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136 Cards in this Set
- Front
- Back
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List the monosaccharides.
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Glucose, fructose, galactose
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What is an oligosaccharide?
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Sugar with 3-12 monosaccharides.
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How big can polysaccharides get?
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Up to thousands of monosaccharides; good example is glycogen.
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What are lipids soluble in?
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Non-polar organic solvents.
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Name four examples of important lipids.
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Fatty acids, Acylglycerols, sphingolipids, and steroids.
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_____, together with ____, make up the principal structural material of living cells.
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Lipids, proteins. Think phospholipid bilayer.
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Fatty acids are aliphatic, which means they are not:
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Aromatic
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Fatty acids have a ____ at one end, and a ____ at the other end.
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Methyl, Carboxyl
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What's an important example of an acylglycerol?
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Triglycerides
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What's the structure of a triglyceride?
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Glycerol with three fatty acids attached through an ester linkage.
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What's the structure of a sphingolipid?
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Similar to an acylglycerol, but has a sphingosine backbone instead of glycerol.
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Give three important examples of steroids.
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Vitamin D, cholesterol, Steroid hormones like estrogens and androgens.
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Why are fatty acids so high in energy?
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They are highly reduced.
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Give 4 important examples of N-containing compounds in the human body.
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Amino acids; purines, pyriminidines, pyridines (N ring structures); nucleosides; nucleotides.
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What's the structure of an amino acid?
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Contains an alpha carbon surrounded by an amino group, a carboxylic acid group, a hydrogen, and a variable side chain.
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What do purines, pyrimidines, and pyridines all have in common?
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They're N-containing ring structures.
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What's the structure of a nucleotide?
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It's a nucleoside with a phosphate attached to the sugar. "Tied with Phosphate"
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What's the structure of a nucleoside?
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N-containing ring structures plus a sugar (usually ribose/deoxyribose).
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What amino acids are considered essential?
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PVT TIM HALL: Phenylalanine, Valine, Tryptophan, Threonine, Isoleucine, Methionine, Histidine, Arginine (conditional), Lysine, and Leucine.
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How many calories in the diet make up a pound of weight?
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3500
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Define overnutrition?
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Expenditure of energy below calories consumed.
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When does a catabolic state occur?
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When calorie expenditure exceeds energy intake. People are undernourished and losing weight.
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When does an anabolic state occur?
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When calories consumed outweigh energy expenditure; individuals are gaining weight.
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What makes up Total Energy Expenditure?
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Resting Energy Expenditure (60%), the Thermic Effect of Food (10%), and Physical Activity (30%). (Unless you exercise a ton)
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In a non-obese person, what percentage of energy is stored as fat?
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15-25% (more in women than men)
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What are the four components of a person's Fat Free Mass?
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Water (intra and extracellular), Protein (skeletal and visceral), the bony skeleton, and glycogen.
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What makes up the Body Cell Mass?
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Intracellular glycogen, intracellular protein, intracellular water, intracellular fat.
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What is the body composition of the standard 70kg man?
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60% water, 17% protein, 17% fat, and 6% carbohydrate and minerals.
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What are the energy stores in the standard 70kg man?
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0.35 kg of glycogen, 6 kg of usable protein, and 12 kg of fat.
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What are agonal respirations?
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Failing breaths as the diaphragm is catabolized (hence, not all protein is usable).
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During a 24 hour fast, energy needs are first met by____and then by ____.
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Glycogen stores in the liver; body protein through gluconeogenesis.
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What is gluconeogenesis?
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Conversion of body protein to glucose.
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During a long fast (over a day), REE ____ by ____%.
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Decreases, up to 25%.
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During a long fast, energy needs are met by ____ and ____; after ____ and ____ are all used up.
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Ketogenesis, muscle protein (gluconeogenesis and direct metabolism); liver glycogen, body protein.
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Normal weight individuals can survive fasting with water for up to:
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2 months.
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With water, an obese person could fast for over:
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A year.
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How many calories are contained in the energy stores of the standard 70 kg man?
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Liver Glycogen: 200g/800 cal
Muscle Glycogen: 150g/600 cal Usable Muscle Protein: 6kg/24,000 cal Fat (stored triglyceride): 12kg/108,000 cal TOTAL: 133,400 calories |
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Assuming intake requirements of 2000 cal/day, how many days can the standard 70kg man live?
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67 days.
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How does the acute stress response alter metabolism?
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It raises it; causes hypermetabolism.
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During the stress of critical illness, how are energy needs met?
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Energy needs are much higher; they are met by protein--skeletal and visceral proteolysis provide amino acids for gluconeogenesis.
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High levels of circulating stress hormones and inflammatory cytokines promote:
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Muscle proteolysis.
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Muscle proteolysis is promoted by ____ and ____.
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High levels of circulating stress hormones; inflammatory cytokines.
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When muscle proteolysis is left untreated, body skeletal and visceral protein can deplete by up to:
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150 g/day.
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When muscle proteolysis is left untreated, body skeletal and visceral protein can decrease by half in only:
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3 weeks.
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Name a few effects of severe muscle proteolysis.
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Impaired cardiac and renal function, fluid retention, muscle atrophy, intestinal mucosa atrophy, loss of intracellular minerals (Zn, Mg, P), diminished cell-mediated immune functions, increased infection risk, death.
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What is the absorptive state?
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It's when your body is absorbing food. It's the 2-4 hour period after a meal; digestion and nutrient absorption are happening at the same time.
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____ and ____ both occur at the intestinal brush border.
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Metabolism of complex nutrients; absorption of those nutrients.
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During the absorptive state, circulating levels of ____, ____ and ____ transiently rise.
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Glucose, amino acids, triglycerides.
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What is the "first pass?"
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After being absorbed, nutrients go first to the liver and pancreas before going to the rest of the body.
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What happens in the pancreas during the first pass?
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Its islet cells secrete insulin in response to elevated levels of circulating glucose.
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When the islet cells of the pancreas secrete ____, ____ pathways are activated in many tissues and cell types.
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Insulin; anabolic.
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The flow of substrates through anabolic and catabolic pathways is regulated by three things. They are:
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Availability of substrates (this is direct regulation of enzymes by allosteric effects); Covalent modification of enzymes (like phosphorylation induced by insulin signaling); and increased synthesis of enzymes.
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What's the quickest way the body regulates the flow of substrates through anabolic and catabolic pathways?
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Direct regulation of enzymes by allosteric effects.
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What's the slowest way the body regulates the flow of substrates through anabolic and catabolic pathways?
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Increased synthesis of enzymes.
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What's exogenous energy?
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Energy derived from the diet.
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What's endogenous energy?
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Energy stored in the body (like glycogen).
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What's a simple carb?
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Mono and disaccharides. They're sweet tasting. "Sugars" according to food science.
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What's a complex carb?
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Oligosaccharides and polysaccharides. They're starchy, not sweet tasting.
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What is the primary storage form of carbohydrate in plants?
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Starch, aka complex carbohydrate.
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Name some examples of sources of complex carbohydrate.
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Grains, potatoes, legumes, most vegetables.
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What's the chemical makeup of sucrose?
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Glucose + Fructose
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What's the chemical makeup of high fructose corn syrup?
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Glucose + Fructose
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What's the chemical makeup of lactose?
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Glucose + Galactose
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What's the chemical makeup of maltose?
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Glucose + Glucose
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Chemically, what happens as fruit ripens?
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Starch gives way to simple carbohydrate (mainly fructose). Taste becomes sweeter.
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Chemically, what happens as vegetables ripen?
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Simple carbohydrate is converted to complex carbohydrate. This is why vegetables taste sweeter when they are young.
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What is fiber?
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A polysaccharide that resists digestion.
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Does fiber yield energy?
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No.
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What's dietary fiber?
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Fiber found in food.
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What's "functional fiber"?
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Fiber that has been shown to have health benefits. Also, a food industry marketing trick.
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Insoluble fiber ____ in water and ____ in the large intestine.
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does not dissolve; is not metabolized.
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Soluble fiber ____ in water and ____ in the ____ intestine, by ____.
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Dissolves or swells; is metabolized; large; bacterial flora.
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What are two sources of insoluble fiber?
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Bran and whole grains.
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What does insoluble fiber do to stool?
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Increases its size, weight, and frequency; decreases its transit time.
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What are some sources of soluble fiber?
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Things with pectin (fruit, legumes), gums (carrageenan), oat bran, psyllium.
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What does soluble fiber do to digestion/absorption?
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Slows digestion and absorption.
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How does soluble fiber slow digestion/absorption?
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Forms a gel that traps nutrients, thus decreasing peak blood levels of glucose and cholesterol.
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How does soluble fiber affect the intestinal epithelium?
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The products of its metabolism promote the integrity of the intestinal epithelium.
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High fiber diets are associated with a ___ risk for both ____ and ____.
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Decreased; heart disease; GI disease.
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What have clinical studies shown about whole grain consumption?
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Whole grain consumption has health benefits. May just be a marker of someone who eats a healthy diet. May be other micronutrients in the whole grain besides fiber that provide the benefits.
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What is the glycemic index?
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The blood glucose response to a carb-containing food compared to a standard (glucose or white bread).
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Name four things that help determine a food's GI.
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Fiber content, level of food processing (particle size), physical structure, fat content.
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What does fat do to a food's GI?
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Lowers it.
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What does protein do to a food's GI?
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Lowers it.
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What's the primary usefulness of the GI?
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Predicting glucose response in diabetes patients.
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What solubility property do all lipids have in common?
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Hydrophobic.
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What's the difference between "fat" and "oil"?
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Fats are solid at room temperature. Oils are liquid.
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In a fatty acid, which end has the carboxyl group?
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The alpha end.
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In a fatty acid, which end is the omega end?
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The one with the methyl group.
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How many double bonds does a polyunsaturated fat have?
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2 or more.
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What do monounsaturated fats look like in the refrigerator?
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They are semi-solid.
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What happens to melting point as the level of fat saturation increases?
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It increases.
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Which fats are essential?
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Omega-3 and omega-6, both polyunsaturated fatty acids.
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How much energy do humans need to get from essential fatty acids?
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About 5% of our energy intake needs to be from EFAs. Deficiency results if we don't meet this.
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What's the reference point when counting carbons to name an unsaturated fat?
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The methyl or omega end.
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How many carbons are in the essential fatty acids?
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18.
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What's the starting compound in the omega 3 family?
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Linolenic acid.
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Name two important omega 3 fats. How many carbons do they have?
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EPA (eicosapentanoic acid) and DHA (docosahexanoic acid). 20 and 22, respectively.
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What are some dietary sources of linolenic acid?
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Canola oil, walnuts.
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Where can EPA/DHA be found?
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In fish
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What's the starting compound in omega 6 fats?
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Linoleic Acid.
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What are some sources of linoleic acid?
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Vegetable oils and their products.
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What is arachidonic acid?
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A 20 carbon fatty acid made from linoleic acid. It is a precursor for prostaglandins.
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What are eicosanoids and how are they synthesized?
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Hormone-like substances made from the essential fatty acids. They are autocrine and paracrine--they act on the cells that secrete them or on nearby cells.
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What effects do omega 3s have in the body?
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Vasodilatory (anti-atherogenic), anti-inflammatory, inhibitory of platelet aggregation.
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What effects do omega 6s have in the body?
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Make eicosanoids that are pro-inflammatory, proaggregatory, and vasoconstrictive.
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Why is the ratio of omega 3 to 6 important?
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In making eicosanoids, omega 3 fats and omega 6 fats compete for the starting enzyme.
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What effect are vegetable oils having on the American diet?
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Too much omega 6 fats. Corn, safflower, and soybean oils are in much of the food we eat.
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What is the predominant dietary fat?
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Triglyceride.
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What is pancreatic lipase?
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An esterase that breaks the ester linkage in triglycerides so they can be absorbed.
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What kind of fat is actually stored in body fat?
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Triglyceride.
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What is elaidic acid?
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A trans fat. Its cis counterpart is oleic acid.
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Why are trans fats bad for us?
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They have the ability to replace natural fatty acids in phospholipids and other compounds in the body. Since they're manmade, our bodies don't know what to do with them and stuff goes wrong.
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Is cholesterol a source of energy?
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No.
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What function does dietary cholesterol have?
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It's a substrate for hormone synthesis and is a structural component in membranes.
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Since lipids aren't water soluble, how do they get around in blood?
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Lipoproteins carry them.
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What's the general structure of a lipoprotein?
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Triglyceride, cholesterol, and apoprotein.
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What determines the density in lipoproteins?
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The protein content.
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LDL particles are mainly made up of:
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Cholesterol.
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What's the primary determinant of high HDL levels?
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Genetics.
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What effect have lifestyle changes been shown to make on HDL levels?
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Small, 5 to 10%.
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What effect does a diet high in mono and polyunsaturated fats have on HDL levels?
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It raises HDL. A good thing. Low fat diets lower HDL (not a good thing).
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How many amino acids are in existence? How many do we consume?
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Over 300 that we know of. Only 20 are used in our diet.
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When is arginine considered essential?
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During times of rapid growth.
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What other amino acids can be considered conditionally essential in some conditions?
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Cysteine, Glycine, Glutamine, and Tyrosine.
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Can you get a complete protein from non-animal sources?
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Soybeans. I'm not convinced, but will memorize this for the test.
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Can you make a complete protein in the kitchen? How?
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Yes. Combine a grain and legume.
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What's nitrogen balance?
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A state in which the amount of N consumed equals the amount of N lost through sweat, urine, and feces.
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When would one be in positive N balance?
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While growing. Nitrogen intake > loss.
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When would one be in negative N balance?
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After injury (burn, cancer, surgery), or through inadequate protein intake. N intake < loss.
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What's the protein requirement for a healthy adult, and what does this figure assume?
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0.8 g/kg body weight/day. Assumes adequate overall energy intake because if intake is too low, the amino acids will go to energy production, not protein building. The protein requirement also correlates with lean tissue content. So, for someone with high body fat, that weight shouldn't be used in the calculation.
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What's kwashiorkor?
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When energy in the diet is adequate but protein is low. Symptoms include swollen abdomen, reddish hair, depigmented skin.
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What causes the swollen belly in kwashiorkor?
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Ascites and grossly enlarged liver due to fatty infiltration.
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What is ascites?
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Fluid in the abdominal cavity. Results from increased capillary permeability and reduced plasma proteins resulting in reduced oncotic pressure and increased osmotic flux through the capillary wall.
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What's marasmus?
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Inadequate calories and inadequate protein. Results in loss of both adipose and muscle tissue.
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What are some common effects of excess protein intake?
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Increased urinary water and salt loss. Increased urinary calcium loss; can contribute to osteoporosis.
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