Protein Flashcards
Elements in protein
Carbon
Hydrogen
Oxygen
Nitrogen
What element in protein is not in others? Why?
Nitrogen for growth
How are amnino acids joined?
Peptide links
What’s a chain of amino acids called
Peptide chain
What are essential amino acids
Amnino Acids which must be obtained from food as they cannot be produced in the body
What are non essential amino acids
Amino acids that can be produced in the body
What is condensation reaction
When peptide bonds form as amino acids join together
What’s the reverse of condensation reaction?
Hydrolysis
Occurs during digestion
What’s the primary structure of protein
Primary structure of protein is the sequence and number of amino acids in the chain
Eg insulin is 51 amino acids in a definite order
What’s the secondary structure of protein
Folding of a polypeptide chain onto another chain or itself causing a spiral shape
Spiralled proteins are called cross links
2 types disulfide and hydrogen bonds
Examples of cross links
Disulphide: two sulphurs join from the same or different polypeptide chains eg in cysteine
Hydrogen bonds: hydrogen from one chain joins with oxygen in a neighboring or same chain eg serine
Functions of cross links
Give protein their unique properties eg gluten in elasticy
Name all Essential Amino acids (10)
Phenylalanine Valine Threonine Tryptophan Isoleucine Methionine Leucine Lysine Histidine Arginine
Amino acids that are just for kids
Histidine
Arginine
Explain hydrolysis
During digestion a water molecule is added to peptide links causing a reverse to occur: broken into smaller, single amino acids which are more digestible and can be used in the body
Important protein in meat connective tissues
Collagen
Important protein in eggs
Albumin
Import at protein in wheat
Gluten
Animal Sources of protein
Cheese Chicken Meat Fish Eggs Milk
Plant source of protein
Soya beans TVP foods Nuts Lentils Peas Beans Cereals
Difference between HBV and LBV proteins
HBV contain all essential amino acids where as LBV only contain some
HBV are also known as complete proteins but LBV are known as incomplete
HBV come form animal sources and soya beans and LBV come from ponga sources and gelatine
RDA of protein
1 g for KG of body weight
Or
Extra during periods of radios growth eg kids and teenagers, pregnant women, Sick people
Digestion of protein
Mouth; food is chewed
Stomach; hydronic acid denatures protein
Enzyme rennin converts caseinogen to casein
Enzyme Pepsin converts proteins to peptones
Small intestine: enzyme trypsin from pancreas converts peptones into peptides
Enzyme peptidase from small intestine converts peptides to amino acids which are ready for absorption in the intestine
Where is protein absorbed?
Amino acids are absorbed Through the villi of the small intestine into blodstream to the liver
What is protein used for in the liver
Maintain and repair liver cells
Sent to bloodstream to form new cells, repair damaged cells, make hormones, enzymes, antibodies and blood proteins
Excess used for heat and energy
Chemical structures of amino acids
1 Hydrogen 1 carbon in middle 1 COOH (acidic carboxyl group) 1 NH2 (alkaline group) 1 R (variable)
How are peptide links formed
Acidic carboxyl group (COOH) of one amino acid reacts with an alkaline group (NH2) of another amino acid
This eliminates a water molecule in a process Called condensation
A CONH bond is formed with the remaining elements and a dipeptide link is formed
Tertiary structure of proteins
Secondary structure is condensed and compressed to make shapes, cross links form between proteins
Shapes in 3rd structure
Fibrous; straight, spiral,zigzag
Globular; spherical
Properties of fibrous structures
Elastic or non elastic
Insoluble in water
Polypeptide chains in straight, zigzag or spiral shape
Example of fibrous protein
Gluten
Properties of globular proteins
Easily denatured
Soluble in water
Polypeptide chains in sphere 3D shape