Question 3 One of your classmates, Mike, is working on a new science fiction novel. He approaches you with questions regarding cell membranes a)Explain the following to Mike i)What are lipids? The term lipid refers to a variety of molecules composed mainly of hydrocarbons. They are water insoluble due to the many non-polar covalent bonds ii)Why are saturated fatty acids more likely to be solid at room temperature than unsaturated fatty acids? Saturated fatty acids are composed of hydrocarbon chains containing only single bonds (i.e. the carbon atoms are saturated with hydrogens). Saturated fatty acids are more linear and can be packed more tightly together. Unsaturated fatty acids contain one or more double bond between the carbon atoms. These molecules are less linear and do not pack together as well b)On the diagrams below label the hydrophilic and hydrophobic regions of the pl phospholipids CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH CH。-CHC -P-oHCH2 hydrophobic regie hydrophilic regions are circled c)Why does the structure of the phospholipid molecule favor the formation of bilayers or membranes? A phospholipid has fatty acid tails that are extremely hydrophobic attached to a phosphate containing head that is hydrophilic. In an aqueous environment, the hydrophobic tails cluster together to exclude water in a manner that allows the hydrophilic end to interact with the water d)Mike proposes the following structure for the membranes of an ali conditions would need to exist to make this arrangement possible? en life form. What ooooo For this arrangement to be stable, the environment surrounding the phospholipid must be hydrophobie Portion of alien membrane 7012Fall20037.012 Fall 2003 3 Question 3 One of your classmates, Mike, is working on a new science fiction novel. He approaches you with questions regarding cell membranes. a) Explain the following to Mike. i) What are lipids? The term lipid refers to a variety of molecules composed mainly of hydrocarbons. They are water insoluble due to the many non-polar covalent bonds. ii) Why are saturated fatty acids more likely to be solid at room temperature than unsaturated fatty acids? Saturated fatty acids are composed of hydrocarbon chains containing only single bonds (i.e. the carbon atoms are saturated with hydrogens). Saturated fatty acids are more linear and can be packed more tightly together. Unsaturated fatty acids contain one or more double bond between the carbon atoms. These molecules are less linear and do not pack together as well. b) On the diagrams below label the hydrophilic and hydrophobic regions of the phospholipids. P O O O O – – CH2 CH CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 hydrophobic regions are boxed hydrophilic regions are circled c) Why does the structure of the phospholipid molecule favor the formation of bilayers or membranes? A phospholipid has fatty acid tails that are extremely hydrophobic attached to a phosphate containing head that is hydrophilic. In an aqueous environment, the hydrophobic tails cluster together to exclude water in a manner that allows the hydrophilic end to interact with the water. d) Mike proposes the following structure for the membranes of an alien life form. What conditions would need to exist to make this arrangement possible? For this arrangement to be stable, the environment surrounding the phospholipid must be hydrophobic. Portion of alien membrane