Test: Primary & Secondary Metabolites - NEET MCQ

Lecithin is a type of phospholipid. Phospholipids are a class of lipids that are major components of cell membranes. They are composed of a hydrophilic (water-loving) head group and hydrophobic (water-fearing) fatty acid tails.

Alkaloids are secondary metabolites, where as rest are primary metabolites

The Molecular Composition of Cells. Cells are composed of water, inorganic ions, and carbon-containing (organic) molecules. Water is the most abundant molecule in cells, accounting for 70% or more of total cell mass.

Pigments - Carotenoids,Anthocyanins
Toxins - Abrin, Ricin
Polymeric substance - Rubber, Gums
Alkaloids - Morphine, Codeine.

Four major classes of macromolecules may be identified, these are proteins, polysaccharides, lipids, and nucleic acids. Out of all macromolecules found in the cell, the proteins are most chemically and physically diverse. 

S-S bonds, also known as disulfide bonds, are covalent bonds formed between two cysteine amino acid residues in a protein. These bonds play a crucial role in stabilising the tertiary structure of a protein.

Glycerides are a type of lipid compound composed of fatty acids that are esterified with glycerol. Glycerol is a trihydric alcohol. When fatty acids react with glycerol, they form ester bonds, resulting in the formation of glycerides.

Macromolecules are giant molecules that are produced by the bonding of smaller molecules. Carbohydrates, lipids, proteins and nucleic acids are all considered to be macromolecules. 
A polysaccharide is one type of macromolecule made up of monosaccharides like glucose and fructose. 

Enzymes isolated from organisms who normally live under extremely high temperatures (e.g. hot vents and sulphur springs) are stable and retain their catalytic power even at high temperatures (up to 80 - 90℃).

Explanation:

In amino acids, the "R group" refers to the side chain attached to the alpha carbon, which varies among different amino acids.

• Serine has a hydroxy methyl group as its side chain (–CH₂OH).
• Glycine has a hydrogen atom as its side chain (–H).
• Valine has an isopropyl group as its side chain (–CH(CH₃)₂).
• Alanine has a methyl group as its side chain (–CH₃).

Thus, the amino acid with a hydroxy methyl group as its R group is Serine.