HAFIZA MADIHA JAFFAR

2. PROTEINS
Presented By: Ms. Hafiza Madiha Jaffar
Clinical Nutritionist

3. INTRODUCTION
• Protein name is derived form a Greek
word PROTOS which means “the first or
the supreme.
• Protein are extremely complicated and
nitrogenous molecule made up of variable
number of amino acid residue joined to
each other by a specific covalent bond
called peptide bond.

4. PROTEINS
o any of a class of nitrogenous organic
compounds which have large molecules
composed of one or more long chains of
amino acids and are an essential part of all
living organisms, especially as structural
components of body tissues such as muscle,
hair, etc., and as enzymes and antibodies.
o Proteins are natural polymer of amino acids.
o Protein molecules contain Nitrogen, Carbon,
Hydrogen and Oxygen.

5. • 300 different amino acids occur in nature –
only 20 as standard amino acids.
• Proteinsare large molecule that may
• consist of hundred or even thousand of
amino acids
• Amino Acid • It’s a group of organic
compounds containing two functional groups
– amino (- NH2) and carboxyl group (-
COOH)

6. PEPTIDE BOND
O When 2 amino acids bond together a peptide
bond is created
O Protein are also called polypeptides because
they contain many peptide bonds

8. AMINOACIDS
OProtein in food is just a source of amino
acids.

9. TYPES OF AMINOACIDS
There are following two types of amino acids
1. Essential Amino acids
2. Non-Essential AminoAcids

10. ESSENTIALAMINO ACIDS
OAmino acids that cannot be made in the
body are called essential amino acids.

11. NAMES OF ESSENTIAL
AMINO ACIDS
1. Histidine 4. Isoleucine 7.Leucine
2. Lysine 5. Methionine 8. Phenylalanine
3. Threonine 6. Tryptophan 9. Valine

12. NON-ESSENTIALAMINO
ACIDS
Amino acids that can be made in the
body are called non-essential amino
acids; include alanine, arginine, asparagine, aspartic acid,
cysteine, glutamic acid, glutamine, glycine, proline, serine,
and tyrosine.

13. CLASSIFICATION
O Proteins are classified according to the types
and amounts of essential amino acid present in
their molecules
1. Complete
2. Partially Complete
3. Incomplete

14. COMPLETE PROTEIN
OContain all essential amino acids according to
the needs of the body
SOURCES:
O Meat
O Milk
O Cheese
O Fish

15. PARTIALLY COMPLETE
O Have one or more than one amino acids present
in insufficient amount according to the needs of
the body.
SOURCES:
Cereals
Legumes
Nuts
Beans

16. INCOMPLETE PROTEIN
OTotally lack one or more than one amino acids
in their molecule
EXAMPLE:
Gelatin

17. FUNCTIONS
1. Proteins are the building blocks of the cells
and tissues in the body and are used for building
and maintenance of tissues.

18. 2. Different types of proteins help in regulating
various body processes such as:
OEnzymes are protein in nature and regulate all
metabolic functions in the cells.
OProtein in plasma help maintain fluid balance
in the body

19. protein which provideO Antibodies are also
immunity to the body
cells
OHormones such as insulin are protein
O Hemoglobin, a protein in red blood
carries oxygen to the cells

20. 3. Protein also provide energy to the body. One
gram of proteins provides 4 kcal.

21. SOURCES
O Milk
O Meat
O Fish
O Cheese
O Eggs

22. O Pulses
O Cereals
O Nuts
OVegetables
O Fruits