Lipids, Fats, and Biochemistry

Water is a polar molecule and lipids are non-polar, i.e. shy lipids cannot be soluble in water. In other words, lipids are hydrophobic in nature.

Both options (2) and (3) are correct. Hence this option (4) is the correct answer.

Serine is needed for the metabolism of fats and fatty acids, muscle growth and a healthy immune system.

Sphingolipids are a class of lipids derived from the aliphatic amino alcohol sphingosine. These compounds play important roles in signal transmission and cell recognition. Sphingolipidoses, or disorders of sphingolipid metabolism, have particular impact on neural tissue.

Saccharolipids describe compounds in which fatty acids are linked directly to a sugar backbone, forming structures that are compatible with membrane bilayers. In the saccharolipids, a monosaccharide substitutes for the glycerol backbone present in glycerolipids and glycerophospholipids.

Lipids are fats, including oils. Their structures include a membrane around the cells, which prevents them from mixing with water. Lipids include fatty acids; triglycerides, which is what most people think of as dietary fat; phospholipids, which are fats attached to a phosphate; and cholesterol, which produces steroids. Lipids are capable of expanding in shape or size.

7-Dehydrocholesterol is a zoosterol that functions in the serum as a cholesterol precursor, and is converted to vitamin D₃ in the skin.The presence of this compound in human skin enables humans to manufacture vitamin D₃ from ultra-violet rays in the sun light, via an intermediate isomer pre-vitamin D₃. It is also found in the milk of several mammalian species.

High-Density Lipoproteins (HDLs) are called 'good' cholesterol because they transport cholesterol from tissues back to the liver for excretion, which helps prevent plaque buildup in arteries. HDL acts as a scavenger, removing excess cholesterol. LDL and VLDL are considered 'bad' cholesterol as they deposit cholesterol in arterial walls, contributing to atherosclerosis.

Docosahexaenoic acid is an omega-3 fatty acid that is a primary structural component of the human brain, cerebral cortex, skin, sperm, testicles and retina. It can be synthesized from alpha-linolenic acid or obtained directly from maternal milk or fish oil.

Glycerophospholipids, usually referred to as phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and cell signaling.

High-density lipoproteins (HDL) collect fat molecules (phospholipids, cholesterol, triglycerides, etc.) from the body's cells/tissues, and take it back to the liver. HDLs are sometimes referred to as good lipoprotein because higher concentrations correlate with low rates of atherosclerosis progression.

Eicosapentaenoic acid is an omega-3 fatty acid. It is obtained in the human diet by eating oily fish or fish oil, e.g. cod liver, herring, mackerel, salmon, menhaden and sardine, and various types of edible seaweed. It is also found in human breast milk.

Steroids are structurally different from the other lipids. The carbon skeleton of steroids is bent to form four fused rings that do not contain fatty acids. The most common steroid, cholesterol, is needed to make both the male (testosterone) and female (estrogen) sex hormones.

Rumenic acid is a conjugated linoleic acid found in the fat of ruminants and in dairy products. It is an omega-7 trans fat.

Phospholipases are enzymes that release fatty acids from the second carbon group of glycerol. This particular phospholipase specifically recognizes the sn-2 acyl bond of phospholipids and catalytically hydrolyzes the bond releasing arachidonic acid and lysophospholipids.