomes
54
What are the ends of chromosomes called?
Telomeres
55
What affect does ageing have on telomeres?
Shortens them
56
What can accelerate the shortening of telomeres?
```
Stress
Poor nutrition
Poor sleep
Lack of exercise
Chemical agents
```
57
What is mutation?
A change in the DNA sequence
58
How can a mutation affect protein synthesis?
Can cause a change in the sequence of amino acids in the protein
This can cause the protein to be a slightly different shape
59
How may a shape change affect a protein?
May affect its functionality
60
How does a mutation cause sickle cell anaemia?
Mutation in gene that codes for the production of haemoglobin proteins
The haemoglobin becomes abnormally shaped and makes the RBCs defective
61
How does a mutation cause haemophilia?
Affects genes associated with clotting factors 8 and 9
| Results in problems clotting
62
How can a mutation cause cancer?
Affects the genes that code for the proteins involved in regulating cell division
63
What is gene expression?
The process by which the instructions in our DNA are converted into a functional product, such as a protein
64
What can influence gene expression?
Environment the genes are bathed in
e.g. amount of toxins we're exposed to
Certain nutrients
65
Which nutrients can influence gene expression?
```
Vit A
Vit D
EFAs
Fibre
Zinc
```
66
Can gene mutations affect enzyme activity?
Yes
67
What is MTHFR?
Enzyme necessary for converting folate (B9) into a form used for methlylation
68
What is the active form of folate called?
Methylfolate
69
What is methylfolate used for?
Metabolising homocysteine
| associated with heart disease and dementia
70
How can people with MTHFR mutations be affected?
Higher homocysteine levels which could lead to heart disease and/or dementia
71
What may people with a MTHFR mutation benefit from?
Taking methylfolate
| Avoiding excessive fortified folic foods e.g. cereals
72
What are enzymes?
Biological catalysts made from protein
73
What do enzymes do?
Create a lower energy way for starting materials to meet and react
Allows reactions to happen quicker in mild conditions within the body
74
Can enzymes be reused?
Yes, they don't get damaged during a reaction process so can be used again
75
What are the molecules at the start of a reaction process called?
Substrates
76
What does an enzyme convert a substrate to?
A product
77
Example of enzyme, substrate, product
Enzyme - pepsin
Substrate - a protein e.g. food
Product - shorter protein chains
78
What happens when a substrate binds to an enzyme?
The enzyme stresses the bond in the substrate
Weakens it
Allows body to more easily break bond
79
What conditions do enzymes need to work correctly?
Correct temperate - 37C
| Correct pH - could be acid or alkaline
80
Does an enzyme reaction need more or less energy than a reaction without an enzyme?
Less
81
What is the area on an enzyme where the substrate binds called?
Active site
82
What are enzyme co-factors?
Usually vitamins or minerals that are needed to activate an enzyme
83
Examples of enzyme co-factors
Zinc
| Selenium
84
How is zinc an enzyme co-factor?
Required to activate the enzyme 'alcohol dehydrogenase' that breaks down alcohol
85
Why is selenium an enzyme co-factor?
Required for the antioxidant enzyme 'glutathione peroxidase'
86
What can a lack of co-factor lead to?
A reduction in enzyme activity
87
What can affect the speed of enzyme reaction?
Substrate concentration
88
What is substrate concentration?
Enzymes work best when there is plenty of substrate
As the concentration of substrate increases, so does the rate of enzyme activity
However, a point will be reached when the enzymes become saturated and no more substrates can fit at any one time even though there is plenty of substrate available
The available substrate has to wait for enzymes to clear their active sites
(wait for a parking space to become available)
89
Example of substrate concentration in nutrition
The same enzyme converts O6 and O3
If someone ingests a lot of O6 and small amount of O3, the O6 will occupy the active sites meaning the O3 won't be converted
90
What happens to molecules at high temperatures?
Move much faster
More collisions
Faster reaction time
91
How can high temperatures affect enzymes?
Atoms in enzymes vibrate too much
The weak bonds holding the 3D structure together can break
Enzyme becomes denatured
92
What effect does over-eating have on enzyme production?
Eating more means more enzymes are produced and used up
Eventually enzyme production can't meet demand
Impairs digestion and the absorption of nutrients
93
Why is it important not to drink whilst eating?
Dilutes the digestive juices containing enzymes
94
Other than over-eating, what other factors can reduce digestive enzyme output?
Prolonged stress
| Nutritional deficiencies
95
What treatment can be used to promote the production of digestive enzymes?
Herbal bitters
| Bitter greens
96
Examples of enzymes in food
```
Bromelain - pineapples
Papain - papaya
Lipase - avocado
Alliinase - garlic
Actinidin - kiwi
```
97
How are plant enzymes different to human enzymes?
Tolerate a wider pH
| Less likely to be denatured
98
What can denature plant enzymes?
Heat
| Microwaving food
99
At what temperature do enzymes start to be destroyed?
Above 40C
100
What are the benefits of eating raw food?
```
More enzymes
More vitamins
More minerals
More probiotics
More antioxidants
```
101
What decreases the antioxidant value of food?
Cooking
102
Which compounds become more readily available during heating?
Lycopene - tomatoes
| Beta carotene - sweet pots, carrots, mangoes
102
When is it advisable not to each raw foods?
SIBO - can cause immediate bloating
Thyroid disorders - raw turnips/cabbage (goitrogenic foods) can disrupt the uptake of iodine in thyroid gland
Yin conditions - lethargy, anaemia, feeling cold
103
Which enzymes are involved in the creation of inflammatory mediators?
Cyclooxygenase 1 and 2
| Lipoxygenase 5
104
Which inflammatory mediator is created by cyclooxygenase 1 and 2?
Prostaglandins
105
Which inflammatory mediator is created by lipoxygenase 5?
Leukotrienes
106
Examples of natural anti-inflammatories
Turmeric
Ginger
Boswellia
107
Which drugs can inhibit enzymes?
Antibiotics
| Statins
108
Which enzymes do antibiotics deactivate?
Zonulin - the enzyme necessary for the connections of amino acids in cell walls
109
Which enzyme does statins inhibit?
HMG-CoA reductase - used by liver to make cholesterol and CoQ10
110
What is systemic enzyme therapy?
Taking a large dose of proteolytic enzymes on an empty stomach so that some of the enzymes are able to reach the stomach intact
111
What are the functions of proteolytic enzymes?
Reduce inflammation
| Efficient clearance of damaged tissue
112
Examples of proteolytic enzymes
Bromelain - pineapple
Serrapeptase
Pancreatic enzymes
113
What properties has bromelain shown to have?
Anti-inflammatory
Anti-cancer
Anti-clotting
Reduce plaques (atherosclerosis)
114
What properties does serrapeptase have?
Anti-inflammatory
115
How does serrapeptase help with reducing inflammation?
Thinning fluids formed from injury
Inhibits release of pain-mediating chemicals
Enhances CV health by breaking down fibrin - a by-product of blood coagulation
(dissolves blood clots/atherosclerotic plaques)
Reduces pain/swelling without inhibiting prostaglandins
116
How does serrapeptase alleviate pain?
By inhibiting release of bradykinin from inflamed tissues
| Hydrolysing histamine
117
Which inflammatory mediator does serrapeptase not inhibit?
Prostaglandins
118
What are the therapeutic uses of serrapeptase?
```
Inflammatory mediated pain
Scar tissue
Endometriosis
Autoimmunity
Excess mucus
```
