Nutrition Exam 2
Chylomicrons
a lipoprotein produced in the enterocytes; transports dietary fat out of the intestinal tract
Triglycerides
a molecule consisting of Three fatty acids attached to a three-carbon glycerol backbone
lipoprotein
a spherical compound in which fat clusters are the center and phospholipids and proteins form the outside of the sphere
Define micelle
a spherical compound made up of bile salts and biliary phospholipids that transports lipid digestion products to the intestinal mucosal cell
Of the approximately 160,000 kcal reserves in the body of a well-nourished 70-kg male
about 85% is from triglycerides, and most of the remaining 15% is from protein.
Excessive ketones are produced when
acetyl CoA is converted to glucose
The B-vitamins act as _________
act as coenzymes to promote energy metabolism
The portion of an amino acid that contains nitrogen is called the
amine group. -The side chain varies for each amino acid. The acid group contains carbon, hydrogen, and oxygen. No portion of an amino acid is known as a nitrate cluster
Nonessential amino acids are
amino acids that the body is able to synthesize in sufficient quantities to meet its needs. -The body needs these amino acids as much as it needs essential amino acids, which are those it is unable to synthesize and that must be consumed in the diet. Except in people with metabolic diseases such as PKU, the body is able to metabolize all 20 amino acids, including phenylalanine
fatty acids
an acid composed of a long chain of carbon atoms bound to each other as well as to hydrogen atoms, with a carboxyl group at the alpha end of the chain
lipoprotein lipase
an enzyme that sits on the outside of cells and breaks apart triglycerides, so that their fatty acids can be removed and taken up by the cell
alpha linoleic acid
an essential fatty acid found in leafy green vegetables, flaxseed oil, soy oil, fish oil, and fish products; an omega-3 fatty acid
long chain fatty acids
fatty acids that are fourteen or more carbon atoms in length
polyunsaturated fatty acids
fatty acids that have more than one double bond in the chain semicolon these types of fatty acids are generally liquid at room temperature
saturated fatty acid
fatty acids that have no carbons joined together with a double bond semicolon these types of fatty acids are generally solid at room temperature
monounsaturated fatty acids
fatty acids that have two carbons in the chain bound to each other with one double bond; these types of fatty acids are generally liquid at room temperature
essential fatty acids
fatty acids that must be consumed in the diet because they cannot be made by the body
Adequate folate intake is essential during early pregnancy because
folate is critical for cell division.
Alpha-linolenic acid (ALA) is
found in leafy green vegetables, flaxseed oil, and fatty fish. -Alpha-linolenic acid (ALA) is not a precursor to linoleic acid; instead, it is a distinct essential fatty acid that must be consumed in the diet. ALA is not a metabolic derivative of EPA and DHA; rather, EPA and DHA are metabolic derivatives of ALA. ALA is not known as arachidonic acid. Linoleic acid is metabolized in the body to arachidonic acid.
During short-term fasts, the body uses
glucogenic amino acids to synthesize glucose.
Research has consistently shown that individuals with poor B-vitamin status
have a reduced ability to perform most types of physical activity.
The risk for cardiovascular disease is reduced in people who have high blood levels of
high-density lipoproteins -HDL-cholesterol is sometimes referred to as "good cholesterol." High blood levels of triglycerides, very-low-density lipoproteins, or low-density lipoproteins would increase the risk for cardiovascular disease.
In which of the following types of chemical reactions is a compound catabolized by the addition of a molecule of water?
hydrolysis
Trans fatty acids
increase the blood's level of the lipids associated with cardiovascular disease. -Trans fatty acids have double carbon bonds, but the hydrogen atoms are attached on diagonally opposite sides of the double carbon bond, not on the same side, as in cis fatty acids. Cholesterol—not trans fatty acids—is synthesized in the liver and intestine.
According to the World Health Organization (WHO), the greatest single cause of preventable brain damage and mental retardation in the world is
iodine deficiency
Adenosine monophosphate
is composed of one molecule of adenosine bonded to one phosphate group.
In the absence of oxygen, the pyruvate produced through glycolysis is converted to
lactate
what are the two essential fatty acids
linoleic acid and alpha-linoleic acid (ALA)
True or False: Liver synthesis of urea increases as dietary protein intake increases.
True
True or False: There is no DRI for sulfur
True
True or False: Wernicke-Korsakoff syndrome is a thiamin deficiency related to chronic alcohol abuse
True
True or False: When cells engage in catabolism, chemical energy is released
True
True or False: When cells engage in catabolism, chemical energy is released.
True
True or False Fried foods are relatively nutritious as long as vegetable shortening is used to fry the foods
True -Cholesterol is required for good health; however; our body can make all the cholesterol we need, so we do not need to consume it in our diet
True or False: During a period of extreme starvation, the body will use heart muscle for energy and to help maintain blood glucose levels
True -During periods of starvation, body proteins are catabolized and their glucogenic amino acids are used in gluconeogenesis.
True or False: A severe deficiency of certain B-vitamins active in energy metabolism can be fatal
True -A severe niacin deficiency can cause pellagra, which once killed thousands of people in the United States alone each year; and thiamin deficiency causes beriberi, which can result in heart failure.
True or False: Every cell of the body is metabolically active
True -All cells are metabolically active, but liver, muscle, and adipose cells are key locations for integration of metabolic pathways
True or False: Most people in the United States consume more protein that they need
True -Most people in the United States consume up to two times more protein than they need.
True or False: To reduce your risk for cardiovascular disease, avoid eating most of your Calories in the evening before bed.
True -Spacing smaller meals and snacks throughout the day decreases the load of fat entering the body at any one time
True or False: Certain vitamins are essential for producing energy in the body
True -Three vitamins essential for energy metabolism are riboflavin, thiamin, and niacin.
high density lipoprotein
a lipoprotein made in the liver and released into the blood semicolon transports cholesterol from the tissues back to the liver; often called good cholesterol
True or False: In the United States, milk is fortified with riboflavin to prevent macrocytic anemia
False -Riboflavin occurs naturally in milk, and macrocytic anemia is associated with deficiency of folate or vitamin B12, not riboflavin. Riboflavin-deficiency disease is ariboflavinosis.
True or False: B-vitamins are water soluble, so there is no risk of toxicity
False -The IOM has set ULs for both niacin and vitamin B6. High intakes of certain B vitamins can cause adverse effects.
In sickle cell disease
-a single gene mutation causes a single amino acid in hemoglobin to be altered -red blood cells lose their characteristic doughnut-like shape. -normal blood flow is disrupted
Alyson is a 22-year-old vegetarian athlete training to compete in the New York City marathon. Her daily recommended protein intake is about
1.2 to 2.0 grams per kilogram of body weight. -Nonvegetarian endurance athletes need to consume slightly less protein, about 1.2 to 1.4 grams per kilogram of body weight. People who are more moderately active, especially if they are vegetarian, need slightly more than 0.8 grams of protein per kilogram of body weight, which is the amount recommended for sedentary adults.
The AMDR for fat is
20% to 35% of total energy. -Fat intakes lower than 20%of total energy do not confer additional health benefits and are not recommended for the general population.
eicosapentaenoic acid (EPA)
A metabolic derivative of alpha-linolenic acid. also available from Marine foods
docosahexaenoic acid (DHA)
A metabolic derivative of alpha-linolenic acid; also available from Marine foods
Which of the following statements about choline is true?
Choline is a vitamin-like compound necessary for the synthesis of bile
True or False: The conversion of dietary Carbohydrate to body fat is less efficient than the conversion of dietary fat to body fat
False -The body stores only enough liver glycogen to provide glucose for red blood cells and other body needs for less than one day. Although muscle glycogen stores are larger, they fuel only muscle cells and would be depleted within 1 to 2 days
True or False: Vegetarian diets can provide adequate protein, even for athletes.
False -A well-planned vegetarian diet can meet and even exceed protein needs, even for athletes, assuming that adequate energy-yielding macronutrients and a variety of complementary plant protein sources are consumed.
True or False: Lecithin is a sterol found in egg yolks.
False -Although lecithin is found in egg yolks, it is a phospholipid and is the primary emulsifier in bile.
True or False: Protein is a primary source of energy for our body.
False -Although protein can be used for energy in certain circumstances, fats and carbohydrates are the body's primary sources of energy for our bodies
True or False: A serving of food labeled reduced fat has at least 25% fewer Calories than a full-fat version of the same food.
False -Although reduced-fat versions of foods often do have fewer Calories than full-fat versions—as is the case, for example, with cow's milk—many reduced-fat foods have nearly the same number of Calories as full-fat versions.
True or False: The B-vitamins are an important source of energy for our body
False -B-vitamins do not directly provide energy. However, they play critical roles in ensuring that the body is able to generate energy from carbohydrates, fats, and proteins
True or False: Dietary cholesterol is not required because our body makes all the cholesterol it needs
False -Cholesterol is required for good health; however; our body can make all the cholesterol we need, so we do not need to consume it in our diet
True or False: Fat is unhealthful, and we should consume as little as possible.
False -Eating too many unhealthful fats such as saturated and trans fatty acids can increase our risk for cardiovascular disease and obesity. However, fat is an essential component of a healthful diet, and we need to consume a certain amount to supply and store energy, provide adequate levels of essential fatty acids, transport fat soluble vitamins, and maintain cell function.
True or False: Any protein eaten in excess is excreted in the urine
False -Excess protein is broken down and its component parts are either stored as fat or used for energy or tissue building and repair. Only the nitrogen component of protein is excreted in the urine.
True or False: Glycolysis yields a net of four ATP that can be used as energy for the cell
False -Glycolysis requires two ATP and produces four ATP, thus yielding a net of two ATP that can be used as energy for the cell
True or False: Glycolysis yields a net of four ATP that can be used as energy for the cell.
False -Glycolysis requires two ATP and produces four ATP, thus yielding a net of two ATP that can be used as energy for the cell
True or False: Iodine is necessary for the synthesis of reproductive hormones
False -Iodine is necessary for the synthesis of thyroid hormones.
True or False: In the United States, if we use table salt, we consume adequate iodine
False -Not necessarily! Although much of the salt sold in the United States is iodized, you need to read the label carefully. Some brands of table salt, kosher salt, sea salt, and other specialty salts do not provide iodine
True or False: Chromium supplementation reduces body fat and enhances muscle mass
False -Research studies have failed to show any consistent effects of chromium supplements on reducing body fat or enhancing muscle mass.
True or False: The conversion of dietary Carbohydrate to body fat is less efficient than the conversion of dietary fat to body fat.
False -The body stores only enough liver glycogen to provide glucose for red blood cells and other body needs for less than one day. Although muscle glycogen stores are larger, they fuel only muscle cells and would be depleted within 1 to 2 days.
True or False: Body fat is the only option for storing energy consumed in excess of short-term energy needs
False -The excess energy from dietary carbohydrate is also stored in the liver and in muscle as glycogen
True or False: You can speed up your liver's breakdown of alcohol by drinking a beverage containing caffeine
False -There is no effective way to speed up the liver's breakdown of alcohol.
True or False: Amino acid supplements help build muscle mass.
False -There is no evidence that consuming amino acid supplements assists in building muscle tissue. Consuming adequate energy and exercising muscles, specifically using weight training, build muscle tissue.
True or False: Trans fatty acids are byproducts of certain types of food processing; they do not occur in nature
False -Trans fatty acids are present in very small amounts in meats and full-fat dairy products
True or False: Certain fats protect against heart disease
False Certain essential fatty acids reduce inflammation, blood clotting, and plasma triglycerides and thereby reduce an individual's risk for heart disease.
Niacin-deficiency disease is called
Pellagra
Which of the following statements about high-protein diets is true?
Research suggests that higher intakes of animal and soy protein protect bone in older women -There is no consensus on the role of high-protein diets in increasing the risk for heart attacks, strokes, or bone fractures.
True or False: High-fat diets cause cancer
True -Cancer develops as a result of a complex and poorly understood interaction between environmental and genetic factors. A diet rich in whole grains, fruits, and vegetables is, however, associated with reduced cancer risk.
The type of lipid found most abundantly in foods is
Triglycerides -Trans fatty acids are only found naturally in small amounts in meats and full-fat dairy products. The majority of trans fatty acids in our diet are found in some processed foods, but their use has declined dramatically in the past decade because of associated health concerns. Phospholipids and sterols are two types of lipids found in foods, but they are present in much smaller amounts than triglycerides.
True or False: Biotin is a B-vitamin involved in carbohydrate, fat, and protein metabolism.
True
True or False: During a long bike ride, lipids are mobilized from adipose tissue for use as energy.
True
True or False: During prolonged starvation, serum levels of free fatty acids increase sharply
True
True or False: During prolonged starvation, serum levels of free fatty acids increase sharply.
True
True or False: Liver synthesis of urea increases as dietary protein intake increases
True
Atherosclerosis
a disease in which arterial walls accumulate deposits of lipids and scar tissue, which built up to a point at which they impair blood flow
lipids are
a diverse group of organic substances that are insoluble in water
High blood levels of the amino acid homocysteine are associated with
an increased risk for cardiovascular disease
Fats are ____________
are a major source of fuel for the body both during physical activity and at rest -Fats provide more than twice the energy, gram for gram, than carbohydrates. Fats enable the absorption of fat-soluble vitamins: neither water-soluble nor fat-soluble vitamins require digestion. Fats don't keep foods from turning rancid; rather, it is the oxidation of the fats in rancid foods that causes their unpleasant odor and taste.
Proteins are ____________
are taken from the blood and body tissues when needed for energy. -Carbohydrates and fats are the body's two primary sources of energy. Nitrogen released from deamination bonds with hydrogen, creating ammonia, which the liver combines with carbon dioxide to make urea, which is then transported to the kidneys for excretion. Proteins contribute very little to an average adult's energy needs.
Glucagon, epinephrine, and cortisol are
catabolic hormones -Insulin is an anabolic hormone. Coenzymes are organic cofactors, which are not hormones at all, but substances that facilitate the action of enzymes.
A trace mineral that assists the function of insulin in glucose transport into cells is
chromium.
The risk for cancer is reduced in people who
engage in regular physical activity.
visible fats
fat we can see in our foods or see added to foods, such as butter, margarine, cream, shortening, salad dressings, chicken skin, and untrimmed fat on meat
short chain fatty acid
fatty acid that contains fewer than 6 carbon atoms in length
Triglycerides within chylomicrons are taken up by body cells with the help of
lipoprotein lipase. -Gastric lipase digests some triglycerides in the stomach. Bile and pancreatic lipase actin the small intestine to emulsify and break down dietary triglycerides into free fatty acids and monoglycerides.
Fatty acids with one double bond between two of their carbon atoms are referred to as
monounsaturated -Saturated fatty acids have no double carbon bonds, and polyunsaturated fatty acids have more than one double bond. Steroids are not fatty acids but sterols with an OH group attached.
Most lipogenesis
occurs in liver cells -Most lipogenesis occurs in liver cells, when individuals consume an excess of carbohydrate, alcohol, or ketogenic—not glucogenic—amino acids. In lipogenesis, acetyl CoA is converted into fatty acid chains, not into glycerol. The fatty acid chains are then attached to glycerol. Lipogenesis does not occur in adipose cells; however, triglycerides are stored in adipose cells
The building blocks of DNA are
peptides.
Three healthful sources of beneficial fats are
plant oils, fish, and seeds. -Although skim milk, fruits, oats, broth-based soups, red wine, and egg whites are healthful foods, they contain only small amounts of fat of any kind, or none at all. Lamb and whole milk contain saturated fat and a small amount of trans fat, and some brands of stick margarine also contain trans fats.
Polypeptides in the small intestine are broken down by
proteases. -Hydrochloric acid and pepsin play roles in protein digestion in the stomach. Phosphofructokinase is an enzyme that influences the rate at which we break down glucose and use it for energy during exercise
Which of the following meals would be appropriate in a balanced and adequate vegan diet
rice, pinto beans, acorn squash, soy butter, and almond milk -Vegans avoid all animal products, including eggs and dairy; therefore, neither a yogurt milkshake nor egg salad would be appropriate items in a vegan meal. A meal consisting solely of brown rice and green tea would be vegan, but it would be neither balanced nor adequate.
Amino acids are unique from other energy-yielding compounds in that
they contain nitrogen, which must be removed before the remaining compound can be used for energy.
Vitamins required for the catabolism of carbohydrates, fats, and proteins for energy include
thiamin, riboflavin, and niacin
examples of lipids
triglycerides, phospholipids, and sterols
A coenzyme assisting in the breakdown of stored glycogen to glucose and in the conversion of amino acids to glucose is
vitamin B6
Which of the following is a good source of protein, fiber, and healthful, unsaturated fats?
walnuts -Red meat and skim milk are good sources of protein, but are low in fiber and unsaturated fats. Skim milk by definition is fat-free. Green, leafy vegetables are nutrient-rich food choices; however, they are not a good source of protein.
