6 Lipids Flashcards
What are lipids?
Nonpolar organic compounds made of carbon, hydrogen, and small amounts of oxygen. Examples include waxes, fats, and oils.
What are the four main functions of lipids in humans?
- Long-term energy storage
- Insulation of internal organs
- Membrane structure
- Hormones (messenger molecules)
What are the five main categories of lipids?
- Fatty Acids
- Fats
- Phospholipids
- Steroids
- Waxes
What is a fatty acid?
A hydrocarbon chain with a carboxyl group at the end. The longer the chain, the less soluble it is.
What is the difference between saturated and unsaturated fatty acids?
- Saturated: Only single bonds, maximum hydrogen.
- Unsaturated: Contains double or triple bonds.
What is a polyunsaturated fatty acid?
A fatty acid with two or more double or triple bonds.
What is the difference between cis and trans fatty acids?
- Cis: Hydrogen atoms on the same side of the double bond (bent shape).
- Trans: Hydrogen atoms on opposite sides of the double bond (linear shape).
What is hydrogenation?
The addition of hydrogen atoms to unsaturated fatty acids, making them saturated.
What are fats?
Lipids formed by dehydration synthesis of glycerol and up to three fatty acids.
What is an ester linkage?
The -COOC- bond connecting a fatty acid to glycerol in a fat molecule
What are monoglycerides, diglycerides, and triglycerides?
- Monoglyceride: Glycerol + 1 fatty acid.
- Diglyceride: Glycerol + 2 fatty acids.
- Triglyceride: Glycerol + 3 fatty acids.
What are saturated fats?
Fats with only saturated fatty acids. They are solids at room temperature because their linear structure allows tight packing.
What are unsaturated fats?
Fats with one or more unsaturated fatty acids. Cis unsaturated fats are liquids (oils) at room temperature.
Why are trans fats unhealthy?
They are solid at room temperature and can increase the risk of:
- High blood pressure
- High cholesterol
- Inflammation
- Heart disease, stroke, and diabetes
What are essential fatty acids?
Alpha-linolenic acid (omega-3) and linoleic acid (omega-6). They affect blood clotting, brain function, inflammation, and mood.
What is the difference between subcutaneous and visceral fat?
- Subcutaneous fat: Found under the skin.
- Visceral fat: Found deep in the body around organs.
Why do animals use fat for long-term energy storage?
Triglycerides provide the most energy by mass compared to other macromolecules.
What are phospholipids used for?
They make up cell membranes.
What does it mean if a molecule is amphipathic?
It has both polar (hydrophilic) and nonpolar (hydrophobic) regions.
What are steroids?
Lipids with four carbon rings. Example: Cholesterol, which keeps cell membranes fluid and permeable.
What is the difference between HDL and LDL cholesterol?
- HDL (good): Removes cholesterol from the body.
- LDL (bad): Can cause artery buildup, leading to heart attacks or strokes.
What are examples of steroid hormones?
- Testosterone: Regulates puberty and body changes.
- Progesterone: Regulates the menstrual cycle and pregnancy.
What is a hormone?
A molecule that regulates growth or behavior in organisms.
What are some side effects of steroids?
Hair loss, mood swings, acne, infertility, and breast enlargement.
What are waxes, and how are they used by organisms?
Large lipids made from fatty acids and alcohols or carbon rings. They are hydrophobic and used for protection and waterproofing.
