Draw the structure of a neuron and explain its function.
Nervous system controls and coordinates the activities, bevahiour of animals, also maintains the homeostasis (internal body temperature) & is composed of two principal cells:-
Neurons (nerve cells)
Neuroglia or glial cells
Neurons:- These are the basic structural & functional unit of nervous system. They are specialized to respond to stimulus (any change in envirionment ,i.e, strong enough to initiate an nerve impulses) can be physical or chemical, conduct nerve impulses and release chemicals called neurotransmitters.
Nerve impulses travels at the speed ranges from 0.5 to 130 meters per second along plasma membrane of a neuron.
Neroglia cells or glial cells (glia-glue) :- These cells nourishes, protects and support the neurons.
Which signals will get disrupted in case of a spinal cord injury?
How does chemical coordination take place in animals?
Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Why is the use of iodised salt advisable?
The brain is responsible for
(a) thinking.
(b) regulating the heart beat.
(c) balancing the body.
(d) all of the above.
How do we detect the smell of an agarbatti (incense stick)?
How do auxins promote the growth of a tendril around a support?
How does our body respond when adrenaline is secreted into the blood?
Which part of the brain maintains posture and equilibrium of the body?
What are plant hormones?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
Give two important uses of washing soda and baking soda.
What is the far point and near point of the human eye with normal vision?
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
Write a balanced chemical equation with state symbols for the following reactions:
Will geographical isolation be a major factor in the speciation of a self-pollinating plant species? Why or why not?
What is geothermal energy?
Which sources produce alternating current?
The magnetic field in a given region is uniform. Draw a diagram to represent it.
Show how you would connect three resistors, each of resistance 6 Ω, so that the combination has a resistance of (i) 9 Ω, (ii) 4 Ω.
Why do HCl, HNO3, etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?