1. The L Ring in Gram-Negative bacterium flagella is associated with _________
a) Peptidogycan
b) Outer Membrane
c) Cytoplasmic Membrane
d) Cell Membrane
Explanation: The flagella in Gram-Negative bacteria has four basal rings. The L Ring of flagella is associated with the outer membrane. The P ring is associated with the peptidoglycan layer and both the M and S rings are associated with the cytoplasmic membrane.
2. Which among the following acts as a transport protein for protons in flagellar motion?
a) fli protein
b) cGMP
c) atp
d) mot protein
Explanation: The proton binds to the Mot protein and this changes the conformation of Mot protein. It results in releasing the ring and helps in flagellar motion. The fli protein helps in changing the direction of flagella.
3. F pilus has a major role as ___________
a) motility of the cell
b) port of entry of genetic material during mating
c) attachment to host cell
d) human infection
Explanation: Pili are hollow, filamentous appendages that are thinner and shorter. They do not function in motility and have other different functions. One type known as F plus or sex plus serves as the port of entry of genetic material during bacterial mating.
4. Prosthecae helps in __________
a) motility
b) nutrient absorption and attachment to surfaces
c) human infection
d) protection from the environment
Explanation: Prosthecae increases the surface area of the cells for nutrient absorption, which is advantageous in dilute environments. Some prosthecate bacteria have an adhesive substance at the end of a prostheca that aids in attachment to surfaces.
5. The capsule of Klebsiella pneumoniae is composed of heteropolysaccharides.
a) True
b) False
Explanation: Heteroploysaccharides are usually synthesized from sugar precursors that are activated within the cell, attached to a lipid carrier molecule, transported across the cytoplasmic membrane and polymerized outside the cell. The capsule of Klebsiella pneumoniae is an example of heteropolysaccharides.
6.When a bacteria swim towards a chemical, it is termed as_________?
a) positive chemotaxis
b) phototaxis
c) negative chemotaxis
d) magnetotaxis
Explanation: When a bacteria swim towards or away from chemical compounds, the phenomenon is known as bacterial chemotaxis. Swimming towards a chemical is termed as positive chemotaxis; swimming away is negative chemotaxis.
7. Which type of force drives the flagellar motion?
a) Protonmotive force
b) ATP driven
c) Protonmotive and ATP driven
d) No protonmotive nor ATP driven
Explanation: It is found that the flagellar motor is driven by the protonmotive force, i.e., the force derived from the electrical potential and the hydrogen-ion gradient across the cytoplasmic membrane.
8. Peptidoglycan layer is present in large quantity in?
a) Gram-positive bacteria
b) Gram-negative bacteria
c) Fungi
d) Algae
Explanation: Gram-positive bacteria usually have a much greater amount of peptidoglycan in their cell walls than do Gram-negative bacteria. It may account for 50 percent or more of the dry weight of the wall of some Gram-positive species, but only about 10 percent of the wall of Gram-negative bacteria.
9. Peptidoglycan is made up of __________
a) N-acetylglucosamine
b) N-acetylmuramic acid
c) N-acetylglucosamine, N-acetylmuramic acid
d) N-acetylglucosamine, N-acetylmuramic acid, amino acids
Explanation: Peptidoglycan differs somewhat in composition and structure from one species to another, but it is basically a polymer of N-acetylglucosamine, N-acetylmuramic acid, Amino acids like-L-alanine, D-alanine, D-glutamate, and a diamino acid.
10. Teichoic acid present in Gram-positive bacteria can bind to which ion?
a) Fe ions
b) Phosphorus ions
c) Mg ions
d) Sulphur ions
Explanation: Teichoic acid bind magnesium ions and there is some evidence that they help to protect bacteria from thermal injury by providing an accessible pool of these cations for stabilization of the cytoplasmic membrane.