Q1.Which of the following is a plant hormone?
🎯 (d) Cytokini
✅ Q2.
The gap between two neurons is called:
🎯 (b) synapse
✅ Q3.
The brain is responsible for:
🎯 (d) all of the above
(thinking, regulating heartbeat, balancing the body)
✅ Q4.
Function of receptors:
• Receptors detect stimuli (light, sound, heat, etc.) and send signals to the brain/spinal cord.
• If receptors don’t work properly → organism may not feel pain, heat, light etc., leading to injury, accidents, or inability to respond.
✅ Q5.
Structure and function of neuron:
Structure:
• Cell body (with nucleus)
• Dendrites (receive signals)
• Axon (carries signal away)
• Axon terminals (pass signal to next cell at synapse)
Function:
To transmit nerve impulses from one part of the body to another.
[Dendrites] → [Cell body] → [Axon] → [Synapse]
✅ Q6.
How does phototropism occur?
• Plants bend towards light due to unequal distribution of auxin (a plant hormone).
• More auxin on shaded side → cells elongate more → bending towards light.
✅ Q7.
Which signals are disrupted if spinal cord is injured?
• Reflex actions below the injury site
• Voluntary movements of limbs below injury
• Transmission of sensory signals to the brain
✅ Q8.
Chemical coordination in plants:
• Done by plant hormones (phytohormones) like auxins, gibberellins, cytokinins, abscisic acid, ethylene.
• These hormones regulate growth, development, and response to stimuli.
✅ Q9.
Why do organisms need control & coordination?
• To respond to environmental changes.
• To maintain balance between different body functions.
• To perform complex activities efficiently.
✅ Q10.
Difference between involuntary actions & reflex actions:
Feature Involuntary action Reflex action
Control Brain Spinal cord
Speed Slower Very fast
Example Heartbeat, breathing Pulling hand from hot object
✅ Q11.
Nervous vs Hormonal control:
Feature Nervous system Hormonal (endocrine) system
Type of signal Electrical impulses Chemical signals (hormones)
Speed Fast Slow
Duration Short-lived Long-lasting
Specificity Specific organs Can affect many organs
✅ Q12.
Difference: Plant vs Human movement:
Feature Movement in sensitive plant Movement in human legs
Type Nastic (non-directional) Voluntary
Control Chemical (hormones, turgor) Nervous & muscular
Energy source Water movement in cells Muscle contraction (ATP)
Example Leaves of Mimosa folding Walking, running