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HNF 461: EXAM 1
What 2 things is the plasma membrane made up of? |
Phospholipids & proteins
|
What gives the plasma membrane its function? |
Proteins
|
Plasma membranes have ___ (greater/less) CHO content and cholesterol content than other membranes |
Greater
|
What is the name of the glycoprotein-polysaccharide coveringthat surrounds the cell membranes of some cells? |
Glycocalyx
|
What is the name of the proteins that contain oligosaccharidechains (glycans)covalently attached to polypeptide side-chains? |
Glycoproteins
|
The ___ (cytoplasmic/mitochondrial) matrix is a microtrabecular lattice or cytoskeleton |
Cytoplasmic
|
What providesa structure for cell organelles, microvillae (as found in intestinal mucosacells), and large molecules? |
Cytoskeleton
|
T or F: Structural arrangement of the cytoplasmic matrix influencesmetabolic pathways |
True
|
The ___ (outer/inner) mitochondrial membrane is porous |
Outer
|
The ___ (outer/inner) mitochondrial membrane is selectively permeable; site of electron transport chain |
Inner
|
What is the site of the TCA cycle (krebs cycle) & beta fatty acid oxidation? |
Mitochondrial matrix
|
What cells do not contain mitochondrion? |
Erythrocytes
|
The nucleoli is condensed ___ (collagen/chromatin) |
Chromatin |
Uracil is in ___ (RNA/DNA) only |
RNA |
Thymine is in ___ (RNA/DNA) only |
DNA |
mRNA is synthesized in nucleus, thenmoves to ___ (RER/SER) in cytoplasmic matrix |
RER
|
___ (Rough/Smooth/Sarcoplasmic) reticulum = protein synthesis and glycosylation |
Rough |
___ (Rough/Smooth/Sarcoplasmic) reticulum = lipid synthesis |
Smooth |
___ (Rough/Smooth/Sarcoplasmic) reticulum = calcium ion pump |
Sarcoplasmic |
What are the structures made up of a network of membranous channels? |
ER
|
Where does protein trafficking & sorting, and glycoprotein modification and additionalprotein glycosylation occur? |
Golgi apparatus
|
Cis-Golginetwork = ___ (entrance/exit) |
Entrance |
Trans-Golginetwork = ___ (entrance/exit) |
Exit
|
The golgi apparatus is connected to ER by what? |
Transport vesicles
|
Lysosomes& peroxisomes are ___ (protein/enzyme)-filled organelles |
Enzyme |
___ (Lysosomes/Peroxisomes) are the cell’s “digestive system” |
Lysosomes
|
Peroxisomes are the site of ___ (oxidative/reductive) ___ (anabolic/catabolic) reactions |
Oxidative, catabolic
|
What are the 4 functions of lysosomes? |
Phagocytosis, autolysis, bone resorption, hormone secretion & regulation
|
What are the 3 functions of peroxisomes? |
Oxidize fatty acids to acetyl CoA, amino acid catabolism, detoxifying reactions
|
What are molecular stimuli that attach to receptors? |
Ligands
|
What is the function of the 1st type of receptor? |
Bind to ligand & convert it tointernal signal
|
What is the function of the 2nd type of receptor? |
Serve as ion channels
|
What is the function of the 3rd type of receptor? |
Internalize stimulus intact
|
The ___ (maximum velocity (Vmax)/Km (Michaelis constant)) is the enzyme velocity at substrate saturation |
Maximum velocity (Vmax)
|
The ___ (maximum velocity (Vmax)/Km (Michaelis constant)) is the concentration of substrate when reaction is at 1/2 of maximum velocity |
Km (Michaelis constant
|
Functionality of enzymes depends on what 2 things?
|
Protein& prosthetic group or coenzyme
|
Covalent modification is usually the addition/removal of what type of groups? |
Phosphate |
___ (Allosteric/Induction) = enzymeswith another site besides catalytic site that can bond with modulator |
Allosteric |
___ (Allosteric/Induction) = changes in concentrations of inducibleenzymes |
Induction |
With transferases, what group is transferred from 1 substrate to another? |
Functional group
|
What type of catalytic proteins are responsible for the cleavage of C-C, C-S, & C-N bonds (nohydrolysis/O-R)? |
Lyases
|
What type of catalytic proteins are responsible for the interconversion of optical or geometric isomers? |
Isomerases |
What type of catalytic proteins are responsible for catalyzing the formation of C-? Bonds (O, S, N, others)? |
Ligases
|
What is free energy (G)? |
The potential energy in bonds ofnutrients that is released
|
Lipase breaks down ___ (TAG/CHO) |
TAG |
Amylase breaks down ___ (TAG/CHO)
|
CHO |
What are the accessory digestive organs? |
Liver, gallbladder, pancreas
|
The mucosalayer of the GI tract is the most ___ (internal/external) |
Internal |
The serosa layer of the GI tract is the most ___ (internal/external) |
External |
What 3 types of cells does the epithelial layer of the GI mucosa contain? |
Absorptivecells, enteroendocrinecells, and exocrine cells
|
Absorptive cells are ___ (enterocytes/enteroendocrine cells/exocrine cells) |
Enterocytes |
___ (Enteroendocrine cells/Exocrine cells) are mucusproducing globlet cells |
Exocrine cells
|
What is beneath epithelial cells in the GI mucosa that anchors them? |
Lamina propria
|
T or F: The lamina propria is made up of gut-associated lymphoid tissue (GALT) |
True |
The main enzyme in saliva is salivary ___ (amylase/lipase) which hydrolyzes alpha ___ (1-4/1-6) bonds in ___ (proteins/starch) |
Amylase, 1-4, starch
|
___ (Chief cells/Parietal cells/Enderoendocrine G-cells) produce enzymes needed for protein digestion |
Chief cells
|
___ (Chief cells/Parietal cells/Enderoendocrine G-cells) produce hydrochloric acid and intrinsic factor, which is needed for the absorption of vitamin B12 |
Parietal cells
|
___ (Chief cells/Parietal cells/Enderoendocrine G-cells) produce the hormone gastrin, which stimulates parietal and chief cells |
Enderoendocrine G-cells
|
Crypts = small tear-drop like areas onbottom of ___ (enterocytes/villi) of the ___ (exocrine/absorptive) cells of the SI |
Villi, absorptive
|
What type of cells are on the bottom of crypts? |
Stem cells
|
___ (Segmentation/Peristalsis) mixes food in the GI tract with chyme |
Segmentation
|
___ (Segmentation/Peristalsis) propels food forward through the GI tract |
Peristalsis |
What is thelargest endocrine organ (tissue) in the GI tract? |
Fat tissue
|
Largeintestine absorbs what from fecal matter? |
Water
|
Intestinal secretions and motility are orchestrated by what 3 things? |
Hormones, signaling peptides, and the nervous system
|
___ (Peptide YY/Cholecystokinin) increases intestinal motility |
Cholecystokinin |
___ (Peptide YY/Cholecystokinin) inhibits gastric secretion |
Peptide YY
|
What is the function of the tight junctions between intestinal epithelial cells? |
Barrier to prevent antigens andpathogens from entering
|
Disregulation of the tight junctions between intestinal epithelial cells can cause what? |
A leakyintestinal barrier
|
A leaky intestinal barrier is associated with what 3 disorders? |
Chronicinflammatory bowel diseases, type 1 diabetes, and multiplesclerosis
|
What type of bacteria provide metabolic signals to helpmaintain a healthy intestinal barrier? |
Commensal (a nonharmful coexistance)
|
GERD = Reflux disease, gastric juice moves up intothe ___ (pharynx/esophagus) and inflames it |
Esophagus |
Stereoisomers have ___ (1/2) or more chiral carbon atoms with ___ (same/different) 4 groupsattached but ___ (are/are not) mirrorimages of each other |
2, same, are not
|
T or F: Stereoisomerismexists in all macronutrients |
True |
T or F: Many enzymes are stereospecific |
True
|
What are 2 examples of enzymes that are stereospecific? |
Hexokinase, amylase
|
In solution, what type of molecules form a cyclic ring structure? |
Monosaccharides
|
In solution, the monosaccharidemolecules form a cyclic ring structure, which is a reaction between what 2 groups? What does this form? |
Carbonyl and hydroxyl. Forms an additional chiral carbon
|
Pentoses contribute ___ (a lot/little) to dietary energy |
Little |
___ (Deoxyribose/Ribose) is a constituent of ATP, ADP, and AMP, cAMP, NAD, NADP, RNA |
Ribose |
What is the constituent of riboflavin, FAD, and FMN–(a reduction product of ribose)? |
Ribitol |
Disaccharides consistof two monosaccharide units joined by what type of bonds? |
Covalent
|
___ (Maltose/Lactose/Sucrose)- partialhydrolysis of starch |
Maltose |
___ (Maltose/Lactose/Sucrose)- Milk sugar |
Lactose |
___ (Maltose/Lactose/Sucrose)- Cane sugar and beet sugar
|
Sucrose |
Maltose is two glucose units linked through an ___ (alpha/beta) (1-4) glycosidic bond |
Alpha
|
Lactose is a galactose unit linked through an ___ (alpha/beta) (1-4) glycosidic bond to glucose |
Beta
|
What is the disaccharide that is a glucose linked to a fructose? |
Sucrose |
Raffinose, stachyoses, & verbascose are ___ (oligosaccharides/polysaccharides) |
Oligosaccharides
|
Starch, glycogen, & c ellulose are ___ (oligosaccharides/polysaccharides) |
Polysaccharides
|
What is composed of polyglucose joinedby beta(1-4) glycosidic bonds? |
Cellulose
|
Sucralose is ___ (stable/unstable) at high temperatures and is ___(200-300/500-600) times sweeter than sucrose |
Stable, 500-600
|
Salivary a-amylase in the mouth and pancreatic a-amylase in the small intestine break down ___ (polysaccharides/disaccharides) |
Polysaccharides |
Where does the digestion of disaccharides occur? |
Microvilli of enterocytes
|
Dextrins are broken down into ___ (lactose/maltose) and limit dextrins in the SI |
Maltose
|
In the brush border, maltase and the alpha- ___ (1,4/1,6) glycosidic bonds in limit dextrins are hydrolyzed, forming ___ (sucrose/glucose) |
1,6, glucose
|
Which GLUT isthe only insulin regulatable transporter of glucose? |
GLUT 4
|
Glucose and galactose require ___ (active/facilitated) transport and ___ (active/facilitated)diffusion |
Active, facilitated
|
Fructose is likely facilitated transport via what GLUT? |
GLUT 5
|
What is the anabolic hormone involved in carbohydrate, lipid, and proteinmetabolism? |
Insulin
|
___ (Insulin/Glucagon) is secreted by the beta-cells of the pancreas |
Insulin |
___ (Insulin/Glucagon) is secreted by the alpha-cells of the pancreas |
Glucagon
|
What GLUT transporter is in muscle and adipose tissue? |
GLUT 4
|
___ (Insulin/Glucagon) causes the translocationof GLUT4 from ___ (GLUT4 storage vesicles/cell surface) to the ___ (GLUT4 storage vesicles/cell surface) |
Insulin, GLUT4 storage vesicles, cell surface
|
Insulin ___ (enhances/inhibits) glycolysis |
enhances |
Insulin ___ (enhances/inhibits) gluconeogenesis |
inhibits
|
Insulin ___ (enhances/inhibits) glycogenolysis |
inhibits |
Insulin ___ (enhances/inhibits) glycogenesis |
enhances |
What is the catabolic hormone antagonistic to insulin? |
Glucagon |
Glucagon affects mostly the what organ? |
Liver
|
Maintaining blood glucose levels is amajor function of what 3 parts of the body? |
Liver, skeletal muscle, adipose tissue
|
Glycemic ___ (index/load) measures how a carbohydrate-containingfood raisesblood glucose? |
Glycemic index
|
How is glycemicload calculated? |
Multiplyingthe glycemic index by the amount of carbohydrate (in grams) provided by a food and dividing the totalby 100
|
T or F: Anindividual can still reach high blood glucose level by consuming a lot of lowGI foods |
True |
Research support the relationship between ___ (high/low) GI orGL diet with the risk of type2 diabetes |
High
|
Long-term consumption of high ___ (GI/GL) diet is also associated with increased risk of obesity and coronary heart disease |
GL |
___ (Long-term/Short-term) = Greater type 2diabetes risk |
Long-term
|
___ (Long-term/Short-term) = Insulin resistance |
Short-term
|
Patients with type2 diabetes willimprove glycemic control byadapting to low ___ (GI/GL) diet |
GI
|
A high GL diet could cause ___ (increased/decreased) insulin demand which would cause beta-cell ___ (exhaustion/production) which would cause glucose ___ (tolerance/intolerance) and then diabetes |
Increased, exhaustion, intolerance
|
What 3 rates determines blood glucose concentration at a given moment |
1. The rate of glucose absorption, 2. The rate of glucose taken up by tissues, 3. The rate of glucose produced by the liver
|
What is the 1st mechanisms of regulation metabolism? |
1. Negative or positive modulation of allosteric enzymes(through binding of effectors), 3. Directional shifts in reversible reactions
|
What is the 2nd mechanisms of regulation metabolism? |
2. Hormonal activation by covalent modification/induction (cAMP and phosphorylation)
|
What is the 3rd mechanisms of regulation metabolism? |
3. Directional shifts in reversible reactions
|
What is the 4th mechanisms of regulation metabolism? |
4. Translocation of enzymes within cells (glucokinase)
|
What are 3 allostericmodulators? |
AMP,ADP, & ATP
|
___ (AMPs/ADPs/ATPs) positive modulation causes shiftfrom inactive to active form of glycogen phosphorylase b |
AMPs
|
AMPs positive modulation causes shift from inactive to active form of glycogen phosphorylase b stimulates what 2 enzymes? |
Phosphofructokinase, pyruvatekinase
|
What are the minor uses of glucose? |
Synthesis of ribose, NADPH, glucose forglycoprotein and glycolipid synthesis
|
What are the lowest priority uses of glucose? |
Substrate for fatty acid and TAGsynthesis
|
The firststep in intracellular metabolism ofglucose converts glucose to what? |
Glucose 6-phosphate
|
What 2 organs havean enzyme to convert G-6-P back to glucose? |
Liverand kidneys
|
What enzyme is involved in glucose phosphorylation? |
Hexokinase
|
Where is glucokinase located? |
Liver,pancreas
|
Where is hexokinase located? |
Muscle,adipose, brain
|
Glucokinase functions at max velocity when bloodglucose levels are ___ (normal/elevated) |
Elevated |
Hexokinase functions at max velocity when blood glucose levels are ___ (normal/elevated) |
Normal |
What happens to glucokinase in liver cells? |
GK is “parked” in the nucleusby bindingto GKRP when glucose levels in the hepatocyte approach fasting levels.
|
Glucokinase is indirectly ___ (inhibited/stimulated) by fructose6-P |
Inhibited
|
Glucokinase is indirectly ___ (inhibited/stimulated) by glucose andtrace fructose |
Stimulated |
What enzyme cleavesthe a-1,4bonds to release G-1-P from nonreducingends of the glycogen polymer during glycogenolysis? |
Glycogenphosphorylase |
What enzyme cleavesthe a-1,6bonds at branch pointsduring glycogenolysis? |
Debranchingenzyme
|
What 2 hormones is glycogenphosphorylase covalently regulated by? |
Glucagon,epinephrine
|
What molecule is glycogen phosphorylase allosterically regulated by? |
AMP
|
In muscle, Ca2+ binds to the calmodulin subunit of phosphorylase kinase, activating it ___ (with/without) phosphorylation, which then ___ (activates/inhibits) glycogen phosphorylase, causing glycogen degradation |
Without, activates
|
In muscle under extreme conditions of anoxia and depletion of ATP ___ (Ca2+/AMP) activates glycogen phosphorylase b ___ (with/without) it being phosphorylated |
AMP, without
|
Where does the TCAcycle occur? |
Mitochondrialmatrix
|
Where does glycolysis occur? |
Cytoplasm
|
Where does the ETC occur? |
Inner mitochondrial membrane
|
The brain exclusively usesglucose for energy under normal circumstances, therefore ____ takes place inthe brain |
Glycolysis
|
Glycogenolysis is active in the___ (fed/fasting) state |
Fasting |
If you eat a pizza and then willnot eat anything in the next 24 hours, what are glucose sources that supplyyour body’s need during the whole process? |
Exogenousglucose, glycogenolysis, gluconeogenesis
|
Liver cells may use glucose forall of the following EXCEPT ___: Energyneeds- Synthesizing ATP, makingglycogen, synthesizingand secreting insulin, synthesizingribose, synthesizingfatty acids |
Synthesizing and secreting insulin
|
Glycolysis produces ___ (lactate/pyruvate) underaerobic conditions, and ___ (lactate/pyruvate) under anaerobic conditions. |
Pyruvate, lactate
|
Whensomebody is skipping meals for 14 hours, what hormones related to carbmetabolism is high in blood? Whatis low? How is each carb metabolicpathways doing in each organ? |
Glucagon, insulin, liver undergoing gluconeogenesis
|
Why may six meals a day lead toweight loss in some people? |
High fiber diets inhibit fat absorption
|
What 2 products does the PPP form? |
Pentose phosphates, NADPH
|
The pentose phosphates formed in the PPP are necessary for the synthesis of what? |
Nucleic acid synthesis for DNA and RNA
|
The NADPH formed in the PPP are necessary for the synthesis of what? |
Fatty acids
|
What are 3 precursors gluconeogenesis can synthesize glucose from? |
Glycerol, lactate, and certain aminoacids
|
What is the key site for gluconeogenesis? |
Liver |
Gluconeogenesis is active when: Insulinlevel is high, glucagonlevel is low, someoneis on a very low carb or carb free diet, allof the above |
Someone is on a very low carb or carb free diet
|
___ (Dietary/Functional) fiber = nondigestibleCHO & lignin that are intact & intrinsic in plants |
Dietary |
___ (Dietary/Functional) fiber = nondigestibleCHO that are isolated, extracted, or manufactured& known to have physiological benefits |
Functional
|
Fiber ___ (lowers/increases) cholesterol |
Lowers
|
T or F: Fiber helps control diabetes |
True |
Most people in the US are ___ (high/low) in fiber |
Low
|
What are the 4 classifications of fiber? |
Source, solubility, fermentability, viscosity
|
What are the 4 properties of fiber that are important for theirfunctions? |
Solubility in water, water holding capacity & viscosity, ability to bind to organic and inorganicmolecules, fermentability
|
Some hemicelluloses, pectin, gums, b-glucans are water ___ (soluble/insoluble) fibers |
Soluble
|
Cellulose, lignin, some hemicelluloses,chitosan, chitin are water ___ (soluble/insoluble) fibers |
Insoluble
|
Soluble fibers ___ (speed up/delay) gastricemptying |
Delay |
Soluble fibers ___ (increase/decrease) transittime |
Increase
|
Soluble fibers ___ (increase/decrease) nutrientabsorption |
Decrease |
Inoluble fibers ___ (increase/decrease) transittime |
Decrease |
Inoluble fibers ___ (increase/decrease) fecalbulk |
Increase |
T or F: Bileacids undergo enterohepatic cycling |
True |
What is diverticulosis? |
The formation of numerous tiny pockets,or diverticula, in the lining of the bowel.
|
Bystimulating bowel movement, ___ (fermentable/nonfermentable) fibers can prevent/relieve diverticulosis/diverticulitis |
Nonfermentable |
Fermentation is done by what? |
Intestinal bacteria
|
Fiber causes ___ (increased/decreased) nutrientdiffusion rate--attenuation of the blood glucose response |
Decreased
|
Fiber causes ___ (increased/decreased) enzymefunction |
Decreased |
Fiber causes ___ (increased/decreased) mixingof gastrointestinal contents with digestive enzymes |
Decreased
|
Fiber causes ___ (increased/decreased) absorption of lipids
|
Decreased
|
Fiber causes ___ (increased/decreased) fecal bile acid excretion |
Increased
|
Where does glycolysis occur? |
Cytoplasm
|
Where does glycolysis occur? |
Cytoplasm
|
Where does gluconeogenesis occur? |
Liver |
What 3 products does glycolysis produce? |
Pyruvate, NADH, ATP
|
What 4 products does the TCA cycle produce? |
CO2, NADH, FADH2, ATP
|
Where does the PPP occur? |
Cytoplasm
|