Module 4.5 Lipids Flashcards
What are the primary functions of lipids?
Energy storage, building cells, cushioning and protecting organs, and hormone production.
Lipids serve multiple essential roles in biological systems.
What is the role of lipids in energy storage?
Lipids are long-term energy storage in plants and animals and are used when carbohydrates are not available.
They provide a more concentrated source of energy.
How do lipids contribute to cell structure?
Lipids build cell membranes in all cells.
Cell membranes are crucial for maintaining cellular integrity.
What is a characteristic of lipids related to their solubility?
Lipids are hydrophobic.
This means they do not mix well with water.
Why are lipids considered hydrophobic?
Lipids are primarily made of carbon and hydrogen, which form nonpolar covalent bonds.
Nonpolar bonds do not interact with polar molecules like water.
What are the three major types of lipids?
Triglycerides, phospholipids, steroids.
Each type has distinct structures and functions.
What are triglycerides composed of?
Triglycerides are made of glycerol and fatty acids.
Glycerol forms the backbone to which fatty acids are attached.
What is the structure of glycerol?
Glycerol has 3 carbons and 3 hydroxyl groups, making it hydrophilic.
This contributes to its role in forming triglycerides.
What defines saturated fatty acids?
Saturated fatty acids have all single bonds and are common in animal triglycerides.
They are solid at room temperature.
What defines unsaturated fatty acids?
Unsaturated fatty acids have one or more double bonds and are common in plant triglycerides.
They are typically liquid at room temperature.
What is a triglyceride?
A triglyceride is a glycerol to which 3 fatty acids are attached via dehydration reactions.
This process involves the formation of ester bonds.
What are the functions of triglycerides?
Energy reserves, carrying fat-soluble hormones and vitamins, insulation, and cushioning organs.
They play a vital role in energy storage and protection.
How do phospholipids differ from triglycerides?
Phospholipids have glycerol + 2 fatty acid chains and a phosphate attached to a polar group.
This gives phospholipids their unique properties in forming cell membranes.
What is the hydrophilic head of a phospholipid?
The phosphate + polar group.
This part interacts with water, while the tails do not.
What arrangement do phospholipids form in water?
Phospholipids arrange in a bilayer with hydrophilic heads facing out and hydrophobic tails facing in.
This structure is essential for cell membrane integrity.
What are steroids made of?
Steroids are made of 4 fused rings.
The specific chemical groups on the rings determine the type of steroid.
Different steroids have different
chemical groups on the rings
What is the role of cholesterol in cell membranes?
Cholesterol stiffens animal membranes and comprises about 30% of our membranes.
It is crucial for maintaining membrane fluidity.
Sex hormones are
Steroids
What are examples of sex hormones?
Estrogen and testosterone.
Both hormones play significant roles in the reproductive system.
What are the potential side effects of anabolic steroids?
Liver damage, violent mood swFings, infertility, and male lactation.
These side effects can occur after prolonged use.
What is the function of cortisol?
Cortisol is a stress hormone released under stress, helping with the fight-or-flight response.
It also reduces swelling and can aid in breathing for asthma patients.
