Alfalfa and mushrooms are the good sources of vitamin D2. About 13.1 mcg of vitamin D2 is present in mushroom portobello and 4.8 mcg in alfalfa. 

Active form of Thiamine is a coenzyme called thiamine pyrophosphate (TPP), which takes part in the conversion of pyruvate to acetyl coenzyme A (CoA) in metabolism.

Vitamin C is also known as L-ascorbic acid. Most of the functions of L-ascorbate as a vitamin relies not on its antioxidant properties.

Vitamin D enhances the absorption of calcium, iron, phosphate, magnesium and zinc. Thus, it is important for the health of bones.

Guinea pigs cannot synthesise ascorbate internally. It has to be taken in from an external source.

Retinoic acid is a hormone-like substance that acts as a growth factor for epithelial cells. It is an irreversibly oxidised form of retinol.

The active form of vitamin B6, i.e. pyridoxal 5'-phosphate serves as a cofactor in biosynthesis of neurotransmitters.

Vitamin B9 (folic acid) deficiency in early embryo development has been linked to neural tube defects.

Vitamin E belongs to a group of compounds called tocopherols.

Vitamin A is stored in the human body in the form of retinol and can be converted to and from its visually active aldehyde form, retinal.

A person's vitamin D status is determined by measuring the serum concentration of Calcidiol and 25-hydroxyergocalciferol.

Passerines lack the ability to carry out the biosynthesis of vitamin C. These birds have lost the ability to synthesise vitamin C with time.

Vitamin B2, i.e. riboflavin, is involved in energy production for the electron transport chain.

Vitamin K3 is a synthetic form of vitamin K, which is toxic to humans.

Milk contains 28 micrograms of vitamin A per 100 grams. Thus, it contains the least amount of vitamin A.

Adenine was earlier known as vitamin B4. It is a nucleobase synthesised by the human body.

NADP, i.e. nicotinamide adenine dinucleotide phosphate, is a coenzyme form of vitamin B3.

The classic clinical syndrome for vitamin B6 (pyridoxine) deficiency is a seborrhoeic dermatitis-like eruption, atrophic glossitis with ulceration, angular cheilitis, conjunctivitis, intertrigo, and neurologic symptoms of somnolence, confusion and neuropathy.

Biotin is a critical coenzyme for acetyl CoA carboxylase, which is involved in the synthesis of fatty acids from acetate.

Menaquinone-7 is not produced by human tissues. MK-7 may be converted from phylloquinone (K1) in the colon by E. coli bacteria.

Deficiency of biotin leads to carboxylase deficiency. It is a form of metabolic disorder involving the failure of carboxylation enzymes.

Cooked kale is the richest source of vitamin K1. 1/2 cup of kale contains 531 micrograms of vitamin K1.

Kakadu plum is the richest source of vitamin C. It contains 1000-5300 mg of vitamin C/1000 g of its serving.

Abetalipoproteinmia is a rare autosomal recessive disorder that interferes with the normal absorption of fat and fat-soluble vitamins like vitamin E. It is an inherited disorder.

Vitamin C deficiency causes scoliosis, lordosis and dark skin colouration in fishes. Scoliosis refers to deformity in spinal cord and lordosis refers to the inner curvature of the spinal cord.

α-Tocopherol functions as an antioxidant in the glutathione peroxidase pathway, and it protects cell membranes from oxidation by reacting with lipid radicals produced in the lipid peroxidation chain reaction.

Retinyl palmitate is used in skin creams, where it is broken down to retinol and metabolised to retinoic acid, which has potent biological activity.

Vitamin A and Vitamin B9 were the first and the last vitamins discovered, respectively. Vitamin A was discovered in 1913 and vitamin B9 was discovered in 1941.

Wheat germ oil contains 215.4 mg of vitamin E per 100 grams of the oil. Out of the four options, wheat germ oil is most abundant in vitamin E.

The tolerable upper limit level of folic acid is 1 mg/day. Higher levels can lead to permanent neurological damage.

The coenzyme form of folic acid, i.e. tetrahydofolate, aids in erythropoisis, i.e. production of red blood cells.

Hypervitaminosis of vitamin A can cause pseudotumor cerebri syndrome. This syndrome has symptoms like headache, blurring of vision and confusion, associated with increased intracerebral pressure.

Vitamin K2 (menaquinone) is not inhibited by salicylates, so menaquinone supplementation can alleviate the chronic vitamin K deficiency caused by long-term aspirin use.

Alpha tocopherol, i.e. vitamin E, induces the expression of connective tissue growth factor, which modulates and coordinates signalling responses involving cell surface proteoglycans.

Craniotabes is caused by vitamin D deficiency in children. Craniotabes is seen mostly in the occipital and parietal bones. The bones become soft and when pressure is applied on them, they will collapse underneath it. When the pressure is relieved, the bones usually snap back into place.

Vitamin C acts as a cofactor in the synthesis of collagen. Its dysfunction results in scurvy.

This is in decreasing order. Calf liver contains 36 mg of vitamin C per 100 g, beef liver contains 31 mg of vitamin C per 100 g, pork liver contains 23 mg of vitamin C per 100 g and lamb liver contains 12 g of vitamin C per 100 g.

Vitamin K is needed for the complete synthesis of certain proteins that the body uses to control the binding of calcium in bones and other tissues.

Hypervitaminosis E is associated with the risk of vitamin K deficiency. This results in bleeding problems.

This is the correct match. Vitamin B1 is involved in RNA and DNA production; vitamin B2 is involved in citric acid cycle; NAD is a coenzyme form of vitamin B3; CoA can be synthesised from vitamin B5.