Lipids - AP Biology
- What distinguishes omega-3 from omega-6 fatty acids?
- Position of the first double bond from the methyl end. Number indicates double bond location from methyl end.
- What is the role of lipids in thermal insulation?
- They reduce heat loss by forming insulating layers. Low thermal conductivity prevents heat transfer.
- Which lipid is known for being a precursor to hormones?
- Cholesterol. Steroid structure serves as backbone for hormone synthesis.
- What is the impact of trans fats on health?
- Increase risk of cardiovascular disease. Artificial trans configuration promotes atherosclerosis.
- What is the main characteristic of amphipathic lipids?
- Contain both hydrophilic and hydrophobic regions. Enable membrane formation and self-assembly.
- What is the main energy source during prolonged fasting?
- Fatty acids from triglycerides. Released through lipolysis when glucose is depleted.
- What are the primary components of lipids?
- Fatty acids and glycerol. Basic building blocks that combine to form complex lipid molecules.
- Identify the process of breaking down triglycerides.
- Lipolysis. Breaks down stored fats into fatty acids and glycerol.
- What is the main structural difference between phospholipids and triglycerides?
- Phospholipids have a phosphate group; triglycerides do not. Phosphate group makes one end hydrophilic.
- Which lipid is a precursor for vitamin D synthesis?
- Cholesterol. UV exposure converts cholesterol to vitamin D.
- What is the structural role of sterols in cell membranes?
- They stabilize membrane fluidity. Regulate membrane fluidity at different temperatures.
- Which lipids are involved in the formation of eicosanoids?
- Arachidonic acid. 20-carbon fatty acid precursor to signaling molecules.
- What is the function of eicosanoids?
- Act as signaling molecules in inflammation and immunity. Regulate inflammatory and immune responses.
- What property of lipids makes them hydrophobic?
- Nonpolar hydrocarbon chains. Long carbon chains repel water molecules.
- Identify the main function of lipids in cells.
- Energy storage and membrane structure. Lipids store energy efficiently and form cell membrane boundaries.
- Identify the molecule from which all steroids are derived.
- Cholesterol. Common steroid backbone for hormone synthesis.
- Which lipid-soluble vitamins are stored in adipose tissue?
- Vitamins A, D, E, K. Require lipids for absorption and storage.
- Identify the lipid responsible for providing buoyancy to marine animals.
- Squalene. Lower density than water provides flotation.
- What is the general structure of a triglyceride?
- One glycerol and three fatty acids. Three fatty acid chains attached to glycerol backbone.
- What is the primary function of bile acids?
- Aid in the digestion and absorption of fats. Emulsify fats for enzyme digestion.
- Differentiate between saturated and unsaturated fatty acids.
- Saturated: no double bonds; Unsaturated: one or more double bonds. Double bonds create kinks affecting molecular packing and fluidity.
- What is the role of essential fatty acids in the body?
- They are precursors to signaling molecules. Required for synthesis of important cellular messengers.
- What is the role of lipoproteins in the body?
- Transport lipids through the bloodstream. Package lipids for transport in aqueous blood.
- Which type of lipid is a major component of cell membranes?
- Phospholipids. Form bilayer structure due to amphipathic properties.
- How do lipids contribute to the fluidity of cell membranes?
- By preventing fatty acid chains from packing tightly. Unsaturated fatty acids prevent rigid packing.
- Identify the type of bond formed between glycerol and fatty acids.
- Ester bond. Covalent bond linking fatty acid to glycerol.
- Identify the lipid that is a key component of bile.
- Cholesterol. Synthesized from cholesterol in the liver.
- What is the function of the lipid bilayer in membranes?
- Acts as a barrier to control substance entry and exit. Selective permeability maintains cellular compartmentalization.
- Which enzyme catalyzes the hydrolysis of triglycerides?
- Lipase. Breaks ester bonds in triglycerides.
- Which type of lipid is most abundant in the brain?
- Phospholipids. Essential for neural membrane structure and function.
- Which type of lipids are involved in signaling within cells?
- Steroids. Act as hormones and membrane components.
- What is the function of sphingolipids in cells?
- Participate in cell signaling and recognition. Membrane components involved in cell communication.
- Which lipids are primarily responsible for water-repellency in plants?
- Waxes. Protective coating on leaves and stems.
- Identify the role of lipids in the nervous system.
- Insulation and protection of nerve fibers. Myelin sheaths protect and insulate axons.
- Identify the process by which triglycerides are formed.
- Dehydration synthesis. Removes water to form ester bonds.
- Identify the lipid type that serves as an energy reserve.
- Triglycerides. Provides concentrated energy storage in adipose tissue.
- Identify the type of lipid involved in waterproofing.
- Waxes. Long-chain fatty acids create protective barriers.
- What is the storage form of lipids in animals?
- Triglycerides. Stored in adipose tissue for long-term energy.
- Which lipid is commonly found in adipose tissue?
- Triglycerides. Fat storage cells for energy reserves.
- What is an essential fatty acid?
- A fatty acid that must be obtained from the diet. Cannot be synthesized by the body.