biochem

Biochemistry

The application of chemistry to the study of biological processes at the cellular and molecular level.

Principles of Biochemistry

All organisms use the same type of molecules (CHO, proteins, lipids & nucleic acids) and the instructions for growth, reproduction, and development are encoded in their DNA. It is a special branch of organic chemistry that deals with matter inside the living cell called Protoplasm.

Carbohydrates

Polyhydroxy aldehydes or ketones, or substances that yield such compounds on hydrolysis.

Haworth Projection

Carbohydrate Cyclic Ring:Carbohydrates can appear in cyclic rings instead of linear molecules due to the reaction between the carbonyl group (aldehyde and ketone) and a hydroxyl group (-OH group).

Monosaccharides

Contain a single polyhydroxy aldehyde or ketone unit and are classified according to the number of carbon atoms they contain.

Disaccharides

Consist of two monosaccharide units linked together by a covalent bond or through a glycosidic linkage.

Oligosaccharides

Contain from three to ten monosaccharide units.

Polysaccharides

Contains hundreds or thousands of carbohydrate units and are not reducing sugars.

Importance of Carbohydrates

Carbohydrates provide energy for the body, supply carbon for the synthesis of cell components, serve as a form of stored chemical energy, and form part of the structures of some cells and tissues.

Occurrence of Carbohydrates

Carbohydrates are abundant in plants, with cellulose as a structural component, starch as an energy reservoir, and glycogen as animal starch found in animal tissues and the human body.

Carbohydrates and Chirality

Carbohydrates can be classified as chiral or achiral, with chiral molecules being optically active and having the ability to rotate the plane of polarized light.

Stereoisomers

Isomers are compounds with the same chemical formula but different structures, and the 2n rule applies to molecules with three or more stereocenters.

Chirality in Organic Compounds

Chiral molecules have two nonsuperimposable mirror images and contain chiral carbons or centers of chirality.

Stereochemistry of Carbohydrates

Carbohydrates, including glyceraldehyde, exist in two isomeric forms that are mirror images of each other, known as enantiomers.

Fischer Projections

Fischer projections are a convenient way to represent mirror images of carbohydrates in two dimensions.

Naming Isomers

When there is more than one chiral center in a carbohydrate, the D-isomer is determined by the hydroxyl group pointing to the right when the carbonyl is "up," and the L-isomer is determined by the hydroxyl group pointing to the left.

Stereochemistry Matters

D-glucose is the most commonly occurring isomer of glucose in nature and serves as a common source of energy, while L-glucose cannot be used as a source of energy in cellular respiration.