Lipids Flashcards
What are hydrocarbons? What are the main properties of hydrocarbons? Are they soluble in water?
They are nonpolar molecules that contain only carbon and hydrogen. Are hydrophobic & Electrons are shared equally in C — H bonds. Are insoluble in water due to long hydrocarbon backbone with hydrophobic functional groups.
What is a fatty acid? What is the difference between a saturated and an unsaturated fatty acid? Which ones are liquid and which ones are solid at room temperature?
They are an Hydrocarbon chain bonded to a carboxyl (–COOH) functional group. They can be saturated or unsaturated.
Unsaturated Fatty Acids: H’s on same side of chain around double bonds. Is liquid.
Saturated Fatty acid: fatty acid chain, if there are only single bonds between neighboring carbons in the hydrocarbon chain. Are saturated with hydrogen. No double bonds in fatty acid chain. Contain the maximum possible number of hydrogens. Solid at room temperature.
What type of lipids are found in animals for long-term energy storage? How about plants?
Animals = fats; consists of two main components—glycerol and fatty acids. No double bonds in fatty acid chain. Contain the maximum possible number of hydrogens. Solid at room temperature.
Plants = oils; One or more double bonds in fatty acid chain creates “kinks” and open spaces in the chain. Liquid at room temperature. unsaturated fats.
What are trans-fats? (Be able to recognize an unsaturated vs a saturated vs a trans-fat on the exam). Are they liquid or solid at room temperature?
Trans-fatty Acids: Double bonds are created so that H’s are on alternating sides of the molecule. In modern food are made synthetically to make unsaturated fats solid at room temperature. Oils are artificially hydrogenated to make them semi-solid.
What are the three most important types of lipids found in cells?
- Steroids
- Triglycerides
- Phospholipids
What is the basic structure of a steroid? (Be able to recognize it on the exam) What are some examples of steroids found naturally in the human body?
Lipids with 4 fused rings.
Ex: Cholesterol is a steroid & it is needed to make other essential steroids like testosterone & estrogen.
What is the basic structure of a triglyceride molecule? Is it soluble in water? What is its main job? How does its structure help it to do its job?
Composed of three fatty acids linked to glycerol. A.K.A fats.
The primary role is energy storage: Large number of high-energy bonds in fatty acid chains
Bonds allow fats to store twice as much chemical energy by mass compared to carbohydrates and proteins. No it is not soluble in water
What is the basic structure of a phospholipid? Is it soluble in water? What is its main job? How does its structure help it to do its job?
Consist of glycerol linked to phosphate group and two hydrocarbon chains. Primary role of phospholipids is to form cell membranes. Arrange themselves into a bilayer, with a hydrophobic inside and water soluble outside.
What are 5 main functions of lipids?
- Store chemical energy
- Act as pigments that
- capture/respond to sunlight
- Serve as signals between cells
- Form waterproof coatings on skin and cells
- Act as vitamins in cellular processes
Plasma membranes/cell membranes, separates life from non life…
- Serves as selective barrier: Allows entry of materials needed by cell. Keeps damaging materials out of cell.
- Facilitates chemical reactions necessary for life: Allows chemical reactions to occur by sequestering appropriate chemicals. Creates its own “mircroenvironment”
How do lipids differ from the rest of the molecules?
They do not possess shared chemical structure. Their structure varies widely (unlike the other macromolecules). The hydrocarbon skeleton can be put together in many different ways.
