Metabolic Fuels And Dietary Components Flashcards
1
Q
What does metabolism mean?
A
Sum of all the chemical reactions that take place within each cell of a living organism
2
Q
What is the daily recommended calorie intake for adults?
A
Females: 2000
Males: 2500
3
Q
What are the 4 different pathways dietary components are metabolised in cells?
A
Biosynthetic
Fuel storage
Oxidative processes
Waste disposal
4
Q
What are anabolic metabolic processes?
A
Synthesise larger molecules from smaller components, requires energy
5
Q
What are catabolic metabolic processes?
A
Breakdown of organic molecules, often yielding energy
6
Q
Which metabolic processes are anabolic?
A
Biosynthetic
Fuel storage
Results in formation of macromolecules
7
Q
Which metabolic processes are catabolic?
A
Oxidative
8
Q
Where does the energy for anabolic pathways come from?
A
Catabolic pathways
From the breakdown of carbohydrates and lipids, energy is released in the form of ATP
9
Q
What is the krebs cycle also known as?
A
Citric acid cycle
As the cycle starts with citric acid
10
Q
What are co-factors?
A
Macronutrients required for enzymes to function
11
Q
Give an example of a co-factor in the krebs cycle?
A
Thiamine
Thiamine pyrophosphate (Vitamin B1)
12
Q
What is thiamine required for?
A
The conversion of pyruvate to acetyl-CoA in the Krebs cycle
The conversion of 5-carbon compound to 4-carbon compound in Krebs cycle
13
Q
What percentage fat is adipose tissue?
A
85%
In the form of triglyceride molecules
14
Q
What is the main function of adipose tissue?
A
Storage of energy rich molecules
15
Q
Are adipose cells metabolically active?
A
No
16
Q
Is the liver metabolically active?
A
Yes very
17
Q
What is the function of the liver?
A
Producing glucose by gluconeogenesis
Removal of toxins
Metabolism of compounds
18
Q
Give examples of compounds the liver metabolises?
A
Xenabiotics
19
Q
What do muscles do?
A
Use fuels to present kinetic energy
20
Q
What is a pathway of gluconeogenesis?
A
The cori cycle
21
Q
What does gluconeogenesis mean?
A
Formation of new glucose
22
Q
What is the concentration of glucose in blood controlled by?
A
Insulin
23
Q
What is the main effect of insulin in adipose tissue?
A
Increase the uptake of glucose and to increase the production of storage compound: triglycerides/tryacelglycerol
24
Q
What is the effect of insulin in liver and muscle cells?
A
Increase the uptake of glucose nirvana essence and the uptake of potassiumand phosphate
Increased synthesis of proteins and glycogen
25
What does insulin stimulate?
Biosynthesis
26
What effect does insulin have on the liver?
Promotes the synthesis of fatty acids from carbohydrates which are transported to the adipose tissue for storage
27
What does insulin inhibit?
The hydrolysis of triglycerides
28
Are the actions of insulin anabolic or catabolic?
Anabolic
29
What are the 3 main dietary energy sources?
●Carbohydrates
●Lipids
●Proteins
30
What is used to calculate healthy weight?
BMI, 18-25 is healthy weight
25-30 is overweight
30+ obesity
31
What is ATP referred as?
The energy currency of the cell
32
How are energy foods processed?
Undergo oxidation to yield energy, release of ATP
33
How many times and how much ATP does the human body recycle each day?
Around 1000 times a day
Breakdown approx our own body weight of ATP a day
34
When does ATP release energy?
When it's broken down to yield ADP
35
What happens to organic compounds in aerobic respiration?
Organic compounds are metabolised in the presence of oxygen to Carbon dioxide and water with the release of energy
36
What is the main carbohydrate?
Glucose
37
What are glucose fructose and galactose examples of?
Monosaccharides
Formula of C6H12O6
38
What disaccharide do glucose and fructose form?
Sucrose (C12H22O11)
39
What is the disaccharide in milk?
Lactose
40
What structure does starch have?
Long chains of carbohydrates
41
What structure does glycogen have?
Branched chains of carbohydrates
42
What are proteins?
Long chains of amino acids
43
Where are proteins broken down in?
Lumen of the gut
44
What can the Carbon backbone of aminoacids be used for?
Can be broken down to yield energy
45
What is an example of gluconeogensis in amino acids?
The conversion of gluconeogenic amino acids such as adenine to glucose
46
What are constitutes of aminoacids?
Amino group
Carboxyl group
R group
47
How much protein do we need each day?
0.8 g/kg
48
How do you convert the protein requirement to nitrogen requirement?
Multiply the protein requirement by 16%
49
What are lipids?
Fats including triglycerides and cholesterol
50
What lipids are used as fuel?
Only triglycerides
51
What is another name for triglycerides?
Triacylglycerol (TAG)
52
What is a feature of triglycerides?
More reduced than other energy sources
53
What is a feature of the structure ofanglyceides?
The glycerol backbone can be used as an energy source that can be converted to glucose by gluconeogenesis
54
How is excess energy stored?
Fat - Adipose tissue (only 15% water)
Carbohydrate – as glycogen in liver and muscles
Protein - Muscle (80% water)
55
What happens to excess energy intake?
Store as triglycerides in adipose (approx 15kg),
Store as glycogen (up to 200g in liver & 150g in muscle), 80g in the liver after overnight fast,
Store as protein in muscle (approx 6kg).
56
How much energy per gram of carbohydrates?
4kcal/g
57
How much energy per gram of protein?
4kcal/g
58
How much energy per gram of alcohol?
7kcal/g
59
How much energy per gram of lipid?
9kcal/g
60
What is the primary source of ATP supplied to the body at rest and during low intensity activities?
The oxidative system (aerobic)
Uses primarily carbohydrates and fats as substrates
61
What is the Basal Metabolic Rate (BMR)?
Energy needed to stay alive at rest
A measure of the energy required to maintain non-exercise bodily functions such as;
●respiration,
●contraction of the heart muscle,
●biosynthetic processes,
●repairing & regenerating tissues,
●ion gradients across cell membranes
62
What are the conditions essential for measuring BMR?
• Post-absorptive (12 hour fast)
• Lying still at physical and mental rest
• Thermo-neutral environment (27 – 29oC)
• No tea/coffee/nicotine/alcohol in previous 12 hours
• No heavy physical activity previous day
• Establish steady-state (~ 30 minutes)
63
What factors decrease BMR?
●Age
●Gender
●Dieting/Starvation
●Hypothyroidism
●Decreased muscle mass
64
What factors increase BMR?
●Body weight (BMI)
●Hyperthyroidism
●Low ambient temp.
●Fever/infection/chronic disease
65
What do thyroid hormones do?
Thyroid hormones regulate metabolic rate, core body temperature, appetite, sympathetic activity and more
66
Why do people with a higher muscle to fat ratio tend to have a higher BMR?
Muscle cells require more energy to maintain than fat cells
67
What is hypothyroidism?
Medical condition with reduced thyroid hormone section
68
Why does BMR tend to decrease with age?
As we get older, we tend to gain fat and lose muscle
69
What is hyperthyroidism?
When the body secretes too much thyroid hormone
70
How is BMR assessed?
• Harris Benedict Equations (1919)
• Schofield Equations (1985)
• Henry equations (2005)
Rough estimate: ~1kcal/kg body mass/hour
71
Example of Henry equation?
Equation for estimating basal metabolic rate from gender, age and weight; (formulae & examples are for interest);
Example: (70 kg X 16) + 545 = 1665 kcal/day (BMR)
72
Why does the Henry equation not use weight?
In the clinical setting height can be difficult to obtain or include in calculations, & other variables may negate the advantage of including height
73
When should the Henry equation be adjusted?
●Adjust for metabolic stress
●Adjust for activity and maybe diet-induced thermogenesis (DIT)
74
What is the NHS Nutrition guideline for patients who are not severely ill or injured, nor at risk of re-feeding syndrome?
25-35 kCal/kg/day
75
How much glucose does the brain require a day?
Around 150g
76
How much glycogen does the liver have after an overnight fast?
80g
77
How is glucose formed during a longer period of fasting/starvation?
Formed from non-carbohydrate sources - gluconeogenesis
78
What happens to secretion of insulin after an overnight fast?
Switched off/decreased
Glycogenolysis
79
What does gluconeogenesis use?
●Lactate
●Amino acids
Muscle
Intestine
Skin
●Glycerol
Fat breakdown
80
What is the hormonal response to starvation
Insulin production switched off
Cortisol being produced
81
What does the hormonal response to starvation facilitate?
Lipolysis
Proteolysis
82
What are the metabolic changes of prolonged fasting?
Liver produces ketones from fatty acids
Brain adapts to using ketones instead of glucose as a fuel
Reduction to BMR
83
What is malnutrition?
A state of nutrition with a deficiency, excess or imbalance of energy, protein or other nutrients,
causing measurable adverse effects
84
What are effects of malnutrition?
Adverse effects are on tissue/body form (shape, size, composition), body function and clinical outcome
85
What is re-feeding syndrome?
Clinical condition caused by re-feeding too quickly after a period of undernutrition
●Re-distribution of phosphate, potassium, magnesium etc due to insulin,
●Switch back to carbohydrates as the main fuel which requires phosphate and thiamine.
86
What are essential amino acids?
They can't be synthesised in the human body so need to be supplemented by food
87
What are essential fatty acids?
Human body can't synthesise so have to be present in the diet or occasionally as supplements
88
What are macronutrients?
Trace elements and vitamins
●Co-factors in metabolism
●Gene expression
●Structural components
●Antioxidants
89
What does vitamin C do?
Facilitates collagen synthesis
Improves iron absorption
Antioxidant
90
Where can vitamin C be found?
Fruit and veg
Ascorbic acid
91
What is Vitamin B12?
Co-factor in synthetic processes such as:
Formation of DNA
Protein synthesis
Regenerate folate (and therefore – cell division)
Fatty acid synthesis
Energy production
92
What does vitamin B1 (Thiamine) do?
Helps with energy production in body
93
What does Vitamin D do?
Increases amount of calcium and phosphorus your body absorbs from foods
Deposits calcium and phosphorus in bones and teeth, making them stronger and healthier
Protects against infections by keeping immune system healthy
94
What are the 4 main fat soluble vitamins?
Vitamins A, D, E and K
95
What does Vitamin A do?
Helps you to see in the day and at night.
Protects you from infections by keeping
skin and other body parts healthy.
Promotes normal growth and development
96
What does Vitamin E do?
Helps to maintain a healthy immune system and other body processes.
Acts as an antioxidant and protects cells from damage
97
What does Vitamin K do?
Makes proteins that cause our blood to clot, when you are bleeding
Involved in making body proteins for your blood, kidney and bones
98
What is the prudent diet?
5+ servings fruit/veg
Base your meals around starchy carbohydrate foods
No more than 5% of the energy we consume should come from free sugars
0.8g/kg/day protein
The average man should have no more than 30g saturated fat a day, & women 20g.
Adults should have no more than 2.4g of sodium per day, which is equal to 6g of salt.
Men and women are advised not to regularly drink more than 14 units of alcohol a week (over >3 days).
Avoid excess dietary supplementation
Adequate Calcium
