Biology
Briefly explain the following terms :
(i) Reflex action
(ii) Power of accommodation
(iii) Photophosphorylation
(iv) Hormone
(v) Synapse
Nervous System
ICSE 2016
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Answer
(i) A reflex action is an automatic/quick/immediate involuntary action in the body brought about by a stimulus.
(ii) Power of accommodation is the ability of the eye lens to focus near and far objects clearly on the retina by adjusting its focal length.
(iii) Photophosphorylation is the formation of energy rich compound Adenosine Triphosphate (ATP) from Adenosine Diphosphate (ADP) and inorganic Phosphate in the presence of light.
(iv) Hormone is a secretion from some glandular part of the body, which is poured directly into blood and which acts on the target organs or cells of the same individual, bringing about coordination between distant parts of the body.
(v) Synapse is the point of contact between the terminal branches of the axon of a neuron with the dendrites of another neuron separated by a fine gap.
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