Nutrition & Metabolism Flashcards
What is the difference between catabolism and anabolism? Define each process.
ANABOLISM = uses energy, reducing power, and raw materials to make molecules for growth and maintenance.
Reductive: H+ + e- used —–> oxidising power
CATABOLISM = breaks down molecules to release energy and reducing power to produce smaller molecules
Oxidative: H+ + e- released —–> reducing power
Define metabolism.
The processes which derive energy and raw materials from food stuffs, and use them to support repair, growth, and activity of the tissues of the body.
Contrast exergonic & endergonic reactions.
EXERGONIC = more energy released than used (Gibbs = negative)
ENDERGONIC = more energy used than released (Gibbs = positive)
What components are needed for nutrition, and why?
CARBOHYDRATES = used as energy or stored PROTEIN = energy & essential amino acids (some "stored" as muscle) LIPIDS = used as energy & essential fatty acids or stored VITAMINS = facilitate metabolic reactions (cofactors) MINERALS = cofactors FIBRE = healthy GI function (increased s.a. for absorption & provides site for digestive enzymes) WATER = medium for chemical reactions
Why do we need “essential” amino acids & lipids?
Essential chemicals cannot be synthesised by humans and so need to be consumed in food.
Essential amino acids are needed for biosynthetic processes e.g. phenylalanine is required for neurotransmitter synthesis
Essential fatty acids are polyunsaturated, as we cannot insert a C double bond after a certain carbon no.
List the essential amino acids, and those that may become essential under certain circumstances.
ESSENTIAL =
Lysine Threonine Phenylalanine
Isoleucine Valine Methionine (-S)
Leucine Tryptophan
MAY BECOME ESSENTIAL =
Histidine Arginine
Tyrosine Cysteine (-S)
What is the definition of body mass index? How do you calculate body mass index?
Simple calculation for the desirable body weight.
weight (kg)/height (m^2)
What is the definition of obesity?
BMI: 30-34.9+
What are the values of the BMI chart?
Underweight = < 18.5 Normal = 18.5 - 24.9 Overweight = 25.0 - 29.9 Obese = 30.0 - 34.9 Morbidly obese = > 35.0
Define the recommended daily allowance (RDA). What does it depend on?
Average amount needed per day to maintain good health.
Depends on age, sex, physical activity, pregnancy
Define the reference nutrient intake.
Amount enough for 97%+ of the population
What determines how much energy is required by an individual?
- Basal metabolic rate
- Voluntary physical activity
- Processing of consumed food
Define the basal metabolic rate? What activities are maintained by the BMR? What factors affect the BMR?
Amount of energy used daily at rest.
Activities maintained:
- cell maintenance (ion transport)
- organ functions e.g. skeletal muscle, liver, brain, heart
- thermoregulation
Factors affecting the BMR:
- Factors affecting body temp. inc. fever, environmental temp.
- Gender (male BMR > female BMR)
- Body surface area
- Endocrine status e.g. thyroid hormones, reproductive hormones
What is the definition of homeostasis? What is regulated by homeostasis?
Dynamic equilibrium which counteracts changes in the internal environment in order to maintain conditions within a range of values.
- supply of nutrients
- supply of oxygen
- blood flow
- body temp.
- removal of waster & CO2
- blood pH
- intracellular calcium -> muscle contraction
Why do cells need a continuous supply of energy?
Energy is needed to carry out essential cell processes e.g.: - exo/endocytosis - active transport - DNA/RNA replication - ion gradient regulation - nerve stimulation - anabolic processes etc.
