Introduction to Cell Biology & Biochemistry: Lipids

This flashcard set covers the biological functions, classifications, signaling roles, and synthesis pathways of lipids as discussed in the cell biology and biochemistry lecture.

Lipids

A collection of organic molecules of varying chemical composition, including fatty acids, glycerides, nonglyceride lipids (sphingolipids, steroids, waxes), and complex lipids like lipoproteins.

Energy Source Value of Fat

When oxidised, each gram of fat releases $9\,kcal$ of energy, which is more than twice the energy released by oxidation of a gram of carbohydrate.

Adipocytes

Cells where energy is stored in the form of triglycerides (TAG).

Eicosanoids

Fatty acid derivatives with a $20$-carbon chain that act as paracrine signals to transmit messages in a localized area.

Paracrine

A type of signaling that acts on nearby cells, derived from the Greek words "para" (nearby) and "ekkrino" (to secrete).

Arachidonic Acid

The specific fatty acid from which eicosanoids are derived.

Sterols

Lipid molecules that are amphipathic, planar (flat), and characterized by having no rotation around their carbon bonds.

Bile Salts

Amphipathic sterol derivatives (such as cholic acid and taurocholic acid) that behave like detergents to emulsify dietary lipids for solubilisation and absorption.

Fat-Soluble Vitamins

A group of vitamins that includes vitamins A, D, E, and K.

Vitamin A (Retinol)

A fat-soluble vitamin important for vision and skin cells, often produced from $\beta\text{-Carotene}$.

Vitamin D

A vitamin made from $7\text{-dehydrocholesterol}$ that is modified to $1,25\text{-dihydroxycholecalciferol}$ to control calcium metabolism.

Rickets

The most common medical condition caused by a lack of vitamin D or calcium.

Vitamin K

A vitamin often used as an antidote against rat poison (coumarin) and as a treatment for anticoagulant (warfarin) overdose.

Acetate

The basic building block for lipids, which is converted to acetyl-coenzyme A (Acetyl-CoA) before being used to make fatty acids and sterols.

Malonyl-CoA

An intermediate molecule formed from Acetyl-CoA during the process of building fatty acids.

Palmitate

A $16:0$ fatty acid produced by fatty acid synthase that serves as the precursor for other fatty acids.

Smooth Endoplasmic Reticulum

The organelle where longer chain fatty acids are made and where part of the synthesis of phospholipids and cholesterol takes place.

Isoprene

A key intermediate molecule in the reaction sequence used to synthesize sterols from acetate.