Question 1

Which fatty acids are NOT synthesized by the body?

Accepted Answer

Essential fatty acids, such as omega-3 and omega-6, cannot be synthesized by the body and must be obtained through diet. Cis, saturated, and short chain fatty acids can all be synthesized by the body.

Question 2

Which is a characteristic of eicosanoids?

Accepted Answer

All of the answer choices are correct. Eicosanoids are hormone-like compounds that are synthesized from omega-3 and omega-6 fatty acids, and they are needed to regulate many body processes.

Question 3

Which statement best describes the relationship between VLDL,IDL,and LDL?

Accepted Answer

VLDLs are produced by the liver and contain mostly triglycerides. When acted on by lipoprotein lipase, they are converted into IDLs, which contain a mixture of cholesterol and triglycerides. Further action of lipoprotein lipase on IDLs leads to formation of LDLs, which are primarily cholesterol-rich and are taken up by cells through LDL receptors. Therefore, statement A is the best choice as it accurately describes the sequence of conversion from VLDLs to IDLs to LDLs.

Question 4

"After digestion particle A enters the lymphatic system and then the blood stream,where it is acted on by an enzyme that converts triglycerides to fatty acids and glycerol.This process converts particle A into particle B." What are particles A & B?

Accepted Answer

This description of the digestion process matches that of chylomicrons, which enter the lymph system and then blood stream. After being acted on by an enzyme, chylomicrons are converted into chylomicron remnants.

Question 5

What is the function of the HDL particle?

Accepted Answer

The function of the HDL particle is to pick up cholesterol from lipoproteins in the blood and transport it to the liver and to organs that synthesize steroid hormones. This is why HDL is commonly referred to as "good" cholesterol.

Question 6

Which fatty acid produces eicosanoids that promote inflammation?

Accepted Answer

Arachidonic acid is a fatty acid that produces eicosanoids, such as prostaglandins and leukotrienes, that promote inflammation. EPA, on the other hand, produces eicosanoids that have anti-inflammatory effects. Unsaturated fats can be either pro-inflammatory or anti-inflammatory depending on their particular fatty acid composition.

Question 7

What is the function of hormone sensitive lipase?

Accepted Answer

Hormone sensitive lipase breaks down stored triglycerides inside fat cells, releasing fatty acids into the bloodstream for energy production.

Question 8

Which hormone plays a central role in the regulation of lipid metabolism?

Accepted Answer

Insulin plays a central role in the regulation of lipid metabolism by promoting the storage of excess lipids in adipose tissue and inhibiting lipolysis in adipose tissue.

Question 9

What happens when excess energy is ingested?

Accepted Answer

When excess energy is ingested, it is converted into triglycerides and stored in adipose tissue. This can lead to weight gain and obesity if excess energy intake persists over time.

Question 10

Which statement best distinguishes between chylomicrons and VLDLs?

Accepted Answer

Chylomicrons are formed in the small intestine and enter the lymphatic system, while VLDLs are formed in the liver and enter the blood stream. This is the key distinguishing factor between the two lipoprotein types.

Question 11

What is the main constituent of adipose tissue?

Accepted Answer

Adipose tissue is primarily composed of triglycerides which are storage forms of fat.

Question 12

What is the effect of high levels of HDLs in the blood?

Accepted Answer

High levels of HDLs, also known as "good" cholesterol, are beneficial as they help remove excess cholesterol from the arterial walls and return it to the liver for processing. This reduces the risk of heart disease by preventing the buildup of plaque in the arteries.

Question 13

What is the primary function of lipoprotein lipase?

Accepted Answer

Lipoprotein lipase is an enzyme that breaks down triglycerides into fatty acids and glycerol, allowing their entry into surrounding cells for use as energy or storage. This is the primary function of lipoprotein lipase.

Question 14

Which word best describes a fatty acid that CANNOT be synthesized in the body?

Accepted Answer

Essential fatty acids are those that cannot be synthesized in the body and must be obtained through the diet. Precursor, beneficial, and nonessential do not specifically describe this type of fatty acid.

Question 15

What are the precursors of eicosanoid formation?

Accepted Answer

The precursors of eicosanoid formation are omega-3 and omega-6 fatty acids, which are essential fatty acids that cannot be synthesized by the body and must be obtained from the diet. Cholesterol and lecithin are not precursors of eicosanoids, and trans fatty acids can actually inhibit the conversion of omega-3 and omega-6 fatty acids into eicosanoids.

Question 16

For which conditions have the anti-inflammatory effects of omega-3 fatty acids may be beneficial for what conditions?

Accepted Answer

The anti-inflammatory effects of omega-3 fatty acids have been shown to be beneficial for a variety of conditions, including heart disease, rheumatoid arthritis, and multiple sclerosis. Therefore, all of the answer choices are correct.

Question 17

When used as a source of energy,fatty acids are converted into what molecule?

Accepted Answer

Fatty acids are converted into acetyl CoA through beta-oxidation in order to enter the citric acid cycle for energy production.

Question 18

Which lipoprotein is responsible for reverse cholesterol transport?

Accepted Answer

HDLs are responsible for reverse cholesterol transport, meaning they remove excess cholesterol from the peripheral tissues and bring it back to the liver for processing and excretion. Chylomicrons, LDLs, and VLDLs are all responsible for transporting cholesterol out of the liver and into the peripheral tissues.

Question 19

Which of the following lipoproteins contains the highest proportion of cholesterol?

Accepted Answer

Low-density-lipoproteins (LDL) contain the highest proportion of cholesterol, often referred to as "bad" cholesterol. This is because they transport cholesterol from the liver to the cells of the body, and if there is an excess amount, it can build up in the arteries and increase the risk of heart disease.

Question 20

Which of the following is needed for cells to take up low-density lipoproteins?

Accepted Answer

LDL (low-density lipoprotein) receptors are necessary for cells to take up LDLs, which are often referred to as "bad" cholesterol. These receptors bind the LDL particles and allow the cell to internalize and use the cholesterol they carry. Lipoprotein lipase is an enzyme that breaks down triglycerides in circulating lipoproteins, but it is not directly involved in the uptake of LDLs. Homocysteine is an amino acid that can be harmful to blood vessels in high levels, but it is not involved in the uptake of LDLs. Insulin is a hormone that helps regulate blood sugar levels, but it is not directly involved in the uptake of LDLs.

Quiz 5: Lipids