Cell-The Unit of Life
- A student wishes to study the cell structure under a light microscope having 10X eyepice and 45X objective. He should illuminate the object by which one of the following colours of light so as to get the best possible resolution?
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Resolving power or limit of resolution is the ability of the eye to distinguish two close objects as separate. Its value is calculated by Abbe’s equation,
Lm = 0.6λ NA
where λ is the wavelength of light.
NA or numerical apperture is multiple of refractive index and sine of angle subtended by optical axis and outer ray covered by objective (sina).Correct Option: A
Resolving power or limit of resolution is the ability of the eye to distinguish two close objects as separate. Its value is calculated by Abbe’s equation,
Lm = 0.6λ NA
where λ is the wavelength of light.
NA or numerical apperture is multiple of refractive index and sine of angle subtended by optical axis and outer ray covered by objective (sina).
- Identify the correct order of organisation of genetic material from largest to smallest :
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Genome > chromosomes > gene > nucleotide.
Correct Option: B
Genome > chromosomes > gene > nucleotide.
- A protoplast is a cell :
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Cell wall is absent in a protoplast.
Correct Option: C
Cell wall is absent in a protoplast.
- A major break through in the studies of cells came with the development of electron microscope. This is because
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A major break through in cell studies came with the development of EM having great resolution power due to which we can see the ultrastructures of cell organelles.
Correct Option: D
A major break through in cell studies came with the development of EM having great resolution power due to which we can see the ultrastructures of cell organelles.
- The term ‘glycocalyx’ is used for
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Glycocalyx or mucilage is the outermost coating of bacterial cells/cell wall which is rich in polysaccharides. A thick and tougher mucilage is called capsule which gives gummy or sticky trait to cells. It protects the cells from dessication, toxins and preventing attachment to foreign invaders.
Correct Option: A
Glycocalyx or mucilage is the outermost coating of bacterial cells/cell wall which is rich in polysaccharides. A thick and tougher mucilage is called capsule which gives gummy or sticky trait to cells. It protects the cells from dessication, toxins and preventing attachment to foreign invaders.
