Il, Lipids a) form essential structural components of cells b) provide roughly t
ID: 205288 • Letter: I
Question
Il, Lipids a) form essential structural components of cells b) provide roughly twice the energy as carbohydrates c) help to maintain body temperature d) help to cushion delicate organs from damage e) all of the above 12. A fatty acid that contains three double covalent bonds in its carbon chain is said to be a) saturated c) polyunsaturated e) carboxylated d) hydrogenated Most of the fat found in the human body is in the form of a) steroids c) triglycerides e) monoglycerides 13, b) phospholipids d) prostaglandins /7. A type of lipid that is produced by nearly every tissue in the body and that acts as a local regulator of metabolism is the a) prostaglandins c) monoglycerides e) glycolipids b) steroids d) phospholipids Cholesterol, phospholipids, and glycolipids are examples of a) dietary fats c) structural lipids e) steroids 15. b) prostaglandins d) lipid drugsExplanation / Answer
11. (e) all of the above.
The lipids form essential structural components of cells which acts as a barrier to the passage of polar molecules and ions. The major structural lipids are glycerophopholipids, galactolipids, sulfolipids, tetraether lipids and sphingolipids.
Lipids are the principal stored forms of energy. Triacylglycerols provide stored energy. The triacylglycerols stored under the skin alsi insulate against low temperatures.
Lipids in the cell membranes are amphipathic, i.e., one end of the molecule is hydrophobic and the other hydrophilic. Their hydrophobic interactions with each other and their hydrophilic interactions with water direct their packing into sheets called membrane bilayers. These cushion delicate organs from damage.
12. (c) polyunsaturated. The lipids molecules having no double bonds are called saturated. Hence, a fatty acid that contains three double covalent bonds in its carbon chain is said to be polyunsaturated.
13. (c) triglycerides. Triglycerides are oil droplets in the aqueous cytosol which serve as depots of metabolic fuel. These are most abundant lipids in human body. Adipocytes or fat cells store large amounts of triglycerides as fat droplets that nearly fill the cell.
14. (d) phospholipids. Phospholipids regulate cell metabolism These molecules in the plasma membranes serves as a specific bindling site for certain cytoskeletal proteins and soluble proteins involved in membrane fusion. These serve as reservoirs of messenger molecules that are released inside the cell in response to extracellular signals interacting with specific receptors on the outer surface of plasma membrane.
15. (c) structural lipids.Cholesterol, phospholipids and glycolipids are the major structural lipids present in the membranes of most eukaryotic cells.