NEET (UG)

Practice Test 1 — Microbes in Human Welfare

12 questions • 18 minutes • auto-graded with full solutions

⏱ 18:00

0 / 12 answered

[object Object]

0 / 12

0Correct

0Wrong

0Skipped

0:00Time used

Back to Study

Section A — MCQ (Single Correct)

Question 1

Curd is produced by:

Solution: Lactic acid bacteria (Lactobacillus) set curd.

Question 2

The CO₂ that makes bread dough rise comes from:

Solution: Saccharomyces cerevisiae (yeast) releases CO₂.

Question 3

The first antibiotic penicillin came from:

Solution: Fleming discovered penicillin from Penicillium notatum.

Question 4

Citric acid is produced by:

Solution: Aspergillus niger produces citric acid.

Question 5

Secondary sewage treatment lowers the:

Solution: The activated-sludge process reduces BOD.

Question 6

The major gas in biogas is:

Solution: Biogas is predominantly methane.

Question 7

Which is a symbiotic nitrogen-fixing biofertiliser?

Solution: Rhizobium fixes nitrogen symbiotically in legume nodules.

Question 8

Cyclosporin A is used as a/an:

Solution: Cyclosporin A (from Trichoderma) is an immunosuppressant.

Section B — Assertion & Reason

Question 9

A: Baker's yeast makes bread soft and puffy.
R: Yeast ferments sugars and releases carbon dioxide, which makes the dough rise.

Solution: CO₂ from fermentation is exactly what makes the dough rise — R explains A.

Question 10

A: A lower BOD indicates cleaner water.
R: BOD measures the oxygen microbes would need to break down organic matter, so less organic pollution means a lower BOD.

Solution: Less organic matter → lower oxygen demand → lower BOD — R explains A.

Question 11

A: Biogas is produced under anaerobic conditions.
R: Methanogens, which generate the methane in biogas, are anaerobic bacteria.

Solution: Methanogens being anaerobic is exactly why biogas forms anaerobically — R explains A.

Question 12

A: Rhizobium increases soil nitrogen.
R: It fixes atmospheric nitrogen in the root nodules of leguminous plants.

Solution: Symbiotic nitrogen fixation is why it enriches soil nitrogen — R explains A.