chapter 5,6,7 study guide answers fnu 203

What are the major functions of lipids in the body?

absorb fat soluble vitamins and phytochemicals, cushions from bumps and bruises, form and maintain cell membranes, participate in cell signaling, insulating the body against cold temperatures, produce steroid hormones, provide and store energy in the form of triglycerides

Describe the advantages and disadvantages of following a high-protein diet.

advantages: weight loss, blood sugar regulation, cardiovascular effects, bone health disadvantages: kidney stress, cardiovascular disease risk, cancer risk, osteoporosis risk

Explain how insulin and glucagon regulate blood glucose levels.

as people eat carbs, blood glucose levels rise and the pancreas secretes insulin into the bloodstream. because insulin enables glucose to enter most cells, the hormone helps reduce blood glucose to normal levels. If hunger signals are ignored, alpha cells of pancreas secrete glucagon. glucagon promotes breakdown of glycogen (glycogenolysis)- releases glucose into the bloodstream and keeps blood glucose from dropping too low

List the chemical names for blood sugar, table sugar, milk sugar, and malt sugar.

blood sugar= glucose, table sugar= sucrose, milk sugar= lactose, malt sugar= maltose

List at least four different functions of proteins in the body.

build new cells and many functional components of cells, as a component of hardened structures, such as hair and nails, as enzymes to speed chemical reactions, as lubricants to ease movement, in clotting compounds in blood, to build antibodies that fight disease organisms, as compounds that help maintain fluid and pH balance, as transporters, to make certain hormones, as a last resort (only under certain conditions) as an energy source

List the major components of an amino acid.

carbon atom that anchors; hydrogen atoms, amino or nitrogen- containing group, R group (side chain), carboxylic acid group

Explain the process of protein turnover.

cellular process of breaking down proteins and recycling their amino acids

A recipe mixes cereals made from wheat, rice, and corn. Use the concept of protein complementation to choose plant foods that could be added to the cereal mixture to improve the balance of amino acids in the meal.

cereal grains such as wheat, rice, and corn are good sources of tryptophan and methionine, but are low in lysine. wheat germ, sesame seeds, sunflower seeds could be added because they are rich in lysine.

What are the components of a phospholipid?

chemically similar to a triglyceride except 1 of the fatty acids is replaced by a chemical group containing phosphorus and often nitrogen, both hydrophilic and hydrophobic at the same time

Explain why protein-energy malnutrition (PEM) is especially devastating for young children.

children with PEM don't grow well and are very weak, irritable and vulnerable to dehydration and infections, such as measles, can kill them. if they do survive, their growth may be permanently stunted, and their intelligence may be lower than normal because malnutrition during early childhood can cause permanent brain damage

Compare the composition of a chylomicron, VLDL, LDL, and HDL.

chylomicron- type of lipoprotein formed in enterocytes to transport lipids away from the GI tract, VLDL: lipoprotein made in the liver, carries much of the triglycerides in the bloodstream, LDL: lipoprotein that carries cholesterol into tissues, HDL: lipoprotein that transports cholesterol away from tissues and to the liver, where it can be eliminated

What structural characteristic distinguishes a trans fatty acid from a cis fatty acid?

cis fatty acids have hydrogen atoms of the double- bonded carbons on the same side of the hydrocarbon chain. trans fatty acids have hydrogen atoms of the double- bonded carbons on opposite sides of the hydrocarbon chain. trans fats are more solid at room temperature than cis fatty acids

Identify at least three dietary sources of complete and incomplete proteins.

complete: meat, fish, poultry, eggs, dairy products incomplete: most plant foods

What is dietary fiber?

complex carbohydrates comprised of monosaccharides connected by bonds that human enzymes cannot break down. it is not digested, but it may be fermented by gut microbiota. any fiber not used by microbiota contributes to feces. two different types: soluble and insoluble; most types are polysaccharides, nondigestible plant material

Identify at least three common food allergens.

cow's milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans

Discuss the health benefits of including soluble and insoluble fiber in diets.

diets rich in soluble fiber can reduce risk of CVD, improve blood lipid levels, lower blood pressure, reduce inflammation markers, block bile reabsorption by the intestine, drops blood cholesterol insoluble fiber helps form large, soft fecal mass, reduces constipation

Suggest at least four ways people can reduce their intakes of saturated fats and increase their intakes of unsaturated fats.

eat fewer solid fats, especially foods made with PHO's such as stick margarine, avoid products using interesterified oil, partially hydrogenated fat, or shortening, use natural peanut/ almond butter, consume commercial frostings in moderation, eat fewer commerically prepared baked goods, snack foods, and fried fast- food items, buy plain popcorn

List at least three ways to increase one's fiber intake.

eat whole grain, bran, or oatmeal breads and cereals, substitute whole- wheat pasta for regular pasta, eat edible peels, pulp, and seeds of fruits and veggies, include more nuts, beans, and seeds in your diet, spread peanut or almond butter on whole- grain crackers

List three food sources of cholesterol.

egg yolks, liver, meat, poultry, dairy products made from cream or whole milk

Define limiting amino acids and discuss their importance in protein synthesis.

essential amino acid found in the lowest concentration in an incomplete protein. if the body does not have an adequate amount of all the amino acids required to make a particular protein, it cannot be synthesized

Explain the differences between essential, conditionally essential, and nonessential amino acids.

essential- must be supplied by the diet, body cannot make them, conditionally essential nutrient- normally nonessential but can become essential under certain conditions, nonessential- body can make these

Explain what happens to dietary fiber in the small and large intestines.

fiber is not digested in the small intestine, eventually enters the large intestine, gut bacteria ferments soluble fiber for energy, insoluble fiber does not fully breakdown and contributes to softer feces

Distinguish between glycogen and starch, including similarities and differences.

glycogen and starch are both glucose polymers. Starch is a storage polysaccharide in plants composed of both amylose and amylopectin. Glycogen is a storage polysaccharide in animals and is the stored form of glucose.

List potential health benefits of plant-based diets.

high amounts of vitamin C, vitamin E, folate, phytonutrients, fiber, magnesium, potassium low amounts of saturated fatty acids

Explain the difference between high-quality and low-quality proteins.

high quality are complete proteins, they are well- digested, absorbed, and used by the body, contains adequate amounts of each of the 9 essential amino acids, low quality proteins are incomplete, contain inadequate amounts of one or more of the essential amino acids

Discuss the possible connection between elevated blood homocysteine levels and CVD.

higher than normal blood levels of homocysteine may injure arterial walls

List the essential amino acids.

histidine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine

List three common signs or symptoms of a food allergy.

hives, swollen throat, face or hands, chest tightness, difficulty swallowing, wheezing and difficulty breathing, abdominal pain, vomiting, diarrhea

Where does the final breakdown step from dipeptides and tripeptides into individual amino acids take place?

inside the mucosa cells of the intestine

Describe the absorption of carbohydrates by the small intestine and their transport to the liver.

intestinal cells absorb glucose and galactose by active transport, fructose is absorbed by facilitated diffusion, monosaccharides then enter capillary network of villus, hepatic portal vein transports the monosaccharides to the liver

Does drinking sugar-sweetened soda contribute to obesity? Explain.

it does not inherently cause obesity, but consumers of sugar- sweetened beverages are more likely to have excessive energy intakes because they don't help you feel full. Studies suggest that people who drink sugar- sweetened beverages do not reduce their energy intake from solid food accordingly

Explain the function of an emulsifier in food preparation and manufacturing.

keep oily and watery ingredients from separating during storage

How does an omega‒3 fatty acid differ from an omega‒6 fatty acid?

omega- 3: first double bond at the third carbon from omega end, lowers LDL cholesterol, omega- 6: first double bond at the sixth carbon from omega end, lowers HDL and LDL cholesterol

Explain why some lactose-intolerant individuals are able to consume yogurt, cheese, and small amounts of milk without experiencing intestinal discomfort.

people with lactose intolerance can reduce dairy intake to about 12-15 g per day. choosing fermented milk products and substituting milk with plant milk alternatives can help. lactaid products can also help because they put external lactase into your body that will break down lactose before it gets to the large intestine

Identify the type of bond that links amino acids in a protein together.

peptide bond

Explain conditions that can cause the body to be in positive nitrogen balance and in negative nitrogen balance.

positive: rapid growth periods (pregnancy, infancy, puberty), recovering from illness or injury, when performing weight training negative: starvation, serious illness or injury

List the four levels of protein structure from simplest to most complex.

primary, secondary, tertiary, quaternary

How are proteins chemically different from carbohydrates and lipids?

proteins are large, complex organic molecules made up of amino acids that contain carbon, hydrogen, oxygen, and nitrogen

Describe four health benefits of omega-3 fatty acid consumption.

reduces risk of alzheimer's, arthritis, certain cancers, dental disease, depression (including postpartum), heart disease, preterm birth may improve: alzheimer's, cognitive development in infants, rheumatoid arthritis symptoms

List the primary sources of added sugars in the typical American diet.

regular soft drinks, energy drinks, cookies, chips, processed snack foods, coffee

According to the 2020-2025 Dietary Guidelines for Americans, how much saturated fat, cholesterol, and trans fat should an adult consume?

saturated fat- less than 10 % of total calories, cholesterol- as little as possible when consuming a healthy diet, trans fat- keep intake as low as possible

Identify at least two foods that are rich sources of (a) saturated fat, (b) monounsaturated fat, and (c) polyunsaturated fat.

saturated fat: meats and poultry, milk, cheese, eggs, tropical oils (coconut and palm), monounsaturated fat: canola oil, olives and olive oil, nuts and nut oils, polyunsaturated fat: corn, safflower, soybean, sunflower, and cottonseed (oils)

What are saturated, monounsaturated, and polyunsaturated fatty acids?

saturated- no double bonds, no sites of unsaturation, monounsaturated- one double bond, one site of unsaturation, polyunsaturated- two or more double bonds, two or more sites of unsaturation

Identify the major functions of carbohydrate in the body

serve as "glue" that holds cells together, cell- cell recognition molecules, lubrication

List the two general categories of carbohydrates

simple and complex

Identify at least two food sources of soluble fiber and two sources of insoluble fiber.

soluble: apples, bananas, citrus fruits, carrots, oats, barley, psyllium seeds, beans, and thickeners added to foods insoluble: all plants, especially whole wheat, rye, brown rice, veggies, whole grains, wheat bran

List five rich food sources of omega-3 fatty acids.

- fish/ shellfish: salmon and tuna - oils: canola, soybean - nuts: walnuts, flaxseeds -other: algae

Discuss the series of physiological changes that occur in arteries and contribute to the development of CVD.

- injured arterial lining becomes inflamed due to immune response, white blood cells in arteries contribute to lesions on blood vessel walls as they attempt to repair damage, enlarged white blood cells get trapped in artery wall, contributing to formation of arterial plaques, plaque roughens normally smooth surface of arterial lining, which slows blood flow, making a clot likely to form, if a clot lodges on plaque and becomes wedged in lumen of artery, blood flow through artery can be completely blocked.

Identify the two essential fatty acids, and describe key signs of an essential fatty acid deficiency.

linolenic acid and alpha- linolenic acid / signs: scaly skin, hair loss, poor wound healing

Bernard's total blood cholesterol level is 195 mg/dL, and his HDL cholesterol level is 62 mg/dL. Based on this information, does Bernard have a high risk or low risk of developing CVD? Explain your answer.

low risk because total blood cholesterol levels are supposed to be under 200 mg/dL and HDL cholesterol for men is desirable above 40 mg/dL

Name the monosaccharides that constitute each molecule of malt sugar, milk sugar, and table sugar.

malt sugar= 2 glucoses, milk sugar= glucose and galactose, table sugar= glucose and fructose

What is a ketone body, and under what conditions does the body form excessive ketone bodies?

molecules formed from metabolism of fat that can be used as an alternative fuel for certain cells in the body when glucose levels are low. ketoacidosis can occur in individuals with type 1 diabetes because insulin levels are deficient

Describe what happens to the fat in a piece of fried chicken as it undergoes digestion and absorption; include the roles of bile, CCK, pancreatic lipase, villi, and micelles.

mouth: inactive lipase in saliva mixes with fat- containing food, acidic environment of stomach activates lipase, which begins fat digestion, small intestine: secretes secretin, which stimulates liver to produce bile and pancreas to secrete bicarbonate rich pancreatic juice, also secretes CCK, which stimulates gallbladder to release bile and pancreas to secrete digestive enzymes, including pancreatic lipase, which removes 2 fatty acids from each triglyceride molecule, glycerol, fatty acids, and monoglycerides are the major products of lipid digestion. bile contains bile salts that emulsify liquids in the watery environment of the small intestine, they surround the fatty acids and monoglycerides to form a water- soluble particle called a micelle, micelles transport the lipids to the edge of the enterocytes, these cells remove the monoglycerides and fatty acids from micelles, the used bile salts then continue to form new micelles

List at least three major risk factors for developing CVD that are non-modifiable and at least five that are modifiable.

non- modifiable: family history, advanced age, male sex, race/ethnic background modifiable: diabetes, elevated LDL, untreated sleep apnea, excess body fat, hypertension, tobacco use or exposure, physical inactivity, unhealthy diet

What is the difference between a nutritive sweetener and a nonnutritive sweetener?

nonnutritive- supply little or no energy per serving, nutritive- sweeten and contribute to energy to foods

Contrast nutrigenomics and nutrigenetics.

nutrigenomics- study of how nutrients affect the expression of a person's genome nutrigenetics- study of how inherited genetic variations influence the body's responses to specific nutrients and nutrient combinations

Sherita ate a whole grain bagel with grape jelly for a snack. As this snack passed through her digestive tract, discuss what happened to the starch, sucrose, and fiber in the food.

starch digestion: begins in mouth as salivary amylase converts starch into maltose, stops after food enters acidic environment of stomach small intestinal enzyme sucrase splits each sucrose molecule, forming one glucose and one fructose molecule, intestinal cells absorb glucose by active transport and fructose by facilitated diffusion. the hepatic portal vein transports monosaccharides to the liver. the liver can use simple sugars to make glycogen or fat. if the body needs energy, the organ releases glucose into the bloodstream. fructose is converted to glucose in the liver. fiber is not digested by the small intestine, it eventually enters the small intestine. intetinal bacteria ferments the soluble fiber (pectin) used in making jellies, for energy. the whole grain bagel (insoluble fiber), doesn't break down completely and contributes to softer, easier to eliminate feces

Explain the basic steps involved in protein synthesis.

stomach: hydrochloric acid denatures food proteins and converts inactive pepsinogen to active pepsin, small intestine: further digestion occurs as pancreas secretes protein- splitting enzymes (trypsin and chymotrypsin), peptides are broken down into amino acids in enterocytes and amino acids move into the capillary network of villus, after absorbed, amino acids enter hepatic portal vein and are transported to the liver, rectum: very little dietary protein is excreted in feces

What effect do plant sterols and stanols have on cholesterol absorption?

they compete for intestinal absorption with cholesterol which reduces the total amount of cholesterol being absorbed

Compare and contrast transamination and deamination reactions.

transamination- occurs when the nitrogen- containing group is transferred to another substance to make a non- essential amino acid deamination- removal of the nitrogen- containing group from an amino acid

List the three major classes of lipids.

triglycerides, phospholipids, sterols

Name two pancreatic enzymes that break down protein in the small intestine.

trypsin and chymotrypsin

Compare type 1, type 2, and gestational diabetes.

type 1: autoimmune disease that results in destruction of the beta cells of the pancreas; insulin must be applied of the affected person regularly through exogenous sources type 2: most common type, beta cells of pancreas produce insulin, but hormone's target cells are insulin resistant gestational: can develop during pregnancy

Explain why cholesterol is necessary for health.

used to synthesize steroid hormones

List at least two strategies for reducing trans fat intake.

uses nonhydrogenated fats, such as olive or canola oils, all spreads, including butter and margarine, should be consumed in moderation

Compare and contrast vegetarian and vegan diets.

vegetarian: plant- based eating pattern that may or may not include some animal foods vegan: diet based solely on plant foods, with complete elimination of animal foods and products

Identify nutrients that can be low or missing from a plant-based diet.

vitamin B-12, vitamin D, riboflavin, zinc, iron, calcium, omega- 3 fatty acids, certain essential amino acids