Biochemistry: Lipids and Glycolysis Review - Questions & Answers

Review Packet for Chapters 10, 13, and 14 Chapter 10: Lipids Know the three major types of lipids. Why are examples of their function? Storage of energy, Structural, Lipids with Specific functions. Functions: Storage, structural, membrane, signaling What is the definition used to describe fatty ac...

Review Packet for Chapters 10, 13, and 14 Chapter 10: Lipids Know the three major types of lipids. Why are examples of their function? Storage of energy, Structural, Lipids with Specific functions. Functions: Storage, structural, membrane, signaling What is the definition used to describe fatty acids? Fatty acids are precursor for many lipids. They are hydrocarbon derivatives. Hydrocarbon chain with a carboxyl group at the end. What is the difference between saturated and unsaturated fatty acids? For saturated fatty acids, every C has as many H’s as possible. For unsaturated fatty acids, it has a double bond which means it can still add a few more H’s. Unsaturated fatty acids are also bent and cannot be straightened out. Know the subtypes for unsaturated fatty acids and how are they different. Properties are different. Mono is made up of one double bond and poly is make up of many double bonds. Know melting point; longer the chain, the higher the melting point. More double bonds= lower melting points Understand the basic structure of a fatty acid for both saturated and unsaturated. For unsaturated fatty acids, the double bonds are almost always in cis-configuration and are almost never conjugated. Carboxyl group is polar, hydrocarbon chain is non-polar. 1 There is a table over the physical properties of fatty acids; be able to differentiate which are saturated fatty acids and which are unsaturated fatty acids (has double bonds). Be able to match as well the ratios to the common name, and understand the trends for melting point and solubility. Know palmitic acid FACT: Most lipids have fatty acids, but not all. An example is cholesterol. In the storage lipids, what is the main structure? Be able to draw the structure of triacylglycerol. Know that glycerol has 3 C’s each have a OH and the chains are linked by the OH’s 2 How does it get hydrolyzed? From hydrolysis (splitting apart by water); example is making soap. Alkali hydroxide will hydrolyze it; in body phospholipase will Go over saponification. Soaps are prepared from fatty acids. Saponification occurs when you add potassium hydroxide (3KOH) to triacylglycerol to make soaps and glycerol. What linkage do waxes contain? Waxes contain covalent linkage between fatty acids and alcohol in ester linkage is a covalent linkage. Waxes are esters of long chain saturated and unsaturated fatty acids with long-chain alcohol. Know that the carboxyl group on the end of the other chain links with the alcohol on the first chain. (on end of other chain that links with alcohol is the carboxyl group?) For structural lipids, there are phospholipids and glycolipids, and among them there are subtypes of lipids. Be able to match the subtypes with their structure. 3 What gives their polarity? The charged group on the end; the phosphate and head group in the phospholipid can have a charged group For glycerophospholipids, there are specific structures mentioned; again be able to match the names to common name. know basic structure Be able to do the same for the specific structures of sphingolipids. know basic structure 4 What are sterols and its three subtypes (and where they may be found)? Sterols are one of the most decorated biomolecule of all time. Three subtypes: Which type of sterol is a precursor for bile salts, vitamin D, and hormones? Cholesterol is the precursor for bile salts, vitamin D, and hormones FACT: Sterols are a type of lipid found with four rings fused together as the main backbone. Lipids have specific biological functions for life. What is the precursor lipid for prostaglandins and eicosanoids? Arachidonic acid because of lots of double bonds How do NSAIDS work? Non-steroid anti-inflammatory drugs work by blocking synthesis of prostaglandin and thromboxane. Know that they inhibit cyclooxygenase 5 Go over the mechanism with the slide for “Arachidonic acid metabolites and their function”. FACT: Aspirin is referred to a “blood thinner” because it inhibits the coagulation process. Its actually not a blood thinner, it just prevents blood clots Know the four fat-soluble vitamins and their function. 6 Quiz 1. The hydrophobicity of fats make them better source of energy over carbs because….? because they don’t have water associated with them so you can store more energy because water takes up space 2. True or False? A ganglioside is a sphingolipid? 3. Arachidonic acid contains 20 carbon and 0 double bonds. 4. Between 20:0 and 20:2 Δ9, 12 which has the higher melting point? Why? 20:0 has the higher melting point because it has no double bonds the single bonds make it easier to have more forces. 5. True or False. The presence of one or more double bond in the unsaturated fatty acids interfere with tight packing of the molecules and thus it melts at low temperatures. 6. Which of the following is not a component of gangliosides? a. Fatty acid b. Phosphate group c. N-acetylneuraminic acid d. Sphingosine 7. The biological role of fat-soluble vitamin A is …….? Helps increase vision 8. The release of inositol 1, 4, 5 triphosphate causes what in the cell? 9. Commercial hydrogenation of an unsaturated fatty acid usually results in a compound having: a. Increased melting point b. Increased solubility c. Decreased melting point d. Decreased solubility 10. Match the general names of the compounds on the left to the specific names on the right. a. Saturated fatty acid i. oleic acid b. Unsaturated fatty acid ii.1-palmitoyl-2-linoleoyl-3stearroyl-glycerol c. Triacylglycerol iii. stearic acid 7  11. What is one disadvantage of lipids over carbohydrates as a source of energy fuel? Solubility and location; carbs are soluble while lipids are not so transporting them is tricky Chapter 13: Bioenergetics What are the basic principles of metabolism? Understand the pathway for catabolism and anabolism. Know whether energy is produced or consumed for both pathways. The basic principles of metabolism are anabolism and catabolism. There are linear and nonlinear metabolic pathways. Nonlinear pathways include converging catabolism, diverging anabolism, and cyclic pathway. Anabolism builds up complex structures like DNA (consumes energy/ endergonic), while catabolism breaks down energy-rich molecules like glucose to release energy (produces energy/ exergonic). FACT: They occur separately. Never simultaneously. FACT: Sources of energy may come from lipids, carbohydrates, and proteins. 8 Going back to Gibbs Free Energy, what is the relationship K’eq has with ΔG˚? What can be mentioned for the direction of a chemical reaction? On a side note, make sure you understand the difference between thermodynamics and kinetics. Hint: be able to tell the difference between what ΔG or ΔG˚ can tell you about a reaction direction versus what the rate will do. Delta G0 is the standard conditions but delta g can be altered. Kinetics is how fast or slow, thermodynamics is the proportion of reactions and products based on free energy of delta g0 Make sure to go over the relationship shown in ΔG˚ = -RTlnK. It explains the relationship between K and ΔG˚, when K is large, ΔG˚ is negative and vice versa. FACT: K ln(K) ΔG K>1 + - K