Assertion Reason Test: Biological Classification - NEET MCQ

Slime moulds – Reproductive phase is plant-like (Cell wall present in spore) – Vegetative phase is animal-like (Cell wall absent)

Both statements are correct, but reason is not the correct explanation.

Both (A) & (R) are correct

Assertion: Secondary mycelium of Agaricus is binucleated.
Reason: Secondary mycelium is formed by somatogamy of primary mycelium.

To understand whether the given assertion and reason are true, we need to analyze the information provided.
1. What is Agaricus?
- Agaricus is a genus of mushrooms that includes the common mushroom (Agaricus bisporus).
2. What is mycelium?
- Mycelium is the vegetative part of a fungus, consisting of a network of branching, thread-like hyphae.
3. What is primary mycelium?
- Primary mycelium is the initial mycelium that is formed after the germination of spores.
4. What is secondary mycelium?
- Secondary mycelium is formed by the fusion (somatogamy) of two compatible primary mycelia.
Now, let's analyze the given assertion and reason:
- Assertion: Secondary mycelium of Agaricus is binucleated.
- This means that the secondary mycelium of Agaricus contains two nuclei.
- This is true because the fusion of two compatible primary mycelia results in the formation of a binucleated secondary mycelium.
- Reason: Secondary mycelium is formed by somatogamy of primary mycelium.
- Somatogamy is the fusion of two compatible hyphae in fungi.
- This is also true because the fusion of two compatible primary mycelia (formed by somatogamy) leads to the formation of a secondary mycelium.
Based on the analysis, we can conclude that both the assertion and reason are true, and the reason is the correct explanation of the assertion.
Therefore, the correct answer is A.

Mycobiont is the dominant parent in lichens.

Fungi is eukaryotic, but algae can be prokaryote or eukaryote.

Unicellular eukaryotes are in protista.

Assertion: Slime moulds form fruiting bodies under unfavourable conditions.
Reason: Naked plasmodium is formed during favourable conditions.

Explanation of the Assertion:
- Slime moulds are organisms that belong to the group of protists.
- Under favorable conditions, slime moulds exist as a naked plasmodium, which is a large, multinucleate mass of cytoplasm.
- The naked plasmodium is capable of undergoing cytoplasmic streaming and feeding on bacteria and other organic matter.
- However, when the conditions become unfavorable, such as when there is a lack of food or moisture, the slime mould undergoes a process called sporulation.
- Sporulation is the formation of fruiting bodies, which are specialized structures that produce and release spores.
- These spores are resistant to harsh environmental conditions and can disperse to new locations, allowing the slime mould to survive and reproduce.
Explanation of the Reason:
- The reason given states that naked plasmodium is formed during favorable conditions.
- This is correct, as under favorable conditions, slime moulds exist as a naked plasmodium.
- The naked plasmodium is the active feeding stage of the slime mould and allows it to grow and thrive in its environment.
Explanation of the Answer:
- Both the assertion and reason are true.
- However, the reason is not the correct explanation of the assertion.
- The reason explains the favorable conditions in which the naked plasmodium is formed, but it does not explain why slime moulds form fruiting bodies under unfavorable conditions.
- The formation of fruiting bodies is a response to unfavorable conditions, such as a lack of food or moisture, and is a mechanism for survival and reproduction.
- Therefore, the correct answer is option B: If both Assertion & Reason are true, but the reason is not the correct explanation of the assertion.

Assertion: DNase can inhibit the process of transformation.
Reason: Transformation is absorption of DNA segment from the surrounding medium by a living bacterium.
Explanation:
The given assertion and reason are both true statements. However, the reason is not the correct explanation of the assertion. Here's a detailed explanation:
- Transformation is a process in which a living bacterium takes up DNA from its surrounding environment and incorporates it into its own genome.
- DNase is an enzyme that degrades DNA by breaking it down into smaller fragments.
- DNase can inhibit the process of transformation by degrading the DNA segments in the surrounding medium before they can be taken up by the bacterium.
- This inhibition occurs because DNase breaks down the DNA segments into smaller fragments, making them less likely to be successfully taken up by the bacterium during transformation.
Therefore, while DNase can indeed inhibit the process of transformation, the reason given (absorption of DNA segment from the surrounding medium by a living bacterium) is not the correct explanation for this inhibition.
Answer: B (If both Assertion & Reason are true, but the reason is not the correct explanation of the assertion)

Assertion: MLOs are pleomorphic and non-motile monerans.
Reason: They are insensitive to antibiotics like penicillin.
Explanation:
- MLOs stand for Mycoplasma-like organisms, which are a group of microorganisms that resemble bacteria but lack a cell wall.
- Pleomorphic refers to the ability of an organism to change its shape or form. MLOs are known to exhibit pleomorphism, meaning they can take on various shapes and sizes.
- Non-motile means that MLOs do not have the ability to move on their own.
- The reason given is that MLOs are insensitive to antibiotics like penicillin. However, this reason does not directly explain why MLOs are pleomorphic and non-motile.
Therefore, the correct answer is option B: If both Assertion & Reason are true, but the reason is not the correct explanation of the assertion.

Majority of bacteria are heterotrophs.

Holophytic protistans – 80% of total photosynthesis – Source of electron is H₂O

Assertion: Sexual spores in pink mould are meiospores produced endogenously.
Reason: They develop flask-shaped fruiting bodies in the sexual life cycle.
Explanation:
The given statement is asking us to evaluate the truthfulness of both the assertion and the reason, and their relationship to each other. Let's analyze the statement and provide a detailed explanation.
Assertion: Sexual spores in pink mould are meiospores produced endogenously.
This assertion states that the sexual spores in pink mould are meiospores and are produced endogenously. To evaluate the truthfulness of this statement, we need to determine if sexual spores in pink mould are indeed meiospores and if they are produced endogenously.
Reason: They develop flask-shaped fruiting bodies in the sexual life cycle.
The reason provided explains the process by which sexual spores develop. It states that they develop flask-shaped fruiting bodies in the sexual life cycle. To evaluate the truthfulness of this reason, we need to determine if sexual spores in pink mould do indeed develop flask-shaped fruiting bodies in their sexual life cycle.
Now, let's evaluate the relationship between the assertion and the reason:
- The assertion and the reason are both true statements.
- Sexual spores in pink mould are indeed meiospores produced endogenously.
- Sexual spores in pink mould do develop flask-shaped fruiting bodies in their sexual life cycle.
Considering the above evaluation, we can conclude that both the assertion and the reason are true, and the reason is indeed the correct explanation of the assertion. Therefore, the correct answer is option A: If both Assertion & Reason are true, and the reason is the correct explanation of the assertion.

Assertion: Azotodesmic lichens are biofertilisers enriching nitrogen contents in soil.
Reason: This ability is due to the presence of heterocystous blue-green algae as phycobiont components.
Explanation:
The given assertion and reason are both true, and the reason provided is the correct explanation of the assertion. Here's a detailed explanation:
1. Azotodesmic lichens as biofertilizers:
- Lichens are composite organisms consisting of a symbiotic relationship between a fungus (mycobiont) and an alga or cyanobacterium (phycobiont).
- Azotodesmic lichens, in particular, have the ability to fix atmospheric nitrogen and convert it into organic forms that can be utilized by plants.
- This process of nitrogen fixation by azotodesmic lichens helps in enriching the nitrogen content of the soil, making it more fertile for plant growth.
2. Heterocystous blue-green algae:
- The reason provided states that the ability of azotodesmic lichens to enrich nitrogen content is due to the presence of heterocystous blue-green algae as phycobiont components.
- Heterocystous blue-green algae, also known as cyanobacteria, have specialized cells called heterocysts that can carry out nitrogen fixation.
- These heterocysts provide a favorable environment for nitrogen fixation, as they lack photosynthetic pigments and can protect the nitrogenase enzyme from oxygen exposure.
- The presence of heterocystous blue-green algae as phycobionts in azotodesmic lichens allows for efficient nitrogen fixation, leading to the enrichment of nitrogen content in the soil.
Therefore, both the assertion and reason are true, and the reason is the correct explanation of the assertion. Hence, option A is the correct answer.

Assertion: Viroids are not included in the five kingdom system.
Reason: They are non-cellular.

The given statement is about viroids and their inclusion in the five kingdom system. Let's analyze the assertion and reason separately:
Assertion: Viroids are not included in the five kingdom system.
- This statement implies that viroids are not classified within the five kingdom system, which is a system used to categorize living organisms into five major groups (Monera, Protista, Fungi, Plantae, and Animalia).
- Viroids are small infectious agents composed solely of circular RNA molecules. They lack a protein coat and are not considered as cells.
- Viroids are known to cause diseases in plants, but they are not classified within any of the five kingdoms of living organisms.
Reason: They are non-cellular.
- This statement suggests that the reason viroids are not included in the five kingdom system is that they are non-cellular.
- Viroids, as mentioned earlier, do not possess a cellular structure. They consist only of RNA molecules and lack a cellular membrane, organelles, and other cellular components.
Explanation:
Based on the above analysis, we can conclude that both the assertion and reason are true and the reason is the correct explanation of the assertion. Viroids are not included in the five kingdom system because they are non-cellular. They do not fit into any of the categories defined by the five kingdom system due to their unique structure and mode of replication. Therefore, option A is the correct answer.
Note: Viroids are now classified separately from the five kingdom system as a distinct group of infectious agents.

Phytophginae generally contain ssRNA.