Components of food necessary for the
body are called Nutrients. Organisms that
prepare food themselves from simple substances are called
Autotrophs and animals take in ready-made food
made by plants are called Heterotrophs.
Herbivores: Animals that eat only
Carnivores: Animals that eat other
Omnivores: Animals that eat both plant
Types of nutrients:
Dietary Fibers and Water
Carbohydrates and Fats
Carbohydrate and fats are the energy
giving food. Carbohydrate give less energy than fats. Animal
fats are saturated fatty
acids, which are harmful for health. We should
choose unsaturated fatty
acids for cooking. Trans
fats are unsaturated fats that damage the heart.
Proteins are body building foods.
Proteins are polypeptides
i.e. linear chains of amino acids linked by peptide
bonds. Enzymes are
proteins which perform role of biological catalysts. Receptors are proteins
which perform function related to communication systems in
the body. Collagen is
the most abundant protein in animal world and Ribulose bisphosphate
Carboxylase-Oxygenase (RuBisCO) is the most
abundant protein in the whole of the biosphere. Protein
Vitamin and Minerals
Vitamin A,E,C are anti-oxidants that absorb free radicals.
The vitamins and minerals deficiency can cause
the diseases mentioned in the table.
Vitamins or minirals
Night blindness / Xeropthalmia
Anemia / Loss of fertility
Bone and tooth decay
poisoning causes mina
mata disease and cadmium poisoning causes
Test to Detect Iodine, Proteins and Fats
Test for starch:
Take small food
quantity and add dilute iodine solution if it turns blue black
then it has starch
Test for proteins:
COPPER SULPHATE + CAUSTIC SODA TEST
Take small food quantity and add copper sulphate and
caustic soda solution if it turns violet
then it has proteins
Test for fats: PAPER
Take small food quantity and wrap it in paper and
crush it. Observe oil
patch in light
Dietary Fibers and Water
Roughage or dietary fibers are present
in plant products like whole grains, pulses, potatoes, fresh
fruits, vegetables. Don’t have nutrients but helps to get
rid of undigested food.
Human body and nutrients
is a process in which complex components of food
are broken into simpler substances.
Saliva breaks down starch into sugars. Stomach
secretes mucous, hydrochloric acid and digestive juices. The
mucous protects the lining of the stomach, acid kills the
bacteria and digestive juices break proteins into simpler
substances. Liver is the largest gland in the body.
It secretes bile stored in the gall bladder, bile is
important in digestion of fats. It produces cholesterol
[lipoprotein]. Low density cholesterol is bad and
high density cholesterol is good.
Humans can’t digest
cellulose. The temperature of a human body is 35-42°
on animals that are covered
by a calcium carbonate shell. The shell is popped
open and then the starfish puts its stomach out of its mouth
to eat the soft animal inside. The stomach then goes back
inside and then the food is slowly digested.
Small intestine is lined with villi which
help in absorption of food. Small intestine is 7.5m
and large intestine is 1.5m.
In herbivores, small intestine is longer
to digest cellulose. In carnivores, small intestine
is smaller as meat
is easily digested.