Microbiology Exam 2 UTA; Questions and
Answers % Correct
Uniporters Correct answer-Transport in one direction across the membrane
Symporters Correct answer-Functions as co-transporters; the two molecules travel in the
same direction; 1. Energy is released as one substituent moves down its concentration gradient
2. This energy moves a second substrate against its gradient into the cell
Anitporters Correct answer-Transport a molecule across the membrane while
simultaneously transporting another molecule in the opposite direction; the actively
transported molecule moves in the direction opposite to the driving ion; 1. Antiporter binds
substrate A on the cytoplasmic side of the membrane 2.Antiporter opens to the outside, where
the concentration of A is less 3. Substrate A leaves its binding site, and substrate B then binds to
its site 4. Antiporter opens to the inside of the cell. Substrate B is released in exchange for
substrate A
The Phosphotransferase System in E.coli Correct answer--Type of group translocation
-Best studied system
-Moves glucose, fructose, and mannose
-Five proteins required
-Energy derived from phosphoenolpyruvate (PEP)
-The product Glucose 6-P is used in glycolysis
, Microbiology Exam 2 UTA; Questions and
Answers % Correct
Group Translocation Correct answer-Substance transported is chemically modified during
transport across the membrane, usually phosphorylated
ABC Systems Correct answer--ATP-Binding Cassette systems
- >200 different systems identified in prokaryotes
-Often involved in uptake of organic compounds (e.g. sugars, amino acids), inorganic nutrients
(e.g sulfate, phosphate), and trace metals
-Typically display high substrate specificity
-Contain periplasmic binding proteins
3 components: Periplasmic binding proteins, Membrane- spanning transporter, and ATP-
hydrolyzing protein (i.e ATPase); also requires ATP energy
Shown in diagram at C
Cell Wall Correct answer-How prokaryotes protect the cell membrane? For most species,
the cell envelope includes at least one structural supporting layer and the most common
structural support is _______?
This confers shape and rigidity to the cell and helps it withstand turgor pressure, can see it for
example in E.coli
, Microbiology Exam 2 UTA; Questions and
Answers % Correct
Mycoplasmas Correct answer-An example of a few prokaryotes who have a cell
membrane with no outer layers
It's difficult to Gram stain
Sacculus Correct answer-The bacterial cell wall, or this, consists of a single- interlinked
molecule; for example disaccharide or peptidoglycan
Needed to maintain high pressure and solubility in order to maintain its shape
Gram- Negative Correct answer-Has thin peptidoglycan (PG)
Gram- Positive Correct answer-Has thick peptidoglycan (PG)
Peptidoglycan or Murein Correct answer-Most bacterial cell walls are made up of this
[only in bacteria]
The molecule consists of:
-Long polymers of two disaccharides called: N-acetylglucosamine (NAG or G) and N-
actelymuramic acid (NAM or M)
-The peptides can form cross-bridges connecting the parallel glycan strands
, Microbiology Exam 2 UTA; Questions and
Answers % Correct
-Can have Lysine (Gram -) or Diaminopimetic acids (Gram +) amino acids
-Cross-linked differently in G+ and G- bacteria
-5 more Glycine in G+
-Peptide bonds are covalent; more peptide bonds in G+
-No inter bridge between G and G
Beta (1,4) Glycosidic Bonds Correct answer-The bonds within peptidoglycan between
NAG and NAM
Peptidoglycan Is Unique to Bacteria Correct answer--Thus the enzymes responsible to its
biosynthesis make excellent targets for antibiotic
-Penicillin inhibits the transpeptidase that cross-links the peptides
-Vancomycin prevents cross-bridge formation by binding to the terminal Ala-Ala dipeptide
-Unfortunately, the widespread use of such antibiotics selects for evolution of resistant strains
Dispersed Zonal Peptidoglycan Growth Correct answer-Wall synthesis direction in bacilli
ex: E.coli (pulse label, 5% doubling time)
Usually growth from the center
Septal Zonal Peptidoglycan Growth Correct answer-Ex. cocci (staphylococcus,
streptococcus)
Answers % Correct
Uniporters Correct answer-Transport in one direction across the membrane
Symporters Correct answer-Functions as co-transporters; the two molecules travel in the
same direction; 1. Energy is released as one substituent moves down its concentration gradient
2. This energy moves a second substrate against its gradient into the cell
Anitporters Correct answer-Transport a molecule across the membrane while
simultaneously transporting another molecule in the opposite direction; the actively
transported molecule moves in the direction opposite to the driving ion; 1. Antiporter binds
substrate A on the cytoplasmic side of the membrane 2.Antiporter opens to the outside, where
the concentration of A is less 3. Substrate A leaves its binding site, and substrate B then binds to
its site 4. Antiporter opens to the inside of the cell. Substrate B is released in exchange for
substrate A
The Phosphotransferase System in E.coli Correct answer--Type of group translocation
-Best studied system
-Moves glucose, fructose, and mannose
-Five proteins required
-Energy derived from phosphoenolpyruvate (PEP)
-The product Glucose 6-P is used in glycolysis
, Microbiology Exam 2 UTA; Questions and
Answers % Correct
Group Translocation Correct answer-Substance transported is chemically modified during
transport across the membrane, usually phosphorylated
ABC Systems Correct answer--ATP-Binding Cassette systems
- >200 different systems identified in prokaryotes
-Often involved in uptake of organic compounds (e.g. sugars, amino acids), inorganic nutrients
(e.g sulfate, phosphate), and trace metals
-Typically display high substrate specificity
-Contain periplasmic binding proteins
3 components: Periplasmic binding proteins, Membrane- spanning transporter, and ATP-
hydrolyzing protein (i.e ATPase); also requires ATP energy
Shown in diagram at C
Cell Wall Correct answer-How prokaryotes protect the cell membrane? For most species,
the cell envelope includes at least one structural supporting layer and the most common
structural support is _______?
This confers shape and rigidity to the cell and helps it withstand turgor pressure, can see it for
example in E.coli
, Microbiology Exam 2 UTA; Questions and
Answers % Correct
Mycoplasmas Correct answer-An example of a few prokaryotes who have a cell
membrane with no outer layers
It's difficult to Gram stain
Sacculus Correct answer-The bacterial cell wall, or this, consists of a single- interlinked
molecule; for example disaccharide or peptidoglycan
Needed to maintain high pressure and solubility in order to maintain its shape
Gram- Negative Correct answer-Has thin peptidoglycan (PG)
Gram- Positive Correct answer-Has thick peptidoglycan (PG)
Peptidoglycan or Murein Correct answer-Most bacterial cell walls are made up of this
[only in bacteria]
The molecule consists of:
-Long polymers of two disaccharides called: N-acetylglucosamine (NAG or G) and N-
actelymuramic acid (NAM or M)
-The peptides can form cross-bridges connecting the parallel glycan strands
, Microbiology Exam 2 UTA; Questions and
Answers % Correct
-Can have Lysine (Gram -) or Diaminopimetic acids (Gram +) amino acids
-Cross-linked differently in G+ and G- bacteria
-5 more Glycine in G+
-Peptide bonds are covalent; more peptide bonds in G+
-No inter bridge between G and G
Beta (1,4) Glycosidic Bonds Correct answer-The bonds within peptidoglycan between
NAG and NAM
Peptidoglycan Is Unique to Bacteria Correct answer--Thus the enzymes responsible to its
biosynthesis make excellent targets for antibiotic
-Penicillin inhibits the transpeptidase that cross-links the peptides
-Vancomycin prevents cross-bridge formation by binding to the terminal Ala-Ala dipeptide
-Unfortunately, the widespread use of such antibiotics selects for evolution of resistant strains
Dispersed Zonal Peptidoglycan Growth Correct answer-Wall synthesis direction in bacilli
ex: E.coli (pulse label, 5% doubling time)
Usually growth from the center
Septal Zonal Peptidoglycan Growth Correct answer-Ex. cocci (staphylococcus,
streptococcus)
