Lipids, Fats, and Biochemistry

Fucus vesiculosus was the original source of iodine, discovered in 1811, and was used extensively to treat goitre, a swelling of the thyroid gland related to iodine deficiency.

Proteins are further broken down to amino acids.

Rancid butter develops its characteristic foul smell due to bacterial hydrolysis of triglycerides, releasing free fatty acids. Butyric acid (C3H7COOH, butanoic acid) is particularly volatile and malodorous. Caproic, stearic, and palmitic acids are either not produced in significant quantities or are less odorous.

Saponification is the alkaline hydrolysis of ester bonds in fats and oils to produce glycerol and soap salts. This reaction requires a strong base like NaOH (caustic soda) rather than neutral water.

Sporopollenin is a highly resistant biopolymer found in pollen grain exines. Chemically, it is derived from carotenoids and fatty acids, forming a complex cross-linked polymer structure that provides exceptional durability.

Carbohydrates do not belong to lipids. They belong to a large group of organic compounds occurring in foods and living tissues and include sugars, starch, and cellulose.

The major ingredient of leather is collagen (option B). Leather is produced from animal hides through tanning, and the primary structural protein in animal connective tissue is collagen, which gives leather its strength and durability. Carbohydrates, polymers, and nucleic acids are not the primary components of leather.

Adipose cells (adipocytes) are specialized for storing fat (triglycerides) in their large vacuoles. They serve as energy reserves and provide insulation. Mast cells mediate immune responses, fibroblasts produce collagen, and macrophages engulf pathogens.

Proteins are the primary building materials for growth and repair of body tissues, making them essential macromolecules for building up the body. Sugars provide quick energy, mineral salts regulate various functions, and fats store energy and insulate organs.

Animals store glucose as glycogen in liver and muscle tissue for short-term energy needs. The liver maintains blood glucose levels for the whole body, while muscles keep glycogen for their own use during exercise. Plants store energy as starch, and while fat is also an energy reserve, glycogen is the primary storage form in liver and muscles.

Flippases are a family of transmembrane lipid transporter enzymes located in the membrane responsible for aiding the movement of phospholipid molecules between the two leaflets that compose a cell's membrane.

Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a magnetic field absorb and re-emit electromagnetic radiation.

Correct answer. Linoleic acid, CH₃(CH₂)₄CH=CHCH₂CH=CH(CH₂)₇COOH, is a polyunsaturated omega-6 fatty acid. It has two carbon-carbon double bonds in its structure.