• We get foods from plants. Green plants are the only source of food. Green plants produce starch through a mechanism called Photosynthesis. Animals get food directly or indirectly from plants.

Components of food:

• Protein	Carbohydrate	Lipid or Fat	Minerals	Vitamins	Roughage
  – Proteins are polymers of amino acids. These are made of C, H, O and N. – These are building blocks of our body. – There are 20 amino acids that are linked with peptide bond tof form polypeptide chain.	– These are made of C, H and O. – The can be classified as mono, di and polysaccharides. – Plants produce carbohydrates in the form of starch. – These provides energy to living beings.	– These act as stored foof or fuel in our body. – Fats are stored in adipose tissue. – Saturated fatty acids are solid and unsaturated fatty acids are liquid at room temperature.	– Minerals are essential for various biological functions. – Essential minerals are sodium, potassium, calcium, magnesium, sulphur, phosphorus, iron, iodine etc.	– Vitamins are essential for metabolism and body functioning. – Various types of vitamins are A, B, C, D, E, K. – They require in small quantity, lack of vitamins lead to deficiency diseses.	– Food derived from plants having cellulose contains adequate amount of roughage. – The are important for bowel movements. – Main sources are vegetables, fruits, whole grains.

Carbohydrates:

– These are monosaccharides (eg. glucose, fructose, galactose), Oligosaccharides (eg. sucrose, lactose, maltose) and polysaccharides (eg. glycogen, starch, cellulose, chitin, insulin).

– 1 gm carbohydrate produces 16.8 K J  i.e. 4 k cal energy.

– During digestion carbohydrates break down into glucose molecules.

– Additional glucose is stored in liver and muscle as glycogen which is called glycogenesis.

– Plant cells contain high cellulose.

– Galactose and Lactose is found in milk.

– Starch is produced by plants by photosynthesis.

– Chitin is found in the exoskeleton of Insects.

Proteins:

– They are important for organisation and repair of our body.

– Proteins are formed by linking the amino acids with the help of peptide bond.

– Amino acids are two types- Essential (Can’t be synthesized by body and come from food) eg. valine, trptophan, methionine etc and non essential (Can be synthesized by body) eg. alanine, aspartic acids, proline, serine etc.

– 1 gm protein produce 5.65 k cal energy.

– Child requires much protein than adults because child grows fast.

– Protein deficiency in child causes Kwashiorkor disease.

– Marasmus disease occurs due to both protein and carbohydrate deficiency. Due to these disease growth stopped and child become lean and thin.

Fats or Lipids:

– They yield much energy than carbohydrate and protein.

– Fats are essential for the absorption of some vitamins.

– Fats are stored in the adipose tissue.

– Fats act as stored energy or reserve food in human body.

Vitamins:

– They require in small quantity and are important for functioning of various biological functions.

– Vitamins are two types- Fat soluble (A, D, E and K) and Water soluble (B and C).

– Vitamins keep our teeth, bones, gums healthy.

Minerals:

– Minerals are required only in small quantity that are essential for normal growth.

– Sodium (Na) and Potassium (k) are important ions of extracellular fluid. They are important for nerve activities.

– Na deficiency causes Cramps and K deficiency causes convulsions.

– chlorine (Cl) is an anion of extracellular fluid. It is important for the synthesis of HCl.

– Magnessium (Mg) is important for the activation of enzyme.

– Mg is the main component of bone and teeth.

– Mg deficiency causes convulsions and hallucinations.

– Sulphur (S) is the main component of protein, enzyme and enzymes.

– Cobalt (Co) deficiency causes Pernicious anaemia.

– Flourine (F) is important enamel of teeth. If Flourine is found excess it can lead to flourosis.

– Calcium (Ca) is the major component of bones and teeth. It is required for blood clotting. Deficiency of Ca causes       rickets, osteoprosis, weak bone, tooth decay etc.

– Iron (Fe) is important part of haemoglobin. Iron deficiency causes anaemia.

– Phsphorus (P) is part of teeth and bones. Deficiency disease is rickets.

– iodine (I) is essential for the production of thyroxine hormone. deficiency causes goitre (bulging of thyroid gland).

Roughage:

– Sources of roughage are vegetables, grains, fruits etc.

– Cellulose containing foods are rich in roughage.

– These are important for bowel mvement.

– The helps in excreting wastes from our body.

Water:

–  Our body contains 70 to 80% water.

– Water regulates the biological reactions.

– It controls body temperature by sweating and evaporation.

– It also helps in excretion process.

Food Preservation:

– Generally two types of food preservation method is used.

Dry preservation and cold preservation or storage.

– Some foods eg- sugar, grains, cerals etc. are preserved by dry preservation method.

– But fruits, vegetables etc are preserved by cold preservation method or deep freezers.

MCQs (For Practice):

1. Which of the following is not fat soluble vitamin?

Ans: d. Vitamin C.

2. Which of the following is important for regular bowel movement?

Ans: c. Roughage

3. Washing the rice many times using a large amount of water before cooking leads to     [CTET May 2012]

Ans: b. loss of Vitamin B

4. Radhika’s gums were often bleeding and her wounds were taking longer time to heal. Her diet could be deficient in which      [CTET May 2016]

Ans: b. Vitamin C

5. Peptide bonds are presents in

Ans: b. Protein

6. Removal of water from biological substance are called 

Ans: C. Dehydration.

7. Which of the following is caorrectly matched

Ans: b.

8. The minerals that are required in the right amount for proper functioning of muscle are    [CTET Jan 2012]

Ans: c. sodium and potassium

9. Which of the following is not correct about minerals

Ans: d. None of the above

10. Which of the following is correct about fat

Ans: d. Fats help in absorption of some vitamins

11. Anaemia is related to

Ans: b. RBC

12. Thyroxine hormone is synthesized by –

Ans: c. Thyroid gland

13. Foods are stored for longer period by adding extra salt. The reason is-

Ans: c. salt plasmolyse the microbial cells leading to their death.

14. Thyroxin hormone is related to which of the following gland?

Ans: c. thyroid gland

15. Which of the following vitamin is necessary for healthy skin-

Ans: d. vitamin E

16.