Biomolecules

1 Carbohydrates

also known as sachharides
basic component: sugars
Cn H2n On - C6 H12 O6 (glucose)

Small Carbohydrates	Large Carbohydrates
soluble in water	insoluble in water
low molecular weight	high molecular weight
sweet taste	taste not sweet
called monosacchrides	called polysacchrides

1.1 Monosachhrides

Deoxyribose (present in DNA)
Ribose (present in RNA)
Glucose, aka blood sugar, corn sugar, grape sugar – common respiratory substrate.
Frucose (fruit sugar) – sweetest of all naturally ocurring sugars.

1.2 Disacchrides

Maltose: glucose + glucose = malt sugar (barley sugar)
Lactose: glucose + galactose = milk sugar
- example of reducing sugar
- reduces Cu2+ to Cu+ in Benedict/Fehling solution

1.3 Polysacchrides

Starch: storage polysachhride of most plants
Glycogen: animal startch (storage), stored in liver and muscles
Cellulose: structural polysachhride

1.3.1 Cellulose

It provides structure to plant cells and is the most abundant organic substance in biosphere. It is a structural polysachharide present in the cell wall of plants. There are several important applications of cellulose and its derivatives:

Cellulose nitrate: used in explosives
Carboxy methyl cellulose (CMC) is used as an emulsifying agent in ice creams, medicine, cosmetics, etc.
Cellulose accetate: in fabricating fibres, plastics, shatterproof glasses, etc.

1.3.2 Chitin

It is another structural polysachharide that is found in the cell walls of fungi and in exoskeleton of insects. It is the second-most abundant organic compound.

1.3.3 Agar-agar

It is obtained from algae and is used as a medium to grow cultures of bacteria.

2 Lipids

Lipids, or fats are a fatty acid esters of alcohol (glycerol) and related substances which are insoluble in water but get dissolved in a number of non-polar organic solvents like ether, benzene, chloroform, etc. (An ester is a compination of acid and alcohol).

Basic unit of all lipids: fatty acids.

2.1 Saturated & Unsaturated Fats

Saturated Fats	Unsaturated Fats
Single bonds between C-C (i.e. Carbon is saturated with H-atoms)	Double bonds between C=C
Solid state, e.g. animal fats like ghee.	Liquid state, e.g. vegetale oils
Higher melting point	Lower melting point
increase blood cholesterol	doesn't increase blood cholesterol as much as saturated fats

2.2 Hydrogenation

It is the process of conversion from unsaturated fats to saturated fats. Metals like nickel and manganese are used in this process.

2.3 Essential Fatty Acids

These fatty acids are needed by animals but their bodies don't have the ability to synthesize them and are required in the diet. The deficiency leads to skin-related disorders. They are:

Linoleic acid
Linolic acid
Arachidonic acid

3 Proteins

They are made of amino acids. All amino acids contain amino group and carboxylic group.

-NH2-COO

20 types of amino acids present in proteins are required by humans. e.g. glycine (the simplest amino acid) which is required for formation of heme (haemoglobin).

Excess amino acids are de-aminated in liver (urea cycle).

Organic amino acids are changed to glucose via gluconeogenesis.

3.1 Essential amino acids

Plants can synthesize all proteins and amino acids they require. Animals cannot synthesize 7 of the amino acids which are called Essential Amino Acids which must be consumed in diet for normal functioning of the body.

3.2 Enzymes & Antibodies

Enzymes and antibodies are formed of proteins.

An antigen is a foreign particle. To destroy the antigen, the body makes antibodies (immunoglobin).

Enzymes are protenacious substances which are capable of catalyzing chemical reactions of biological origin without themselves undergoing any change. Almost all enzymes are proteins.

Restriction endonuclease is an enzyme used for cutting DNA at specific site. Ligase is an enzyme joining the DNA segments.

ELISA (Enzyme Link Immuno-Sorbent Assay) is the test used to diagnose AIDS.

Detergents contain protease for brighter washing of clothes.

Soap acts after mycin formation in the process called saponification.
Dishwasher contains amylase, which is also used in digestion.
Baby foods contain trypsin which is added to predigest babyfood.

3.3 Examples of proteins

Diet / Function	Protein / Enzyme
Milk	casein
Egg (white)	albumin
Iron-storage in animal tissue	ferritin
Muscle contraction	actin, myosin
oxygen carrier protein	heme
blood clotting	fibrinogen, thrombin
dishwasher, digestion	amylase
baby food	trypsin
soap	mycin
Biotechnology	ligase, restriction endonuclease
dissolve blood clots in vessels	streptokinase
anti-coagulant	heparin
fermentation, brewing, baking	zymase
cheese production	rennet/rennenin
green coffee	pectinase

Sidenote: In the process of blood clotting, the proteins involved are fibrinogen and thrombin, the mineral involved is calcium and the vitamin involved is Vitamin K.

Protein deficiency leads to PEM diseases (Protein Energy Malnutrition diseases) like kwashiorkor and marasmus.

4 Vitamins

They are the essential food factors which are required in small quantities for optimum functioning of metabolic pathways and body functions.

First vitamin to be discovered	Thiamine (B1)
Vitamin which can be made by intestinal bacteria	Vitamin A
Vitamin created from cholesterol derivatives in the presence of sunlight	Vitamine D

4.1 Classification

Fat soluble: A, D, E, K
Water soluble: B, C