Correct match: (a) – (iii), (b) – (iv), (c) – (i), (d) – (ii)

Actinibacteria is gram-positive. It is responsible for the peculiar odour emanating from the soil after rain (petrichor), mainly in warmer climates. The chemical that produces this odour is known as geosmin.

Spirochetes are long and slender bacteria, and placed in domain bacteria (prokaryote). These are thin, corkscrew-shaped, gram-negative and flexible organisms that range in length from a few to as many as 500 µm.

Choroflexus are gram-negative filamentous anoxygenic phototrophic (FAP) organism that do not produce oxygen as a byproduct of photosynthesis, in contrast to oxygenic phototrophs like cyanobacteria. It uses reduced sulphur compounds such as thiosulphate or elemental sulphur.

Instead of using the Calvin-Benson-Bassham Cycle typical of plants, Chloroflexus aurantiacus has been demonstrated to use a novel autotrophic pathway known as the 3-hydroxypropionate pathway.

Chloroflexus aurantiacus that can survive using either respiration or photosynthesis are of interest in on-going attempts to trace the evolution of photosynthesis.

Wrong answer

Treponema pallidum and Borrelia burgdorferi are spirochetes.

Homogenisation cell fraction is the rupturing of cells in order to release various constituents and then keeping them in their natural state by means of a special 0.25 M sucrose solution kept at 0⁰ - 4⁰ centigrade.

Gram's staining consists of four components:

1- Primary stain (Crystal violet, methyl violet or Gentian violet)

2- Mordant (Gram's iodine)

3 - Decolouriser (Ethyl alcohol, acetone or 1 : 1 ethanol-acetone mixture)

4 - Counterstain (Dilute carbol fuchsin, safranin or neutral red)

Glaucophyta is a small group of freshwater microscopic algae.

Correct answer

Correct answer 

Correct answer:

Acetic acid: Produced by the bacterium Acetobacter aceti and other acetic acid bacteria (AAB). Butyric acid (butanoic acid): Produced by the bacterium Clostridium butyricum . Lactic acid: Lactobacillus and others commonly called as lactic acid bacteria (LAB). Citric acid: Produced by the fungus Aspergillus niger.

Phase-contrast microscope is best for mitosis study. It has annular diaphragm and phase plate, and is useful in the study of living cells and their internal happenings.

Correct answer:

Both (A) and (R) is correct but (R) is not the correct expalanation of (A).

Some mycoplasmas (PPLO’S) are named as L-forms where ‘L’ stands for Lister Institute. L-forms can be obtained by treating the bacterial cultures with enzymes like lysozyme or an antibiotic such as penicillin. They lyse the cell walls, due to which small spherical bodies resembling mycoplasmas (PPLO'S) are formed.

Metachromasis is the phenomenon of certain tissues and cell components showing colour other than their fundamental one, e.g. basic aniline stain.