Railway Science (Biology – Micro Organism)

Total Questions: 18

1. The presence of which bacteria is an indicator of water pollution? [RRC Group D 17/08/2022 (Afternoon)]

Correct Answer: (b) E. coli Coliform
Solution:

Coli Coliform - The presence of this bacteria is an indicator of faecal contamination in water. Salmonella Typhi - is a bacteria that infects the intestinal tract, and the blood and causes typhoid.
Vibrio Cholerae - found in contaminated water or food, causes bacterial disease Cholera. Mycobacterium Tuberculosis - species of pathogenic bacteria in the family Mycobacteriaceae and a causative agent of Tuberculosis.

2. Which of the following is an example of a virus? [RRC Group D 23/08/2022 (Afternoon)]

Correct Answer: (a) HIV
Solution:

A viral disease occurs when an organism's body is invaded by pathogenic viruses, and infectious virus particles attach to and enter susceptible cells. Example: Dengue, AIDS, Influenza, Polio, Measles etc.
Anthrax is an infection that is caused by the bacteria Bacillus anthracis. Elephantiasis is caused by filarial parasites.

3. A unicellular organism has a definite shape, takes food in at a specific spot, and uses hair like cilia to move food to that spot. Identify the organism, [RRC Group D 01/09/2022 (Evening)]

Correct Answer: (a) Paramaecium
Solution:

Lice are parasitic insects that can be found on people's heads. Human lice survive by feeding on human blood. Euglena is a genus of eukaryotic, unicellular and flagellated microorganisms.
They contain a well-defined nucleus and other cellular organelles. Plasmodium is a type of protozoa, a single-celled organism that is able to divide only within a host cell.

4. How does the following organism get rid of its nitrogenous wastes? [RRC Group D 29/09/2022 (Afternoon)]

Correct Answer: (b) By simple diffusion
Solution:

Amoeba is unicellular, doesn't have any special excretory organs and undigested food particles are present in the food vacuole. The vacuole is pushed towards the exterior of the cell and is ejected out via diffusion. Specialized vacuoles known as contractile vacuoles are also present, they collect the wastes generated by the cell and move towards the plasma membrane where it ruptures to release the waste material.

5. Which statement regarding molecular movement (living character) of viruses is correct? [RRC Group D 11/10/2022 (Evening)]

Correct Answer: (c) Inactive until they infect some cells.
Solution:

Virus: A submicroscopic infectious agent that replicates itself only inside the living cells of other organisms. Viruses possess the characteristics of both the living and the non-living.
For instance, viruses can reproduce inside a host just like any other living organism, but this ability to reproduce is lost when the virus is outside the host cell.
They are not placed in three domains of life because they don't possess any of their traits. They have DNA or RNA strands covered with capsid and can't perform any kind of metabolic activity due to lack of cell organelles.

6. What ingredient is put in bread to make it rise? [RRB NTPC CBT - I (29/01/2021) Morning]

Correct Answer: (c) Yeast
Solution:

Yeast consumes the sugar present in the dough and burps out carbon dioxide gas and alcohol called ethanol. This gas gets trapped inside the bread dough due to the presence of gluten in it, thus making the dough rise.

7. What is the shape of the Cocci bacteria? [RRB JE 25/05/2019 (Evening)]

Correct Answer: (d) Spherical
Solution:

Bacteria are small single-celled organisms. They are found almost everywhere on Earth and are vital to the planet's ecosystems. The human body is full of bacteria. Bacteria are grouped under five categories based on their shape: Spherical (cocci), rod (bacilli), spiral (spirilla), comma (vibrios) or corkscrew (spirochaetes).

8. What causes decomposition of organic matter? [RRB JE 26/05/2019 (Evening)]

Correct Answer: (c) Bacteria
Solution:

Decomposers - The micro-organisms that convert the dead plants and animals to humus. Examples - Bacteria and Fungi. Decomposition- The process by which decomposers break down complex organic matter into inorganic substances like carbon dioxide, water and nutrients.

9. Blue green algae contains - [RRB JE 30/05/2019 (Morning)]

Correct Answer: (b) Thylakoid, membranes
Solution:

Thylakoid membranes:- It is an interconnected disc - like sacs of the internal membrane system of the chloroplast and cyanobacteria. Blue-green algae (cyanobacteria) - A group of prokaryotic, autotrophic microorganisms that contain the photosynthetic pigments (chlorophyll and phycocyanin).
Due to its dense growth, the color of water turns green, blue-green or brownish-green. Cyanobacteria - first photosynthetic oxygen liberating organisms to appear on earth. Mitochondria (produce energy), Lysosomes (digestive system of cell), Golgi Bodies (prepares proteins and fat) are the organelles of cells.

10. Bacteria that can grow and produce lethal toxins even inside the refrigerator are - [RRB JE 01/06/2019 (Evening)]

Correct Answer: (c) Clostridium Botulinum
Solution:

Clostridium Botulinum : A bacterium that produces dangerous toxins (botulinum toxins) under low-oxygen conditions. It blocks nerve functions and can lead to respiratory and muscular paralysis.
Salmonella infection (salmonellosis) is a common bacterial disease that affects the intestinal tract. Enterococcus faecalis : Often found in the large intestine of humans. Escherichia coli : Found in the environment, foods, intestines of people and animals.