Protein Flashcards
What is the main function of protein?
Proteins are important constituents of muscle, organs, glands, connective tissue, skin, hair and bone e.g skin firming creams/ hair strengthening shampoo. the protein is synthesised during growth, maintenance and is replaced during life to form a source of amino acids to draw in on during emergencies, but at the expense of the tissue it comes from
what is protein (dynamic/static), what does protein provide that no other nutrient provides?
Protein is not static, it is a dynamic constituent which means its in a continuous state of flux. protein is the only source of nitrogen which is an essential constituent of all living cells
Name the homeostatic functions of protein
- formation of enzymes - enzymes are instrumental in facilitating the chemical reactions in the body e.g digestion of nutrients, synthesis of chemical substances
- hormones, of which many contain amino acids. These act as messengers in the circulation e.g regulation of metabolic rate, regulation of blood glucose levels
- Antibodies, protein plays a key role in the function of the immune system and a deficiency could lead to a defective immune system.
- Acid - base balance - protein acts as buffers In the circulatory system, this helps to maintain a fairly constant PH in the blood and other fluids
could result in a deficient immune system
What is a secondary source of energy?
not all protein supplied by food will be of biological value to use for growth and repair, there may also be excess protein not needed for growth and repair. this excess protein can be used for energy and the amino acids not required are deaminated in the liver and the amino acids molecule containing nitrogen are removed to form urea - a waste product. The urea is carried in the blood to the kidneys in which it is excreted. the
deaminated molecules contain CHO and they enter a chain of reactions in which glucose is oxidised in the cells and energy is released.
1 gram of protein = 17kj or 4kcal of energy
what are the novel sources of protein?
- quorn
- textured vegetable protein
- tofu
what is the definition of an indispensable amino acid?
an indisponible amino acid cannot be synthesised by the body and must be provided through protein in the diet
8 for adults
10 for children
Whats the definition of a dispensable amino acid
A dispensable amino acid can be synthesised by the diet by converting one amino acid into another within the body cells
what is the definition of biological value
Biological value is a measure of protein quality - a measure of how effectively a protein can meet the bodys biological needs
What is the equation for biological value
BV = retained nitrogen/absorbed nitrogen x100
what us the protein complementation equation.
LBV + LBV = HBV
what meals are specified as protein complication and what are key words?
Beans and toast, lentil soup and bread
key words: limiting and in excess
limiting amino acid is lysing
this achieves an overall balance showing protein complementation
What is the definition of the nitrogen balance
An overall indicator of protein metabolism is the nitrogen balance which is the difference between the nitrogen input and nitrogen output
what is a positive nb?
a positive nitrogen balance is when protein is being retained in the body indicating protein sysnthesis which is growth and major tissue repair e.g body building or pregnancy.
What is a negative nb?
A negative nitrogen balance is when protein is being depleted in the body and the losses exceed the intake e.g chronic illness or starvation
