Session 1 Lecture 1 Flashcards
(95 cards)
1
Q
Define metabolism
A
The chemical processes that occur within a living organism in order to maintain life.
2
Q
Define catabolic processes
A
Break down molecules to release energy in the form of reducing power.
3
Q
Define anabolic processes
A
Use energy and raw materials to make larger molecules for growth and maintenance.
4
Q
What are the four main branches of metabolism
A
- Oxidative pathways
- Fuel storage and mobilisation pathways
- Biosynthetic pathways
- Detoxification pathways
5
Q
Define energy
A
The capacity to do work
6
Q
What do living cells require energy for?
A
- Biosynthetic work - synthesis of cellular components
- Transport work - movement of ions etc
- Mechanical work - muscle contraction
- Electrical work - nervous conduction
- Osmotic work - kidney
7
Q
What form of energy is used in the body to drive activities?
A
Chemical bond energy
8
Q
What is an exergonic reaction?
A
Energy released is greater than the energy input
9
Q
What is an endergonic reaction?
A
Energy input is greater than the energy released
10
Q
Reactions that require an input of energy are driven by…
A
Coupling it reactions that release energy. Coupling is usually via the ATP-ADP cycle.
11
Q
What process releases the chemical bong energy in fuel molecules?
A
Oxidation
12
Q
Can ATP be stored in the body?
A
No, but things that produce ATP such as fat and glycogen are stored in the liver.
13
Q
Describe the ATP-ADP cycle
A
- When last phosphodiester bond is broken, energy is released.
- Some of this energy is conserved by the formation of ATP from ADP and pI.
- The remainder of the energy is lost as heat.
14
Q
What is the official SI unit of food energy?
A
Kilojoules (KJ)
15
Q
What does ‘calorie’ in everyday use actually mean?
A
Actually means kilocalorie (1000 calories)
16
Q
Define 1 kcal
A
The amount of energy needed to raise temperature of one kilogram of water by one degree celsius
17
Q
How many KJ in a Kcal?
A
1Kcal = 4.2 KJ
18
Q
What ar the different food groups?
A
- Carbohydrate
- Protein
- Fat
- Minerals
- Vitamins
- Water
- Fibre
19
Q
What are the macronutrients?
A
Carbohydrate
Protein
Fat
20
Q
What are the micronutrients?
A
Minerals
Vitamins
21
Q
Which food group mostly supplies our energy?
A
Carbohydrate
22
Q
Describe the molecular structure of carbohydrates
A
- General formula (CH2O)n
- Contains aldehyde or ketone group
- Multiple OH groups
23
Q
What are the different types of carbohydrates?
A
- Monosaccharide - single sugar units
- Disaccharide - 2 units
- Oligosaccharides - 3-12 units
- Polysaccharides - 100s of units
24
Q
Give some example of carbohydrates
A
- Starch
- Sucrose
- Lactose
- Fructose
- Glucose
25
Name the polymers of glucose?
Starch - storage molecule in plants
| Glycogen - storage molecule in animals
26
What is sucrose made of?
Glucose-fructose disaccharide
27
What is lactose made up of?
Galactose - glucose disaccharide
28
What is maltose made up of?
Glucose - glucose disaccharide
29
Describe the structure of proteins
Composed of amino acids joined to form linear chains
30
How many amino acids are used for protein synthesis in the body?
20
31
What are 'essential amino acids' and how many are there?
- There are 9
| - They can't be synthesised by the body hence must be obtained by the diet.
32
Name all the essential amino acids
Isoleucine, Lysine, Threonine, Histidine, Leucine, Methionine, Phenylalanine, Tryptophan and Valine
33
Why are certain amino acids conditionally essential?
Some amino acids become essential at periods of rapid growth as the body can't make them fast enough.
34
What amino acids might children and pregnant women particularly need in their diet?
Arginine
Tyrosine
Cysteine
35
What is high quality protein?
- Protein of animal origin
| - Contains all essential amino acids
36
What is low quality protein?
- Protein of plant origin
| - Deficient in one or more essential amino acid
37
Describe the molecule structure of fats?
Lipid composed of triacylglycerols
| 3 fatty acids esterified to one glycerol
38
How much energy does fat have?
Fat contains much less oxygen than carbohydrate or protein.
| Fat is more reduced so yields more energy when oxidised.
39
Why is fat so necessary in the body?
- Required for absorption of the fat-soluble vitamins (A,D,E & K) from the gut.
- Provides essential fatty acids eg linoleic and linolenic acids which can't be synthesised in the body.
40
Why are minerals important in the diet?
Electrolytes establish ion gradients across membranes & maintain water balance.
41
Give example of where minerals are used in the body
- Calcium and phosphorus needed for bones and teeth
- Calcium is an important signalling molecule
- Enzyme co factors - iron, magnesium, manganese, cobalt
- Iron essential component of haemoglobin
42
What are the three main electrolytes needed in the body?
- Sodium
- Potassium
- Chloride
43
Why are vitamins so essential in the body?
Deficiency diseases if inadequate intake
44
What is hypervitaminosis?
Condition of abnormally high storage levels of vitamins
45
What are B12 and folate necessary for?
- Essential for DNA synthesis
| - Deficiency leads to anaemia
46
Give examples of fat soluble vitamins
A D E K
47
Give examples of water soluble vitamins
B1, B12, B6, biotin, C, choline, folate, niacin, pantothenic acid and riboflavin
48
Where is dietary fibre found?
Cereal foods such as bread, beans, fruit and veg.
49
Even though we can't break down cellulose, why is it essential in our body?
Essential for a normally functioning GI tract
50
Why can't we break down cellulose?
Humans don't have the enzyme to break the b-1,4 linkages in cellulose
51
What is the recommended average intake of dietary fibre for adults?
18g/day
52
What is low fibre associated with?
Constipation and bowel cancer
53
What is high fibre associated with?
Reduce cholesterol and risk of diabetes
54
What are DRVs?
- Dietary Reference Values
| - Series of estimates of the amount of energy and nutrients needed by different groups of healthy UK population
55
Give some examples of DRVs
RNI, EAR and LRNI
56
RNI
- Reference nutrient intake
| - Used for protein, vitamins and minerals
57
EAR
- Estimated average requirement
- Used for energy
- Requirement for roughly 50% of the population
58
LRNI
- Lower reference nutrient intake
- Intakes below this are insufficient for most people
- Majority of people need more than these values
59
What is the eat well plate?
- This shows how much of what you eat should come from each food group.
- This is the method used by the government to try and get the message out to everyone.
60
What is the daily energy expenditure of a 70kg adult male?
12 000 KJ/day
61
What is the daily energy expenditure of a 58kg adult female?
9500 KJ/day
62
Why do daily energy expenditures vary between individuals?
Depends o age, sex, body composition and physical activity.
63
What are the different components of daily energy expenditure?
- Basal metabolic rate
- Diet - induced thermogenesis
- Physical activity level
64
What is BMR?
- Basal Membrane rate
- This is the measure of the basal energy required to maintain life.
- Maintains resting activities of the body.
65
What are the major tissues contributing to the BMR?
- Skeletal muscle - 30% BMR
- Liver - 20% BMR
- Brain - 20% BMR
- Heart - 10 % BMR
- Other - 20% BMR
66
What factors affect BMR?
- Body size (surface area)
- Gender (males higher than females)
- Outside temperature (higher in cold)
- Endocrine status
- Body temperature (12% per degree)
67
What does voluntary physical activity reflect the energy demands of?
- Skeletal muscle
- Heart muscle
- Respiratory muscles
68
How much extra energy does a sedentary person, moderately active and very active person use?
Sedentary person - 30 KJ/Kg/day
Moderate activity - 65 KJ/Kg/day
Very active - 100 KJ/Kg/day
69
What are the energy stores of the body?
Adipose tissue and glycogen
70
What are the long term energy stores in the body?
Adipose tissue
71
What happens to body weight if energy intake is equal to energy expenditure?
Body weight is stable
72
What happens to body weight if energy intake exceeds expenditure?
Energy stores (fat) will increase
73
What happens to body weight if energy expenditure exceeds intake?
Energy stores deplete
74
Define obesity
- Excessive fat accumulation in adipose tissue which impairs health
- BMI >30
75
What causes obesity?
Result of energy intake exceeding expenditure over a period of years
76
What other health conditions can obesity lead to?
- Cancers
- Cardiovascular diseases
- Type 2 diabetes
77
How do you work out BMI?
Weight / height ^2
78
What units is BMI measured in?
Kg/m2
79
What is BMI used for?
Used clinically to evaluate patients
80
Why might BMI not be useful for everyone?
Very muscular individuals might be wrongly classified as obese
81
Why alternative can be used to BMI?
Waist/hip ratio
82
What BMI is underweight?
<18.5
83
What is the BMI range of the desirable weight?
18.5 - 24.9
84
What is the BMI range of overweight?
25 - 29.9
85
What is the BMI range of obese?
30 - 34.9
86
What BMI is severely obese?
>35
87
What is a greater proportion of fat in upper body associated with?
Insulin resistance, hyperinsulinism, type 2 diabetes, hypertension, hyperlipidaemia, stroke and premature death.
88
Define malnutrition
Any condition caused by an in-balance between what an individual eats and what that individual requires to maintain health.
89
What causes malnutrition?
Eating too much, eating too little or incorrect balance of nutrients
90
What causes malabsorption conditions? (e.g. coeliac disease)
Failure to digest and/or absorb ingested nutrients.
91
What is protein-energy nutrition?
This covers a spectrum of clinical conditions seen in starving adults and children.
92
What is marasmus?
Type or protein-energy malnutrition most commonly seen in children under the age of 5. Obvious signs of muscle wasting and loss of body fat although there is no oedema.
93
What is kwashiorkor?
Severe form of malnutrition caused by low protein intake. Oedema is characteristic of this. (albumin is always low)
94
What causes oedema in kwashiorkor?
- Insufficient amino acids for the liver to make normal level of blood proteins such as albumin.
- Decreases plasma oncotic pressure
- Increases the net flow of fluid from the capillaries to the interstitium by Starling's law
- This leads to oedema
95
What is the normal fasting plasma concentration of glucose?
3.3 - 6.0 mmol/L
