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Q:
Most of the digestive enzymes produced by the intestinal enterocytes function
a. in the stomach.
b. in the intestinal lumen.
c. at the brush border.
d. within the cytoplasm of the enterocytes.
Q:
Approximately how much chyme per minute is allowed to enter the duodenum from the stomach?
a. 1-5 mL
b. 6-10 mL
c. 11-15 mL
d. 16-20 Ml
Q:
Which medication inhibits hydrogen release into the gastric juice, which reduces GI mucosal irritation?
a. Pepcid
b. Nexium
c. Tums
d. Tagamet
Q:
Pepcid, a drug that is classified as a H2 receptor antagonist, acts by _____.
a. inhibiting the secretion of hydrogen ions by the parietal cells
b. inhibiting the release of acetylcholine by the vagus nerve
c. inhibiting the binding of gastrin to the parietal cells
d. inhibiting the binding of histamine to the parietal cells
Q:
The product(s) of pepsin's action is/are _____.
a. disaccharides
b. amylose
c. short-chain fatty acids
d. hydrolyzed proteins
Q:
Which of the following digestive fluids is the most alkaline?
a. bile
b. pancreatic juice
c. saliva
d. gastric juice
Q:
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?
a. lack of carbohydrate digestion
b. decreased protein digestion
c. destruction of bacterial in the stomach
d. gastric ulcer
Q:
A function of hydrochloric acid in the gastric juice is to
a. digest protein, functioning as an endopeptidase.
b. protect the stomach lining from damage.
c. inhibit secretion of gastrin and CCK.
d. act as a bactericide agent.
Q:
The parietal cells secrete _____.
a. hydrochloric acid and intrinsic factor
b. instrinsic factor and gastrin
c. gastrin and zymogens
d. zymogens and hydrochloric acid
Q:
The chief cells secrete _____.
a. gastrin
b. mucus
c. zymogens
d. hydrochloric acid
Q:
Which specialized cell of the gastric epithelium secretes a hormone?
a. neck
b. parietal
c. chief
d. G-cell
Q:
What cells found in oxyntic glands in the body of the stomach secrete pepsinogens?
a. neck cells
b. parietal cells
c. chief cells
d. enteroendocrine cells
Q:
What cells found both in oxyntic glands and pyloric glands of the stomach secrete hydrochloric acid and intrinsic factor?
a. neck cells
b. parietal cells
c. chief cells
d. enteroendocrine cells
Q:
What product produced by neck cells in the oxyntic gland of the stomach protects the epithelium from mechanical and chemical damage?
a. amylase
b. pepsin
c. gastrin
d. mucus
Q:
The volume of a normal stomach ranges from 50 mL (~2 oz) when empty to _____ when full.
a. 100 mL (~4 oz)
b. 250 mL (~1 cup)
c. 750 mL (~3 cups)
d. 1.5 L (~ 6 cups)
Q:
Which stage of swallowing moves structures of the mouth and throat to avoid the aspiration of food?
a. oral stage
b. pharyngeal stage
c. esophageal stage
Q:
Which is NOT a component of saliva?
a. mucus
b. enzymes
c. water
d. proteases
Q:
What is the name of the digestive enzyme in saliva that digests starch?
a. lipase
b. synthetase
c. amylase
d. lactase
Q:
What is the most probable problem if the function of the parotid glands is decreased?
a. lack of triglyceride digestion
b. hard to form bolus
c. saliva that is too thin " a high water to mucus ratio
d. diarrhea due to malabsorption
Q:
Bile is most important for the digestion and absorption of _____.
a. carbohydrates
b. proteins
c. fats
d. vitamins
Q:
Which of the following is NOT considered an accessory organ?
a. pancreas
b. liver
c. gallbladder
d. spleen
Q:
Which structural component of the gastrointestinal tract is within the muscularis externa and controls the contractions that cause motility?
a. muscularis mucosae
b. submucosal plexus
c. myenteric plexus
d. lumen
Q:
Within the lamina propria, lying just below the epithelium, is the mucosa-associated lymphoid tissue, which
a. controls secretions from the mucosal glands.
b. contains white blood cells and protects against ingested microorganisms.
c. initiates peristalsis.
d. secretes mucus, hormones and digestive juices into the lumen.
Q:
MATCHINGClassification 1) oxidoreductases 2) hydrolases3) transferases4) lyases5) ligasesExamplesa. Enzymes that catalyze cleavage of C-C, C-S, and certain C-N bonds (excluding peptide bonds) without hydrolysis or oxidation-reduction b. Enzymes forming bonds between carbon and other atoms, such as acetyl-CoA carboxylase, which adds bicarbonate to acetyl-CoA to initiate fatty acid synthesis in the cytoplast c. Enzymes in the election transport chain in the mitochondria d. Enzymes that catalyze cleavage of bonds by addition of water, such as digestive enzymes e. Enzymes that catalyze reactions, not oxidation or reduction, in which a functional group is moved from one substrate to another, such as transaminase
Q:
What lifestyle change would be most important to individuals with a common variant in the GST gene that impairs protections against toxins?
a. increasing levels of daily exercise
b. eating a low-fat diet
c. increasing ingestion of cruciferous vegetables
d. increasing intake of omega-3 fats
Q:
The primary mechanism by which gene expression is modified by bioactive factors in food appears to be _____.
a. mutations causing cancer
b. interactions with transcription factors
c. production of SNPs
d. downregulation of translation
Q:
A common mutation in the 5,10-methylenetetrahydrofolate reductase enzyme (MTHFR) _____.
a. prevents the individual from activating the B vitamin folate
b. diminishes the activity of the enzyme
c. increases the activity of the enzyme
d. both a and b
Q:
The discipline of nutritional genomics studies _____.
a. the interactions among genes and bioactive components in food that change gene expression without changing the DNA nucleotide sequence (nutritional epigenetics)
b. inborn changes in DNA nucleotide sequences or gene variants (nutrigenetics)
c. genetic alterations that can be compensated for by increasing or decreasing specific nutrients (nutrigenomics)
d. all of the above
Q:
Discuss the concept of coupled reactions in the transfer of energy.
Q:
Describe the uphill-downhill concept.
Q:
Describe the process of apoptosis in relation to the life span of the cell.
Q:
Describe the process by which the cytochrome P450 system contributes to the detoxification and metabolism of different drugs.
Q:
Describe the cytoskeleton (microtrabecular lattice) and its role as an intercommunication system of proteins and other macromolecules.
Q:
Why is cholesterol important in plasma membrane function?
Q:
Choose THREE (3) of the following terms and in ONE SENTENCE per term, provide a concise definition of that term: nucleus, mitochondria, RER, transcription, translation, apoptosis, replication.
Q:
List the three mechanisms that can be used to regulate the function of a protein (e.g., an enzyme) and briefly (1-2 sentences) describe their key features.
Q:
The melting temperature of the lipids in the lipid bilayer of the plasma membrane is _____ than normal mammalian body temperature because it generally contains a relatively large proportion of _____ fatty acids. Explain the physiological significance for human beings of this statement by relating structure to function.
Q:
The catabolic enzyme that degrades hydrogen peroxide into water and molecular oxygen is _____ and it is located in the _____.
Q:
The lipid bilayer determines the _____ of the plasma membrane while the proteins are primarily responsible for the _____ of the membrane.
Q:
Membrane fluidity and permeability are regulated and controlled by the fat-soluble compound _____.
Q:
True/FalseAllosteric regulation of enzymes is carried out by modulators, other proteins that bind to the enzyme to inhibit its activity.
Q:
True/FalseMost cellular reactions are irreversible since the same enzyme that catalyzes the conversion cannot catalyze the reverse reaction.
Q:
True/False
If two enzymes (e.g., pyruvate dehydrogenase and pyruvate carboxylase) compete for the same substrate (pyruvate), the one with the higher Km has less affinity and will be more active when pyruvate concentrations are high.
Q:
True/FalseWhen discussing enzyme kinetics, Km refers to the substrate concentration at which the enzyme is saturated and functioning at maximal velocity.
Q:
True/FalsePolysomes function to transcribe mRNA into proteins.
Q:
True/FalseThe reason different cells express different proteins is because they contain different sequences of DNA in the nucleus.
Q:
True/False
Peripheral proteins are involved in cell-cell recognition, whereas integral proteins function primarily as receptors/ transporters.
Q:
True/False
The various components within a cell (e.g., mitochondria) are not "free-floating" in the cytosol, but rather are held in place by the cytoskeleton.
Q:
True/FalseThe lipid bilayer determines the function of the plasma membrane while the proteins are primarily responsible for the structure of the membrane.
Q:
True/FalseThe plasma membrane is a sheet-like structure composed solely of lipids.
Q:
In electron transfer, an electron donor reduces the electron receptor and in the process becomes
a. oxidized.
b. transformed.
c. reduced.
d. flavin mononucleotide.
Q:
When the terminal phosphate group of ATP is removed by hydrolysis, forming ADP and inorganic phosphate, the type of reaction that occurs is _____.
a. endothermic
b. exothermic
c. standard
d. free
Q:
Phosphorylation of ADP is an example of _____.
a. an exothermic reaction
b. an endothermic reaction
c. an energy-releasing reaction
d. a downhill reaction
Q:
If an exothemic reaction releases -3,300 cal/mol of energy, how much energy is required for the reaction to be reversed?
a. +3,300
b. -3,300
c. +6,600
d. -6,600
Q:
The energy pool that serves as the major linking intermediate between energy-yielding and energy-demanding chemical reactions is:
a. activation energy.
b. NAD.
c. ATP.
d. free energy.
Q:
The net energy transformation when nutrients are systematically oxidized to carbon dioxide and water is _____.
a. reversible
b. catalytic
c. endothermic
d. exothermic
Q:
The energy needed to raise the energy of a reactant sufficiently to cause an exothermic reaction to occur is referred to as the
a. transition state.
b. barrier state.
c. activation energy.
d. free energy.
Q:
The quantity of energy released in an exothermic reaction is _____ the quantity required for the reverse endothermic reaction.
a. the same as
b. greater than
c. less than
d. not related to
Q:
One trigger of apoptosis is
a. overexpression of Bcl-2.
b. inactivation of Casp-9.
c. swelling of the cell.
d. release of mitochondrial cytochrome c.
Q:
Which of the following enzymes has diagnostic value for disease?
a. isocitrate dehydrogenase
b. ornithine carbomoyl transferase
c. isozymes of lactate dehydrogenase
d. isozymes of phosphofructokinase
Q:
Diagnostic enzymology focuses on
a. enzymes that are widely distributed among many tissues.
b. intracellular enzymes that express their activity in the blood abnormally due to a disease process.
c. secreted enzymes such as clotting proteins in blood.
d. nuclear enzymes.
Q:
Substances that bind with allosteric sites and alter the activity of regulatory enzymes are called _____.
a. transport proteins
b. modulators
c. Na pumps
d. sarcoplasmic reticula
Q:
A high Km means _____ affinity and is stated in units of _____.
a. low; concentration (e.g., M; mM; μM)
b. high; rate (e.g., molecules/sec; moles/min)
c. high; time (e.g., hours; min; sec)
d. low; does not have any units
Q:
Maintaining balance in the regulation of metabolic pathways necessary for life of the organism includes all of these catalytic regulatory mechanisms EXCEPT _____.
a. increasing the synthesis of constitutive enzymes
b. covalent modification through hormone stimulation
c. modulation of allosteric enzymes
d. increasing adaptable enzyme concentration by induction
Q:
Most human enzymes are synthesized intracellularly and function
a. within the same cell.
b. in another location after secretion.
c. in the bloodstream due to leakage from the synthesizing cell.
d. to promote tumors unless quickly degraded.
Q:
If you measure the abundance of an enzyme (or any other protein) and it increases, that increase is most likely due to:
a. decreased transcription.
b. increased translation.
c. posttranslational modification.
d. allosteric regulation.
e. two of the above
Q:
For active transport (e.g., of glucose), you need:
a. ATP.
b. a Na-K pump.
c. Na.
d. an integral protein.
e. all of the above
Q:
Highly specialized membrane proteins that modify the cell's response to its environment are _____.
a. transport proteins
b. enzymes
c. receptors
d. peroxisomes
Q:
Leader sequences attached to the amino end of newly synthesized proteins that remain within the cell are required for proteins
a. destined for degradation.
b. to move to the appropriate site for proper function.
c. to function within lysosomes and peroxisomes.
d. requiring post-translational activation.
Q:
The organelle that detoxifies by oxidizing molecules such as hydrogen peroxide and ethanol is the _____.
a. peroxisome
b. endosome
c. lysosome
d. ribosome
Q:
The organelle that serves as the digestive system for the cell is the _____.
a. polysome
b. endosome
c. lysosome
d. ribosome
Q:
The Golgi apparatus is prominent in neurons and secretory cells and functions
a. to stop the synthesis of proteins that may need carbohydrate additions.
b. to add polysaccharide or lipid moieties to polypeptides.
c. only for constitutive secretion of proteins.
d. only for regulated secretion of proteins.
Q:
What structural body made up of flattened cisternae flanked by tubular networks is thought to be an extension of the endoplasmic reticulum?
a. nucleus
b. cytoplasm
c. lysosome
d. Golgi apparatus
Q:
The smooth endoplasmic reticulum (SER) is associated with
a. lipid synthesis.
b. protein synthesis.
c. the calcium ion pump necessary for the contractile process.
d. ribosomes and cytochrome P450 enzymes.
Q:
Translation is the process by which
a. the genetic information (base sequence) in a single strand of DNA is used to specify a complementary sequence of bases in an mRNA chain.
b. a daughter duplex DNA molecule that is identical to the parental duplex DNA is synthesized.
c. the polypeptide chain of the protein product is extended.
d. genetic information in an mRNA molecule specifies the sequence of amino acids in the protein product.
Q:
Which of the following nitrogenous bases is unique to RNA?
a. guanine
b. uracil
c. thymine
d. cytosine
Q:
Encoded within the nuclear DNA of each cell is
a. the entire genome for that organism.
b. the genes coding for proteins needed by that particular cell in the organism.
c. chromatin.
d. a cell-specific histone.
Q:
The cell organelle responsible for most of the initiation and regulation of cellular activity is the _____.
a. cytoplast
b. nucleus
c. mitochondrion
e. nucleolus
Q:
What type of cell depends solely on energy produced through anaerobic mechanisms?
a. hepatocyte
b. enterocyte
c. glucocyte
d. erythrocyte
Q:
Genes contained in mitochondrial DNA are inherited only from the mother and code for
a. all proteins functioning within the mitochondrial matrix.
b. non-functional ancient proteins considered remnants of evolution.
c. proteins vital to the production of ATP.
d. antioxidant proteins.