Chapter 5: Lipids

Five grams of dietary fat contribute __________ kilocalories. - 20 - 35 - 45 - 50

- 45

Which of the following statements correctly identifies the process of lipid transport? - Sterols such as cholesterol are not digested, but pass freely into the portal vein from the enterocyte. - Micelles transport lipids through the lymphatic system before they enter the bloodstream. - Different lipids are absorbed based on their structure. Short-chain and medium-chain fatty acids are absorbed into the lacteal to enter the lymphatic system as part of a chylomicron, whereas long-chain fatty acids are transported directly into the portal vein. - A layer of proteins, phospholipids, and cholesterol molecules surrounds each chylomicron to facilitate transport.

- A layer of proteins, phospholipids, and cholesterol molecules surrounds each chylomicron to facilitate transport.

Chylomicron, VLDL, LDL, HDL, Micelle - This lipoprotein contains the most triglyceride and the least protein. - This lipoprotein contains a mixture of lipids, most of which is 60% triglycerides, and about 10% protein. - This lipoprotein contains 50% of its composition as protein, and the other 50% is composed of triglycerides, cholesterol, and phospholipids. - This lipoprotein contains the most cholesterol of all the lipoproteins and about 25% protein.

Chylomicron: - This lipoprotein contains the most triglyceride and the least protein. VLDL: - This lipoprotein contains a mixture of lipids, most of which is 60% triglycerides, and about 10% protein. LDL: - This lipoprotein contains the most cholesterol of all the lipoproteins and about 25% protein. HDL: - This lipoprotein contains 50% of its composition as protein, and the other 50% is composed of triglycerides, cholesterol, and phospholipids. Micelle: - N/A

Chylomicron, VLDL, LDL, HDL - This lipoprotein delivers triglycerides from the liver to the body's cells, including adipose cells. - This lipoprotein is release from the liver and picks up cholesterol from the cells to transport it back to the liver. - This lipoprotein, formed after VLDLs have released some of their triglycerides, transports cholesterol to the cells of the body. - This lipoprotein transports dietary lipids out of the enterocyte.

Chylomicron: - This lipoprotein transports dietary lipids out of the enterocyte. VLDL: - This lipoprotein delivers triglycerides from the liver to the body's cells, including adipose cells. LDL: - This lipoprotein, formed after VLDLs have released some of their triglycerides, transports cholesterol to the cells of the body. HDL: - This lipoprotein is release from the liver and picks up cholesterol from the cells to transport it back to the liver.

Risk Factors You Can't Control, Risk Factors You Can Control, Emerging Risk Factors - family history of heart disease - hypertension - physical activity level - type 1 diabetes - body weight - high levels of homocysteine - HDL level - type 2 diabetes - elevated C-reactive protein (CRP)

Risk Factors You Can't Control: - family history of heart disease - type 1 diabetes Risk Factors You Can Control: - hypertension - physical activity level - body weight - HDL level - type 2 diabetes Emerging Risk Factors: - high levels of homocysteine - elevated C-reactive protein (CRP)

- Blood flow is slowed or stopped. - LDL cholesterol becomes oxidized. - Macrophages travel to the site and engulf the oxidized LDLs, and foam cells form. - LDL and other substances seep through the injury and deposit within the arterial wall. - Foam cells accumulate to create a fatty streak. - Arterial lining is injured. - Plaque forms, and artery passageway narrows.

Step 1: - Arterial lining is injured. Step 2: - LDL and other substances seep through the injury and deposit within the arterial wall. Step 3: - LDL cholesterol becomes oxidized. Step 4: - Macrophages travel to the site and engulf the oxidized LDLs, and foam cells form. Step 5: - Foam cells accumulate to create a fatty streak. Step 6: - Plaque forms, and artery passageway narrows. Step 7: - Blood flow is slowed or stopped.- Blood flow is slowed or stopped.

Fatty acids that are liquid at room temperature are generally __________. - cholesterol - unsaturated - linoleic acid - saturated

- unsaturated

Lipids are hydrophobic, which means __________. - rancid - indigestible - water fearing - water loving

- water fearing

1. The narrowing of arteries, also called ________, is thought to start with an injury to an artery's interior wall. 2. The buildup of ________ within an artery wall can greatly obstruct blood flow through the artery's passageway. 3. Once macrophages "gobble up" cholesterol-laden LDL and become enlarged, they are transformed into ________. 4. A person whose blood pressure is 140/90 is said to have ________. 5. When a blood vessel leading to the heart is blocked by a clot, a ________ can result. 6. The ________ are the large blood vessels that supply oxygen and other nutrients to the heart. 7. ________ is a used as a marker for the presence of atherosclerosis. 8. Smoking, diabetes, and chronic high blood pressure are examples of ________.

1. atherosclerosis 2. plaque 3. foam cells 4. hypertension 5. heart attack 6. coronary arteries 7. C-reactive protein (CRP) 8. controllable risk factors

1. Fatty acids are broken off from the glycerol backbone using water in a process called ________. 2. This compound, which is the most common lipid in foods, is made up of three fatty acids attached to a glycerol backbone and is called a ________. 3. The enzyme ________, secreted from the chief cells in the stomach, begins the digestion of some triglycerides. 4. When fat enters the duodenum, an emulsifier called is released into the small intestine to break up the large fat globules into smaller fat droplets. 5. This alcohol, called ________, is made up of three carbons, three hydroxyl groups, and five hydrogen ions. 6. This enzyme, which catalyzes the hydrolysis of the two fatty acids from the glycerol backbone in the intestine, is called ________. 7. The structure composed of a glycerol backbone and one fatty acid is called a ________. 8. Long-chain fatty acids are transported via chylomicrons from inside the enterocyte into the ________ to be delivered to the bloodstream and then the rest of the body. 9. The hormone ________ stimulates the gallbladder to release bile through the common bile duct into the duodenum. 10. The products of lipid hydrolysis are transported to the enterocytes in ________.

1. hydrolysis 2. triglyceride 3. gastric lipase 4. bile 5. glycerol 6. pancreatic lipase 7. monoglyceride 8. lymphatic system 9. cholecystokinin 10. micelles

Which of the following statements correctly describes the metabolic fate of the lipids transported by lipoproteins? - The HDL cholesterol is often referred to as the "bad cholesterol" because it transports cholesterol released from the liver and may deposit the cholesterol in the arterial cells, increasing the risk of atherosclerosis or blocked arteries. - Cholesterol removed from the cells by LDLs is carried back to the liver and excreted through bile, decreasing the risk of atherosclerosis or blocked arteries. - As the VLDL moves along the bloodstream, an enzyme hydrolyzes protein from the surface of the lipoproteins to be taken up by the muscle and adipose cells. - The LDL cholesterol interacts with receptor sites on the surface of cells to release cholesterol that can be used to make bile, hormones, and vitamin D.

- The LDL cholesterol interacts with receptor sites on the surface of cells to release cholesterol that can be used to make bile, hormones, and vitamin D.

A primary risk factor for cardiovascular disease is elevated blood lipids, especially LDL cholesterol. The level of total cholesterol and HDL cholesterol relative to LDL cholesterol in the blood can be useful in determining the health of the arteries and the risk of developing heart disease. The optimal level of blood lipids includes a lower total cholesterol and LDL cholesterol to reduce the amount of lipids that infiltrate the arterial wall creating plaque buildup. A higher HDL cholesterol may help protect against cholesterol buildup in the arterial wall. Which of the following blood lipids typically analyzed in a blood lipid profile are considered optimal to reduce the risk of heart disease? - Total cholesterol between 200-239 mg/dl LDL cholesterol <100 mg/dl HDL cholesterol between 40-60 mg/dl - Total cholesterol <200 mg/dl LDL cholesterol 100-129 mg/dl HDL cholesterol 40 mg/dl - Total cholesterol between 200-210 mg/dl LDL cholesterol >190 mg/dl HDL cholesterol >60 mg/dl - Total cholesterol <200 mg/dl LDL cholesterol <100 mg/dl HDL cholesterol >60 mg/dl

- Total cholesterol <200 mg/dl LDL cholesterol <100 mg/dl HDL cholesterol >60 mg/dl

Day-to-day choices can help reduce the risk of heart disease. One of the major risk factors for development of heart disease is elevated LDL, which can be affected by dietary factors like the types and amounts of dietary fat consumed. Read the statements below and select all of the correct statements regarding how various dietary fats affect LDL cholesterol levels. - Trans fats are worse for heart health than saturated fats because they raise LDL cholesterol and lower HDL cholesterol. - Increasing intake of EPA and DHA through consuming fish may be helpful for most adults, but a physician should be consulted before taking fish oil supplements. - Fried fish can be a good way to increase a person's intake of heart-healthy omega-3 fatty acids if he or she does not like baked fish. - Increasing intake of plant foods may be one of the easiest ways to decrease LDL blood cholesterol. - Typically, the higher the consumption of unsaturated fats, the higher the LDL cholesterol levels in the blood.

- Trans fats are worse for heart health than saturated fats because they raise LDL cholesterol and lower HDL cholesterol. - Increasing intake of EPA and DHA through consuming fish may be helpful for most adults, but a physician should be consulted before taking fish oil supplements. - Increasing intake of plant foods may be one of the easiest ways to decrease LDL blood cholesterol.

The body has an unlimited ability to store excess energy as fat in __________. - enzymes - adipocytes - glycogen - cholesterol

- adipocytes

The liver is able to synthesize all the __________ the body needs. - omega-3 fatty acids - linoleic acid - cholesterol - triglycerides

- cholesterol

Which of the following prefer(s) utilizing lipids as fuel? - heart - red blood cells - nervous system - brain

- heart

Controllable risk factors for heart disease include __________. - type 1 diabetes and physical activity - high blood pressure and smoking - age and family history - smoking and gender

- high blood pressure and smoking

What is the major phospholipid found in cell membranes? - choline - glycerol - cholesterol - lecithin

- lecithin

The best way to decrease the amount of trans fat in your diet is to __________. - increase your intake of processed foods - limit your intake of processed foods - decrease your total kilocalorie intake - decrease your milk consumption

- limit your intake of processed foods

The two essential fatty acids are __________. - cholesterol and glycerol - linoleic acid and alpha-linolenic acid - linoleic acid and sterol - chylomicrons and VLDLs

- linoleic acid and alpha-linolenic acid

Enzymes that digest lipids are called __________. - maltase - lipases - lactase - sucrase

- lipases

Transport vehicles for lipids in the blood and lymph are called __________. - lipoproteins - enterocytes - adipocytes - micelles

- lipoproteins

Consumption of which dietary fat lowers LDL cholesterol levels but maintains (or improves) HDL levels? - trans fat - saturated fat - polyunsaturated fat - monounsaturated fat

- monounsaturated fat

Phospholipids make good emulsifiers because __________. - one end is hydrophilic, or water loving - they are saturated - they taste great - they are dense

- one end is hydrophilic, or water loving

Which of the following foods does NOT contain dietary cholesterol? - peanut butter - low-fat milk - cheese - chicken

- peanut butter

Most lipid digestion occurs in the __________. - small intestine - mouth - large intestine - stomach

- small intestine

To reduce the risk of cardiovascular disease, it's best to increase the amount of __________ in your diet. - trans fat - total fat - saturated fat - soluble fiber

- soluble fiber

Many low-fat products contain added __________, which contributes to empty kilocalories. - fiber - sugar - protein - minerals

- sugar

A key difference between omega-3 fatty acids and omega-6 fatty acids is __________. - the location of the first double bond - hydrogenation of the omega bond - omega-6 fatty acids never become rancid - the configuration or shape around the double bond

- the location of the first double bond

The most common lipid(s) found in both foods and the body is/are __________. - cholesterol - lecithin - triglycerides - glycerol

- triglycerides

The process of lipid digestion begins even before you take your first bite of food. Just the smell of food can begin digestive juices flowing. The most common lipids found in foods are primarily in the form of triglycerides. These lipids are hydrolyzed during digestion to yield monoglycerides, glycerol, and free fatty acids. Rank the events from taking a bite of food rich in lipids to triglycerides being released to cells. - Bile from the gallbladder emulsifies large fat globules into smaller ones in the small intestine. - Fats are broken up into smaller droplets in the stomach, and chief cells release gastric lipase, which hydrolyzes some triglycerides. - Inside enterocytes, components of micelles re-form to create chylomicrons that enter the lymph; short-chain fatty acids enter bloodstream directly. - As chyme enters the duodenum of the small intestine, cholecystokinin stimulates the gallbladder to contract and secrete bile and stimulates the secretion of digestive enzymes from the pancreas. - Pancreatic lipase hydrolyzes triglycerides into monoglycerides, glycerol, and fatty acids. - Fatty acids, monoglycerides, and other lipids form micelles, and micelles transport products of lipids digestions to enterocytes. - Solid fats melt during mastication, and lingual lipase begins digestion of triglycerides.

Step 1: - Solid fats melt during mastication, and lingual lipase begins digestion of triglycerides. Step 2: - Fats are broken up into smaller droplets in the stomach, and chief cells release gastric lipase, which hydrolyzes some triglycerides. Step 3: - As chyme enters the duodenum of the small intestine, cholecystokinin stimulates the gallbladder to contract and secrete bile and stimulates the secretion of digestive enzymes from the pancreas. Step 4: - Bile from the gallbladder emulsifies large fat globules into smaller ones in the small intestine. Step 5: - Pancreatic lipase hydrolyzes triglycerides into monoglycerides, glycerol, and fatty acids. Step 6: - Fatty acids, monoglycerides, and other lipids form micelles, and micelles transport products of lipids digestions to enterocytes. Step 7: - Inside enterocytes, components of micelles re-form to create chylomicrons that enter the lymph; short-chain fatty acids enter bloodstream directly.

Stomach, Pancreas, Small Intestine, Gallbladder, Mouth - lingual lipase - pancreatic lipase - phospholipase - gastrin - cholecystokinin - gastric lipase - bile

Stomach: - gastrin - gastric lipase Pancreas: - pancreatic lipase - phospholipase Small Intestine: - cholecystokinin Gallbladder: - bile Mouth: - lingual lipase