Advanced Nutrition Final
Disaccharides
- 4 kcals per g - maltose, lactose, sucrose
The gallbladder
- 40-50 ml - stores bile - CCK stimulates release of bile - bile emulsiphies lipids and is essential for the digestion of fat
Pancreas digestive enzymes
- Alpha-amylase (50% of ingested CH1) - proteases (50%) > Pepsin breaks down proteins into proteases - Lipases (80%)
Ketones are formed in the liver and can be oxidized for energy via the Krebs cycle in all of the following tissues
- Brain - Kidney - Muscle - Heart - NOT liver
Stimulators of HCl release
- CCK - Gastrin - Acetylcholine - Histamine
Physiological effects of NON-fermentable fibers
- Detoxification: increasing sequestering of substances or toxins - Increased fecal bulk - laxative effect - greater frequency of defecation - reduced intestinal transit times
What characteristics of fiber may protect against developing colon cancer?
- Fibers adsorb primary bile acids to promote their excretion. - Fibers increase fecal bulk and dilute carcinogen concentrations. - Fibers can be fermented to butyric acid, which may slow proliferation of cancer cells
Prebiotics
- Fructans: inulin, oligofructose, fructooligosaccharides > garlic, asparagus, leeks, bananas - Oligosaccharides: raffinose, stachyose, verbascose > soybeans, chickpeas, lentils BEANO contains enzyme that digests oligosaccharides
Facilitated transport or diffusion (slow)
- GLUT2 facilitates glucose absorption of high glucose concentration; also moves all monosaccharides out of enterocytes - GLUT5 transporter protein for fructose (not responsive to insulin, induced with high fructose consumption); malabsorption common >50 g
Fiber lowers serum cholesterol concentrations by all of the following mechanisms
- Increased excretion of bile acids in the feces - a shift of bile acid pools toward chenodeoxycholic acid, which inhibits HMG-CoA reductase - production of propionic acid from gut fermentation of fiber - NOT increased transit time of cholesterol in the gut
Essential amino acids
- Leucine (stimulates insulin and protein synthesis) - Isoleucine - Valine - Lysine - Histidine - Tryptophan - Threonine - Phenylalanine - Methionine
Which of the following are attributes common to all membranes?
- Membranes form sheet-like structures. - Membranes are fluid structures. - Membranes protect cellular components. - They are NOT symmetrical
Things that depend on PH level of stomach
- Too high pH = not acidic enough - vitamin B12 absorption - iron absorption/anemia - preventing bacterial overgrowth - 25-54% of adults in western countries (2008) take antacids or medications to reduce acid production
Monosaccharides
- absorbed in the small intestine - fructose, glucose, galactose - all carbs are absorbed in the form of monosaccharides (majority), small amount of disaccharides
Increased fiber decreased risk for CV disease and cancer
- low in energy density - lower fat content - rich in micronutrients
Carbohydrates
- major source of energy in diet - 4 calories per gram - RDA 130 g/day > 45-65% total kcals/day (based on avg. amount of glucose required for brain, typically exceeded to meet energy needs with acceptable intake of fat and protein)
Cytoplasmic matrix
- microtrabecular lattice - cytoskeleton - microtubules - microfilaments - intermediate filaments - gel-like - intercellular communication and transport system
Fatty acid oxidation
- mitochondria - reduction of FADH+ and NAD+ - requires activation of FA by Acetyl-CoA - Simulated by glucagon, epinephrine and norepinephrine, TSH (inhibited by insulin)
Non-immunological mechanisms explaining other health benefits of friendly bacteria in the gut:
- modicfication of gut pH - antagonize pathogens through production of antimicrobial compounds - Compete for nutrient and growth factor binding and receptor sites - produce lactase - enhance fecal bulk, decreasing transit time
Intestinal bacteria (gut microbiota)
- most are anaerobes - Fermentation of CHO*/amino acids > short chain fatty acids + lactic acid + gas + biotin + vitamin K
Somatostatin
- most important inhibitor - inhibits gastric sections and motility - released from pancreas
What percent of daily caloric intake is provided by our gut microbiota through the process of fermentation?
10-15%
In addition to the RDA for protein, the Institute of Medicine has published an Acceptable Macronutrient Distribution Range for the macronutrients. What is the Acceptable Macronutrient Distribution Range for protein?
10-35%
After which of the following situations would you expect the Cori cycle to be most active?
100 meter sprint
The current Dietary Guidelines for Americans recommends that Americans consume less than 10% of calories per day from added sugars. If you consume 2100 calories per day how many teaspoons of added sugar could you consume and still be compliant with the current recommendation?
13
Which of the following would you expect to be the most immediate metabolic response to the following meal? Captain crunch cereal, skim milk, and a low-fat blueberry muffin.
An increase in triglycerides
Which of the following is an indicator of the total number of atherogenic lipoproteins in the blood?
Apolipoprotein B-100
What is the nutritional significance of stereoisomers?
Certain metabolic enzymes require a particular structure.
According to the AND (the Academy of Nutrition and Dietetics) position paper on Food and Nutrition misinformation, which of the following BEST describes the role of nutrition professional on this subject?
Dietitians and nutrition professionals should actively correct food and nutrition misinformation.
Under fasting conditions, one would expect to find large amounts of free ammonia in the bloodstream due to the breakdown of amino acids for energy.
FALSE
When discussing enzyme kinetics, Km refers to the substrate concentration at which the enzyme is saturated and functions at maximal velocity.
FALSE
Which of the following best describes HOW fructose may be more lipogenic than glucose?
Fructose bypasses the key regulatory step in glycolysis and supplies a ready supply of glycerol-3 phosphate which can be used for lipogenesis
When fibers form viscous gels in the stomach, which of the following occurs?
Gastric emptying is delayed or slowed.
Which of the following amino acids is an energy source for enterocytes, a carrier of Nitrogen in the blood, crosses the blood brain barrier, and is gluconeogenic?
Glutamine
Which of the following is true about glycemic index?
Glycemic index is a measure of how high insulin levels increase after consuming a given amount of a food containing glucose.
Which of the following is a TRUE statement about glycemic index?
Glycemic index is the increase in blood glucose level over the a baseline level during a 2-hour period for 50 grams of carbohydrate compared with the same amount of carbohydrate in glucose.
Which of the following enzymes is activated by glucagon and inhibited by ATP, glucose-6 phosphate, and caffeine?
Glycogen phosphorylase
______________ occurs in the cytoplasmic matrix. This is important so that the products of this pathway are in close proximity to the mitochondria.
Glycolysis
PPARS (peroxisome proliferator-activated receptors) are a type of nuclear receptor transcription factor. Which of the following is TRUE about PPARS?
PPARS are proteins that when bound by specific fatty acids that come from the diet and to specific segments of DNA impact the expression of genes involved in fat metabolism.
What is the current Tolerable Upper Intake Level established for protein and amino acids?
No Tolerable Upper Intake Level has been established.
Which of the following would be most advantageous for the prevention of constipation?
Slowly fermented fiber
_______ fibers such as ___________ increase fecal bulk and _________ transit time.
Slowly fermented, cellulose, decrease
Which of the following statements is TRUE about short and medium chain fatty acids?
They travel bound to albumin in the blood and travel directly to the liver.
Which of the following is the best indicator of insulin resistance?
Triacylglycerols, or triacylglycerol to HDL ratio
_____________ stimulates hepatic gluconeogenesis and suppresses glycolysis by reducing the concentration of fructose-2,6-bisphosphate, the most potent positive modulator of phosphofructokinase.
glucagon
Amino acids from muscle breakdown provide the chief substrate for which metabolic process?
gluconeogenesis
Which of the following is the predominant monosaccharide produced by the digestion of all dietary carbohydrates?
glucose
The final molecules that are absorbed from the digestion of the carbohydrates found in macaroni and cheese are which of the following?
glucose and galactose
Galactose is converted to _____ in the _________.
glucose, liver
A particular amino acid is very important for several metabolic pathways in enterocytes and so it is often added to nutritional mixtures used for hospitalized patients who are in critical illness. This amino acid is
glutamine
Which of the following amino acids is actively metabolized by enterocytes and is part of glutathione, an important antioxidant?
glutamine
Insulin is an anabolic hormone. Which process does insulin stimulate?
glycogenesis
Gluconeogenesis is essentially the reversal of which pathway?
glycolysis
The main benefits of prebiotics relate to their capacity to promote the _____ of bacteria and production of _____.
growth; fatty acids
Bile salts are synthesized from cholesterol in the _____.
hepatocytes
Insulin inhibits the activity of which of the following enzymes?
hormone sensitive lipase (aka, intracellular lipase)
The parietal cells secrete _____.
hydrochloric acid and intrinsic factor
The product(s) of pepsin's action is/are _____.
hydrolyzed proteins
Which of the following explains the mechanisms behind the fat malabsorption commonly observed in Crohn's disease (a type of inflammatory bowel disease)?
impaired recirculation of bile
Glycemic control is _____ in response to foods rich in fiber or to fiber supplements.
improved
FDA approved health claims
increase soluble fiber decreases heart disease
If you measure the abundance of an enzyme (or any other protein) and it increases, that increase is most likely due to which of the following?
increased translation of the gene that codes for the protein.
The primary mechanism by which gene expression is modified by bioactive factors in food appears to be _____.
interactions with transcription factors
The cell organelle responsible for most of the initiation and regulation of cellular activity is the _____.
nucleus
The carbohydrate moieties of the plasma membrane glycoproteins and glycolipids are oriented _____.
outwardly, away from the cytoplasmic matrix
During exercise, which of the following contributes only minimally to the amount of ATP used by working muscles?
oxidation of amino acids
____________ provides the main source of ATP in the human body.
oxidative phosphorylation
What is the normal product of the fatty acid synthase system?
palmitic acid, C16:0
In what organ are enzymes produced that are responsible for digestion of 50% of carbohydrate and protein and 80-90% of fat?
pancreas
Which of the following is considered an accessory organ to the GI gract?
pancreas liver gallbladder -NOT spleen
Choose the correct order of enzyme activities in protein digestion.
pepsin, trypsin, carboxypeptidases, dipeptidases
Which of the following enzymes is the most important regulatory enzymes of glycolysis and is allosterically inhibited by citrate?
phosphofructokinase
Which volatile short-chain fatty acid is believed to lower serum cholesterol by acting as an inhibitor of cholesterol biosynthesis?
propionic acid
When the diet is lacking in the amino acids histidine and methionine __________.
protein synthesis will be limited
Genes contained in mitochondrial DNA are inherited only from the mother and code for
proteins vital to the production of ATP.
Which of the following amino acids represent the branched-chain amino acids found in systemic circulation?
valine, leucine, isoleucine
nutrigenetics
variation of a specific gene affecting metabolism
Gram for gram which of the following whole grains provides the least amount of fiber?
whole grain corn
During protein digestion, peptides are broken into free amino acids mainly
within the enterocyte
Most human enzymes are synthesized intracellularly and function
within the same cell
The chief cells secrete _____.
zymogens, inactive forms of enzymes
Short chain fatty acids produced by intestinal bacteria
- acetic acid (absorbed in colon, taken to liver, used as substrate for cholesterol and fatty acid synthesis) - butyric acid (preferred energy source for colon cells, may have anti-inflammatory effects) - propionic acid (substrate for hepatic gluconeogenesis)
The following are neurotransmitters
- acetylcholine - epinephrine - serotonin - NOT insulin
Functions of HCl in gastric juice
- activating pepsinogen to pepsin - denaturing proteins (NOT digesting them) - releasing nutrients from organic complexes - bacteriocide
Which of the following tissues expresses GLUT4 proteins?
- adipocytes (fat cells) - muscle cells - NOT hepatocytes
Secretin
- alkalize intestinal contents by stimulating secretion of bicarbonate from pancreas - inhibits gastric acid
Pancreatic juice that enters the duodenum through the sphincter of Oddi contains all of the following _____.
- anions such as bicarbonate and chloride - cations such as sodium, potassium, and calcium - digestive enzymes - NOT intrinsic factor
Gallstones
- bile contains too much cholesterol - bile contains too much biliruben - gallbaldder doesn't empty correctly
enzymes
- catalyze reactions - synthesized in RER, used in THAT cell - Have an active center with specificity for a specific substrate
Gene expression is controlled by
- cis-acting control elements (binding sites, segments of DNA, for proteins) - trans-acting factors
Which of the following is a way that our bodies regulate metabolic pathways?
- covalent modification of key enzymes .through hormone stimulation - modulation of allosteric enzymes by endproducts of reactions. - increasing adaptable enzyme concentration by induction. All of the listed mechanisms are ways that human cells regulate metabolic pathways
Fatty acid synthesis
- cytoplasm - oxidation of NADPH - Acetyl CoA carboxylase is important regulatory enzyme - Acetyl CoA bound to malonyl- CoA in enzyme complex
IBD (ulcerative colitis/Chrons disease)
- damages bowel tissue - inflammatory bowel disease - fat MALABSORPTION - low fat diet> MCT supplementation (medium chain triglycerides)
Which of the following is a typical gastrointestinal response to ingestion of dietary fiber?
- delayed gastric emptying - increased bile-acid excretion - increased fecal bulk - NOT increased glucose aborption
Which of the following metabolic pathways takes place in the cytoplasm?
- fatty acid synthesis - hexosemonophosphate shunt - glycolysis - NOT krebs cycle also called the citric acid cycle
kreb's cycle
- final catabolic pathway - mitochondria (oxidative phosphorylation > electron transport chain) - CHO, fat, Pro > CO2 + H2O + energy - intermediate used for gluconeogenesis, AA synthesis, glucose > 2 pyruvate > 2 acetyl CoA > Krebs - Acetyl CoA > Krebs cycle is only one step
GLUT5
- fructose NOT glucose - intestine, testes, kidney
Fructose is more lipogenic than glucose because
- fructose bypasses the key regulatory step in glycolysis (phosphofructokinase) - then fructose enters glycolysis - uric acid production increases lipogenesis - unregulated source of glycerol-3P for lipogenesis ( see figure in textbook)
Active transport (fast)
- glucose and galactose - SGLT1 (sodium-glucose transporter 1) protein carrier - Na+/K+ ATPase pump
Metabolic pathways that occur in the cytoplasmic matrix
- glycolysis (glucose converted to pyruvate) - hexose monophosphate shunt (pathway that metabolized glucose-6-phophatase to pentose phophate, producing NADPH) - glycogenesis and glycogenolysis - fatty acid synthesis, including the production of nonessential, unsaturated fatty acids
Glycogen
- highly polar, stored with water (4:1) in muscle and liver
Viscosity
- hydration capacity - Pectins, gums, some hemicellulose, B-glucan, psyllium (high water holding capacity/ bulkers) - Low water holding capacity: cellulose, lignin - All viscose fibers are soluble, not all soluble fibers are viscose - increased viscosity increases satiety, delays gastric and intestinal emptying - slow down the absorption of monosaccharides but also other nutrients: reduced enzyme function and reduced nutrient diffusion rates
Enzymes found in saliva
- illingual lipase - salivary amylase: hydrolyzes a 1-4 bonds in starch
Fiber lowers serum cholesterol concentrations by all of the following mechanisms
- increased excretion of bile acids in the feces - a shift of bile acid pools toward chenodeoxycholic acid, which inhibits HMG-CoA reductase - production of propionic acid from gut fermentation of fiber - NOT increased transit time of cholesterol in the gut
LES pressure
- increased with protein - decreased by spearmint, chocolate, HF foods, alcohol, nicotine (make acid more likely)
How does good bacteria enhance the host's immune system?
- increases secretory IgA production - tightens the mucosal barrier (prevents "leaky gut") - enhances phagocytic activity - enhances intestinal cell mucin production
Nucleus
- initiates and regulates cell activities - largest organelle of most cells - genetic info dictates the cells response to stimuli
Occur in the mitochondria
- krebs cycle - electron transport chain (mitochondrial matrix) - oxidative phosphorylation - apoptosis - reactive oxygen species formation (ROS) - amino acid metabolism - fatty acid oxidation - oxidative decarboxylation
The following are gluconeogenic
- lactate - glycerol - alanine - NOT palmitic acid
Maintenance of blood glucose levels
- liver (glycogenesis/glycogenolysis) - skeletal and adipose tissue (insulin> promotes uptake of glucose and lowers blood glucose concentration) (glucagon, cortisol > promotes release of glucose to the blood via gluconeogenesis and glycogenolysis)
Gut associated lymphoid tissue (GALT)
- mucosa-associated/ gut-associated lymphoid tissue - about 70% of body's immune system is found in GI tract - "first line of defense" : intestinal bacteria > mucos contains lgA antibodies and other immune cells (T & B lymphocytes, macrophages, etc.) - inflammation of the GI tract > malabsorption
Components of saliva
- mucus - enzymes - water - NOT proteases
All of the following are required for fat digestion
- pancreatic lipase - colipase - bile - NOT lysolecethin
All of the following enzymes are negatively regulated (i.e., allosterically inhibited) by increasing levels of ATP
- phosphofructokinase - pyruvate dehydrogenase complex - citrate synthase - NOT hexokinase
All of the following enzymes are negatively regulated (i.e., allosterically inhibited) by increasing levels of ATP
- phosphofructokinase - pyruvate dehydrogenase complex - citrate synthase - NOT hexokinase
Components of typical cells
- plasma/cell membrane - cytoplasmic matrix - nucleus - mitochondria - endoplasmic reticulum - golgi apparatus - lysosomes and peroxisomes
Enteroendocrine g-cells
- produce gastrin
Parietal cells
- secrete Hcl and intrinsic factor
Neck cells
- secrete mucus
Chief cells
- secrete pepsinogens and zymogens - produce enzymes and gastric lipase
GLUT4
- sensitive to INSULIN - muscle, heart, brown and white adipocytes
Passive diffusion (slower)
- sorbitol, xylitol
Polysaccharides
- starch > plants - amylose (15-20%) - amylopectin (80-85%) - Glycogen > animals
All of the following are functions of apolipoproteins
- stimulating enzymatic reactions that regulate the metabolic functions of lipoproteins. - stabilizing circulating lipoproteins in the blood. - conferring specificity for recognition by receptors on cells. - NOT decreasing the density of the lipoprotein.
All of the following are functions of apolipoproteins
- stimulating enzymatic reactions that regulate the metabolic functions of lipoproteins. - stabilizing circulating lipoproteins in the blood. - conferring specificity for recognition by receptors on cells. - NOT decreasing the density of lipoprotein
Bile salts
- synthesized from the cholesterol in the hepatocytes
The following are part of the innate immune system
- the digestive system - cytokines - macrophages - NOT acute phase reactant proteins
The discipline of nutritional genomics studies _____.
- the interactions among genes and bioactive components in food that change gene expression without changing the DNA nucleotide sequence. - inborn changes in DNA nucleotide sequences or gene variants that impact the use of nutrients. - genetic alterations that can be compensated for by increasing or decreasing specific nutrients.
Insulin is a potent anabolic hormone and stimulates all of the following?
- translocation of GLUT4 protein from the cytosol to the plasma membrane in muscle cells - protein synthesis - cholesterol synthesis - NOT gluconeogenesis
Zollinger-ellison syndrome
- tumors that secrete extra gastrin > HCl - rare
Pectins are part of the cell wall and middle lamella, are often used to make jams and jellies, and are _____.
- water soluble - gel forming - stable at acidic pHs
Solubility
- water soluble > some hemicellulose, pectin, gums, B-glucan - soluble > delay gastric emptying, increase transit time, decrease nutrient absorption - insoluble > increased fecal bulk, sped gastric emptying and transit time
GLUT2
-when insulin levels are high, GLUT2 translocates - liver, B-cells of pancrease, kidney, small intestine - BIDIRECTIONAL TRANSPORTER - transports everything out of small intestine into blood
Dosages of ~2. 5 to 10-15 g/day of prebiotics taken for at least _____ are required to increase the intestinal flora population.
1 week
In which of the following stages would protein degradation be highest?
2 days into a fast (2 days after your last meal)
What is the desirable amount of dietary fiber recommended for most population groups each day?
20-40 g
What is the approximate ratio of glucose to fructose in high fructose corn syrup?
50:50
The total bile acid pool in the human body is 2. 5 to 5 g. What percentage of bile is reabsorbed in the small intestine?
90%
According to the AND model of evidence analysis, which of the following would be considered the lowest level of scientific evidence?
A case-study
Which of the following is most important for the enterohepatic recirculation of bile?
A functioning ileum
Added sugar recommendations
AHA: no more than 6-9 tsp/day
How much fiber do typical American adults consume?
About half the RDA, about 15 grams per day
Natural sugar vs. added sugar
Added: not found in foods before being packaged and produced (mono and disaccharides), includes naturally occurring sugars that are isolated and concentrated Natural: Mono and disaccharides found in whole foods
In which of the following tissues is insulin resistance primarily seen?
Adipocytes and muscle
Which of the following is a true statement about high fructose corn syrup?
After digestion, the chemical structures of high fructose corn syrup and sucrose are identical.
Which of the following is a TRUE statement regarding whole grain?
All whole grains contain bran.
Choose the best description of the action of bile.
Bile emulsifies dietary lipid to increase its surface area.
Which of the following lipoproteins would NOT be present in a fasted individual (aka, someone who hasn't eaten in 8 hours or more)?
Chylomicron
Which of the following is a true statement regarding probiotics?
Colonizing gut microbiota are important to health in a variety of ways and probiotics may enhance some of these effects.
Peptic ulcers
Common causes: - helicobacter pylori infection - chronic use of asprin, alcohol, NSAID Common treatment: - H2 receptor blockers (Zantac, pepcid, axia) - proton pump inhibitors (prilosec, nexium)
Which of the following fatty acids is the least stable because it is most susceptible to oxidation?
Eicosapentaenoic acid (EPA; C20:5)
Sources of protein
Exogenous: - animal protein (complete) - Plant protein (incomplete, but complementary) Endogenous (70 + g/day) - mucus - digestive enzymes and glycoproteins
Adequate synthesis and secretion of bile are important in the digestion and absorption of amino acids.
FALSE
Adipocytes' primary function is to store fat as triacylglycerol; thus, they do not require glycolysis and the TCA cycle for energy needs.
FALSE
All cellular reactions are irreversible since the same enzyme that catalyzes the conversion cannot catalyze the reverse reaction.
FALSE
All essential amino acids are gluconeogenic.
FALSE
All saturated fatty acid are known to raise serum LDL cholesterol levels and thus raise serum cholesterol levels?
FALSE
Allosteric enzymes are often modulated by a protein which is very similar in structure to the enzyme itself.
FALSE
Bile is the GI enzyme that hydrolyzes dietary triacylglycerol into free fatty acids and glycerol.
FALSE
Dietary proteins must be completely hydrolyzed to free amino acids, because only free amino acids are absorbed by the enterocyte.
FALSE
Muscle supplies its own glucose for energy needs by first using glycogen stores, and then converting amino acids into glucose.
FALSE
The liver is the site for transamination of all amino acids.
FALSE
The muscle can synthesize glucose and release it into the blood to help maintain blood glucose homeostasis.
FALSE
The plasma membrane is a sheet-like structure composed solely of lipids.
FALSE
There is a unique cell membrane receptor for each and every unique amino acid. This means there is very little potential for competition for the absorption of different amino acids.
FALSE
Which of the following competes with LDL at its receptor site on non-hepatic cells and is responsible for reverse cholesterol transport?
HDL
"Promotion for financial gain, a health remedy that doesn't work - or hasn't yet been proved to work and that is promoted to improve health, well-being, or appearance", is the AND definition for which of the following?
Health fraud
free resonse
High fructose corn syrup is not necessarily uniquely contributing to the twin epidemics of obesity and diabetes and does not need to be specifically avoided. According to the paper by Raatz et al., the body recognizes different types of sugars in approximately the same way. In other words, one type of sugar, like high fructose corn syrup, is not of better or worse value to the body nutritionally. It may be that obesity and diabetes are both affected by high intakes of sugar in general, however, which can be taken into consideration. Still, the chemical structure of the different types of sugars are recognized as very similar and not nutritionally significant in comparison. When looking at levels of increases in glucose, insulin, blood pressure, c-reactive protein, HDL cholesterol, and triglycerides, the Raatz et al. study showed that there would not be a significant difference in the type of sugar.
What is the likely blood glucose response to eating a high glycemic index meal in the middle postprandial period (that is 2-4 hours after eating the meal)?
Hypoglycemia
Which of the following conditions causes abdominal cramping including bloating, diarrhea, and sometimes constipation but does NOT cause changes in the bowel tissue itself?
IBS
Scientific evidence supports which of the following relationships regarding associations between dietary fiber, whole grains, and risk of colorectal cancer?
Increasing intake of fiber by 10 grams is associated with a modest 10% reduction in risk of colorectal cancer.
Grace was in a bad car accident and has been taken to the hospital with multiple bone fractures and massive internal bleeding. Which of the following would you expect to be elevated?
Insulin Blood glucose Epinephrine Glucagon
According to current evidence from peer-reviewed studies examining associations between gut microbiotia and health, which of the following statements is TRUE?
Lean and metabolically healthy people and mice tend to have more bacteriodetes and a greater variety of bacteria in their microbiome than do obese mice and people.
Order of sweetness levels
Less lactose maltose glucose sucrose fructose sucralose MORE
free response
Many people are not aware of the importance of gut bacteria, or the fact that there are more bacteria within or body than there are human cells. The bacteria in our gut specifically are beneficial in many ways including tightening the mucosal barrier, enhancing intestinal cell mucin production, and enhancing phagocytic activity. These mechanisms are all helpful in enhancing the host's immune system. The Lecomte v et al. study done on mice was scientific evidence that may suggest that a high fat diet leads to a decrease in the lactobacilli bacteria which is helpful in colon health in humans. Without this bacteria, it is possible that obesity is more likely. A dietary strategy that may help to improve or change the profile of gut bacteria in this instance would be to partake of a lower fat diet, and to consume probiotics.
The organelle that detoxifies by oxidizing molecules such as hydrogen peroxide and ethanol is the _____.
Peroxisome
Adsorpiton and binding ability
Physiological effects: - diminished absorption of lipids - increased fecal bile acid excretion - altered mineral balance - lowered serum cholesterol concentrations
Which of the following was found by Lecomte et al. in the paper titled Changes in Gut Microbiota in Rats Fed a High Fat Diet Correlate with Obesity-associated Metabolic Parameters? This was the paper that you were assigned to read and write an annotated bibliography on for the Gut Bugs Hot Topic day.
Propionate and acetate producing bacteria were more abundant in the rats fed the high fat diet vs. the rats fed the regular chow diet; the presence of these bacteria were positively associated with adiposity and metabolic risk markers including triglyceride levels and insulin.
Degradability/ fermentability
Quick fermentability - Gums - B-glucan - pectins - psylium - hemicellulose - cellulose -lignin Slow fermentability
Protein
RDA = 0.8 g/kg - some believe most can benefit from greater intakes - growth and repair may increase needs - no UL is established but upper level of recommended intake is set at 35% of total kcals - acceptable macronutrient distribution range for protein is 10-35%; most Americans are at 15%
Which of the following is a true statement about the paper by Raatz et al. that you were assigned to read for the Sugar Sweet Hot Topic day? All response options are in reference to the differences in metabolic effects observed for participants consuming 50 grams of the said sweetener for a 2 week period of time. Worse effects refer to observance of metabolic parameters that are known to be associated with insulin resistance, diabetes, and cardiovascular disease including increases in glucose, insulin, blood pressure, c-reactive protein, HDL cholesterol, and triglycerides.
Sucrose, honey, and high fructose corn syrup were similar.
A mutation in the genetic code (i. e. , DNA) could result in the wrong amino acid inserted into the synthesis of a given protein, thereby affecting the ability of the protein to function properly due to changes in its conformation.
TRUE
Allosteric enzymes are enzymes that change their physical conformation upon binding of a modulator. The modulator binds to a specific site on the enzyme that is different than the site specific to the substrate. Binding of the modulator profoundly influences the activity of these allosteric enzymes.
TRUE
In addition to protein synthesis, the brain uses amino acids for the synthesis of other N-containing compounds such as neurotransmitters.
TRUE
Peripheral proteins are involved in cell-cell recognition, whereas integral proteins function primarily as receptors/ transporters.
TRUE
The mitochondrial membrane is impermeable to NADH.
TRUE
The process of gluconeogenesis occurs partially in the mitochondria, and partially in the cytosol.
TRUE
Unlike long-chain fatty acids, short-chain fatty acids from the diet leave the enterocyte via the portal vein and go directly to the liver.
TRUE
Which of the following is true of uncoupling proteins?
They allow proteins to "leak" across the inner mitochondrial membrane and thus make ATP synthesis less efficient (less ATP is produced for a given amount of reducing equivalents)
Which of the following is a TRUE statement about the carbon-carbon bonds of a fatty acid in the "Trans" configuration?
They extend the fatty acid into a linear shape.
Glycemic index is defined by which of the following statements?
The increase in blood glucose over the baseline level during a 2-hour period for a defined amount of carbohydrate in a test food compared to the increase in blood glucose over the baseline level during a 2-hour period for the same amount of carbohydrate in a reference food.
free response
The most interesting thing I learned during this unit was about the importance of the pH levels of the stomach and how many different factors are affected by it (vitamin B12 absorption, iron absorption, and the prevention of bacterial overgrowth). This is important because without the proper amount of acid production in the stomach, these things can be thrown off. This is also interesting because of the high number of adults in western countries that take antacids or medications to reduce acid production. This is something I can take into consideration in the future when examining the diets of people with excessive acid production, or those that may be having an issue with absorption due to a pH that is too low.
What cells found in oxyntic glands in the body of the stomach secrete pepsinogens?
chief cells
Acetyl-CoA produced from whatever source can be used for which of the following?
cholesterol synthesis ketone synthesis energy lipogenesis
Arterial fatty steaks are formed primarily due to
accumulation of foam cells filled with cholesterol.
There can be no net conversion of _______________ to glucose.
acetyl CoA
What is formed when fatty acids are oxidized in the mitochondria (i. e. , what is the end product of beta-oxidation)?
acetyl-CoA
A function of hydrochloric acid in the gastric juice is to
act as a bactericide agent.
Which of the mechanisms responsible for absorption of nutrients into the epithelial cell of the villus requires energy?
active transport
Choose the best description of the main method of glucose absorption in the small intestine.
active transport with sodium
glucokinase
acts as a "glucose sensor", triggers shifts in metabolism or cell function in response to rising or falling blood levels of glucose - found in liver, pancreatic, gut, and brain cells
The primary stimulus for glucagon secretion is
alanine
What are the two amino acids primarily released from muscle during starvation?
alanine and glutamine
What is the carrier for medium-chain fatty acids in portal circulation?
albumin
What is the name of the digestive enzyme in saliva that digests starch?
amylase
Which of the following homopolysaccharides contributes the most energy to typical Western diets?
amylopectin
Which of the following hydrolytic products of phospholipids are released from the plasma cell membrane of cells and serve as a precursor for pro-inflammatory eicosanoids?
arachidonic acid
The brain cannot use fatty acids for energy because
fatty acids cannot cross the blood-brain barrier.
Which of the following fibers stimulate the growth of bifidobacteria and thus are considered prebiotics?
fructans
The arrangement of the electron transport chain components within the inner membrane is beneficial
because it brings them into close proximity to both the oxidizable products released in the matrix and O2
People with type 1 diabetes have
below-normal glucokinase activity because of low insulin levels.
What fiber found in cereal brans such as oats and barley are especially effective in reducing serum cholesterol?
beta-glucans
Choose the correct sequential order for participants in lipid digestion.
bile, colipase, pancreatic lipase, micelles
Which of the following parts of the whole grain contains the most fiber?
bran
What causes gout?
built up uric acid
Of the 3 short-chain fatty acids created by gut bacteria, which one is the preferred energy source for colonic epithelial cells?
butyric acid
Protein kinase (PKA) is activated by ___________ and results in the ____________ of enzymes. This is an example of ______________ regulation of an enzyme.
cAMP, phosphorylation, covalent
The majority of energy in the typical American diet comes from:
carbohydrate
Crypt of liberkuhn
cellular differentiation
Which of the following is the main function of the crypt of Lieberkühn?
cellular differentiation
Which fiber component is provided primarily by the outer layers of cereal grains?
cellulose
Which fiber type is the least fermentable?
cellulose
Common food sources of fructans, which are pre-biotic fibers, are _____.
chicory, onions, artichokes, and bananas
km, Michaelis constant
concentration of a substrate
In the cell structure the _____ provides support and controls the movement of cell organelles.
cytoskeleton
Which hormonal changes occur in response to a fall in blood glucose concentration?
decreased insulin, increased glucagon
When the pH of the stomach is increased to avoid GERD, over time the stomach may not be acidic enough. Which of the following might occur?
decreased protein digestion
In what form are MOST proteins absorbed?
di and tri peptides
Sucrose digestion is initiated in the _____.
duodenum
The disaccharidases are synthesized by the _____.
enterocytes
Two hormones that stimulate glycogenolysis in the muscle and liver, respectively, are _____.
epinephrine and glucagon
What type of cell depends solely on energy produced through anaerobic mechanisms because it doesn't have a mitochondria?
erythrocyte
Cholesterol serves as a precursor for all of the following
estrogens and androgens bile acids vitamin D - NOT phosopholipids
The reason different cells express different proteins is because they contain different sequences of DNA in the nucleus.
false
Abnormal LDL receptors fail to remove cholesterol from the bloodstream, resulting in _____.
familial hypercholesterolemia
Whole grains are limited in lysine. Which of the following foods is considered complementary because it is a good source of lysine?
legumes
Which of the following types of foods contributes the most fiber (consider one serving of the food)?
legumes, beans
Which of the following amino acids promotes insulin sensitivity and an anabolic response?
leucine
Which fiber type is poorly fermentable?
lignin
Choose the list of molecules that would be found in a micelle.
linolenic acid, 2-monoacylglycerols, cholesterol, vitamin D
Which enzyme or zymogen is secreted from the pancreas?
lipase
Which of the following enzymes is responsible for the intravascular hydrolysis of triglycerides in the form of free fatty acids and diacylglycerols out of chylomicrons?
lipoprotein lipase
What organ serves as the primary site of amino acid metabolism?
liver
How can metabolic syndrome be reversed during its early stages?
loss of at least 7% of body weight
Fat malabsorption for those with pancreatitis
low amounts of lipase
A high Km means the enzyme has _____ affinity for the substrate and is stated in units of _____.
low; concentration (e. g. , M; mM; µM)
Functional fiber
manufactured, shown to have beneficial physiological effect in humans; isolated or extracted
A genetic defect diminishing branched-chain alpha-keto acid dehydrogenase complex activity results in
maple syrup urine disease
In the process of oxidizing carbohydrates to generate energy, where in the cell is MOST of the energy released?
mitochondrion
receptor proteins
modify the cell's response to its environment
nutrigenomics
modulation of gene expression
Substances that bind with allosteric sites and alter the activity of regulatory enzymes are called _____.
modulators
In what form do carbohydrates enter the bloodstream?
monosaccharides
glutamate/glutamine
most abundant AA in AA pool
Which of the following is a source of whole grains?
multi-grain bread (first ingredient: whole wheat flour)
Due to a lack of the enzyme glucose-6-phosphatase, which tissue capable of glycogenesis cannot contribute to blood glucose levels between meals?
muscle
GLUT4 is the primary glucose transporter for which of the following tissues?
muscle
Which of the following is the alpha-keto skeleton of alanine?
pyruvate
Which of the following enzymes forms oxaloacetate from pyruvate?
pyruvate carboxylase
Glycemic load considers the _____ in the food.
quantity and quality of carbohydrate
Which level of organization determines the final form of a protein molecule consisting of several polypeptide chains?
quaternary
During the end reaction of the electron transport chain, molecular oxygen becomes _____.
reduced to water
transport proteins
regulate the flow of nutrients into and out of the cell
Alanine
released from muscle, participates in cori cycle
The hormone whose major action is to alkalize intestinal contents by stimulating secretion of bicarbonate from the pancreas and by inhibiting gastric acid secretion and gastric emptying is _____.
secretin
Prebiotics act as substrates for the growth of beneficial bacteria in the colon and are _____.
selected fibers
FODMAP
short chain, fermentable, oilgo, di, monosaccharides, and polyols that are poorly absorbed in the small intestine > gas/bloating
In general, in which portion of the gastrointestinal tract does most absorption occur?
small intestine
Which regulatory peptide synthesized in the pancreatic and intestinal cells appears to inhibit release of gastrin, secretin, and motilin?
somatastatin
A homopolysaccharide that is important in human diets is _____ and the end product formed from the complete digestion of this homopolysaccharide is _____.
starch; glucose
A protein-sparing shift in metabolism from gluconeogenesis to lipolysis occurs during the
starvation state
Cholecystokinin (CCK)
stimulates gallbladder, releases bile
The major role of gastrin in the GI tract is that of _____.
stimulation - stimulates the release of HCl
The smooth endoplasmic reticulum (SER) is associated with
the calcium ion pump necessary for the contractile process.
polymorphism
the existence of a gene in several allelic forms; single nucleotide polymorphisms (SNPs) are one type
Where is galactose converted to glucose?
the liver
Intestinal microbiota and obesity
the microbiota in obese mice is associated with an increased capacity to "harvest energy" from the diet
A function of hydrochloric acid in gastric juice during protein digestion is
to denature the quaternary, tertiary, and secondary structures of protein.