Primer - all sections Flashcards
Chief cells of the stomach secrete…
Lipase
Pepsinogen
Intrinsic factor
Glycoproteins
Lipase
Pepsinogen
Parietal cells of the stomach secrete….
Lipase
Pepsinogen
Intrinsic factor
Glycoproteins
Intrinsic factor
Mucous cells of the stomach secrete…
Lipase
Pepsinogen
Intrinsic factor
Glycoproteins and bicarbonate
Glycoproteins and bicarbonate
Roles of gastric acid
Destruction of microorgs Activation of pepsinogen to pepsin Activation of IF Denaturation of macromolecules Faciliation of breakdown of protein and polypeptides by pepsin
All of the above
Roles of gastrin
Acts on chief and parietal cells to stimulate HCl and pepsinogen
Stimulates gastric peristalsis
Both
Order of small intestine sections
Jejunum, short duodenum, ileum
Short duodenum, jejunum, ileum
Ileum, jejunum, short duodenum
Short duodenum, jejunum, ileum
Cholecystokinin stimulates…
Pancreatic secretion of zymogens
Gallbladder contraction
HCl release
A and B
A and B
Zymogens are
Active digestive enzymes
Inactive enzyme precursors / -ogens
Another name for bile
Inactive enzyme precursors
All of the following are zymogens except
Trypsinogen Proelastase Chymotrypsinogen Procolipase Procarboxypeptidase A and B None of the above - all are
All are
What is the role of bicarbonate (pancreatic)?
Buffers HCl into strong base
Buffers HCl into weaker acid
Makes HCl into stronger acid
Buffers HCl into weaker acid
Salivary amylase works best at what pH?
8-8.5
3-4.5
1.5-3.5
6.75-7
6.75-7
Pepsin and lipase work best at what pH?
8-8.5
3-4.5
1.5-3.5
6.75-7
1.5-3.5
What are micelles?
Sppherical clusters of bile salts
Collections of lipid soluble dietary subcomponents surrounded by water soluble bile salts
Both
T/F: Most of the bile salts excreted into the intestine are reabsorbed in the ileum and the salts are transported back to the liver via enterohepatic circulation.
T
Which mechanism of nutrient absorption uses the energy of diffusion through a semi permeable membrane from higher to lower osmotic pressure?
Passive diffusion (simple diffusion) Facilitated diffusion (carrier-mediated transport) Osmosis Active transport (solute pumping) Filtration
Osmosis
Which mechanism of nutrient absorption uses hydrostatic pressure to drive the movement of solutes and water through a semipermeable membrane from higher to lower hydrostatic pressure?
Passive diffusion (simple diffusion) Facilitated diffusion (carrier-mediated transport) Osmosis Active transport (solute pumping) Filtration
Filtration
Which mechanism of nutrient absorption uses the potential energy created by a difference in nutrient concentration across a membrane to move nutrients from an area of higher to lower concentration?
Passive diffusion (simple diffusion) Facilitated diffusion (carrier-mediated transport) Osmosis Active transport (solute pumping) Filtration
Passive diffusion
Which mechanism of nutrient absorption uses the potential energy created by a difference in nutrient concentration across a membrane to move nutrients from an area of higher to lower concentration? Even if attached to a lipid soluble membrane carrier protein?
Passive diffusion (simple diffusion) Facilitated diffusion (carrier-mediated transport) Osmosis Active transport (solute pumping) Filtration
Facilitated diffusion
In which mechanism of nutrient absorption does a nutrient move through mucosal cell membranes against a concentration gradient?
Passive diffusion (simple diffusion) Facilitated diffusion (carrier-mediated transport) Osmosis Active transport (solute pumping) Filtration
Active transport
Most amino acids are absorbed via…
Passive diffusion (simple diffusion) Facilitated diffusion (carrier-mediated transport) Osmosis Active transport (solute pumping) Filtration
Active transport
Most lipid soluble compounds are absorbed via…
Passive diffusion (simple diffusion) Facilitated diffusion (carrier-mediated transport) Osmosis Active transport (solute pumping) Filtration
Passive diffusion
Most carbs are absorbed via…
Passive diffusion (simple diffusion) Facilitated diffusion (carrier-mediated transport) Osmosis Active transport (solute pumping) Filtration
Facilitated diffusion
GALT accounts for how much of the total number of immune cells in the body?
10-20%
30-40%
50-60%
80-90%
50-60%
GALT provides which immunity via secretion of IgA?
cell-mediated
humoral
both
both
Cell mediated immunity is …. while humoral immunity is ….
antibodies via plasma cells…T lymphocytes
T lymphocytes…antibodies
B
T/F: Urinary excretion of high lactulose - with normal, hight, or low mannitol - indicates small intestinal permeability
T
Glutathione synthesis
Homocysteine -> cystathione -> cysteine // cysteine + glutamate -> y-glutamylcysteine // y-glutamylcysteine + glycine -> glutathione
What amino acid is the primary source of fuel for enterocytes?
Glycine
Glutathione
Glutamine
Glutamate
Glutamine
Which of the following does glutamine inadequacy not result in?
Thinnig of villi and decreased digestive function
Decreased absorptive function
Loss of intestinal barrier integrity
Increased translocation of antigens and pathogens from lumen into extracellular fluid and blood
None of the above
None
Parts / order of the large intestine
Ascending colon > transverse colon > descending colon > sigmoid colon
descending colon > transverse colon > ascending colon > sigmoid colon
Ascending colon > sigmoid colon > descending colon > transverse colon
Ascending colon > descending colon > transverse colon > sigmoid colon
Ascending colon > transverse colon > descending colon > sigmoid colon
Which is NOT a major function of the large intestine?
Digest protein Reabsorb water from digesta Absorb vitamins produced by intestinal bacteria Ferment dietary fiber Elimination
Digest protein
T/F: the following are examples of SOLUBLE fiber:
beta glucans, gums, mucilages, pectins, hemicellulose
T
T/F: the following are NOT examples of INSOLUBLE fiber:
celluloses, lignins, hemicellulose
F
Non fermentable fiber includes which of the following
oat hulls
methylcellulose
wood pulp cellulose
mucilages
A, B, C
T/F: Lactobacilli comprise about 50% of all intestinal microflora and ferment dietary fiber carbs to SCFAs
F - Bifidobacteria
T/F: Bifidobacteria suppress growth of pathogenic species by maintaining a slightly acidic colonic pH
T
Lactobacilli ferment dietary fiber carbohydrates to ____ and SCFAs
Lactic acid
Saccharomyces boulardii is / does all except
is antagonistic to candida albicans
stimulates enterocyte secretion of brush border enzymes
relieves constipation
stimulates GALT production and sIgA
relieves constipation
Butyrate is metabolized to … within colonocytes
propionate
acetate
acetyl CoA
SCFAs
acetyl CoA
Which SCFA is required for the formation and maintenance of tight junctions?
acetate
propionate
butyrate
butyrate
In breastfed infants, over ___ of intestinal bacteria consist of Bifidobacterium infantis.
50%
65%
80%
90%
90%
Wheat, onion, asparagus, chicory, banana, and artichoke are common sources of prebiotic ____
fructans
oligofructoses
probiotics
fructans
T/F: Fructooligosaccharides (FOS) are specifically fermented to SCFAs by Lactobacilli and are converted to lactic acid
F - Bifidobacteria and are NOT converted to lactic acid
How does acetylcholine impact digestion?
intestinal smooth muscle contraction
squeezes food and fluids along the GI tract
stimulates release of enzymes
All
All
The ability to digest dietary starches and animal fats is minimal until about how old?
4 months
6 months
1 year
5 years
6 months
Most iron is transported in the blood via the plasma carrier:
a. heme.
b. erritin.
c. transferrin.
d. albumin.
transferrin
A required prerequisite to the digestion of proteins is the HCl-dependent process called:
a. hydrolysis.
b. evaporation.
c. denaturation.
d. distillation.
denaturation
The true digestibility of dietary fatty acids is:
a. 65% to 75%.
b. 75% to 85%.
c. 85% to 95%.
d. > 95%.
95%
An example of a digestive enzyme secreted from the brush border of microvilli
to help with digestion is:
a. sucrase
b. protease
c. amylase
d. hydrochlaoric acid
sucrase
Insulin…
acts to stimulate glucose uptake by GLUT4 transporter in monocytes and adipocytes
acts to stimulate glycogenesis in hepatocytes and myocytes
glycolysis
adipocyte lipoprotein lipase activity (increases triglyceride storage in adipocytes)
amino acid uptake and protein synthesis in the liver and muscle
inhibits glylcogenolysis and gluconeogenesis (decreasing lipolysis of stored triglycerides)
ALL
Glucagon
secreted when decreased plasma glucose concentration by a-cells
acts to stimulate hepatic glycogenolysis
stimulates gluconeogenesis from AAs
ALL
The formation of GLYCOGEN from GLUCOSE is…
Glycolysis
Glycogenesis
Gluconeogenesis
Glycogenolysis
Glycogenesis
when high amount of glucose and ATP present / storage in muscle and liver
The conversion of glycogen (from liver and muscles) is converted to Glucose-1-phosphate then into glucose-6-phosphate during low blood glucose or stress…
Glycolysis
Glycogenesis
Gluconeogenesis
Glycogenolysis
Glycogenolysis
The process of synthesizing glucose from non-carb sources with a starting point of pyruvic acid, lactic acid, etc. is called…
Glycolysis
Glycogenesis
Gluconeogenesis
Glycogenolysis
Gluconeogenesis
First step in breaking down glucose for energy for cellular metabolism…
Glycolysis
Glycogenesis
Gluconeogenesis
Glycogenolysis
Glycolysis
Ghrelin vs leptin
ghrelin stimulates food intake / leptin signals satiety
inflammation can cause leptin resistance
Adiponectin
enhances insulin sensitivity reduces insulin sensitivity enhances glucose homeostasis reduces glucose homeostasis A and C B and D
A and C
T/F: Monosaccharides (in carbs) contain either 5 carbons or 6 carbons
T
Common disaccharides (two monos joined together) include all of the following except:
lactose
fructose
maltose
sucrose
fructose
Glycogen, starch, and fiber are examples of…
Monosaccharides
Disaccharides
Polysaccharides
Fructose
Polysaccharides
___ are composed of monosaccharide units joined together by glycosidic bonds while ____ are long chain oligosaccharides that contain 2+ monosaccharides linked together in a repeating pattern
Polysaccharides, oligosaccharides
Oligosaccharides, polysaccharides
Disaccharides, polysaccharides
Polysaccharides, disaccharides
Oligosaccharides, polysaccharides
With AAs, ___ structures are determined by cross-linking of some of the AAs within the proteins, while ___ structures are determined by physico-chemical interactions between the AAs and surrounding water that result in precise folding into characteristic 3d conformations
Primary, secondary
Primary, tertiary
Secondary, tertiary
Tertiary, secondary
Secondary, tertiary
All of the following are conditionally essential AAs except…
Arginine Lysine Cysteine Glutamine Tyrosine
Lysine
Essential AAs
Arginine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine
Non essential AAs
Alanine Asparagine Aspartic acid Cysteine Glutamic acid Glutamine Glycine Proline Serine Tyrosine
BCAAs
Isoleucine
Leucine
Valine
T/F: Saturated FA have two double bonds
F
no double bonds
The most important MUFA is
stearic acid
palmitic acid
oleic acid
linoleic acid
oleic acid
Sources of palmitic acid (saturated FA) include all but:
coconut oil
olive oil
palm oil
palm kernel oil
olive oil
Sources of ___ include olive, almond, avocado, peanut, fibert, canola, pecan, and macadamia nut oils
MUFA
SFA
PUFA
MUFA
PUFAs contain ____ double bond(s)
one
more than one
more than 3
zero
more than one
PUFAs include all but the following:
linoleic acid
linolenic acid
oleic acid
omega 3s - EPA and DHA
oleic acid
SCFAs contain ___ carbon atoms while MCFAs contain ___ and LCFA contain ____
<3; 5-10; >14
< 6; 7-12; >14
< 5; 6-14; >16
>6; 7-12; <14
< 6; 7-12; >14
T/F: FAs can be classified by the degree of saturation of their carbon atoms OR their chain length.
T
also conformation (cis FAs or trans FAs), structural criteria like triglycerides
T/F: Borage, evening primrose, and black current oils are great examples of arachidonic acid while meats and animal products are good examples of GLAs
F
Purines and pyrimidines are examples of ___-containing bases in nucleotides
oxygen
carbon
hydrogen
nitrogen
nitrogen
Ribonucleosides of RNA
adenosine, guanine, cytidine, uridine
Deoxyyribonucleosides of DNA
2-deoxyadenosine
…cytidine
…guanosine
…thymidine
Which is produced in the fermentation of carbs and starches and is an important component of beverages?
acetaldehyde
ethanol
methanol
xylitol
ethanol
What is the end product of glycolysis?
acetate
pyruvate
butyrate
b-hydroxybutyrate
pyruvate
T/F: acetate is a SCFA produced from pyruvatee and during beta-oxidation of FAs
T
___ is a dietary organic acid that binds calcium very tightly and is found in many veggies like spinach, beet, greens, parsley.
Oxalate
T/F: Lipophilic vitamins require facilitated transport through membranes
F - hydrophilic ones do
Decreased plasma glucose levels stimulate ______ secretion by pancreatic alpha cells.
a. Insulin
b. Glucagon
c. Glucocorticoids
d. Epinephrin
glucagon
The hormone that is synthesized in adipose tissue and signals satiety is:
a. adiponectin
b. glucagon
c. leptin
d. ghrelin
leptin
The C677T base substitution in the gene that synthesizes the enyzyme methyl-
tetrahydrofolate reductase is a genetic abnormality called:
a. a base substitution
b. a genetic anomaly
c. a single nucleotide polymorphism
d. an epigenetic phenomena
SNP
The structures of linoleic acid and gamma-linolenic acid differ in their:
a. chain lengths.
b. double bond positions.
c. numbers of double bonds.
d. side chain moieties.
number of double bonds
18: 2ω6 - 18 carbon bonds, 2 double bonds, double bond in 6th position
20: 3ω6 - 20 carbon bonds, 3 double bonds, double bond in 6th position
In the polypeptide chain of a protein, the sequential order of the amino acids is called the: a. primary structure. b. secondary structure. c. tertiary structure. d. quaternary structure.
primary
Vitamin reserves can become depleted because all vitamins are:
a. synthesized inefficiently.
b. essential nutrients.
c. metabolized quickly.
d. excreted rapidly.
essential nutrients
___ like carrageenan, dextrin, lecithin, and xanthan gum are used as thickening agents while ____ are used to hold food constituents together and are especially important with dietary supplements and ___ are used to suspend oily material in water.
Stabilizers, binders, emulsifiers
Emulsifiers, binders, stabilizers
Binders, stabilizers, emulsifiers
Stabilizers, emulsifiers, binders
Stabilizers, binders, emulsifiers
Fortification vs nutrification vs enrichment
Fortification - addition of nutrients to foods without adding back nutrients lost during processing / nutrient may or may not be present in the original food and can be added in greater amounts than original
Nutrification - makes a food more nutritious
Enrichment - adding nutrients BACK into a food that were lost during processing
Difference between enzyme and coenzyme
Unlike an enzyme, a coenzyme
participates in the reaction by either transferring to the reactants an electron, reduced
proton, phosphate, hydroxyl or methyl group or by accepting such a substance from the
reactants, and must be regenerated.
Difference between coenzyme and cofactor
Cofactor - nutrient required by enzyme for full activation of the enzyme. Unlike a coenzyme, a cofactor functions as part of the enzyme and is not consumed by the reaction.
Coenzyme A is derived from:
a. Pantothenic acid
b. Pyrodoxine
c. Cobalamin
d. Tetrahydrobiopterin
Pantothenic. acid
Glycolysis is considered a/an ___ process
anaerobic
aerobic
anaerobic because oxygen isn’t involved
Glycolysis is energy producing or energy consuming?
Energy producing
Which cells lack mitochondria and can’t metabolize pyruvate to CO2?
Erythrocytes
so pyruvate is converted to lactate
What is the TCA cycle?
Metabolic pathway that oxidizes acetate derived from the acatabolism. of FAs, AAs, and carbs to CO2
The TCA cycle is aerobic or anaerobic?
aerobic - requires ability to transfer excess electrons to oxygen molecules via mitochondrial cytochromes (ETC) to regenerate NAD+ and FAD
What is the pentose monophosphate shunt?
Alternate ppathway of glucose catabolism that is also involved in the biosynthesis of pentose sugars (like ribose) and NADPH2 through the production of ribulose 5P.
What is gluconeogenesis?
glucose synthesized de novo from lactate pyruvate or alanine in the liver (90%) and kidney (10%)
T/F: in general gluconeogenesis is the reverse of glycolysis
T
However, 3 irreversible glycolytic enzymes (glucokinase,
phosphofructokinase, and pyruvate kinase) must be bypassed via additional enzymatic pathways
that operate only during gluconeogenesis in order to avoid futile cycling.
Pyruvate kinase catalyzes the irreversible conversion. of PEP to pyruvate and needs to be bypassed in two steps. Describe…
HINT: pyruvate –> oxaloacetate –> phosphoenolpyruvate (PEP)
Pyruvate –> oxaloacetate (requires acetylCoA to activate pyruvate carboxylase enzyme (pyruvate carboxylase also requires biotin)
oxaloacetate –> PEP (via PEP carboxylase requires 1 molecule of high energy GTP)
Phosophofructokinase catalyzes the irreversible conversion of fructose 6P to fructose 1,6-PP is bypassed by which enzyme?
fructose 1,6-biphosphatase
Glucokinaase catalyzes the irreversible formation of glucose. 6-P is bypassed by which enzyme?
glucose 6-phosphatase
produces glucose and inorganic phosphate
Alanine cycle
pyruvate aminated to produce alanine
alanine deaminated to reform pyruvate
gluconeogenesis produces glucose from pyruvate and glucose circulated to muscle cells
Cori cycle
glucose metabolized to pyruvate and then lactate in muscles
lactate is converted back to pyruvate and then glucose (via gluconeogenesis)
Ketones result from the metabolismof:
a. fatty acids.
b. simple sugars.
c. amino acids.
d. complex carbohydrates.
fatty acids
Glycolysis is a metabolic process that involves:
a. glycogen synthesis
b. the conversion of glucose to glycogen
c. the conversion of glucose to pyruvate.
d. the conversion of fatty acids to ATP
c. the conversion of glucose to pyruvate.
T/F: the effects of nutrients are dose-dependent and unidirectional.
F… curvilinear. relationships between intake and. outcome (hormesis)