Riboflavin: Vitamin B2

Riboflavin, or vitamin B2, helps to release energy from foods, promotes good vision, and healthy skin. It also helps to convert the amino acid tryptophan (which makes up protein) into niacin.

RDA Males: 1.3 mg/day; Females: 1.1 mg/day

Deficiency : Symptoms of deficiency include cracks at the corners of the mouth, dermatitis on nose and lips, light sensitivity, cataracts, and a sore, red tongue.

Vitamin B6: Pyridoxine, Pyridoxal, Pyridoxamine

Aids  in protein metabolism and red blood cell formation. It is also involved in the body’s production of chemicals such as insulin and hemoglobin.

Vitamin B6 Deficiency Deficiency symptoms include skin disorders, dermatitis, cracks at corners of mouth, anemia, kidney stones, and nausea. A vitamin B6 deficiency in infants can cause mental confusion.

CALCIUM

Total calcium in the human body is 1 to 1.5kg, out of which 99% is seen in bone and 1% in extracellular fluid. The main source of calcium is milk.

The daily requirement of calcium for child is 1200mg/day and for adult it is 500mg/day. During pregnancy /lactation the calcium requirement is 1500mg/day.

The absorption of calcium takes place in 1st and 2nd part of deuodenum. Calcium absorption requires carrier protein, helped by Ca²⁺ - dependent ATpase.

Factors responsible for increase in calcium absorption include Vitamin D, Parathyroid hormone, acidity and amino acids. Factors such as phytic acid,oxalates, malabsorption  syndromes and Phosphates decreases calcium absorption. The normal calcium level in blood is 9-11mg/dl.

K_eq, K_w and pH

As H₂O is the medium of biological systems one must consider the role of this molecule in the dissociation of ions from biological molecules. Water is essentially a neutral molecule but will ionize to a small degree. This can be described by a simple equilibrium equation:

H₂O <-------> H⁺ + OH^-

This equilibrium can be calculated as for any reaction:

K_eq = [H⁺][OH^-]/[H₂O]

Since the concentration of H₂O is very high (55.5M) relative to that of the [H⁺] and [OH^-], consideration of it is generally removed from the equation by multiplying both sides by 55.5 yielding a new term, K_w:

K_w = [H⁺][OH^-]

This term is referred to as the ion product. In pure water, to which no acids or bases have been added:

K_w = 1 x 10^-14 M²

As K_w is constant, if one considers the case of pure water to which no acids or bases have been added:

[H⁺] = [OH^-] = 1 x 10^-7 M

This term can be reduced to reflect the hydrogen ion concentration of any solution. This is termed the pH, where:

pH = -log[H⁺]

Sphingosine is an amino alcohol present in sphingomyelins (sphingophospholipids).  They do not contain glycerol at all.

Sphingosine is attached by an amide linkage to a fatty acid to produce ceramide. The alcohol group of sphingosine is bound to phosphorylcholine in sphingomyelin structure. .

Sphingomyelins are important constituents of myelin and are found in good quantity in brain and nervous tissues.

Classification of Fatty Acids and Triglycerides

Short-chain: 2-4 carbon atoms

Medium-chain: 6-12 carbon atoms

Long-chain: 14-20 carbon atoms

Very long-chain: >20 carbon atoms

• are usually in esterified form as major components of other lipids

A16-carbon fatty acid, with one cis double bond between carbon atoms 9 and 10 may be represented as 16:1 cisD⁹.

Double bonds in fatty acids usually have the cis configuration. Most naturally occurring fatty acids have an even number of carbon atoms

Examples of fatty acids

There is free rotation about C-C bonds in the fatty acid hydrocarbon, except where there is a double bond. Each cis double bond causes a kink in the chain,