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.
Which of the following are required for the dark
reaction of photosynthesis?
A. Light
B. Chlorophyll
C. CO2
D. ATP
E. NADPH
Choose the correct answer from the options given
below:
Given below are two Statements: Statement I: Chromomes become gradually visible under light microscope during leptotene stage. Statement II: The begining of diplotene stage is recognized by dissolution of synaptonemal complex.
In the light of the above statements, choose the
correct answer from the options given below:
Explanation:
Statement I is true: chromosomes begin to condense during leptotene and become visible under light microscopy as threads. Statement II is false according to NCERT: the dissolution of the synaptonemal complex begins after the zygotene stage and is not used to define the onset of diplotene as per NCERT wording. Hence, the correct option is 4.
🧠 Did You Know?
In diplotene, chiasmata become visible as homologous chromosomes start to separate while remaining joined at crossover points.
💡 NCERT Memory Line:
Leptotene: chromosomes first condense; Diplotene: desynapsis begins with synaptonemal complex dissolution not used to mark diplotene onset in NCERT phrasing.
