Question 1

Synthesis of cholesterol takes place in the ________.

Accepted Answer

Cholesterol synthesis occurs mainly in the liver, although other organs such as the intestines and adrenal glands can also synthesize cholesterol.

Question 2

The most common type of gallstones is composed of almost pure ________.

Accepted Answer

The most common type of gallstones is composed of almost pure cholesterol.

Question 3

Answer the following question(s)about the diagram shown below. 
-In this diagram of a cell membrane,the object labeled (B)is a ________.

Accepted Answer

The object labeled (B) in the diagram represents the hydrophobic region of the phospholipid bilayer, which is composed of two layers of phospholipid molecules with their hydrophilic heads facing outwards and hydrophobic tails facing inwards. The hydrophobic region creates a barrier that separates the inside and outside of the cell, controlling what substances can enter or exit. Therefore, the best choice is D, phospholipid bilayer. A is incorrect because steroids are a type of lipid molecule that can be found in the membrane but not represented by (B) in the given diagram. C is incorrect because membrane proteins are embedded in the lipid bilayer, but they are not represented by (B) in the diagram. E is incorrect because carbohydrate side chains are attached to the membrane proteins or lipids, but they are not represented by (B) in the given diagram.

Question 4

Answer the following question(s)about the diagram shown below. 
-In the fluid-mosaic model that describes cell membranes,________.

Accepted Answer

The fluid-mosaic model describes a cell membrane as having two layers of phospholipid molecules with their nonpolar sections oriented to the inside of the membrane, creating a hydrophobic environment for the cell's contents. The model also includes various types of proteins and other molecules that are embedded in or attached to the membrane, creating a mosaic-like pattern. There are not three layers of phospholipids and the nonpolar sections are not along the outer surface of the membrane. A single row of phospholipid molecules would not be sufficient to form a barrier between the inside and outside of the cell, and two layers of proteins do not separate the contents inside a cell from the surrounding fluids.

Question 5

Which of the following is not a function of glycerophospholipids?

Accepted Answer

Glycerophospholipids do not aid in digestion. They primarily function in the formation of cell membranes and the regulation of cellular permeability. They can also play a role in protecting nerve cells and transporting cholesterol. However, they are not involved in the transport of triacylglycerols, which is typically carried out by lipoproteins.

Question 6

Accepted Answer

The structure depicted in the identifier code is a glycerophospholipid, which consists of glycerol, two fatty acid chains, a phosphate group, and a polar head group.

Question 7

The steroid hormone that increases the blood glucose and glycogen levels from fatty acids and amino acids is ________.

Accepted Answer

Cortisone is a glucocorticoid hormone that increases the blood glucose and glycogen levels by stimulating the conversion of fatty acids and amino acids into glucose in the liver. Aldosterone regulates salt and water balance, progesterone and estrogen mainly regulate the female reproductive system, and prednisone is a synthetic corticosteroid used to treat inflammation and immune system disorders.

Question 8

Which of the lipid types listed below is most soluble in water?

Accepted Answer

Glycerolphospholipids have a polar head group (containing a phosphate group) and two nonpolar fatty acid tails, which allows them to interact with both water and nonpolar molecules.

Question 9

Which of the following is not a lipoprotein that carries nonpolar lipids through the bloodstream?

Accepted Answer

Glycerol is a small polar molecule and is not a type of lipoprotein that carries nonpolar lipids (such as cholesterol and triglycerides) through the bloodstream. The other answer choices (B-E) are all lipoproteins that transport nonpolar lipids in varying forms.

Question 10

Which of the following compounds is a glycerophospholipid?

Accepted Answer

Glycerophospholipids are a type of phospholipid that contain a glycerol backbone, two fatty acid chains, a phosphate group, and a polar head group. Lecithin is a common glycerophospholipid found in cell membranes. Choice A is a wax, choice B is a steroid hormone, choice D is a triglyceride, and choice E is a fatty acid, all of which are not glycerophospholipids.

Question 11

The components in the following glycerophospholipid are ________.

Accepted Answer

The answer of The components in the following glycerophospholipid are...

Question 12

Answer the following question(s)about the diagram shown below. 
-In this diagram of a cell membrane,the small branched object labeled (A)is part of a ________.

Accepted Answer

The small branched object labeled (A) in a diagram of a cell membrane is typically part of a carbohydrate side chain. These carbohydrate side chains are often attached to proteins or lipids on the extracellular surface of the cell membrane, forming glycoproteins and glycolipids, respectively, which play key roles in cell recognition and signaling.

Question 13

Answer the following question(s)about the diagram shown below. 
-In this diagram of a cell membrane,the objects labeled (E)are ________.

Accepted Answer

The answer of Answer the following question(s)about the diagram shown...

Question 14

A lipoprotein particle functions to ________.

Accepted Answer

Lipoprotein particles are responsible for transporting nonpolar lipids, such as cholesterol and triglycerides, to body cells. They do not dissolve polar lipids for excretion or dissolve polar lipids in urine. While lipids can be metabolized into new substances, lipoprotein particles themselves do not carry out this process. Additionally, lipoprotein particles do not store lipids in tissues.

Question 15

Accepted Answer

The answer of 
...

Question 16

According to the fluid-mosaic model of a cell membrane,the main component of a membrane is ________.

Accepted Answer

The fluid-mosaic model describes the cell membrane as composed of a lipid bilayer, which is made up of phospholipids, cholesterol, and glycolipids. The proteins embedded in this lipid bilayer create a mosaic pattern, hence the name “fluid-mosaic model.” While the other answer choices may be present in the cell membrane, they are not the primary component.

Question 17

The main lipid components in cellular membranes are ________.

Accepted Answer

Glycerolphospholipids are the main lipid components of cellular membranes, as they form the phospholipid bilayer that surrounds and defines the cell. Fatty acids also contribute to membrane structure, but are not the main component. Steroids, triacylglycerols, and waxes are not typically found in significant quantities in cellular membranes.

Question 18

The type of lipid that gives a cell membrane its structure is a ________.

Accepted Answer

Glycerophospholipids, also known as phospholipids, are a major component of cell membranes and give the membrane its structure. Triacylglycerols and waxes are used for energy storage, prostaglandins are signaling molecules, and fatty acids can be used for energy or as building blocks for other lipids but do not contribute to membrane structure.

Question 19

Answer the following question(s)about the diagram shown below. 
-In this diagram of a cell membrane,the object labeled (C)is a ________.

Accepted Answer

The object labeled (C) in the diagram is a glycerophospholipid, which is a type of phospholipid that makes up a significant part of the cell membrane. Steroids, proteins, and carbohydrates are also components of the cell membrane, but they are not the object labeled (C) in the diagram. Mitochondria are not part of the cell membrane at all.

Question 20

Accepted Answer

The answer of 
...

Quiz 15: Lipids