Understanding Lipids: Types and Functions

Study Notes

Favism and G6PD Deficiency

Favism is linked to G6PD deficiency, causing jaundice from bilirubin absence.
G6PD deficiency can arise from complications of chronic diseases.

Lipids

Lipids: enhance flavor, serve as energy sources, and act as thermal insulators.
Store fat-soluble vitamins A, D, and E; form the backbone of hormones and cell membranes.
Types of lipids:
- Simple Lipids: include fats (solid), oils (liquid), and waxes.
- Compound Lipids: contain myonaises, e.g., lecithin.
- Derived Lipids: consist of fatty acids, glycerol, steroids, alcohol, and aldehydes.

Cholesterol and Heart Disease

Cholesterol is essential but excessive levels in blood contribute to heart disease.
Primarily synthesized in the liver, with some being obtained from dietary sources.

Essential Fatty Acids

Must be consumed as the body cannot synthesize them.
Prostaglandins: present in nerves and contribute to pain.
Thromboxanes: aid in nerve formation.
Leukotrienes: promote muscle tension and inflammation.
Prostacyclin: plays a role in blood coagulation balance.
LDL (low-density lipoprotein): transports cholesterol from liver to tissues.
HDL (high-density lipoprotein): returns cholesterol from tissues back to the liver.

Enzymes

Enzymes are biological catalysts, mainly proteins that speed up biochemical reactions.
Key roles include digestion and toxin elimination.
Two main sites:
- Catalytic site: involved in catalysis.
- Substrate binding site: where reactants bind.
Properties:
- Produced by living cells.
- Serve as powerful catalysts.
- Highly specific, except for ribozymes.

Importance of Enzymes in Healthcare

Enzymes provide insights into diseases for diagnosis and prognosis.
High enzyme levels in serum can indicate tissue damage.
Can be used therapeutically.

Enzyme Classifications

Co-factors: non-protein components of holoenzymes.
Metal-activated enzymes: have loosely bound metals.
Co-enzymes: low molecular weight, non-protein organic molecules.
Metalloenzymes: tightly bound metals as prosthetic groups.
Isoenzymes: different structures with similar functions.

Types of Enzymes

Oxidoreductase: catalyze redox reactions.
Transferases: transfer molecular groups.
Hydrolases: introduce water to cleave bonds.
Lyases: form double bonds or add groups.
Ligases: join molecules together.

Factors Affecting Enzyme Activity

Denaturation caused by pH and temperature changes.
Vitamins play vital roles in enzyme functions; many cannot be synthesized by mammalian cells.

Vitamins Overview

Fat-soluble vitamins: A, D, E, K, stored in liver and fatty tissues.
Water-soluble vitamins: C and B-complex vitamins.

Specific Vitamins and Their Significance

Vitamin A: necessary for vision; deficiency leads to night blindness and xerophthalmia.
Vitamin D: regulated calcium metabolism; deficiency causes rickets and osteomalacia.
Vitamin E: acts as an antioxidant; deficiency leads to increased RBC fragility and neurological disorders.
Vitamin K: essential for blood clotting; deficiency can lead to hemorrhagic syndrome.
Vitamin B9 (Folate): found in leafy vegetables; deficiency can result in megaloblastic and macrocytic anemia.

Thalassemia Indicators

Elevated HbF suggests thalassemia; elevated HbA2 indicates possible heterogeneity.
Normal ranges for hemoglobin variants:
- HbA1: 95-98%
- HbA2: 1.5-3.5%
- HbF: usually less than 2.5%.

Description

Explore the different types of lipids, including simple, compound, and derived lipids. Learn about the functions of lipids such as providing energy, forming cell membranes, and storing fat-soluble vitamins.