exam 3 Flashcards
Where does lipid digestion begin?
Lipid digestion begins in the mouth and stomach.
What enzymes help with lipid digestion in the mouth and stomach?
Lingual lipase and gastric lipase help with lipid digestion in the mouth and stomach.
Where are most triglycerides digested?
Most triglycerides are digested in the small intestine.
What substances help with triglyceride digestion in the small intestine?
Bile and pancreatic lipase help with triglyceride digestion in the small intestine.
How are digested lipids transported from the lumen of the GI tract into enterocytes?
Micelles transport digested lipids from the lumen of the GI tract into the enterocytes.
How are short- and medium-chain fatty acids absorbed?
Directly into the bloodstream.
How are longer-chain fatty acids and other remnants of fat digestion transported?
Longer-chain fatty acids and other remnants of fat digestion are packaged into chylomicrons, which transport them through the lymphatic system until they enter the bloodstream.
What do lipoproteins transport?
Lipoproteins transport triglycerides, cholesterol, and other lipids through the lymph and bloodstream.
What is the function of LDLs?
LDLs deposit cholesterol in artery walls.
What is the function of HDLs?
HDLs remove cholesterol from arteries and deliver it to the liver, which uses it in the synthesis of bile and other compounds.
What is the function of stored triglycerides in the body?
Stored triglycerides cushion and protect bones, organs, and nerves and help maintain body temperature.
What is the role of dietary fat in the body?
Dietary fat provides essential fatty acids and is needed for the absorption of fat-soluble vitamins and carotenoids.
What are eicosanoids, and how are they synthesized?
Eicosanoids are substances that regulate several body functions. Essential fatty acids are precursors to arachidonic acid and EPA, which are used to synthesize eicosanoids.
What is the function of cholesterol in the body?
Cholesterol is used to make sex hormones, bile, and vitamin D.
What are phospholipids and cholesterol, and where are they found in the body?
Phospholipids and cholesterol are part of cell membranes.
Why are dietary lipids, particularly essential fatty acids, important for a healthy diet?
Dietary lipids, particularly essential fatty acids, are important for a healthy diet because they provide key nutrients.
What types of fats should be limited in the diet?
Saturated fats, trans fats, and cholesterol should be limited in the diet.
What should the range of dietary fat intake be as a percentage of total kilocalories?
The range of dietary fat intake should be from 20 to 35 percent of total kilocalories.
How much of total daily kilocalories should come from linoleic acid to meet essential fatty acid needs?
5-10 percent of total daily kilocalories should come from linoleic acid to meet essential fatty acid needs.
How much of total daily kilocalories should come from alpha-linolenic acid to meet essential fatty acid needs?
0.6-1.2 percent of total daily kilocalories should come from alpha-linolenic acid to meet essential fatty acid needs.
What is the recommended limit for dietary intake of saturated fat?
The recommended limit for dietary intake of saturated fat is no more than 10 percent of total fat consumption
How much of fat consumption should be from trans fats?
Less than 1 percent of fat consumption should be from trans fats.
Are dietary cholesterol and phospholipids essential nutrients?
No, dietary cholesterol and phospholipids are not essential nutrients, as they are both made in the body.
What are the best food sources to obtain essential fatty acids and limit saturated and trans fats?
Lean meat and poultry, fish, low-fat or nonfat dairy products, and limited amounts of nuts and cheese are the best food sources to obtain essential fatty acids and limit saturated and trans fats.
Why should commercially prepared baked goods and snack items be consumed rarely?
Commercially prepared baked goods and snack items are high in kilocalories, saturated fat, and trans fats, and should be consumed rarely.
What should be used in place of butter?
Vegetable oils should be used in place of butter.
Where are trans fats found, and how are they labeled on food products?
Trans fats are found in commercially prepared foods made with partially hydrogenated oils (PHOs). Any trans fats in a food must be listed on the Nutrition Facts panel.
Has the FDA banned partially hydrogenated oils (PHOs) from processed foods?
Yes, the FDA has banned all PHOs from processed foods by July 2018.
Where is cholesterol found in the diet?
Cholesterol is found mostly in animal-based foods.
What do plant-based foods mostly contain in place of cholesterol?
Plant-based foods contain mostly phytosterols in place of cholesterol.
What are fat substitutes, and what are they made of?
Fat substitutes can be carbohydrate-based, protein-based, or fat-based
Do reduced-fat or fat-free foods still contain kilocalories?
Yes, reduced-fat or fat-free foods still contain kilocalories and should be eaten in limited amounts.
What is the primary cause of heart disease?
Heart disease is primarily caused by atherosclerosis, a narrowing of the arteries due to a buildup of plaque.
What are some uncontrollable risk factors for heart disease?
Uncontrollable risk factors for heart disease include age, gender, and genetics
What are some controllable risk factors for heart disease?
Controllable risk factors for heart disease include high LDL blood cholesterol, low HDL blood cholesterol, high blood pressure, excess body weight, inactivity, type 2 diabetes, and smoking
What dietary choices are associated with a reduction in the risk of heart disease?
Limiting saturated fat, cholesterol, and trans fat, increasing fish consumption, and consuming antioxidant-rich fruits, vegetables, whole grains, and nuts are dietary choices associated with a reduction in the risk of heart disease.
Can drinking a moderate amount of alcohol help reduce the risk of heart disease?
Yes, drinking a moderate amount of alcohol may help reduce the risk of heart disease in middle-aged and older adults
What can regular exercise and maintaining a healthy body weight help with in regards to heart disease?
Regular exercise and maintaining a healthy body weight can help lower LDL cholesterol concentrations and raise HDL cholesterol concentrations.
What should you do if you currently smoke?
If you currently smoke, you should quit because smoking damages the walls of the arteries.
What are proteins made of?
Proteins are made of chains of amino acids linked together with peptide bonds.
What are amino acids composed of?
Amino acids are composed of a central carbon with a carboxyl group, a hydrogen, a nitrogen-containing amine group, and a unique side chain.
How many different side chains are there and how many amino acids?
There are 20 different side chains and therefore 20 unique amino acids.
What determines the function of a protein?
The precise three-dimensional shape that the protein folds into determines its function.
What can denature a protein and alter its shape and function?
Heat, mechanical agitation, acids, bases, and salts can denature a protein and alter its shape and function.
Where does chemical digestion of protein begin?
Chemical digestion of protein begins in the stomach.
What stimulates the release of HCl and pepsinogen in the stomach during protein digestion?
Gastrin stimulates the release of HCl from the parietal cells and the inactive enzyme pepsinogen from the chief cells during protein digestion.
How does HCl contribute to protein digestion in the stomach?
HCl denatures the protein and converts pepsinogen to pepsin, which breaks polypeptides into shorter chains.
What hormone stimulates the release of pancreatic proteases during protein digestion?
Cholecystokinin from the duodenum stimulates the release of trypsinogen, carboxypeptidase, and chymotrypsinogen from the pancreas during protein digestion.
What do proteases do during protein digestion?
Proteases hydrolyze the shorter protein chains into tripeptides and dipeptides.
How are tripeptides and dipeptides further hydrolyzed during protein digestion?
Dipeptidases and tripeptidases hydrolyze the tripeptides and dipeptides into single amino acids.
How are absorbed amino acids used in the body?
Absorbed amino acids are used to synthesize new proteins or are converted to nonessential amino acids, ATP, glucose, or fat.
How are proteins broken down during digestion?
Proteins are broken down into amino acids with the help of gastric juices, enzymes in the stomach and small intestine, and enzymes from the pancreas and small intestinal lining.
What are amino acid pools?
Amino acid pools are a limited supply of amino acids that act as a reservoir for protein synthesis.
What happens to surplus amino acids in the body?
Surplus amino acids are deaminated, with the carbon-containing remnants used for glucose or energy or stored as fat, depending on the body’s needs.
What happens to the nitrogen in amine groups during deamination?
The nitrogen in amine groups is eventually converted to the waste product urea and excreted in urine.
How are nonessential amino acids synthesized?
Nonessential amino acids are synthesized through transamination.
What do proteins provide in the body?
Proteins provide structural and mechanical support in the body.
What is the most abundant protein in the body?
Collagen is the most abundant protein in the body.
Where is collagen found in the body?
Collagen is found in all connective tissues, including bones, tendons, and ligaments.
What is the function of collagen in the body?
Collagen provides support and elasticity to connective tissues and forms scar tissue to repair injuries.