(I)Symbiotic association of fungi with plant roots
(B)Parasite
(II)Decomposition of dead organic materials
(C)Lichens
(III)Living on living plants or animals
(D)Mycorrhiza
(IV)Symbiotic association of algae and fungi
Choose the correct answer from the options given
below:
Explanation:
Correct match: A-Saprophyte ↔ II-Decomposition of dead organic materials; B-Parasite ↔ III-Living on living plants or animals; C-Lichens ↔ IV-Symbiotic association of algae and fungi; D-Mycorrhiza ↔ I-Symbiotic association of fungi with plant roots. So the pairings are (A)-(II), (B)-(III), (C)-(IV), (D)-(I), i.e., option 4. This follows NCERT definitions: saprophytes decompose dead matter; parasites live on hosts; lichens are a fungus-alga mutualism; mycorrhiza is a fungus-plant root symbiosis.
🧠 Did You Know?
Mycorrhiza improves water and nutrient uptake for plants, while lichens can survive in harsh environments due to their composite organism.
💡 NCERT Memory Line:
Saprophytes decompose dead organic materials; Mycorrhiza is a fungus–plant root symbiosis; Parasites live on living hosts; Lichens are a fungus–alga mutualism.
From evolutionary point of view, retention of the
female gametophyte with developing young embryo
on the parent sporophyte for some time, is first
observed in:
In gymnosperms, the phloem does not have sieve tubes or companion cells. Instead, it contains sieve cells with associated albuminous cells. Thus, it lacks both sieve tubes and companion cells.
? Did You Know?
NCERT describes gymnosperm phloem as having sieve cells and albuminous cells, not sieve tubes or companion cells.
? NCERT Memory Line:
Gymnosperm phloem: sieve cells + albuminous cells (no sieve tubes, no companion cells).
Inhibition of Succinic dehydrogenase enzyme by
malonate is a classical example of:
Explanation:
Malonate inhibits succinic dehydrogenase by competing with succinate for the enzyme’s active site, making it a competitive inhibitor. This prevents normal substrate binding and slows the reaction in the citric acid cycle (succinate to fumarate). In NCERT terms, the inhibition occurs at the active site and is overcome by high substrate concentration, which is characteristic of competitive inhibition.
🧠 Did You Know?
Competitive inhibitors resemble the normal substrate and can be outcompeted by increasing substrate concentration.
💡 NCERT Memory Line:
Inhibition that resembles the substrate and competes for the active site = competitive inhibition.
