How does chemical coordination occur in plants?
Plants do not have nervous or muscular system for movement or responsiveness like animals have. Plants only shows the growth (by growth hormones like phytohormones) with the attached substratum by giving them appropriate soil moisture, favourable environmental or physiological conditions. Various plant hormones are present for the plant growth like auxin, gibberellin, cytokinin, ethylene or abscisic acid.
Auxin is responsible for the growth of the stem, gibberellins are those growth hormones which enhances the long growth of stem according to the plant in the presence of meristematic cells, cytokinin acts on the cell division part of the plant, ethylene is a gas present in atmosphere and mainly responsible for fruit growth or ripening with root initiation ,And abscisic acid is responsible for seed development, stomatal closing, bud dormancy etc.
Draw the structure of a neuron and explain its function.
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?
Which part of the brain maintains posture and equilibrium of the body?
How does our body respond when adrenaline is secreted into the blood?
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?
A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is (i) pushed into the coil, (ii) withdrawn from inside the coil, (iii) held stationary inside the coil?
Why is DNA copying an essential part of the process of reproduction?
A solution of a substance 'X' is used for whitewashing.
(i) Name the substance 'X' and write its formula.
(ii) Write the reaction of the substance 'X' named in (i) above with water.
Do basic solutions also have H+(aq) ions? If yes, then why are these basic?
What would you observe when zinc is added to a solution of iron(II) sulphate? Write the chemical reaction that takes place.
What are the components of the transport system in highly organised plants?
What will happen if we kill all the organisms in one trophic level?
What are the components of the transport system in human beings? What are the functions of these components?
Give any two ways in which non-biodegradable substances would affect the environment.
Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?