Section A: High Order Thinking Skills (HOTS)
- Mechanism of Action: How does an electrical impulse trigger the release of
neurotransmitters even though the axon ending is sealed? (Vesicle fusion concept).
- Limitations of Nervous System: Why do multicellular organisms need a hormonal
system despite having a fast nervous system? (Limitations: Not all cells connected, continuous
signaling not possible).
- Artificial Ripening: Fruits are often ripened artificially using chemicals like
Carbide (which releases Acetylene/Ethylene). Which natural plant hormone is being mimicked here?
- Adrenal Stress: Why does dry mouth and increased heartbeat occur when you are
scared? Explain the pathway from perception to physiological response. (Brain -> Adrenal Gland ->
Blood -> Heart).
- Feedback Loop: Explain with a flowchart how the body would react if you ate a very
sweet dessert. (Glucose Rise -> Insulin Rise -> Glucose Fall -> Insulin Stop).
Section B: Experimental Competency (Case Studies)
Case I: Auxin Competency. A student cuts off the tips of two bean plants. To one cut tip
(A), he applies a paste containing synthetic Auxin. To the other (B), he applies plain lanolin paste.
Both are kept in light.
- What will happen to the growth of Plant A vs Plant B?
- Why does removing the tip normally stop vertical growth? (Apical Dominance source removed).
- What does this experiment prove about the site of Auxin production?
- If light was applied from one side only to an intact plant, how would the distribution of auxin
change?
Case II: Hydrotropism. A sieve filled with moist sawdust is placed tilted. Germinating
seeds are placed on it.
- Initially, the radicles grow downwards due to gravity. What happens later?
- Why do the roots bend towards the moisture despite gravity acting downwards?
- Which tropism is stronger here: Geotropism or Hydrotropism?
Section C: Assertion & Reasoning
Directions: Read Assertion (A) and Reason (R) and select the correct option.
- Assertion (A): The brain is not involved in a reflex action.
Reason
(R): Reflex arcs are formed in the spinal cord for quick response.
(A is partially
false as brain is informed later, but for immediate action A is true in context of 'initiation').
- Assertion (A): Abscisic acid is a growth promotor hormone.
Reason
(R): It helps in the wilting of leaves.
(A is False, R is True).
- Assertion (A): Diabetes is caused by the deficiency of Insulin.
Reason
(R): Insulin controls the conversion of glucose to glycogen in the liver.
(Both
true and R explains A).
- Assertion (A): Plants do not have a nervous system, yet they
coordinate.
Reason (R): Plants use electro-chemical means to convey information
from cell to cell.
(Both true).
