Practice Questions

TLS Online TPP Program

#Question id: 935

Microorganisms capable of fixing nitrogen into a form usable by animals obtain the energy for this process from ________.

#Biochemistry

More Questions

#Question id: 40486

#Applied Microbiology

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): The thickness of the ozone layer is measured in Dobson Units (DU).

Reason (R): The ozone layer is found in the Troposphere and protects us from harmful UV-B radiation.

#Question id: 40487

#Applied Microbiology

Match the Chemical/Term (List I) with its description or impact (List II).

List I (Term)	List II (Description)
A. CFCs	1. Replacement for CFCs; zero ODP but high GWP.
B. HFCs	2. Used in fire extinguishers; contains Bromine which depletes ozone.
C. Halons	3. Major ODS used in refrigerants; releases Chlorine.
D. UV-B	4. Radiation absorbed by the ozone layer; causes skin cancer.

#Question id: 40488

#Applied Microbiology

The water activity ( $a_w$ ) of pure water is equal to:

#Question id: 40489

#Applied Microbiology

Which class of microorganisms is specifically adapted to grow in environments with very low water activity (high salt concentration)?

#Question id: 40490

#Applied Microbiology

Read the following statements regarding water availability:

Statement I: Water activity ( $a_w$ ) is defined as the ratio of the vapor pressure of the solution to the vapor pressure of pure water.

Statement II: Most pathogenic bacteria require a water activity ( $a_w$ ) greater than 0.90 for growth.Which of the options is correct?

#Question id: 40491

#Applied Microbiology

Assertion (A): Foods like jams and jellies rarely undergo bacterial spoilage even at room temperature.

Reason (R): High concentrations of sugar reduce the water activity ( $a_w$ ), creating hypertonic conditions that dehydrate bacteria (plasmolysis).