BMB 402 3.26

Types of Molecules Considered Lipids

• Lipids play crucial roles in biological systems.

• Long chain alcohols and fatty acids are examples of lipid structures, leading to unique properties and functions.

Glucagon Signaling

• Glucagon is elevated when blood sugar levels are low.

• It stimulates the release of triglycerides from adipose tissue into fatty acids, which are then bound to albumin in the bloodstream.

Lipid Droplets and Their Structure

• Misunderstanding of lipid droplets; they are not just droplets but structured organelles.

• Surrounded by a phospholipid monolayer and contain proteins regulating metabolism.

• Accumulation of these droplets in astrocytes is linked to neurodegenerative diseases (e.g., Alzheimer's).

Cholesterol and Bile

• Cholesterol is metabolized and excreted via bile, which is crucial for the emulsification of fats in digestion.

• Bile acids help transport lipids through the lymphatic system to the bloodstream.

Chylomicrons

• Formed from lipids processed in the intestine; they include triacylglycerols and are crucial for lipid transportation.

• Albumin binds to lipids in the bloodstream, facilitating their transport.

Asymmetric Distribution of Phospholipids

• Phospholipids are not distributed randomly; the outer and inner leaflets of the plasma membrane have different lipid compositions.

• Understanding this asymmetry is important for cell signaling and membrane functionality.

Myelin and Sphingomyelin

• Myelin sheaths contain sphingomyelin which insulates axons, enhancing the speed of nerve signal conduction.

• Particularly essential in long axons, such as those found in larger animals like giraffes.

Neurological Disorders and Gangliosides

• Tay Sachs disease is linked to a failure to metabolize specific gangliosides, resulting in severe neurological degradation.

• Such conditions highlight the importance of lipid regulation in maintaining neurological health.

Cholesterol Structure and Function

• Composed of 27 carbons with a four-ring structure, it influences membrane fluidity and the organization of membrane components.

• Cholesterol levels affect signaling molecule assemblies and transporters in membranes.

Lipids in Cancer and Cellular Differentiation

• Lipid composition is linked to cancer development and cell differentiation.

• Understanding lipid and protein interactions is crucial for cancer research.

Effects of Cortisol

• Cortisol influences various bodily functions, including immune response and liver metabolism.

• Sudden withdrawal from corticosteroids can cause severe headaches due to brain swelling.

• Used therapeutically in conditions like asthma to suppress inflammation.

Synthetic Androgens and Prostate Cancer

• Androgens play roles in male characteristics and are often misused in fitness circles for muscle gain.

• Their antagonists are effective in treating prostate cancer but have side effects impacting quality of life.