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Proteins are vital to
any living organism. They are the important
constituent of tissues and cells of our body. They form an important component of muscles and other tissues and vital
body fluids like blood.
Proteins in the
form of enzymes and hormones are concerned with a wide range
of vital metabolic processes in the body. They supply body
building material and make good the loss that occurs due to wear
and tear. As antibodies, they help in defending the body against
infection. Thus they are vital to living process and
carry out a wide range of functions essential for sustenance
of life. Proteins are classified as :
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- Simple proteins
e.g.
albumin, globulin, fibrous
proteins
- Conjugated proteins
e.g. nucleo-proteins,
haemoglobin.
- Derived proteins
e.g. coagulated proteins, peptones, peptide.
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Digestion and Absorption
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Site |
Enzymes |
Product |
Absorption |
Stomach |
Pepsin |
Polypeptide |
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Small intestine |
Chymotrypsin peptidase, trypsin |
Free amino acids |
Absorbed in small intestine. |
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Functions
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- Replaces daily loss of body proteins.
- Provides amino-acids for the formation of tissue proteins during
growth, formation of enzymes, blood proteins and certain hormones of protein nature.
- Provides amino acids for growth of foetus in pregnancy and for
production of milk proteins during lactation.
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Protein content of foods
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Foodstuff |
Protein content (g/ 100 g) |
Cereals and millets |
6 - 14 |
Pulses (legumes), dry |
18 - 24 |
Oilseeds and nuts (except coconut) |
18 - 40 |
Meat, fish and liver |
18 - 20 |
Eggs |
14 - 15 |
Milk (fresh) |
3.5 - 4.0 |
Milk, dried whole |
26 - 28 |
Milk, dried, skimmed |
33 - 38 |
Vegetables, fresh and leafy |
1 - 4 |
Roots and tubers |
1 - 1.5 |
Other vegetables |
1 - 7 |
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Protein Requirement
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Group |
Particulars |
Proteins (g) |
Man |
Sedentary work
Moderate work
Heavy work |
60 |
Woman |
Sedentary work
Moderate work
Heavy work |
50 |
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Pregnancy (0-6 months) |
65 |
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Lactation ( 0-6 months) |
75 |
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Lactation
( 6-12 months) |
68 |
Infants |
0-6 months |
2.3 - 1.8 |
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7-12 months |
1.8 - 1.1 |
Children |
1 year |
7 |
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2 years |
18 |
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3 years |
20 |
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4-6 years |
22 |
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7-9 years |
33 |
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10-12 Years |
55 |
Adolescents |
13-15 years (Boys) |
70 |
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13-15 years (Girls) |
65 |
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16-18 years (Boys) |
78 |
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16-18 years (Girls) |
63 |
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Disease due to Protein Malnutrition
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