Microbial Physiology Exam 1 info

How are the outer membrane and peptidoglycan of Gram-negative bacteria connected?
a. TonB protein connect them.
b. The lipid moiety of the murein lipoprotein is embedded in the outer membrane, and the protein moiety is crosslinked to PG.
c. The outer membrane is loosely attached to PG
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How are the outer membrane and peptidoglycan of Gram-negative bacteria connected?
a. TonB protein connect them.
b. The lipid moiety of the murein lipoprotein is embedded in the outer membrane, and the protein moiety is crosslinked to PG.
c. The outer membrane is loosely attached to PG
b. the lipid moiety of the murein lipoprotein is embedded in the outer membrane and the protein moiety is linked to PG
How are nutrient molecules transported into Gram-negative bacteria?
a. All nutrient molecules diffuse across both the outer and cytoplamic membrane.
b. Hydrophilic molecules are transported through porins in the cytoplasmic membrane.
c. Nutrient molecules pass across the outer membrane to enter the periplasm through porins or specific proteins. Specific ABC or other transporters bring them across the cytoplasmic membrane.
c. nutrient molecules pass across the outer membrane to enter the periplasm through porins or specific proteins. Specific ABC or other transporters bring them across the cytoplasmic membrane
What is incorrect about the cytoplasmic membrane?
a. Water, gases, and small hydrophobic molecules can diffuse through the phospholipid bilayer.
b. The phospholipid bilayer is permeable to proton.
c. Integral proteins and peripheral proteins of the cytoplasmic membrane carry out a broad range of physiological activities such as electron transport, solute transport, ATP synthesis, and transduction of environmental signals.
b. the phospholipid bilayer is permeable to proton
The cell wall of Gram-negative bacteria contains______________.
a. pili
b. flagella
c. capsule
d. only peptidoglycan
e. LPS and peptidoglycan
f. Pili, flagella, capsule, and peptidoglycan
f. pilli, flagella, capsule, and peptidoglycan
Which statement is incorrect on S layer?
a. The S layer is made of glycan or polysaccharides.
b. The S layer is a protein sheet that surrounds prokaryotic cells.
c. The S layer provides mechanical support against osmotic pressure.
d. The S layer confers resistance against low pH.
e. The S layer provides protection against virus and phagocytosis
a. the S layer is made of polysaccharides or glycan
What are the major difference between Gram-positive and Gram-negative bacteria?
a. The difference in the cell wall structure differentiates Gram-positive and Gram-negative bacteria.
b. Gram-positive bacteria have LPS
c. Gram-negative bacteria have lipoteichoic acid.
a.
Which is incorrect about archaea in comparison with bacteria?
a. Archaeal phospholipid uses ester linkages but bacterial phospholipid uses ether linkages.
b. Archaea do not have peptidoglycan.
c. Many archaea just use the S layer for mechanical stabilization of cells
d. Lysozyme cannot hydrolyze PG-like molecules present in some archaea.
e. Ribosomes in bacteria are quite different from those in archaea.
a. archeael phospholipid uses ester linkages but bacterial phospholipid use ether linkages
Which statement is correct about pili in bacteria?
a. Some pili are fibrous proteins on cell surface for binding of bacteria to certain types of surface or molecules.
b. Pili are usually made of carbohydrates.
c. Pili are the S layer of certain bacteria and most of archaea.
d. None of pili are involved in bacterial mobility.
a. some pili are fibrous proteins on cell surface for binding of bacteria to certain types of surface or molecules
The porins _____.
a. are located in the outer membrane of Gram-positive bacteria to allow small hydrophilic molecules to diffuse to the cytosol
b. allow small hydrophilic molecules to move into the periplasm of Gram-negative bacteria
c. are for transport of all kinds of molecules across the cell membrane
d. are made of carbohydrates
b. allow small hydrophilic molecules to move into the periplasm of G- bacteria
Which is incorrect about a protein catalyst?
A. It reduces the activation energy of the reaction that it catalyzes.
B. It has a region with amino acids that are involved in substrate binding or play a role in catalysis.
C. Its active site may contain a derivative of a vitamin.
D. It is consumed by the reaction.
d. it is consumed by the reaction
How do enzymes enhance reaction rates? A. They lower the activation energy of the reactions. B. They bind substrate in a way in which catalytic residues are in close proximity to the susceptible bond(s) of substrate(s). C. Some enzymes form covalent intermediates with part of substrate to lower the activation energy. D. Some enzymes use base and acid to transiently extract proton from substrate and donate proton to substrate, respectively. E. a, b, and c. F. a, b, c, and d.f. A, b, c, dAn activating allosteric effector of a regulatory enzyme___________. A, enhances the substrate binding B. alters the G of the reaction C. catalyzes the reaction D. a and c E. a, b, and ca. enhances the substrate bindingWhat is not correct about the Michaelis-Menten kinetics of enzymes? A. The plotting of observed rate of an enzyme catalyzed reaction versus substrate concentration is hyperbolic. B. The determining factor of the Michaelis-Menten kinetics is that the enzyme first forms a complex with substrate prior to the step to form product. C. The double reciprocal plotting of observed rates and substrate concentrations is linear. D. The plotting of observed rate of an enzyme catalyzed reaction versus substrate concentration is linear.d. the plotting of observed rate of an enzyme catalyzed reaction v substrate concentration is linearWhich is incorrect about allosteric enzymes? A. Enzymes that are subject to regulation in metabolic pathways are usually allosteric enzymes B. Allosteric enzymes in metabolic pathways have an active site for substrate and another site for binding regulatory effector molecule. C. Binding of allesteric effector molecule to allosteric enzyme alters the conformation of the enzyme and, thereby, alters the binding of substrate. D. Some allesteric enzymes have more than one effector-binding sites. E. Some effectors enhance enzyme reaction rates whereas some effectors can inhibit enzyme reaction. F. The kinetics of allosteric enzymes follows the Michaelis-Menten equation.f. the kinetics of allosteric enzymes follow M-M kineticsWhat is incorrect about regulation of metabolic pathways? A. The first step of the pathway is always the control point. B. The control point is unique to the pathway but not used or connected to other pathways. C. The control point is often at branch points in the metabolic network. D. The enzymes at control points are usually allosteric enzymes, and allosteric effectors can be precursor, product, and metabolite from a different pathway. E. In feedback inhibition, the control enzyme is inhibited by the final product of the pathway. F. If a precursor is an alosteric effector, it usually enhances but not inhibits the enzyme reaction.a. the first step of the pathway is always the control pointWhich is incorrect on group transfer reaction? A. Phosphoenolpyruvate (PEP) can transfer its phosphate group to ADP to form ATP and because PEP has higher group transfer potential than ATP. B. The reverse reaction of the PEP-ADP reaction in answer A can spontaneously occur. C. In protein synthesis, amino acid has to be activated by acquiring AMP from ATP so that the activated form of amino acid can donate its acyl group to tRNA.b. the reverse reaction of the PEP-ADP reaction in answer A can spontaneously occurWhat is substrate-level phosphorylation? A. ATP synthesis by ATP synthase using deltaP B. ATP synthesis in which ADP acquires phosphate group from metabolites that have phosphate group and have higher phosphate group transfer potential than ATP. C. Oxidative phosphorylationb. ATP synthesis in which ADP acquires phosphate group from metabolites that have phosphate group and have higher phosphate group transfer potential than ATPWhich is the best answer about the central metabolic pathways? A. The EMP, ED, and PPP pathway oxidize glucose into pyruvate, generating ATP through substrate-level phosphorylation, NAD(P)H, and precursor metabolites for biosynthesis. B. The citric acid cycle oxidizes acetyl-CoA into CO2, generating NADH and FADH2 and metabolites for biosynthesis. C The oxidative phosphorylation oxidizes NADH and FADH2 by O2 through the aerobic respiration, generating the proton gradient that is used to generate ATP and drive other cellular processes. The process also regenerate NAD+ to allow the glycolysis and citric acid pathway to occur continuously. D. All of the above.d. all of the aboveWhich is not correct about the glycolysis or EMP pathway? A. 2 ATP molecules are invested to break one glucose molecule into two triose molecules. B. The purpose of the isomerization of glucose-6-phosphate into fructose-6-phosphate is to generate a carbonyl group or C=O at the second carbon so that this carbonyl group reacts with the amino group of the catalytic lysine residue of aldolase to form a Schiff base, weakening the C-C bond between the third and fourth C. C. The pay-off phase consists of 5 reactions that generate NADH and ATP. D. 4 types of enzyme are used in the pathway: kinase, aldolase, isomerase or mutase, and dehydrogenase. E. The end product of the EMP pathway is acetyl CoA.e. the end product of the EMP pathway is acetyl Co-AWhich statement about the enzymes in the EMP pathway is incorrect? A. Fructose bisphosphate dehydrogenase cleaves Fructose 1,6-bisphosphate to form dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. B. 1,3-Bisphosphoglerate is converted into 3-phosphoglycerate in the phosphoglycerate kinase-catalyzed reaction. C. The phosphoglycerate mutase catalyzes the conversion of 3-phosphoglyerate into 2-phosphoglyerate. D. Glyceraldehyde 3-phosphate is oxidized to 1,3-bisphosphoglycerate by Glyceraldehyde 3-phosphate dehydrogenase or GAPDH.a. fructose bisphosphate dehydrogenase cleaves fructose 1,6-bp to form dihydroxyacetone phosphate and glyceraldehyde 3-phosphateAldolase in glycolysis can catalyzes_____________. A. the reversible conversion between triose dihydroxyacetone phosphate (DHAP) and another triose, glyceraldehyde-3-phosphate (G3P) B. the formation of fructose-1,6-bisphosphate from DHAP and G3P in gluconeogenesis C. the oxidation of G3P into 3-phosphoglycerateb. the formation of fructose-1,6bp from DHAP and G3P in gluconeogenesisGAPDH ________. A. has kinase activity to transfer a phosphate from ATP to glyceraldehyde-3-phosphate. B. uses its catalytic cysteine residue to react with glyceraldehyde-3-phosphate to form sequential intermediates for transfer H to NAD+ and transfer acyl group to phosphate. C. use His and Glu residues-based acid base catalysis to facilitate the conversion between dihydroxyacetone phosphate and glyceraldehyde-3-phosphate.b. uses its catalytic cysteine residue to react with glyceraldehyde 3 phosphate to form sequential intermediates for transfer H to NAD+ and transfer acyl group to phosphateThe EMP pathway in Pyrococcus archaea _______. A. is identical with the EMP pathway in mitochondria. B. produces pyruvate as its final product. C. uses ADP in the investment phase and generate final products of acetate, CO2, and H2.c. uses ADP in the investment phase and generate final products of acetate, CO2, and H2