Metabolism Flashcards
(32 cards)
What are the essential components of the diet?
Carbohydrates, Fats, Proteins, Fibre, Vitamins, Minerals and Water
Why do we need fibre?
Because it is indigestible material that helps to maintain the normal functioning of the gastrointestinal tract.
What do living cells require energy for? (Name 5 things)
Biosynthetic work, Transport work, Mechanical work, Electrical work and Osmotic work.
What is calorie equivalent to?
4.184 Joules
True or false: When covalent bonds in reacting molecules are split, energy is released.
False. An input of energy is required to break these bonds.
Where is excess dietary fuel stored?
As fat in adipose tissue or as glycogen in liver and muscle.
In the ATP-ADP cycle, what combines with ADP to make ATP?
An inorganic phosphate.
Daily Energy Expenditure is made up of three components. What are these?
Energy to support our basal metabolism (BMR). Energy for voluntary physical activities. Energy required to process the food we eat (diet-induced thermogenesis)
What is BMR?
BMR is a measure of the basal energy required to maintain life (the functioning of tissues at rest).
What are the major tissues contributing to BMR and what percentage of the BMR do they make up?
Skeletal Muscle (30%), CNS (20%), Liver (20%) and Heart Muscle (10%).
How do you calculate a rough estimate of BMR (in kJ/24hr)?
BMR = 100 x weight in kg (Unless the individual is obese, in which case this is unlikely to give a good estimate).
Why is BMR lower for women than men (on average)?
Because women tend to have more adipose tissue than men of the same weight, and adipose tissue has a lower metabolic activity than lean tissue.
Name one condition that may increase BMR.
Hyperthyroidism.
How does voluntary activity increase our daily energy expenditure?
More voluntary physical activity increases the activity of skeletal muscle and heart muscle so the Daily Energy Expenditure will increase.
What is Diet Induced Thermogenesis?
The energy required to process the food we eat. It is approximately equal to 10% of the energy content of the injested food.
What is an RDA?
The recommended daily allowance of a type of nutrient for an average person (e.g. protein).
What is the energy content of a) Fat b) Carbohydrate c) Protein and d) Alcohol in kJ/g?
a) Fat = 37kJ/g
b) Carbohydrate = 17kJ/g
c) Protein = 17kJ/g
d) Alcohol = 27kJ/g
In a typical western diet, how much energy is derived from fat?
45% of our energy requirement
Which two types of tissues need a constant supply of glucose?
Brain and Red Blood Cells
Why are fats important to the diet?
They have an energy yield 2.2 times greater than carbohydrates or proteins.
Fat is necessary for the absorption of vitamins A,D, E and K from the gut.
Certain fatty acids cannot be synthesised in the diet and so must be consumed (linoleic and linolenic acids).
Why do we require proteins?
Proteins break down to form amino acids. These are very important in the synthesis of creatine, purines, pyrimidines and the haem part of haemoglobin.
How do we dispose of the nitrogen of degraded amino acids?
It is excreted in the urine as urea.
What is the average daily requirement of protein in an adult male?
Approximately 55g
What is the average daily requirement of carbohydrate in an adult male?
Approximately 300g
