Protein Flashcards
Protein functions
Make up a large portion of muscles
Hormones and enzymes are both proteins
Secondary source of energy
Sources from food
Red meat
Eggs
Shellfish
Dairy
Beans and pulses
Deficiency of protein (kwashiorkor)
Wrinkled face
Impaired immune defence system
Growth failure
Muscles wasting
Hunger oedema
Deficiency marasmus
Otherwise known as wasting - mostly affects babies under 1 year old
Body uses muscles as a food source, energy just supplied to vital organs. Child becomes weak ans will eventually die
Excess protein
A diet rich in protein, saturated fat and cholesterol raises harmful LDL cholesterol levels.
Increases the risk of coronary heart disease, diabetes, stroke and several types of cancer.
Can put strain on kidneys
You may miss out on other essential nutrients by focusing on a protein rich diet
Non essential amino acids
Made by the body
Not needed to obtain from food
Essential amino acids
Not made by body
Need obtaining from food
Adults require 8
Two include leucine and isoleucine
Children need 10 - histidine and arginine
Biological value
Animal foods - all of the essential amino acids = high biological value
Plant foods - only some of amino acids - low biological value
HBV sources
Red meat, eggs, dairy, shellfish, soy milk, tofu, quinoa
LBV
Beans and pulses, peas, nuts, baked beans
Complementary proteins
When two LBV protein foods are eaten together and become a HBV source of protein
Chemical composition of amino acid
H. H. O
/. /. /
H - N - C - C - OH
/
R
Simplest amino acid = glycine
COOH
/
H2N - C - H
/
H
Dipeptide
2 amino acids join together through a peptide bond and condensation reaction
Condensation reaction
When amino acid and acidic group join and release water
Polypeptide bond
Many amino acids join together to form a polypeptide
Structure of proteins
Primary - sequence of a chain of amino acids
Secondary protein structure - local folding of the polypeptide chain into helices or sheets
Tertiary protein structure - three dimensional folding pattern of a protein due to side chain interactions
Quaternary protein structure - protein consisting of more than one amino acid chain
