Biomolecules and Enzymes

Chromoproteins are proteins, such as hemoglobin or rhodopsin containing a pigmented nonprotein group, as heme, riboflavin, or retinal.

Keratin - A fibrous scleroprotein that occurs in the outer layer of the skin and in horny tissues such as hair, feathers, nails, and hooves Collagen - A fibrous scleroprotein in bone and cartilage and tendon and other connective tissue; yields gelatin on boiling Elastin - A fibrous scleroprotein found in elastic tissues such as the walls of arteries.

RuBisCO (Ribulose-1, 5-bisphosphate carboxylase) is thought to be the most abundant protein in the world, since it is present in every plant that undergoes photosynthesis and molecular synthesis through Calvin cycle.

Nitrate reductases are molybdenum containing enzymes that reduce nitrate to nitrite. Xanthine dehydrogenase (XDH) is a molybdenum-containing hydroxylase involved in oxidative metabolism of purines. 

Cysteine is a sulphur containing α-amino acid with the chemical formula HOOCCH(NH₂)CH₂SH. Methionine is sulphur containing α-amino acid with the chemical formula HOOCCH(NH₂)CH₂CH₂SCH₃.

Human sperms contain clupein protein.

This is a cell matrix component.

Amino acids are obtained by the break down of proteins. Glycerol is obtained by the break down of fats.

The collagen component of bone.

This option is correct, in eukaryotes the organisation is much more complex, there is a set of positively charged, basic proteins called histones.

This option is correct. Lysine is an amino acid.

Serum albumin accounts for more than 50 percent of blood protein. It is produced in the liver and transports hormones, fatty acids and bilirubin throughout the body.

Osborne (1924) classified seed storage proteins into groups on the basis of their extraction and solubility in water (albumins), dilute saline (globulins), alcohol-water mixtures (prolamins), and dilute acid or alkali (glutelins). In Crucifereae or Bressicaceae family, the seed storage proteins are called napins. The examples of cruciferae family are- Berssica campestris, Degenia velebitica, Arabis aculeolata, etc. Zea mays belongs to the family Poaceae and contains zein as seed storage proteins.

Six amino acids are considered conditionally essential in the human diet, meaning their synthesis can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress. These six are 2-Amino-3-sulphydrylpropanoic acid, 2-Amino-5-guanidinopentanoic acid, Aminoacetic acid, 2-Amino-4-carbamoylbutanoic acid, Pyrrolidine-2-carboxylic acid and L-2-Amino-3-(4-hydroxyphenyl) propanoic acid.

The indispensable amino acids are those amino acids that cannot be synthesised by the organism being considered and therefore must be supplied in its diet. The amino acids regarded as essential for humans are 2-Amino-4-methylpentanoic acid, 2,6-Diammoniohexanoic acid, etc. Hence, C and D both are indispensable amino acids and others are conditionally amino acids.