1.
Which is NOT a function of lipids
Correct Answer
A. Storage of genetic material
Explanation
Lipids are not involved in the storage of genetic material. Lipids primarily function as a source of energy or fuel for the body, as components of cell membranes, and as precursors to steroid hormones. However, they do not have a role in storing genetic material, which is mainly carried out by nucleic acids such as DNA and RNA.
2.
Which functionla group is found in triglycerides
Correct Answer
C. Ester
Explanation
Triglycerides are a type of lipid molecule composed of three fatty acid chains attached to a glycerol backbone. The bond between the fatty acid chains and the glycerol molecule is an ester bond. Therefore, the functional group found in triglycerides is an ester.
3.
Which is a hydrolyzable lipid
Correct Answer
B. Waxes
Explanation
Waxes are hydrolyzable lipids because they can be broken down or hydrolyzed into their constituent fatty acids and alcohol molecules. This process occurs when waxes are exposed to water and specific enzymes called esterases. Therefore, waxes can be classified as hydrolyzable lipids, unlike steroids, eicosanoids, and vitamins, which do not undergo hydrolysis in the same way.
4.
Which is not a saturated fatty acid
Correct Answer
C. Arachidonic acid
Explanation
Arachidonic acid is not a saturated fatty acid because it contains one double bond in its carbon chain, making it unsaturated. Saturated fatty acids, on the other hand, do not have any double bonds and have a straight carbon chain. Lauric acid, myristic acid, palmitic acid, and stearic acid are all examples of saturated fatty acids as they do not contain any double bonds.
5.
Which unsaturated fatty acid contains 3 double bonds
Correct Answer
C. Linolenic acid
Explanation
Linolenic acid is the correct answer because it is an unsaturated fatty acid that contains 3 double bonds. Oleic acid contains only one double bond, linoleic acid contains 2 double bonds, arachidonic acid contains 4 double bonds, and myristic acid is a saturated fatty acid with no double bonds. Therefore, linolenic acid is the only option that satisfies the given criteria.
6.
What type of solvents are used to classify lipids
Correct Answer
D. All of the above
Explanation
All of the solvents mentioned (toluene, dioxane, and carbon tetrachloride) can be used to classify lipids. Lipids are a diverse group of compounds that are insoluble in water but soluble in organic solvents. Toluene, dioxane, and carbon tetrachloride are all organic solvents commonly used in lipid extraction and analysis. Therefore, all of the above solvents can be used to classify lipids.
7.
Having both hydrophobic and hydrophilic portions is called
Correct Answer
B. AmpHipathic
Explanation
Amphipathic molecules have both hydrophobic and hydrophilic portions. The hydrophobic portion repels water, while the hydrophilic portion is attracted to water. This property allows amphipathic molecules to interact with both water and nonpolar substances. Therefore, amphipathic is the correct term to describe molecules with both hydrophobic and hydrophilic regions.
8.
A lipid that contains glycerol and three fatty acids is
Correct Answer
B. A trilgyceride
Explanation
A triglyceride is a type of lipid that contains glycerol and three fatty acids. Triglycerides are the main form of fat found in the body and are used as a source of energy. They are also stored in adipose tissue and can be broken down when energy is needed. Unlike phospholipids, which have a phosphate group attached to glycerol, or steroids and eicosanoids, which have different structures and functions, triglycerides are composed of only glycerol and fatty acids.
9.
Animal fats are ___ in unsaturated fatty acids
Correct Answer
B. Low
Explanation
Animal fats are low in unsaturated fatty acids. Unsaturated fatty acids are typically found in plant-based oils and are known to be healthier for the body as they can help lower cholesterol levels. Animal fats, on the other hand, are high in saturated fats which can contribute to increased cholesterol levels and the risk of heart disease. Therefore, the correct answer is low.
10.
A ___ reaction breaks a triglyceride into glycerol and 3 fatty acids
Correct Answer
B. Hydrolysis
Explanation
Hydrolysis is the correct answer because it is a chemical reaction that involves the breaking of a compound through the addition of water. In the case of a triglyceride, hydrolysis breaks it down into glycerol and three fatty acids by adding water molecules to the ester bonds that hold the fatty acids to the glycerol molecule. This reaction is commonly seen in processes like digestion, where enzymes in the body catalyze the hydrolysis of dietary fats into their component parts for absorption and use by the body.
11.
Enzymes called ___ hydrolyze triglycerides in the body
Correct Answer
B. Lipases
Explanation
Lipases are enzymes that break down or hydrolyze triglycerides in the body. Triglycerides are a type of fat molecule, and lipases help to break them down into smaller components such as fatty acids and glycerol. This process is important for the digestion and absorption of fats in the body. Therefore, lipases are the correct enzymes responsible for the hydrolysis of triglycerides in the body.
12.
Hydrogenation reactions add ___ to the unsaturated fatty acid
Correct Answer
C. Hydrogen
Explanation
Hydrogenation reactions involve the addition of hydrogen to unsaturated fatty acids. This process converts double bonds in the fatty acid molecules into single bonds, making them more saturated. Hydrogenation is commonly used in the food industry to convert liquid vegetable oils into solid or semi-solid fats, such as margarine or shortening. By adding hydrogen, the fatty acids become more stable and have a longer shelf life. Therefore, the correct answer is hydrogen.
13.
Linear, unbranched lipids containing 14-36 carbons is best described as a
Correct Answer
D. Wax
Explanation
Linear, unbranched lipids containing 14-36 carbons are best described as waxes. Waxes are long-chain fatty acids combined with long-chain alcohols, and they are typically found in nature as protective coatings on plants and animals. They have high melting points and are insoluble in water, making them useful for providing waterproofing and protection against moisture loss. Unlike steroids, triglycerides, and phospholipids, waxes do not have specific biological functions such as hormone regulation or energy storage.
14.
Which is an amino alcohol found in phospholipids
Correct Answer
B. Choline
Explanation
Choline is an amino alcohol that is commonly found in phospholipids. Phospholipids are a major component of cell membranes and choline plays a crucial role in their structure and function. Choline is also involved in various biological processes such as neurotransmitter synthesis, lipid metabolism, and cell signaling. Therefore, choline is the correct answer to the question.
15.
What makes up the backbone of a sphingolipid
Correct Answer
B. SpHingosine
Explanation
Sphingosine is a component of the backbone of a sphingolipid. Sphingolipids are a class of lipids that contain a sphingosine backbone, which is a long chain amino alcohol. This backbone is attached to various fatty acids and other functional groups to form different types of sphingolipids. Glycerol, choline, and ethanolamine are not part of the backbone structure of sphingolipids.
16.
What type of steroid emulsifies fats
Correct Answer
B. Bile salts
Explanation
Bile salts are a type of steroid that emulsifies fats. They are produced by the liver and stored in the gallbladder. When we consume foods that contain fats, bile salts are released into the small intestine where they help break down the fats into smaller droplets, making it easier for enzymes to digest and absorb them. This process is essential for the digestion and absorption of dietary fats in the body.
17.
What nonhydrolyzable lipid is derived from arachidonic acid
Correct Answer
B. Eicosanoids
Explanation
Eicosanoids are nonhydrolyzable lipids that are derived from arachidonic acid. They are important signaling molecules that play a role in various physiological processes such as inflammation, blood clotting, and immune response. Eicosanoids include prostaglandins, thromboxanes, and leukotrienes, among others. These molecules are synthesized from arachidonic acid through enzymatic reactions and act as local hormones, exerting their effects in the immediate vicinity of their production site.
18.
What lipids are found in the cell membrane
Correct Answer
B. Cholesterol, pHospHopids
Explanation
The cell membrane is composed of a lipid bilayer, which consists of two layers of phospholipids. Phospholipids have a hydrophilic (water-loving) head and a hydrophobic (water-fearing) tail, making them ideal for forming the structure of the cell membrane. Cholesterol is also present in the cell membrane and helps maintain its fluidity and stability. Triglycerides, waxes, and vitamins are not typically found in high amounts in the cell membrane.