MEH 1.1 Flashcards
List the fuel molecules that can be used by cells.
- Glucose
- Fatty acids
- Amino acids
- Ketone bodies
- Lactate
- Glycerol
- Alcohol
An obese individual is considered to have a BMI of _________.
Equal or more than 30
What molecule acts as a small store of free energy in muscle cells?
Creatine phosphate
How does creatine phosophate act as an energy store in muscle cells?
When ATP concentration is high, it is used to synthesise creatine phosphate from creatine. When ATP falls again, it can be regenerated by the reverse reaction.
When is the creatine phosphate store in skeletal muscle particularly important?
During the first few seconds of vigorous muscle activity, such as sprinting.
Is catabolism oxidative or reductive?
Oxidative ( NAD -> NADH)
Which molecules class as ‘high-energy’ signals?
ATP
NADH
What molecules are ‘low energy’ signals and what effect do they have in the cell?
ADP
AMP
NAD+
They increase catabolism by signalling to the cell that is had inadequate energy levels.
What is catabolism?
The metabolic breakdown of larger molecules into smaller ones.
Obesity is a risk factor for which conditions ?
Type 2 diabetes Hypertension CHD Gall bladder disease Osteoarthritis Cancer
What s the average daily energy expenditure of a 70kg adult male?
12,000 kJ
What is the average daily expenditure of a 58kg adult female?
9500 kJ
Define the components of your daily average expenditure.
- Basal metabolic rate
- Physical activity
- Energy to process food
Outline why CNS and cardiac muscle is more affected by cardiac arrest than skeletal muscle.
Cardiac muscle and CNS do not contain significant stores of fuel or oxygen.
They also have very limited capacity for anaerobic respiration.
Require constant supply of fuel and oxygen.
Define energy.
The capacity to do work.
What type of energy do cells use?
Chemical bond energy
Compare and contrast exergonic and endergonic.
Exergonic - when the energy released is greater than the energy input
Endergonic - when the energy input is greater than the energy released
What process releases chemical bond energy in fuel molecules?
Oxidation
Most of our energy comes from the oxidation of ________.
Lipids
Carbohydrates
Protein
(Alcohol)
Converts ADP to ATP and releases Co2, H20 and heat.
What are the 3 components of daily energy expenditure?
- Maintaining BMR
- Voluntary physical activity
- Energy to process food we eat (diet-induced thermogenesis)
What is basal metabolic rate?
The basal level of energy required to maintain life,at physical, digestive and emotional rest.
How can BMR be calculated in non-obese individuals?
BMR = 100 x weight in kg
What 3 things increase BMR?
- Hyperthyroidism
- Pregnancy
- Lactation
BMR is controlled by __________ hormones.
thyroid
What components of the diet are used to yield energy?
Mainly carbohydrates and fats
Can metabolise proteins and alcohol to produce energy.
Why is there no absolute requirement for glucose in the diet?
Body can synthesise own via gluconeogenesis from amino acids + glycerol (from TAG breakdown)
Why are fats important in the diet?
- Much higher yield of energy than carbohydrates (2.2x)
- Absorption of fat soluble vitamins from the gut (A,D,E and K)
- Provides essential fatty acids (e.g linoleic and linolenic acids) used for cell membrane structure.
Why are proteins are important component of the diet?
- Amino acids used for protein synthesis
2. Synthesis of N-containing compounds - purines, pyrimidines, haem, creatine
How much protein should the average 70kg male intake in order to maintain zero nitrogen balance?
35g
Which patients might have a positive nitrogen balance?
Growing children and pregnant women as they need to intake more than is lost.
What are the 9 essential amino acids?
Isoleucine Lysine Threonine Histidine Leucine Methionine Phenylalanine Tryptophan Valine (If learned, this huge list may prove truly valuable)
What is the function for fibre in the diet?
Indigestible fibre (e.g cellulose) is required to maintain GI function.
Certain amino acids are conditionally essential, explain what this means with an example.
Children and pregnant women have a higher rate of protein synthesis, so may also require arginine, tyrosine and cysteine in the diet.
Describe the structure of glucose.
Hexose sugar (6 carbons). Monosaccharide
How can BMI be calculated?
BMI = weight (kg)/ height squared (m ^2)
A BMI of below _________ is underweight.
18.5
What is the desirable range of BMI values?
18.5 - 24.9
What BMI values are overweight?
25-29.9
What BMI values are classed as obese?
30 - 34.9
A BMI of over ________ is classified as severely obese.
35
Excess body fat is associated with increased risk of which diseases?
Hypertension Heart disease Stoke Type 2 diabetes Certain cancers Osteoarthritis Gall bladder disease
Name 2 malabsorption conditions and explain how they may lead to malnutrition.
Coeliac disease and Crohn’s disease.
Failure to digest or absorb ingested nutrients.
What condition is common in developing countries with low availability of food?
Protein-energy malnutrition
What is marasmus ?
Type of protein-energy malnutrition.
Common in children <5.
Signs of muscle wasting and loss of body fat. No eodema.
Thin, dry hair, diarrhoea and anaemia.
What is kwashiorkor?
Typically young child.
Diet with some carbs but very low protein.
Apathetic, lethargic, anorexic (lost appetite).
Generalised Oedema.
Abdomen distended due to hepatomegaly and ascites.
Serum albumin low, anaemia.
Why is ascites a feature of kwashiorkor?
Insufficient amino acids for the liver to make a normal level of albumin, decreased ONCOTIC pressure.
(Starlings law)
Why are minerals an important dietary component?
- Electrolytes establish ion gradients across membranes and maintain water balance
- Calcium and phosphorus essential for structure (bones and teeth)
- Calcium is a very important signalling molecule
- Enzyme co-factors e.g manganese
- Iron essential component of haemoglobin
Which 3 electrolytes are the most important for cell maintenance?
Na+, K+, Cl-
Name the diseases associated with deficiencies in vitamins A,D,E and K.
A = xerophthalmia D = rickets E = neurological abnormalities K = defective clotting
Why is cellulose non-digestible by humans?
Polymer of glucose but it contains beta 1-4 linkages, humans don’t produce enzymes which can break these bonds.
What are the benefits associated with high fibre diet?
Decreased cholesterol - sequesters bile salts, so liver uses up cholesterol to make more
Reduced diabetes risk
What factors affect BMR?
Body size Gender (males> females) Environmental temp Body temp Endocrine status (hyperthyroidism)
What is the normal fasting plasma cholesterol?
< 5 mmol/L
What monosaccharides make up sucrose?
Glucose- fructose
Which monosaccharides are components of lactose?
galactose and glucose
Which 3 dietary carbohydrates are glucose polymers?
Starch
Glycogen
Cellulose
The daily excretion of creatinine can be used as an indicator of what?
Skeletal muscle mass
Increased secretion may indicate active muscle wasting.
Measurements of creatinine concentrations in the blood and urine can be used as an indicator of what?
Kidney function.
Kidney normally very efficient at removing creatinine from blood. Abnormally high blood creatinine and low urinary creatinine indicated reduced kidney function.
What anabolism?
Anabolism is the building up of larger molecules from smaller ones, requiring energ
What is catabolism?
Catabolism is the breakdown of larger molecules into smaller ones, releasing energy (oxidative).
