Nutrition, Diet & Body Weight Flashcards
Define cell metabolism?
Set of processes which drive energy and raw material from food stuffs and use them to support repair, growth and activity of the tissues of the body to sustain life
What is the function of metabolism?
Conversion of food stuffs to be used as energy
What is interconversion with regards to metabolism?
Conversion of nutrients to be stored
Outline what anabolism is
Synthesise larger important cellular components from intermediary metabolites, needs ATP, reductive = uses H
Define catabolism
Break down larger molecules into smaller ones, releases large amounts of free energy, oxidative = release H (has reducing power)
Name some products of catabolic metabolism
Building block materials: sugars, AA, fatty acids.
Organic precursors: acetyl CoA. NADH, NADPH.
Cell energy: ATP
What does a cell require energy for?
Synthesis, maintaining ion gradient, nutrient uptake, transport, mechanical work, electrical work, osmotic work
What unit of energy is food measured in?
Joule (J), 1,000 joules = 1kJ
How many calories does 1 Kcal equal?
1kcal = 1000 calories
What forms does energy exist in?
Heat, light, mechanical electrical, osmotic,
cells use = chemical bond energy
The characteristic energy change accompanying each chemical reaction can be defined as?
Exergonic = release energy,
endergonic = requires energy
What is the difference in free energy between an exergonic and endogenic reaction?
Exo = < 0, endo = > 0
What type of reaction can occur spontaneously?
Exergonic
What is the role of redox reactions in metabolism?
OILRIG, NAD, NADP and FAD act as major H carrier molecules that undergo redox reactions to facilitate ATP prod and biosynthesis
Explain the biological roles of ATP
Biochemical money = form of energy by releasing a phosphate = ADP then = AMP
Explain the biological role of creatine phosphate
Acts as an energy store = store of high energy phosphate bonds in phosphocreatine
Explain the roles of high and low energy signals in the regulation of metabolism
Tell the cell more or less energy is needed e.g. ATP vs ADP and AMP
Where is ATP stored?
It isn’t. we store things that can have their bonds broken to help form ATP
The 3 phosphate groups in ATP are referred to as what?
Alpha, beta and gamma
What does 1 Kcal equate to?
amount of energy needed to raise temp of 1 kilogram of water by 1 degree Celsius
What does the food we eat provide?
Carbs, protein, fat, minerals, vits, water, fibre
Outline the structure of carbs
General formula (CH2O)n, contain aldehyde or keto group,
monosaccharide – single unit (3C = triose, 5C = pentose, 6C = hexose),
disaccharide = 2 units, oligosaccharide = 3-12 units, polysaccharide = 10-1000s
What are the different forms of carb?
Starch = plant storage, sucrose = glu-fruc disaccharide, lactose = milk, fructose = fruit, glucose = blood, maltose = glu-glu disaccharide, glycogen = animal storage
How many essential AA exist?
9 cannot be synthesised and must be obtained
What are the essential amino acids?
Isoleucine, lysine, threonine, histidine, leucine, methionine, phenylalanine, tryptophan, valine
What are high and low quality proteins?
High = animal origin contain all essential AA, low = plant origin
What is fat composed of?
Triacylglycerol’s (3 fatty acids esterified to 1 glycerol)
Why does fat yield more energy than carb or protein?
Contain less oxygen than carb/protein
= more reduced so yeilds more energy when oxidised
What are the essential fatty acids?
Linoleic and linolenic acid
What is the role of minerals in the body?
Establish ion gradients, Ca and phosphorus essential for structure, Ca for signalling, enzyme co-factors iron in Hb
Which vitamins are fat soluble?
A, D, E, K
Fibre is essential for what?
Normal functioning of the GI tract – low intake associated with constipation and bowel cancer, high levels reduce cholesterol and risk of diabetes
Outline RNI, EAR, LRNI
RNI: reference nutrient intake (meets needs of 97.5%, may need less),
EAR: estimated average requirement (~50%),
LRNI: lower reference nutrient intake (2.5%, majority need more)
What is the male and female daily energy expenditure?
70kg M = 12,000kJ/day,
58kg F = 9,500kJ/day
The daily energy expenditure is the sum of?
Basal metabolic rate + diet-induced thermogenesis + physical activity level
What does basal metabolic rate maintain?
Resting activities of the body: maintenance of cells, functions of organs, body temp
Where are the energy stored in the body?
Short term in muscle, immediate use in carb stores, long term stores in adipose
Obesity BMI is?
> 30
How is BMI measured?
Weight (kg) / height squared (m)
What is an alternative measurement to BMI?
Waist/hip ratio
Underweight BMI is?
<18.5
Desirable weight BMI is?
18.5-24.5
Overweight BMI is?
25-29.9
Severely obese BMI is?
> 35
What does evidence regarding fat distribution show?
Greater proportion of upper body fat rather than fat on the hips is associated with: insulin res, T2DM, hypertension, stroke, hyperlipidaemia
What is kwashiorkor?
Low protein intake, low circulating protein = decreased plasma oncotic pressure = oedema
What role does fibre play in the diet?
We are unable to break the bonds present between glucose-beta chain in fiber, it gives structure to faeces so that it can be pushed through
What is sucrose made up of?
Glucose-fructose
What is lactose made up of?
Glucose-galactose
What carb is a sourse of dietary fibre?
Cellulose
List 3 main components of the diet that can be metabolised for energy
Carb, lipid, protein
