Metabolism L1.1 Flashcards
Describe metabolism
Chemical reactions which mainytain the living state of cells in our body
Reactions allow extraction of chemical energy from food to carry out diverse fucntions + biosynthesis of all molecules essential to maintain life
Whole body metabolism = Refers to mebaolic processes in organism
Cell metabolism = Refers to chemical reactions inc cells
Describe the different pathways involved in metabolism
- Degradative pathways: Convert food to energy
- Biosynthetic pathways: Produce structural + functional cell components
- Fuel storage + mobilisation pathways: Allow fuel to be stored + mobilised when we are not eating / need to increase energy
- Detoxification pathways: remove toxins
Define catabolism
Break down of larger molecules into samller molecules to release energy
Define anabolism
Using energy (from catabolism) to synthesise larger molecules from smaller ones
Diagram showing how energy is extracted from food
State the two groups of nutrients
- Macronutrients
- Micronutrients
State exampless of macronutrients
- Carbs - energy
- Proteins - energy + amino acids
- Fats - energy + fatty acids
State examples of micronutrients
- Vitamins + minerals
- Water - hydration, digestion, temp regulation
- Dietry fibre (type of carb, does not provide energy) - necessary for normal function of GI tract
9 essential amino acids (do not need to memorise at the moment)
Proteins of animal origin = high quality (becasue contain all essential amino acids)
Proetins of plant origin = low quality (deficient in 1/more essential amino acid) (thats why veg diet needs to have proteins from wide variety of sources)
State the most common class of dietry fats
Triacylglycerols (TGs)
Where are TGs stored in humans?
Adipose tissue
What are the products of digestion of TGs
- Fatty acids
- Glycerol
State uses of fatty acids in body
Most important: Omega 6 (linoleic) and omega 3 (a-linolenic), cannot be synthesised in body, need to come from diet. ESSENTIAL
- Structural components of cell membranes
- Precursors of eicosanoids (regulatory molecules)
- Required for absorptuon of fat-soluble vitamins (A,D,E,K) from gut
State risks of high fat intake
- Weight gain
- Insulin resistance
- Non-alcoholic liver disease
- Heart disease
- Colorectal cancer
Describe different types of fatty acids
- Saturated (with C-C): Dairy, meat, veg, oils. High intake leads to cholestrol levels rising, risk of heart disease
- Unsaturated (C=C cis): Plant=based, fish oils, nuts e.g. Oleic. Good for brain + heart
- Unsaturated (C=C trans): Partially hydrogenated oils, readt-made cookies, deep fried foods e.g. elaidic. High intake leads to heart disease
State the use of dietry fibre
Carb, not broken down by human digestive enzymes
- Essential for optimal use of GI tract
Describe types of dietry fibre
- Soluble (oats, fruits, veg): pecrin + gums - help lowering cholestrol
- Insuluble (whole grains, veg): lignin, cellulose. HUMANS DO NOT HAVE DIGESTIVE ENZYMES TO BREAK B-1,4 LINKAGES IN CELLULOSE. add bulk to stool, promoting bowel movements
State risk factors of low fibre intake
Constipation + bowl cancer
State risk factors of high fibre intake
Reduce cholestrol, risk of diabetes
State recommended intake of dietry fibre for adults daily
30g
Are Vitamins Fat / Water soluble?
Yes
Fat soluble vitamins
DO NOT NEED TO MEMORISE
Xeropthalima - very dry eyes
WATER SOLUBLE VITAMINS
Scurvy - saw, bleeding, gums
State important minerals
- Electrolytes (Establish ion gradients across membranes, maintain water balance)
- Calcium + phosphorus (structure of bone + teeth)
- Calcium (signalling)
- Minerals are Enzyme co-factors (iron, magnesium, manganese, copper, zinc, molybdenum)
- Iron - essential component of haemoglobin
- Iodine - thyroid hormone synthesis
Catabolic
Carbs, proteins, fats
ADEK
What factors affect dietary reference values (DRVs)?
- Age
- Gender
- Growth
- Physical activity
(asses intake of nutriantes to prevent deficiencies)
State types of DRVs
Describe daily energy expenditure
Total energy expended by individual in day.
Sum of:
- Basal metabolic rate (BMR)
- Diet induced thermogenesis (DIT)
- Physical activity level (PAL)
Define basal metabolic rate
Energy required during physical, digestive, emotinal rest at 18 degrees celcius. Sum of all tissues in body
MAINTAINS RESTING ACTIVITIES OF BODY
- functions of cells
- ion transport across membranes
- biochemical reactions
FUNCTIONS OF ORGANS
BODY TEMP
Describe energy utilisation in the body
Basal metabolic rateL energy used in physical, digestive + emotional rest at 19 degrees celcius. Sum of all tissues in body
Physical activity (muscular work)
Specific dynamic action of food: energy used in ingestion, digestion, absorption of heat
Energy lost as heat
State factors affecting BMR
Describe the balance between energy and body weight
State the formula for BMI
Body Mass Index
Define BMI
Evaluates healthy weight in relation to height
State two considerations when measuring BMI
(height measured without shoes, weight in minimal clothing)
Describe the correlation between BMI and overall body fat
Positive correlation
However, very muscular individuals wrongly classified as obese
Define WHR (waist-to-hip-ratio)
Measures fat distrobution around abdomen + hips
This is fat around central area
Fat around central area = more metabolically active
This can lead to hyperinsulinemia
Describe the risks of a greater proportion of fat in upper body (abdomen) compared to hips
Only Question 2
- Energy lost as heat / diet induced thermogenesis
- Physical activity (muscular work)
- Specific dynamic action of food: energy used in ingestion, digestion, absorption of heat
- Basal metabolic rateL energy used in physical, digestive + emotional rest at 19 degrees celcius. Sum of all tissues in body
State causes and risk factors of obesity
Cause: excess energy intake, reduced physical activity, reduced sleep, genetics, medications, diseases
Risk factors: Diabetes, cardiovascular diseases, cancers
State causes and risk factors of malnutrition
Diet not providing righht amounts of nutrients / energy
Describe causes and risk factors of Kwashiorkor
Cause: protein deprivation is greater than total energy intake
(very low protein intake), they may be having energy from other sources, but so protein deprived
Presents with Oedema (swelling), stunted growth, decreased fat, muscle mass, hepatomegaly (enlraged liver), anaemia
Describe causes and risk factors of marasmus
Cause:
Calorie deprivation greater than reduction in protein intake (INADEQUATE ENERGY IN ALL FORMS, protein and calories)
Presents with stunded growth, extreme muscle wasting, loss of fat, anaemia
DOES NOT PRESENT WITH OEDEMA
How can we distinguish between kwashiorkor and marasmus
Marusmus does not present with oedema (as there is some protein in diet)
Describe the use of MUST (Malnutrition Universal Screening Tool)
Evidenbce based tool used to screen malnutrition
5 steps. Identifies malnutrition in adults
