Biochemistry Punjab Board Class 10 Notes Cha 13 Pdf Download

Proteins are present in all living organisms throughout their bodies. They are major components of all cells and tissues of animals. Over 10,000 different proteins are found and needed in the body for maintaining life. They are found in muscles, bones, skin, hair, and virtually every other body part.

Uses of carbohydrates
(i) Carbohydrates provide energy for working muscles.
(ii) They regulate the amount of sugar level in our body.
(iii) They provide fuel for the central nervous system.
(iv) They help muscles of the intestines to move food efficiently through the digestive tract.
(v) They help in lowering cholesterol and regulating blood pressure.

Answer:
Plants synthesize carbohydrates from carbon dioxide and water by photosynthesis in the presence of sunlight and green pigment chlorophyll.

Characteristics of monosaccharides
(i) They are the simplest form of sugar.
(ii) They are usually white crystalline solids.
(iii) They are sweet in taste.
(iv) They are soluble in water.
(v) They are reducing in nature.

Carbohydrates which on hydrolysis produce two monosaccharides are called disaccharides. Lactose is a disaccharide of glucose and galactose i.e. it produces two monosaccharides on hydrolysis as shown below:
C₁₂H₂₂O₁₂ + H₂O → C₆H₁₂O₆ + C₆H₁₂O₆
Lactose                    Glucose      Galactose

The ten amino acids are essential for us because, unlike non-essential amino acids, they cannot be synthesized by our body. As a result, they must come from food.

A protein molecule is made from a long chain of amino acids, each linked to its neighbour through a covalent peptide bond with a loss of water molecule. The carbon atom from the carboxyl group of one amino acid shares electrons with the nitrogen atom from the amino group of the second amino acid.

Gelatin is a protein obtained by heating bones and tendons in water.

The general formula of lipids is:

Butyric acid: C₃H₇COOH
Palmitic acid: C₁₅H₃₁COOH

Types of vitamins
There are two types of vitamins.
(i) Water-soluble vitamins
Water-soluble vitamins dissolve in water. These vitamins are carried to the body’s tissues but are not stored in the body. If taken in excess, they are readily excreted from the body. Hence, they are not toxic even if taken in excess.
Examples: Vitamin B complex and Vitamin C
(ii) Fat-soluble vitamins
Fat-soluble vitamins dissolve in fat. Taking a large quantity of these vitamins can cause diseases. However, their deficiency can also be harmful.
Examples: Vitamin A, D, E and K.

Significance of vitamins
Vitamins are used in many different ways inside our bodies. They boost the immune system, support normal growth and development and help cells and organs do their jobs. Overall, vitamins make bodies work properly. While vitamins do not directly serve as a source of energy, they do help the enzymes that generate energy from nutrients such as carbohydrates and fats.

Sources of vitamin A
High vitamin A foods include milk, butter, eggs, oils and fats, fish. It is also found in fresh green vegetables, carrots and liver.
Uses of vitamin A
Vitamin A supports healthy eyesight, immune function, skin, bones and teeth.

The genetic code is the set of rules by which information stored in DNA is passed as instructions from generation to generation on how to synthesize particular proteins from amino acids. This information determines whether an organism is a man, donkey or a tree. It also determines the type of cell.

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living things. It contains all the information for making a complete individual. All known cellular life and some viruses contain DNA. The main role of DNA is the storage of information and its transmission to next generations.