How is the amount of urine produced regulated?
Urine is the fluid and the dissolved waste materials which are excreted out by the kidney. Urine formation involves three processes:
When the amount of water or any fluid get increased above the normal amount, then ultrafiltration process will be increase due to increase in blood pressure of the glomerulus. Then this sends the signal to the brain or the hypothalamus to stop the release of the hormone vasopressin or antidiuretic hormone (ADH) which automatically helps in the regulation of the amount of the urine. ADH hormone deficiency slows down the permeability of the cells of the distal convoluted tubule and collecting duct that decrease reabsorption of water. This more filtration and less reabsorption produce dilute urine and then finally, the amount of urine get back into the normal state. That is how the amount of urine produced is regulated.
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What are the different ways in which glucose is oxidised to provide energy in various organisms?
What criteria do we use to decide whether something is alive?
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm. (c) chloroplast.
(b) mitochondria. (d) nucleus.
What are the differences between autotrophic nutrition and heterotrophic nutrition?
What are the components of the transport system in highly organised plants?
What are outside raw materials used for by an organism?
What would be the consequences of a deficiency of haemoglobin in our bodies?
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Where do plants get each of the raw materials required for photosynthesis?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
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 difference between a reflex action and walking?
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?
How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?
What is the difference between displacement and double displacement reactions? Write equations for these reactions.
Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
Explain the following.
(a) Why is the tungsten used almost exclusively for filament of electric lamps?
(b) Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
(c) Why is the series arrangement not used for domestic circuits?
(d) How does the resistance of a wire vary with its area of cross-section?
(e) Why are copper and aluminium wires usually employed for electricity transmission?
You have two solutions, A and B. The pH of solution A is 6 and pH of solution B is 8. Which solution has more hydrogen ion concentration? Which of this is acidic and which one is basic?
Find the focal length of a lens of power – 2.0 D. What type of lens is this?
Write an equation to show the reaction between Plaster of Paris and water.
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?
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows.
Metal | Iron(II) sulphate | Cooper(II) sulphate | Zinc sulphate | Silver nitrate |
A | No reaction | Displacement | ||
B | Displacement | No reaction | Displacement | |
C | No reaction | No reaction | No reaction | No reaction |
How could the Modern Periodic Table remove various anomalies of Mendeléev’s Periodic Table?