Where do plants get each of the raw materials required for photosynthesis?
Photosynthesis is the anabolic process by which green plants (autotrophs) synthesize their own food in the form of glucose or carbohydrates from the simple inorganic compounds like carbon dioxide and water. So, this process is the transformation of light energy into the chemical energy to make their food in their own food,i.e, carbohydrates by green plants.
So, the following raw materials are required like carbon dioxide, water, chlorophyll and sunlight to make complex organic material from the simple inorganic material.
Carbon dioxide:- carbon dioxide is taken up from the atmosphere through the stomata and releases oxygen.
Water:- plants take water from the soil through the roots to the leaves. And, the transportation of water from the soil to the roots and then to the root cortex and then finally transported to the leaves from the stem occurs through the xylem.
Sunlight is obtained from the sun to make the food, necessary for the producers (green plants).
Chlorophyll:- when organisms take carbon dioxide and water from the environment, they use sunlight and convert them into the glucose or oxygen and this is taken up by the chlorophyll.
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
How is the amount of urine produced regulated?
What criteria do we use to decide whether something is alive?
What are the different ways in which glucose is oxidised to provide energy in various organisms?
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 outside raw materials used for by an organism?
What would be the consequences of a deficiency of haemoglobin in our bodies?
What are the components of the transport system in highly organised plants?
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?
Explain the underlying principle and working of an electric generator by drawing a labelled diagram. What is the function of brushes?
Use the data in Table 12.2 to answer the following –
(a) Which among iron and mercury is a better conductor?
(b) Which material is the best conductor?
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 |
Translate the following statements into chemical equations and then balance them.
(a) Hydrogen gas combines with nitrogen to form ammonia.
(b) Hydrogen sulphide gas burns in air to give water and sulpur dioxide.
(c) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic Table.
(a) The elements become less metallic in nature.
(b) The number of valence electrons increases.
(c) The atoms lose their electrons more easily.
(d) The oxides become more acidic.
If all the waste we generate is biodegradable, will this have no impact on the environment?
Write the balanced equation for the following chemical reactions.
1. Hydrogen + Chlorine → Hydrogen chloride
2. Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
3. Sodium + Water → Sodium hydroxide + Hydrogen
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
In the Modern Periodic Table, calcium (atomic number 20) is surrounded by elements with atomic numbers 12, 19, 21 and 38. Which of these have physical and chemical properties resembling calcium?
Under what soil condition do you think a farmer would treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate)?