Q: Describe the menstrual cycle in human beings.
A: The changes in the female reproductive system is known as menstrual cycle. It consists of
(1) Proliferative Phase, (2) Secretory Phase.
During proliferative phase cells present in the follicle, fallopian tube, uterus, vagina increase in number by repeated divisions.
In menstrual cycle first 12 to 14 days the follicle matures and releases the ovum on 14th day.
The second phase is known as secretory phase. During this phase the ruptured follicle is converted into corpus luteum and uterine walls are thickened.
Uterus waits for the embryo to reach uterus. After fertilization the formation of egg stops.
If this does not occur by 26th day the cells of corpus luteum and the walls of uterus are detached and are expelled along with some amount of blood.
Immediately after this, the proliferative phase once again starts.
Q: What is "tissue culture"? What are the advantages of it?
A: A cell or tissue taken from a plant cultured in suitable containers which is called tissue
culture. New plants can be obtained from the single cell or tissue.
Advantages:
(i) Desirable plants can be rapidly multiplied.
(ii) Multiplication can be done in a small space under controlled conditions.
(iii) It is possible to obtain plants that are free from pathogens, particularly viruses.
(iv) Embryos that do not develop in ovaries can be grown in culture media.
(v) Plants can be isolated by creating these conditions in culture medium.
(vi) New hybrid species can be evolved by tissue culture.
(vii) We can select desirable mutants in a relatively small places or in a very short time.
(viii) Useful chemicals can be produced in plant cell culture in liquid media.
Junior Inter Physics Imp Questions - Thermal Properties of Matter
Q: Can a substance contract on heating? Give an example.
A: Yes. Substance will contract on heating.
Eg: Leather, cast iron, rubber.
Q: Why gaps are left between rails on a railway track?
A: To compensate expansion of rails during summer, a gap is left between ends of two successive rails.
Q: Why do liquids have no linear and areal expansion?
A: Liquids have only volume expansion. They do not have their own shape, they occupy the shape of the container. Hence they do not have linear and areal expansions.
Q: What is specific gas constant? Is it same for all gases?
A: Universal gas constant per unit mass is called specific gas constant 'r'. It's value changes from gas to gas.
Q: Why utensils are coated black? Why the bottom of utensils are made of copper?
A: Since black bodies are good absorbers of heat, so lower portion of utensil is coated black. Copper is a good conductor of heat. It promotes the distribution of heat over the bottom of the vessel for uniform cooking.
Q: What is green house effect? Explain global warming.
A: Green House Effect: It is a process by which thermal radiation from earth's surface is absorbed by atmospheric gases (CO2, methane, nitrous oxide) and is re-radiated in all directions. The part of this re-radiation is
back towards the surface which results in heating up of earth's surface and atmosphere.
Global Warming: Concentration of green house gases enhanced due to human activities making earth warmer which cause problems for human life, plants and animals.
Q: Roof of buildings are often painted white during summer. Why?
A: White colour is a good reflector of heat. Good reflector is a bad absorber of heat. So, buildings are kept cool during summer.
A: Yes. Substance will contract on heating.
Eg: Leather, cast iron, rubber.
Q: Why gaps are left between rails on a railway track?
A: To compensate expansion of rails during summer, a gap is left between ends of two successive rails.
Q: Why do liquids have no linear and areal expansion?
A: Liquids have only volume expansion. They do not have their own shape, they occupy the shape of the container. Hence they do not have linear and areal expansions.
Q: What is specific gas constant? Is it same for all gases?
A: Universal gas constant per unit mass is called specific gas constant 'r'. It's value changes from gas to gas.
Q: Why utensils are coated black? Why the bottom of utensils are made of copper?
A: Since black bodies are good absorbers of heat, so lower portion of utensil is coated black. Copper is a good conductor of heat. It promotes the distribution of heat over the bottom of the vessel for uniform cooking.
Q: What is green house effect? Explain global warming.
A: Green House Effect: It is a process by which thermal radiation from earth's surface is absorbed by atmospheric gases (CO2, methane, nitrous oxide) and is re-radiated in all directions. The part of this re-radiation is
back towards the surface which results in heating up of earth's surface and atmosphere.
Global Warming: Concentration of green house gases enhanced due to human activities making earth warmer which cause problems for human life, plants and animals.
Q: Roof of buildings are often painted white during summer. Why?
A: White colour is a good reflector of heat. Good reflector is a bad absorber of heat. So, buildings are kept cool during summer.
10th Class Physics - Concepts and Differences
Glass blowing: Glass blowing is a technique by which glass articles are shaped by melting glass and blowing air in to it till desired shape is obtained. Different shapes of decorative articles are prepared by this technique.
Saponification: Soaps can be directly obtained from oils or fats by hydrolysis in the presence of a base. This process is called saponification of oils.
Mono Saccharides: Glucose, fructose, mannose etc.
Oligo saccharides: Sucrose, maltose... etc.
Poly saccharides: Starch, Cellulose.
Addition Polymers: Polyethylene, Poly vinyl chloride, Polyacrylonitrile, Orlon.
Saponification: Soaps can be directly obtained from oils or fats by hydrolysis in the presence of a base. This process is called saponification of oils.
Mono Saccharides: Glucose, fructose, mannose etc.
Oligo saccharides: Sucrose, maltose... etc.
Poly saccharides: Starch, Cellulose.
Addition Polymers: Polyethylene, Poly vinyl chloride, Polyacrylonitrile, Orlon.
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