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On the basis of structure, proteins are classified into three categories: 

1. Simple proteins: 

a. Simple proteins on hydrolysis yield only amino acids. 

b. These are soluble in one or more solvents. 

c. Simple proteins may be soluble in water. 

d. Histones of nucleoproteins are soluble in water. 

e. Globular molecules of histones are not coagulated by heat. 

f. Albumins are also soluble in water but they get coagulated on heating. 

g. Albumins are widely distributed 

e.g. egg albumin, serum albumin and legumelin of pulses are albumins. 

Importance: They are involved in structural components; they also act as a storage kind of protein.

Some are associated with nucleic acids in nucleoproteins of cell. 

2. Conjugated proteins: 

a. Conjugated proteins consist of a simple protein united with some non-protein substance. 

b. The non-protein group is called prosthetic group 

e.g. haemoglobin. 

c. Globin is the protein and the iron containing pigment haem is the prosthetic group. 

d. Similarly, nucleoproteins have nucleic acids. 

e. Proteins are classified as glycoproteins and mucoproteins. 

f. Mucoproteins are carbohydrate-protein complexes e.g. mucin of saliva and heparin of blood.

g. Lipoproteins are lipid-protein complexes 

e.g. conjugate protein found in brain, plasma membrane, milk etc. 

Importance: They are involved in structural components of cell membranes and organelles.

They also act as a transporter. 

Some conjugated proteins are important in electron transport chain in respiration. 

3. Derived proteins: 

a. These proteins are not found in nature as such. 

b. These proteins are derived from native protein molecules on hydrolysis. 

c. Metaproteins, peptones are derived proteins. 

Importance: They act as a precursor for many molecules which are essential for life.

Polysaccharides (carbohydrate) polymer of monosaccharide, polypeptides (proteins) polymer of amino acids and polynucleotides (nucleic acids) polymer of nucleotides are the three basic macromolecule present in the living organisms.

1. Living organisms are classified as unicellular (consisting of single cell) and multicellular (having many cells). 

2. Example of unicellular organisms: bacteria, yeast. 

Example of multicellular organisms: plants, animals.

Chemical analysis of all living organisms indicates the presence of the most common elements like carbon, hydrogen, nitrogen, oxygen, sulphur, calcium, phosphorus, magnesium and others with their respective content per unit mass of a living tissue.

1. Biochemistry is biological chemistry that provides us the idea of the chemistry of living organisms and molecular basis for changes taking place in plants, animals and microbial cells. 

2. It develops the foundation for understanding all biological processes and communication within and between cells as well as chemical basis of inheritance and diseases in animals and plants.

1. Biochemistry is biological chemistry that provides us the idea of the chemistry of living organisms and molecular basis for changes taking place in plants, animals and microbial cells. 

2. It develops the foundation for understanding all biological processes and communication within and between cells as well as chemical basis of inheritance and diseases in animals and plants.

Amylose which is linear polymer of α‐glucose and amytopectin which is branched  polymer of α glucose. Amylose is water soluble where as amylopectine is water  insoluble.

Keratin is insoluble in water. 

RNA and DNA are responsible for generic characteristics : 

DNA preserves the information and uses it by producing duplicate identical DNA molecules. RNA carries messages and transports them.

Option : (b) Starch

Carbohydrates are often termed as saccharides or sugars.

Option : (d) Sucrose

Glucose is stored in the form of glycogen in the animal body.

Nucleic acids, both DNA and RNA, are polymers of nucleotides, formed by joining the 3′ – OH group of one nucleotide with 5′ – phosphate of another nucleotide. 

Two ends of polynucleotide chain are distinct from each other. 

One end having free phosphate group of 5′ position is called 5′ end. 

The other end is 3′ end and has free OH – group at 3′ position.

Option : (d) tetrasaccharides