Question

Given below are two statements:
Statement (I): Lichens are the symbiotic associations between a photobiont and mycobiont
Statement (II): The photosynthetic partner in lichens can be either be a green algae, a blue-green algae or both
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are false.
• B. Both Statement (I) and Statement (II) are true.
• C. Statement (I) is true but Statement (II) is false.
• D. Statement (I) is false but Statement (II) is true.

Hint:

Remember the core partners of a lichen: the mycobiont (usually an Ascomycete fungus) and the photobiont (which can be a green alga, a cyanobacterium, or both together in tripartite lichens).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Lichens are complex organisms composed of a mutualistic symbiotic association between a photosynthetic partner and a fungal partner.
The photosynthetic partner is referred to as the photobiont, and the fungal partner is referred to as the mycobiont.

Step 2: Detailed Explanation:
Let us evaluate each statement to determine its scientific accuracy:
Statement (I) describes the fundamental definition of a lichen.
A lichen is indeed a stable, obligate symbiotic partnership between a photobiont (which provides organic carbon through photosynthesis) and a mycobiont (which provides physical structure, protection, and absorbs water and minerals).
Thus, Statement (I) is true.
Statement (II) describes the biological diversity of the photobiont partner.
The photobiont is typically a green alga (usually chlorophytes such as Trebouxia) or a blue-green alga (cyanobacteria such as Nostoc).
In some cases, a single lichen can contain both a green alga and a cyanobacterium as photobionts, where the cyanobacterium is located in specialized structures called cephalodia to fix atmospheric nitrogen.
Thus, Statement (II) is also true.
Because both statements are scientifically correct, the most appropriate choice is that both statements are true.

Step 3: Final Answer:
Therefore, the correct choice is represented by option (B).