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A fatty acid that has two double bonds between its carbon atoms is called __________. Possible Answers:
an unsaturated fatty acid
a hydrogenated fatty acid
Correct answer: an unsaturated fatty acid Explanation: An unsaturated fatty acid has one or more double bonds in its hydrocarbon tail. These double bonds are formed by the removal of hydrogen atoms from the carbon tail, resulting in a kink in the tail. As such, they are not fully saturated with hydrogen atoms. Cholesterol is a type of lipid that contains four hydrocarbon rings in its structure. Hydrogenated fatty acids are unnatural saturated fatty acids that are modified for their physical properties.
Three fatty acids each joined to glycerol by an ester linkage is a __________. Possible Answers:
Correct answer: triacylglycerol Explanation: A triacylglycerol (also called commonly referred to as a fat or a triglyceride) is composed of three fatty acid chains linked to glycerol via an ester linkage. The fatty acids can be the same or two or three different types. Steroids are derived from cholesterol, a molecule that contains four hydrocarbon rings attached together. Phospholipids only have two fatty acid tails linked to a glycerol head and a phosphate group.
Which of the following is an example of a lipid? Possible Answers:
Correct answer: triacylglycerol Explanation: Triacylglycerol (also called a fat or triglyceride) is a type of lipid. Amino acids are the subunits that make up proteins. Chitin and cellulose are polysaccharides, or carbohydrates.
Which of the following terns best describes a molecule that contains three fatty acid chains bonded to a glycerol molecule? Possible Answers:
Correct answer: Triglyceride Explanation: Structurally speaking, a triglyceride molecule contains three fatty acid chains covalently bonded to glycerol—specifically where the hydroxyl groups are located on the glycerol molecule.
A polyunsaturated lipid contains which of the following that is/are not contained in saturated lipids? Possible Answers:
Sulfur atoms in place of carbons
Correct answer: Multiple double bonds Explanation: The term saturated when describing a lipid means that a molecule has the maximum number of hydrogens on its carbons, it is saturated with hydrogens. An unsaturated lipid has less than the maximum amount of hydrogens bonded to its carbons because there is a double bond between two of the carbons. Lipids molecules can have one carbon to carbon double bond (mono-unsaturated) or multiple (poly-unsaturated).
All of the following biomolecules form true polymers except __________. Possible Answers:
Correct answer: fatty acids Explanation: Fatty acids occur as free molecules in trace amounts in living organisms. They usually occur as a component of several types of lipid molecules, and are not true monomers, even though 1-3 of them can be attached to a polar head group such as glycerol or a phosphate group. The rest of the choices listed form polymers. Amino acids form proteins, sugars such as glucose form carbohydrates, and nucleotides form both DNA and RNA.
Which of the following statements regarding lipid molecules is true? Possible Answers:
They store genetic information
They are soluble in water
They must contain a phosphate group
They can be used as a source of energy
Correct answer: They can be used as a source of energy Explanation: Lipids can be used as an energy source and are often used by cells to store energy for future use. Phosphate groups are not found in all lipids. For example most steroids, which are lipids, do not have phosphate groups. Lipids are hydrophobic and are repelled by water.
Which of the following correctly describes saturated fats? Possible Answers:
In saturated fats, the carbons have double bonds between them.
Saturated fats have single bonds between nitrogen and carbon.
In saturated fats, the carbons contain the maximum amount of hydrogens bonded to them.
Saturated fats are usually liquid at room temperature.
Correct answer: In saturated fats, the carbons contain the maximum amount of hydrogens bonded to them. Explanation: In saturated fats, the carbons have single bonds between them and the maximum number of hydrogen atoms. Saturated fats do not have nitrogen, and they are solid at room temperature.
Which of the following is true of unsaturated fats? Possible Answers:
The nitrogens are bonded to a phosphate group in a chain.
Unsaturated fats have one or more double bonds between between carbons in the fatty acid chain.
Unsaturated fats have the maximum number of hydrogens bonded to the carbons.
Unsaturated fats are solids at room temperature.
Correct answer: Unsaturated fats have one or more double bonds between between carbons in the fatty acid chain. Explanation: Unsaturated fats have at least one double bond between two carbons in the fatty acid and do not have the maximum number of hydrogens. They do not contain nitrogen and are usually liquid at room temperature.
Which of the following is not a function of lipids? Possible Answers:
Maintaining body temperature
Forming membranes around organelles
Correct answer: Folding proteins Explanation: Lipids are what make up fats. Fats store energy and help insulate animals against the cold. They also form lipid bilayers that surround cells and organelles. All steroid hormones are derived from cholesterol, a lipid. Thus, lipids play a significant role in signal transduction. Folding proteins is a function left to other proteins.
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Kevin
Johns Hopkins University, Bachelor in Arts, Biology, General.
Abdul
The University of Texas at Austin, Bachelor of Science, Biology, General. University of Phoenix-Online Campus, Masters in Edu...
Sarah
Rensselaer Polytechnic Institute, Bachelor of Engineering, Biomedical Engineering.
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