How is oxygen and carbon dioxide transported in human beings?
Exchange of the gases – oxygen and carbon dioxide, take place in various ways in the human beings.
Transport of the oxygen occurs in the two forms:- one is in the form of solution, dissolved oxygen in water and about 3% of the solution present in the plasma. And, another form is oxyhaemoglobin, about 97 percent of oxygen diffuses from plasma into the red blood cells and it loosely joins with iron of haemoglobin to form oxyhaemoglobin and then it combines with one oxygen molecule.
Carbon dioxide transport is carried by the blood in the three forms:- physical solution, bicarbonate ions and carbaminohemoglobin. About 7% of the carbon dioxide dissolves in the plasma and serve as a physical solution. In the bicarbonate ions 70% carbon dioxide released by tissue cells, diffuses into the plasma and then into the red blood cells. Carbon dioxide combines with water to form carbonic acid by the carbonic anhydrase enzyme, then this acid splits into bicarbonate and hydrogen ion. And, they are joined by the sodium and potassium to maintain pH of the blood. And about 23% of the CO2 enters into the red blood cells and combines with amino group of the reduced Hb (haemoglobin) to form carbaminohemoglobin.
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
How is the amount of urine produced regulated?
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?
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?
If a woman is using a copper -T, will it help in protecting her from sexually transmitted diseases?
Compare the above system with the probable systems in hilly/mountainous areas or plains or plateau regions.
How is the process of pollination different from fertilisation?
How does phototropism occur in plants?
What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
You are given a hammer, a battery, a bulb, wires and a switch.
(a) How could you use them to distinguish between samples of metals and non-metals?
(b) Assess the usefulness of these tests in distinguishing between metals and non-metals.
Can any source of energy be pollution-free? Why or why not?
Identify the substances that are oxidised and the substance that are reduced in the following reactions.
(i) 4Na(s) + O2(g) → 2Na2O(s)
(ii) CuO(s) + H2(g) → Cu(s) + H2O(l)
An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be
(a) calcium
(b) carbon
(c) silicon
(d) iron.
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?