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Nutrition review exam2
 

Nutrition review exam2

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  • Sequence of amino acids (polypeptide chain) strung together by chemical bonds (peptide bonds)
  • Polypeptide chain twists into a helix or folds into a pleated sheet. Determined by weak electrical attractions within the polypeptide chain.
  • Polypeptide chain twists and folds into complex, tangled shapes such that hydrophilic groups are on the surface and hydrophobic side groups are tucked inside
  • Interactions between two or more polypeptides. Example: Hemoglobin, which is made of four associated polypeptide chains
  • Although fat cannot be used to make amino acids, amino acids can be converted to tryglycerides which are stored as fat
  • BMR - the energy required to sustain basic life processes when body at rest (does not include digestion!) TEF - the energy required for digestion Hyperplasia - increasing number Hypertrophy - increasing size
  • Obesity: abundance of food, high-calorie convenience foods, portion distortion, lack of physical activity, poverty

Nutrition review exam2 Nutrition review exam2 Presentation Transcript

  • Nutrition 101Exam 2 Review Session TAs: Helen Corless and Delma Betancourt
  • Chapter 6Protein: Amino Acids
  • Which of the following atoms is not a component of carbohydrate or fat?a) Hydrogenb) Nitrogenc) Oxygend) Carbon
  • Which of the following atoms is not a component of carbohydrate or fat?a) Hydrogenb) Nitrogenc) Oxygend) Carbon
  • Carbohydrates, lipids, and proteins are all composed of carbon, hydrogen and oxygen in various arrangementsBut…protein is unique in that it also contains nitrogen
  • Which of the following differentiates amino acids from each other?a) Number of carbon-carbon double bondsb) The side groupc) The amino groupd) Hydrogenation
  • Which of the following differentiates amino acids from each other?a) Number of carbon-carbon double bondsb) The side groupc) The amino groupd) Hydrogenation
  • There are 20 different amino acids, eachwith its own unique side group
  • An amino acid that the body can synthesize is called:a) Indispensableb) Essentialc) Conditionally essentiald) Non-essential
  • An amino acid that the body can synthesize is called:a) Indispensableb) Essentialc) Conditionally essentiald) Non-essential
  • Most amino acids are nonessential, meaning the body can synthesize them for itself (as long as building blocks are available)Essential amino acids must come from the diet, because the body cannot make these in sufficient quantities (indispensable)Conditionally essential: normally nonessential but must be supplied by diet under special circumstances (e.g. PKU -> tyrosine)
  • Proteins form when _______ bonds join amino acids in a ________ reaction.a) Carbon; hydrolysisb) Carbon; anabolicc) Peptide; condensationd) Peptide; catabolic
  • Proteins form when _______ bonds join amino acids in a ________ reaction.a) Carbon; hydrolysisb) Carbon; anabolicc) Peptide; condensationd) Peptide; catabolic
  • Peptide bonds link amino acids through condensation reactions (anabolic process) to form proteinsRemember: amino acids are the building blocks of proteins!
  • Which of the following describes the structure of aprotein that is folded into complex, tangled shapessuch that hydrophilic groups are on the surfaceand hydrophobic side groups are tucked insidea) Primaryb) Secondaryc) Tertiaryd) Quaternary
  • Which of the following describes the structure of aprotein that is folded into complex, tangled shapessuch that hydrophilic groups are on the surfaceand hydrophobic side groups are tucked insidea) Primaryb) Secondaryc) Tertiaryd) Quaternary
  • Primary Structure
  • Secondary Structure
  • Tertiary Structure hydrophilic hydrophobic
  • Quaternary Structure
  • True or False: the sequence of amino acids determines the function of a proteina) Trueb) False
  • True or False: the sequence of amino acids determines the function of a proteina) Trueb) False
  • Sequence -> Shape -> FunctionIf there is a mutation in the sequence, thenthe protein may not function properly (e.g.sickle cell anemia)This also explains why proteins that aredenatured (uncoiled) no longer can performtheir functions
  • Which of the following is true about protein digestiona) Pepsin in the stomach begins break down of proteins into amino acidsb) Proteins are only uncoiled in the stomach, but are not digestedc) Hydrochloric acid in the stomach cleaves proteins into smaller polypeptides and amino acids
  • Which of the following is true about protein digestiona) Pepsin in the stomach begins break down of proteins into amino acidsb) Proteins are only uncoiled in the stomach, but are not digestedc) Hydrochloric acid in the stomach cleaves proteins into smaller polypeptides and amino acids
  • In stomach: Hydrochloric acid denatures proteins (uncoils them) Pepsin begins protein digestion by cleaving denatured proteins into smaller polypeptides and amino acids (hydrolysis)In small intestine: Pancreatic and intestinal proteases and peptidases complete protein digestion
  • Which of the following is true of protein absorption?a) Absorbed amino acids may be used by intestinal cells for energyb) Amino acids enter the lymph system and bypass the liver to enter blood streamc) Most proteins are absorbed intact and travel to the cells where they are needed
  • Which of the following is true of protein absorption?a) Absorbed amino acids may be used by intestinal cells for energyb) Amino acids enter the lymph system and bypass the liver to enter blood streamc) Most proteins are absorbed intact and travel to the cells where they are needed
  • Once absorbed, amino acids may be usedby the intestinal cells for energy or tosynthesize needed compoundsUnused amino acids enter the blood streamand are transported to the liverMost proteins are broken down into aminoacids before absorption
  • Which of the following describes how proteins differ from carbohydrates and lipidsa) Protein is not a macronutrientb) Protein cannot be used for energyc) Protein has no specialized storage formd) Protein is needed in larger amounts
  • Which of the following describes how proteins differ from carbohydrates and lipidsa) Protein is not a macronutrientb) Protein cannot be used for energyc) Protein has no specialized storage formd) Protein is needed in larger amounts
  • Protein is a macronutrient, meaning it is a nutrient the body requires in relatively large amounts (many grams daily).Protein can be used as a source of energy during times of starvation or inadequate carbohydrate intake (gluconeogenesis). Protein yields 4kcal/gAMDR for protein is 10-35% which is actually the lowest of macronutrients (recommendation for fat is 20-35% and for carbohydrate is 45-65%)
  • The body does not make a specialized storage form of protein as it does for carbohydrate or fatGlucose is stored as glycogen in the liver and fat as triglycerides in adipose tissue, but protein in the body is available only from the working and structural components of the tissues.Over time, energy deprivation always causes wasting of lean body tissue
  • Amino acids in the “amino acid pool” of acell can be used to make…a) Proteinb) Energyc) Fatd) All of the above
  • Amino acids in the “amino acid pool” of acell can be used to make…a) Proteinb) Energyc) Fatd) All of the above
  • The amino acid pool is made up of aminoacids from protein turnover and from the dietThese amino acids can be used to makebody proteins or other nitrogen-containingcompounds, or they can be stripped of theirnitrogen and used for energy (eitherimmediately or stored as fat for later use)
  • Positive nitrogen balance occurs in which of the following situations:a) Healthy adultb) Starving childc) Pregnant womand) Burn victim
  • Positive nitrogen balance occurs in which of the following situations:a) Healthy adultb) Starving childc) Pregnant womand) Burn victim
  • Nitrogen balance refers to the amount of nitrogen consumed as compared to the amount of nitrogen excreted in a given time.During periods of growth, such as pregnancy, nitrogen intake > nitrogen output (positive nitrogen balance)In people who are starving or suffering other severe stresses, such as burns, injuries, infections, and fever, nitrogen intake < nitrogen output (negative nitrogen balance)
  • Which of the following organs filters urea out of the blooda) Pancreasb) Liverc) Kidneysd) Small intestine
  • Which of the following organs filters urea out of the blooda) Pancreasb) Liverc) Kidneysd) Small intestine
  • Liver creates urea from the products of amino acid breakdown (NH3) and releases it into the bloodstream.The kidneys filter urea out of the bloodstream for excretion in the urine
  • So...if you have liver disease, you willhave high levels of ammonia in yourblood (because the liver is not convertingammonia to urea), but if you have kidneydisease, you will have high levels of ureacirculating in your blood (because thekidneys are not filtering urea out of theblood.
  • Which of the following is not a function of protein in the body?a) Acid base balanceb) Energy storagec) Hormonesd) Antibodiese) All of the above
  • Which of the following is not a function of protein in the body?a) Acid base balanceb) Energy storagec) Hormonesd) Antibodiese) All of the above
  • The body does not have a specialized storage form of proteinThe following are all functions of protein - Growth and maintenance - Enzymes - Hormones - Fluid balance - Acid-base balance - Transportation - Antibodies - Energy and glucose
  • A protein that contains all the essential amino acids is called a/an…a) Complementary proteinb) Complete proteinc) Essential protein
  • A protein that contains all the essential amino acids is called a/an…a) Complementary proteinb) Complete proteinc) Essential protein
  • A complete protein contains all the essential aminoacids in the amounts we require (e.g. animalproteins, soy proteins)An incomplete protein lacks one or more essentialamino acids (e.g. most plant proteins)Complementary proteins are two or more dietaryproteins whose amino acid assortmentscomplement each other, such that aa’s missingfrom one are supplied by the other
  • Which of the following describes the condition of chronic, severe protein- energy malnutrition that is characterized by muscle wastinga) Marasmusb) Kwashiorkor
  • Which of the following describes the condition of chronic, severe protein- energy malnutrition that is characterized by muscle wastinga) Marasmusb) Kwashiorkor
  • Kwashiorkor results from acute protein deficiency and is characterized by abdominal swelling, edema, and muscle wasting with subcutaneous fat retentionKwashiorkor may also result from an infection or illness
  • Chapter 7Energy Metabolism and Alcohol
  • The only form of energy that can be used directly by the cells to do the work they need to do is calleda) Glucoseb) Pyruvatec) Acetyl-CoAd) ATP
  • The only form of energy that can be used directly by the cells to do the work they need to do is calleda) Glucoseb) Pyruvatec) Acetyl-CoAd) ATP
  • ATP (adenosine triphosphate) is one of the main energy storage molecules and is the only form of energy that can be used directly by cells to do workWhen the high energy bonds between phosphate groups in ATP are broken, energy is released; this energy can fuel another energy-requiring action (coupled reactions)
  • Energy released from the breakdown ofcarbohydrates, fats and proteins is capturedin the form of ATP
  • TRUE or FALSE: Anabolic reactions release energy.a) Trueb) False
  • TRUE or FALSE: Anabolic reactions release energy.a) Trueb) False
  • Anabolic reactions require energy. ex. Creating bonds between glucose molecules to form glycogenCatabolic reactions release energy. ex. Breaking down glycogen into glucose molecules
  • The break down of glucose is called:a) Gluconeogenesisb) Glycolysisc) Glycogenolysis
  • The break down of glucose is called:a) Gluconeogenesisb) Glycolysisc) Glycogenolysis
  • Glycolysis is the metabolic breakdown ofglucose, it does not require oxygen(anaerobic reaction)Gluconeogenesis is the making of glucosefrom a non-carbohydrate sourceGlycogenolysis is the breakdown ofglycogen into individual glucose units
  • Glycolysis yields…a) No energyb) 2 molecules of glucosec) 2 molecules of pyruvated) 2 molecules of acetyl CoA
  • Glycolysis yields…a) No energyb) 2 molecules of glucosec) 2 molecules of pyruvated) 2 molecules of acetyl CoA
  • Glycolysis is the metabolic breakdown of glucoseto pyruvate.1 glucose -> 2 pyruvateNet energy yield from glycolysis is 2 ATP (releases4 ATP, requires 2 ATP)H atoms and electrons released in the process arecarried by coenzymes (niacin) to the electrontransport chain
  • Which of the following is not true of coenzymes?a) They are facilitators of metabolic reactionsb) They are organicc) They associate with enzymesd) They are required for a metabolic reaction to take place
  • Which of the following is not true of coenzymes?a) They are facilitators of metabolic reactionsb) They are organicc) They associate with enzymesd) They are required for a metabolic reaction to take place
  • While coenzymes themselves are not thefacilitators of metabolic reactions, withoutthem enzymes cannot function.We can think of coenzymes as facilitators ofenzymes.
  • Which of the following can be converted back into glucosea) Acetyl CoAb) Pyruvatec) Fatty acids
  • Which of the following can be converted back into glucosea) Acetyl CoAb) Pyruvatec) Fatty acids
  • Glycolysis is reversible, so pyruvate can beconverted back to glucose to some extent inthe body (kidneys and liver)The conversion of pyruvate to acetyl CoA isnot reversible, so acetyl CoA cannot beconverted to glucose.
  • Recall that triglycerides are broken downinto a glycerol head and three fatty acidtails.Glycerol can be converted to pyruvate,which can then be converted to glucoseFatty acids, however, can only be convertedto acetyl CoA, which cannot be converted topyruvate. Therefore fatty acids cannot beconverted into glucose
  • In the anaerobic pathway, pyruvate is converted intoa) Lactateb) Acetyl CoAc) Oxaloacetated) Glucose
  • In the anaerobic pathway, pyruvate is converted intoa) Lactateb) Acetyl CoAc) Oxaloacetated) Glucose
  • When the body needs energy quickly andnot enough oxygen is available, pyruvatewill enter the anaerobic pathway.The lack of oxygen prevents the ETC fromaccepting the hydrogen ions attached to thecoenzymes (from glycolysis).
  • In the anaerobic pathway, pyruvate is ableto accept these hydrogens, becominglactate (i.e. lactic acid).This frees the coenzymes, allowing them toaccept more hydrogens from glycolysisreactions (allows glycolysis to continue).Remember glycolysis is an anaerobic rxn.
  • This is not efficient and not sustainable!
  • QUESTION:If the anaerobic breakdown of glucose (topyruvate to lactate) cannot be sustained forlong periods of time, then how can runnerssprint for minutes at a time?
  • ANSWER:Endurance training can actually increase thenumber of mitochondria in the muscle cells.This increases the mitochondrias’ ability tokeep pace with the muscles’ demand forenergy.
  • TRUE or FALSE: Lactic acid can be converted back to pyruvatea) Trueb) False
  • TRUE or FALSE: Lactic acid can be converted back to pyruvatea) Trueb) FalseLactic acid can be converted back to pyruvate in the CORI cycle!
  • In the aerobic pathway, pyruvate is converted into…a) Lactateb) Acetyl CoAc) Oxaloacetated) Glucosee) None of the above
  • In the aerobic pathway, pyruvate is converted into…a) Lactateb) Acetyl CoAc) Oxaloacetated) Glucosee) None of the above
  • When oxygen is available, pyruvate willenter the aerobic pathway.In this pathway, a carbon is cleaved frompyruvate and released as CO2You can’t get that carbon back (you breatheit out) so this step is irreversible!
  • Which of the following is true about the TCA cycle?a) It is the final step in energy metabolismb) It generates lots of ATPc) It generates lots of hydrogens and electronsd) It requires energy
  • Which of the following is true about the TCA cycle?a) It is the final step in energy metabolismb) It generates lots of ATPc) It generates lots of hydrogens and electronsd) It requires energy
  • (FYI this is probably more difficult of aquestion than she would ask you)The TCA cycle generates a lot of hydrogenions and electrons which then enter theelectron transport chain and power thesynthesis of ATP.
  • The TCA cycle does not require any energyinputs and it does, in fact, yield some energy(but not much!)The TCA cycle is not the last step in energymetabolism. It precedes the ETC which isthe final step.
  • True or false: Increasing protein intake will not increase muscle developmenta) Trueb) False
  • True or false: Increasing protein intake will not increase muscle developmenta) Trueb) False
  • A person cannot grow muscle simply by overeating protein, rather they will likely grow fat!When a person overeats protein…1. Surplus used to replace normal daily losses2. Increases protein metabolism (displaces fat in the fuel mix)3. Additional protein is deaminated, converted to fatty acids -> stored as fat
  • When excess carbohydrate is consumed…a) The body uses more glucose for fuelb) Excess is stored as glycogenc) Excess is converted to fat directlyd) Both a and be) All of the above
  • When excess carbohydrate is consumed…a) The body uses more glucose for fuelb) Excess is stored as glycogenc) Excess is converted to fat directlyd) Both a and be) All of the above
  • When excess carbohydrate is consumed, the excess is stored as glycogen (limited)Body uses more glucose for fuel when there is an excessive diet intake of carbohydrate (displaces fat in fuel mix)Glucose can also be converted to fat directly, but this pathway is relatively minor and only occurs after glycogen stores have been filled
  • How glucose can be converted to fat:Glucose -> Pyruvate -> Acetyl CoAAcetyl CoA -> fatty acidsFatty acids -> triglycerides stored in adipose tissue
  • Some important things to note about this diagram: • Glycerol can be converted to either glucose and pyruvate BUT neither glycerol nor fatty acids can be used to make amino acids • Some amino acids can be converted to pyruvate (reversible), others can be converted to acetyl CoA (irreversible) -> depends on the AA • Fatty acids can be converted to acetyl CoA (reversible), but since acetyl CoA cannot be converted back to pyruvate, fatty acids cannot generate glucose
  • True or false: Increasing dietary fat intake will increase fat metabolisma) Trueb) False
  • True or false: Increasing dietary fat intake will increase fat metabolisma) Trueb) False
  • Unlike excess protein and carbohydrate, which both enhance their own metabolism, eating too much fat does not promote fat metabolism.Instead, excess dietary fat moves efficiently into the body’s fat stores
  • Possible short answer question:Describe what happens when someonefasts for a short time. Explain where theirbody gets energy from and what it is usedfor.
  • Possible short answer question:Describe a few ways in which alcohol cannegatively impact your health.
  • Possible answer:• Nutrient displacement – Getting calories from alcohol displaces calories from healthy foods – Can lead to nutrient deficiencies• Interference with nutrient metabolism, especially the B vitamins (Folate, B6, B12, Thiamin)
  • Possible short answer question:What are some of the possible healthbenefits of consuming alcohol (within therecommended limits of 1 drink per day forwomen and 1 drink per day for men)?
  • Possible answer : – Reduce risk of developing heart disease – Reduce risk of dying of a heart attack – Possibly reduce risk of strokes – Lower risk of gallstones – Possibly reduce risk of diabetes
  • Chapter 8 & 9Energy Balance and Weight Management
  • What I think you should know…• What are considered normal ranges for percentage body fat (men vs. women)• Concept of energy balance as it relates to weight gain/loss• Energy outputs: BMR, TEF, exercise• Hyperplasia vs. hypertrophy
  • Possible short answer questions• Describe some of the different ways to measure body composition and list a pro and con for each• Explain one problem with using BMI to measure body fat• Describe some of the causes of obesity• Describe some treatment options for obesity