Flashcards in Met 1 - Energy production Deck (99)
The breakdown of molecules to release energy
Breakdown of molecules via oxidation produces:
Uses energy and raw materials to make larger molecules for growth and maintenance
How many kJ are released per gram of carbohydrate?
~ 17 kJ/g
Name the 5 dietary carbohydrates:
What is the normal range of fasting blood glucose in mM?
~ 3.3-6 mM
What are the 7 essential components of our diet?
Approx. how many grams of protein should we consume per day?
~ 35 g/day
Name the 9 essential amino acids:
How many amino acids are 'essential'?
Name a 'complete protein', which contains all the essential amino acids:
- Dairy (Milk/yoghurt/whey)
- Hemp seeds
- Chia seeds
How many of the 22 amino acids required, can be synthesised by the body?
13 amino acids
Which vitamins are fat soluble?
Vitamins A, D, E and K
How many kJ are released per gram of protein?
~ 17 kJ/g
How many kJ are released per gram of fat?
~ 37 kJ/g
Name the 2 essential fatty acids:
1) alpha-Linoleic acid
2) Linolenic acid
Which 2 vitamins have antioxidant roles?
1) Vitamin C
2) Vitamin E
Which vitamins require fats to be absorbed?
Vitamins A, D, E and K
What percentage of an Adults body weight is water?
~ 50-60 %
What is the average water loss from your body per day?
~ 2.5 L/day
How is water lost from the body?
- Expelled air
How many grams of fiber should be ingested per day?
~ 18 g/day
Approx. how many liters of water should be ingested per day?
~ 2-3 L
Why is cellulose non-digestable (fibre)?
Humans do not possess an enzyme to break the beta-1,4-glycosidic bonds
How does fibre increase metabolism of food in the GI tract?
It increases the SA of the gut to which substrates can bind, increasing the chance of enzymes finding them = food digested quicker.
A low fiber diet is a risk factor for which type of cancer?
Daily Energy Expenditure is the sum of :
1- Basal Metabolic Rate
2- Diet-Induced Thermogenesis
3- Physical activity level
What is 'diet-induced thermogenesis'?
The energy required to digest food (~10% of energy content of ingested food)
What is the recommended intake of a 70kg man doing moderate exercise per day in kJ?
~ 12,000 kJ/day
What is the recommended intake of a 58 kg woman doing moderate exercise per day in kJ?
~ 9,500 kJ/day
How is Basal Metabolic Rate calculated?
weight in kg x 100 = kJ/day
Why is a woman's BMR less than a man?
Women have more adipose tissue than men, which is less metabolically active, so less energy expended.
What is the average BMR of a 70kg man in kJ/day?
~ 7000 kJ/day
What is the avergae BMR of a 58kg woman in kJ/day?
~ 5800 kJ/day
How is BMI calculated?
(weight in kg) / (height in m)^2 = kg/m^2
What is the range of a healthy BMI?
18.5 - 24.9 kg/m^2
A man is classified as overweight. What range must his BMI lie within?
25 - 29.9 kg/m^2
A woman is classified as obese. What range must her BMI lie within?
30 - 34.9 kg/m^2
Severely obese is a BMI over what value?
Why is total starvation not a preferred method of weight loss?
Total starvation increases protein metabolism, decreasing amount of lean tissue, and causes fats to be broken down into ketone bodies which disrupts pH
What is the main disadvantage of using BMI to estimate health?
BMI may wrongly classify a muscular individual as overweight/obese
What ratio can be used as an alternative to BMI?
Which body shape has a higher risk of disease and death: apple or pear?
Apple: Fat distribution on torso carries a higher risk.
What name describes protein-energy malnutrition?
What is the classic presentation of someone suffering from marasmus?
What name describes protein malnutrition?
What is the classic presentation of Kwashiorkor?
Thin discoloured hair
Ascites (distended abdomen)
Large fatty liver
Why is kwashiorkor common in children after they have been weaned off breast milk? (in underdeveloped countries)
Breast milk contains protein and essential amino acids, keeping the child healthy.
Breast milk is then often replaced with diet high in carbohydrates, but protein deficient.
What causes the large fatty liver seen in patients with Kwashiorkor?
- Apolipoproteins cannot be synthesised
- vLDLs cannot be synthesised
- Lipid synthesised by liver cannot be exported to adipose
What 4 forces contribute to Starling's Law of the Capillary?
1) Hydrostatic pressure of the capillary
2) Hydrostatic pressure of the tissue fluid
3) Plasma oncotic pressure
4) Interstitial oncotic pressure
The maintenance of a stable internal environment, via a dynamic equilibrium
Which groups of people does the EatWell plate NOT apply to?
- Children under 2yrs
According to the EatWell plate, what percentage of our intake should be:
- High in fat/sugar foods
Bread/Rice/Pasta = ~ 33%
Fruit/Vegetables = ~ 33%
Dairy = ~ 15%
Meat/Fish/Eggs/Beans = ~ 12%
High in fat/sugar foods = ~ 8%
Which is the only cell type which doesn't synthesis cell components?
Red Blood Cells
Which tissue types allow storage of nutrients?
Which tissue types allow the interconversion of nutrients?
Is Catabolism oxidative or reductive?
Oxidative (releases H+)
Is Anabolism oxidative or reductive?
Reductive (Uses H+)
Name the 5 types of cell work which requires energy:
- Mechanical work
- Biosynthetic work
- Transport work
- Electrical work
- Osmotic work
Approx. how long can the body survive with only water intake?
~ 20-70 days, depends on energy stores
Via which mechanism is ATP synthesised DIRECTLY?
Via which mechanism is ATP synthesised INDIRECTLY?
How much energy (in kJ/mol) is released when ATP ---> ADP + Pi?
~ 37 kJ/mol
Why is ATP a carrier of energy, not a store?
Due to limited amount of ATP and ADP in a cell, they must be constantly recycled
Which reaction does Creatine Kinase catalyse?
Creatine + ATP ---> Creatine Phosphate + ADP
What molecule is used as a store of energy in cardiac/skeletal muscle, which provides instant energy for sprinting?
How much energy is released from 1 mole of Creatine Phosphate? (kJ/mol)
~ 43 kJ/mol
How much energy is released from 1 mole of Phosphoenolpyruvate (+ ADP ---> Pyruvate + ATP)
~ 62 kJ/mol
How much energy is released from 1,3-Bisphosphoglycerate (+ADP ---> 3-Phosphoglycerate + ATP)
~ 49 kJ/mol
Name the main 4 high energy molecules containing phosphate groups:
2) Creatine phosphate
What marker is used as an indicator of skeletal muscle wasting and/or kidney function?
Skeletal muscle wasting would increase excretion of Creatinine. Why?
Skeletal muscle contain Creatine and Creatine Phosphate, which are released when these cells die. They can both form Creatinine non-enzymatically = increased excretion.
Working at 95% effort for 10 secs would cause skeletal muscle cells to use what substrates for energy?
- Creatine kinase
Working at 95% effort for 10 mins would cause skeletal muscle cells to use what substrates for energy?
- Muscle glycogen
- Fatty acids
What is the general formula of carbohydrates?
Why are carbohydrates hydrophilic?
Contain multiple -OH groups (attract H2O)
What word is used to describe a single sugar unit?
How many C atoms does a monosaccharide contain?
~ 3-9 C atoms
What is the naturally occurring form of monosaccharides?
What can't carbohydrates passively cross a cell membrane?
Why do carbohydrates require less O2 for complete oxidation compared to fatty acids?
Carbohydrates are already partially oxidised
What is a disaccharide?
2 sugar units connected via a glycosidic bond
What sugar units form Maltose?
2 x Glucose units
What sugar units for Galactose?
Glucose + Galactose
What sugar units form Fructose?
Glucose + Sucrose
Name the highly branched polymer of glucose mainly found in mammals:
In which tissues is Glycogen (mainly) stored?
Which bonds does Glycogen contain?
Which polymers of Glucose are mainly found in plants?
When Starch is hydrolysed in the GI tract, what molecules are released?
Glucose + Maltose
Which bonds does Starch contain?
When Glycogen is hydrolysed in the GI tract, what molecule(s) are released?
Which bonds does Cellulose contain?
Which polysaccharide is not digestable by humans?
Which enzymes are required for the hydrolysis of dietary polysaccharides?
Glycosidase enzymes ie:
- Salivary amylase
- Pancreatic amylase
Which bonds are cleaved by Amylase enzymes?
Where in the GI tract are the enzymes which hydrolyse dietary disaccharides?
Brush border of epithelial cells, lining the Duodenum and Jejunum
Which enzymes are required for the hydrolysis of dietary disaccharides?
Glycosidase enzymes ie: