2. Proteins are molecular machines, building
blocks and arms of a living cell.
Proteins are built up of amino-acids
Proteins have the greatest importance in
human nutrition, they are composed of
carbon, hydrogen, oxygen, nitrogen and
sulphur in varying amounts.
3. Amino-acids are organic compounds that
combine to form proteins.
Amino-acids and proteins are the building
blocks of life
When proteins are digested or broke down,
amino-acids are left. The human body uses
amino acids to make proteins to help the
body:
1. Break down
2. Grow
3. Repair body tissues
4. Perform many other body functions
5. They are called as essential amino-acids because the body
can-not synthesize them.
Essential amino-acids cannot be made by the body, they
must come from the food.
The 9 essential amino-acids are
1. Histidine
2. Isoleucine
3. Leucine
4. Lysine
5. Methionine
6. Phenylalanine
7. Threonine
8. Tryptophan
9. Valine
6. These are called as Nonessential amino-acids because
they are synthesized by the body.
Nonessential means that our bodies produce an amino
acid, even if we do not get it from the food we eat
Nonessential amino-acids include:
1. Alanine
2. Arginine
3. Asparagine
4. Aspartic acid
5. Cysteine
6. Glutamic acid
7. Glutamine
8. Glycine
9. Proline
10. Serine
11. tyrosine
7. Conditional amino-acids are usually not
essential, except in times of illness and stress.
Conditional amino-acids include:
1. Arginine
2. Cysteine
3. Glutamine
4. Tyrosine
5. Glycine
6. Ornithine
7. Proline
8. Serine
8. There are two main sources of proteins
1. Animal source
2. Plant source
9. Proteins of animal origin are found in meat,
eggs, fish, milk, cheese etc
Animal protein contain all the essential
amino-acids in adequate amounts, these are
called as first class proteins
10. Proteins of plant origin are found in pulses,
beans, nuts, oil-seeds, cakes, cereals, they
are poor in essential amino-acids
11. The Indian council of medical research(ICMR)
in 1985 recommended 1.0 gram protein per
kg BW for an Indian adult.
12. 1. For growth and development:- proteins
furnish the body building material that is
the amino-acids from which the body
proteins are synthesized
2. For repair of body tissues and their
maintenance:- it has been shown that
the body proteins are being constantly
broke down they have to be repaired for
which fresh protein intake is required.
3. Bolsters immune system
4. Transports and stores nutrients
5. Provides energy
13. 1. Still birth, low birth and anaemia
2. During infancy and early child hood,
Marasmus, Kwashiorkor, metal-retardation
etc
3. Adults:- loss of weight, poor musculature,
anaemia, increased susceptibility of
infection
4. General lethargy, cirrhosis of liver, oedema,
delay of wound healing.