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Ask QuestionPosted by Yug Patel 6 years, 6 months ago
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Posted by Bipin Joshi Bipin Joshi 6 years, 6 months ago
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Harsh Deep 6 years, 6 months ago
Posted by Polak Das 6 years, 6 months ago
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Yogita Ingle 6 years, 6 months ago
a) Chemical method of preservation is done by adding certain chemicals which have the capability of preserving the food. Preservatives include sodium benzoate and sodium metabisulphite used in jams and squashes.
b) Preservation by vinegar is done by adding vinegar as microorganisms cannot live in sour environment provided by the same.
c) Preservation by sugar is done by adding sugar which reduces moisture in food. It also inhibits the growth of microbes that spoil food. Jams, jellies and squashes are preserved using sugar.
d) Preservation by oil is done by adding oil, as bacteria and fungi cannot live in an environment provided by oil.
e) Sun drying is one another method of preserving food. Food like vegetables and fruits are sliced and sundried in order to remove moisture from them. These dehydrated food products can be stored and preserved.
f) Salting is done by using common salt. Sodium chloride used as common salt absorbs moisture from food, making it dry and uninhabitable for microbes.
Posted by Anjali Pal 6 years, 6 months ago
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Polak Das 6 years, 6 months ago
Posted by Vani Singh 6 years, 6 months ago
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Meghna Thapar 5 years, 6 months ago
Objective: To show experimentally that carbon dioxide is released during respiration.
Apparatus and Materials Required: A conical flask, a beaker, a cork with a hole, a glass tube bent at right angles at two places, a small test tube, KOH solution, thread, coloured water.Theory:
Respiration is a catabolic process which involves the breakdown of food or complex organic molecules into simpler products, with the release of energy. This process can take place either in the presence of oxygen (aerobic respiration) or in its absence (anaerobic respiration).
The overall reaction mechanism of aerobic respiration involves the oxidation of carbohydrate and the subsequent production of CO2, H2O and energy.
C6H12O6+6O2 → 6CO2 + 6H2O + Energy
Procedure:
1. Take the conical flask and place some germinating gram or pea seeds in it.
2. Insert the shorter end of the glass tube through the hole in the cork and fix it on the conical flask.
3. Before fixing the cork, hang a test tube containing KOH solution inside the conical flask with the help of a thread.
4. Take coloured water in the beaker and keep the longer end of the glass tube dipped inside it.
5. Make the conical flask airtight by applying Vaseline on its rim.
6. Note the initial level of water in the tube.
7. Observe and note the rise in the water level after an hour, without disturbing the apparatus.
Observations:
Water level rises up in the bent tube.
Result:
The rise in the level of water indicates that CO2 is produced by germinating seeds during respiration. Actually, the germinating seeds respire and produce CO2, which is absorbed by KOH solution. This creates a vacuum in the conical flask. The air present in the bent glass tube moves into the conical flask. This pulls the water in the bent tube further up.
Precautions:
1. Keep the conical flask airtight.
2. Fix the shorter end of the glass tube in such a way that it does not touch the seeds.
3. Use freshly prepared KOH solution.
Posted by C Roy 6 years, 6 months ago
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Prathamesh Chakrawar 6 years, 6 months ago
Jayanti Rawat 6 years, 6 months ago
C Roy 6 years, 6 months ago
Posted by R Nagendra Rao 6 years, 6 months ago
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Posted by Polak Das 6 years, 6 months ago
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Riya Nagpal 6 years, 6 months ago
Yogita Ingle 6 years, 6 months ago
Pasteurisation is one type of food preservation method. Pasteurisation is the process developed by Louis Pasteur, especially to store milk. In pasteurisation, milk is first heated to about 70 degrees Celsius for 15 to 30 seconds. Then it is suddenly chilled and stored. This prevents the growth of microbes. Pasteurisation deactivates the microbes and reduces the enzyme activity by reduction of temperature.
Rishika Pushkar 6 years, 6 months ago
Posted by Polak Das 6 years, 6 months ago
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Yogita Ingle 6 years, 6 months ago
Milk sold in packets can be stored for 2 or 3 days as it was packed after the process of pasteurisation.
Pasteurisation is one type of food preservation method. Pasteurisation is the process developed by Louis Pasteur, especially to store milk. In pasteurisation, milk is first heated to about 70 degrees Celsius for 15 to 30 seconds. Then it is suddenly chilled and stored. This prevents the growth of microbes. Pasteurisation deactivates the microbes and reduces the enzyme activity by reduction of temperature.
Posted by Polak Das 6 years, 6 months ago
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Prathamesh Chakrawar 6 years, 6 months ago
Yogita Ingle 6 years, 6 months ago
It is necessary to give small children vaccine or oral drops to prevent them from some diseases like polio malaria and typhoid . It is also to Kill the harmful bacteria present inside the body
Posted by Šhivâ Luđhîâñã 6 years, 6 months ago
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Posted by Abcd. Efgh. 6 years, 6 months ago
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Harsh Deep 6 years, 6 months ago
Shriyam Singh 6 years, 6 months ago
Posted by Anshu Anand 6 years, 6 months ago
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Meghna Thapar 5 years, 10 months ago
The amount of heat energy produced on complete combustion of 1 kg of a fuel is called its calorific value. The calorific value of a fuel is expressed in a unit called kilojoule per kg (kJ/kg). The calorific value of wood is 17000 - 20000 whereas the calorific value of LPG is 55000. Hence, LPG is more efficient than wood.
Posted by Anshu Anand 6 years, 6 months ago
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Posted by Hans Raj Meena 6 years, 6 months ago
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Meghna Thapar 5 years, 10 months ago
Metals - Sodium, potassium, magnesium, aluminium and copper.
Non-metals - Carbon, hydrogen, sulphur, nitrogen and chlorine.
Physical Properties of Metals:
- Physical State: All metals are solids at room temperature.
Exceptions: Mercury and gallium are liquids at room temperature.
- Lustre: All metals in their pure state have a shine and can be polished to give a highly reflective surface.
- Malleability: Metals have the ability to withstand high tensile strength and can be made into thin sheets. This property of metals is called malleability.
Physical Properties of Non-Metals:
- Non-metals are either in the solid or gaseous state.
Exception: Bromine is an exception which exists in the liquid state.
- Non-metals do not have lustre.
Exception: Iodine crystals are lustrous.
Chemical Properties of Metals:
- Reaction of Metals with Oxygen: Almost all metals react with oxygen to form metal oxides.
Metal + Oxygen → Metal oxide
ii. Reaction of Metals with Water: Metals react with water to produce metal oxides with the release of hydrogen gas. But all metals do not react with water.
Metal + Water → Metal oxide + Hydrogen
Posted by Polak Das 6 years, 6 months ago
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Polak Das 6 years, 6 months ago
Posted by Polak Das 6 years, 6 months ago
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8B 35 Thanmay Rooba Nathan S 4 years, 11 months ago
Prathamesh Chakrawar 6 years, 6 months ago
Madesh Waran 6 years, 6 months ago
Posted by Polak Das 6 years, 6 months ago
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Posted by Polak Das 6 years, 6 months ago
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Posted by Sadhya Prasad 6 years, 6 months ago
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Shriyam Singh 6 years, 6 months ago
Posted by Sadhya Prasad 6 years, 6 months ago
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Posted by S V 6 years, 6 months ago
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Posted by Ashwani Mishra 6 years, 6 months ago
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Meghna Thapar 5 years, 10 months ago
Diseases like polio and chicken pox are caused by viruses. In chicken pox there is a blister-like rash, which first appears on the face and trunk, and then spreads throughout the body.
Posted by R Nagendra Rao 6 years, 6 months ago
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Yogita Ingle 6 years, 6 months ago
- Monocots show fibrous root system whereas dicots show tap root system.
- Monocot leaves have parallel venation whereas dicot leaves have reticulate venation.
- Monocots have a single cotyledon in their seeds whereas dicots show 2 cotyledons in their seeds.
- The flowers of monocots are trimerous which means they have three or multiple of three petals. The flowers of dicots are pentamerous which means they possess five or multiple of five petals.
Posted by Chinnari Raaghava 6 years, 6 months ago
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Chinnari Raaghava 6 years, 6 months ago
Posted by Shreyash Raut 6 years, 6 months ago
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Yogita Ingle 6 years, 6 months ago
If kharif crops are grown in season of rabi crops, then the plants do not grow properly and both the quantity and quality of crop is poor. Each type of plants require a specific conditions for growth and maturation, so if they are not provided then the plants will not grow.
Posted by Shreyash Raut 6 years, 6 months ago
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Sarthak Khatri 6 years, 6 months ago
Yogita Ingle 6 years, 6 months ago
The seeds should be sown at appropriate depth because seeds sown superficially can be eaten by the birds. But they should not be sown too deep also. In addition to this, the seeds should not be sown too close as the plants will not get sufficient space to grow and will compete for space, nutrients and sunlight.
Posted by Alok Shah 6 years, 6 months ago
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Posted by Vashunthira B 6 years, 6 months ago
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Meghna Thapar 5 years, 6 months ago
Bacteria do not age, generally because every individual becomes a germinal cell in division. Germinal cells are biologically immortal, after all. However, bacteria may eventually cause death by old age in humans. If they do not quickly find “other employment” they die with their host. Bacteria divide somewhere between once every 12 minutes and once every 24 hours. So the average lifespan of a bacterium is around 12 hours or so.
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Bhoomi Deswal 6 years, 6 months ago
1Thank You