Tag: microscope

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Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

Binding of specific proteins on regulatory DNA sequences can be studied by means of

  1. Electron microscope

  2. Light microscope

  3. Centrifugation

  4. X-ray crystallography
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The detailed structural views of protein-DNA interfaces have been obtained through X-ray crystallography and NMR spectroscopy.

Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

Zernike was awarded Noble prize for the discovery of 

  1. TEM

  2. SEM

  3. Fluorescent

  4. Phase contrast microscope
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Phase contrast microscope was developed by Zernike and in 1953 he got noble prize for this discovery. The microscope has a phase plate and an annular diaphragm. They bring about changes in light rays passing through the specimen producing differences in light intensity. Denser parts, alter path of light more than the thinner parts. This produces varying contrast for different regions. The microscope is useful in the study of small living organisms, living cells, constituents of living cells, effect of various factors over living structures, and study of various cellular events like behaviour of chromosomes during mitosis and meiosis, spindle formation, cytokinesis, pinocytosis, phagocytosis, cyclosis, glandular secretions, spermatogenesis, oogenesis etc.
So, the correct answer is 'Phase contrast microscope'.
Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

The branch of biology dealing with structure, function and reproduction of cell is 

  1. Cytology

  2. Anatomy

  3. Histology

  4. Cell biology
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Cell biology is the study of all aspects of cells and their components including their structure, biochemistry, development and physiology. It treats the cell as fundamental unit of life.
So, the correct answer is 'Cell biology'.
Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

Phase contrast microscope is 

  1. Based on the scattering of light and using a dark field condenser.

  2. Used for the study of living cells.

  3. Related to retardation and thickness of object.

  4. The best method for studying non-living ultra structure.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Phase contrast microscopy is particularly important in biology. It reveals many cellular structures that are not visible with a simpler bright field microscope. These structures were made visible to earlier microscopists by staining, but this required additional preparation and killed the cells. The phase contrast microscope made it possible for biologists to study living cells and how they proliferate through cell division. After its invention in the early 1930s, phase contrast microscopy proved to be such an advancement in microscopy, that its inventor Frits Zernike was awarded the Nobel prize in 1953.

Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

A fluorescent microscope is used

  1. For increasing resolving power.

  2. For obtaining X-ray diffraction pattern of DNA.

  3. To study cell and their components in a living state.

  4. To localise cell structure stained with fluorochrome dyes.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A fluorescence microscope is an optical microscope that uses fluorescence and phosphorescence instead of or in addition to, reflection and absorption to study properties of organic or inorganic substances. The "fluorescence microscope" refers to any microscope that uses fluorescence to generate an image, whether it is a more simple set up like an epifluorescence microscope or a more complicated design such as a confocal microscope, which uses optical sectioning to get better resolution of the fluorescent image. So, fluorescent microscope is used to localise cell structure stained with fluorochrome dyes and not for increasing resolving power, for obtaining X-ray diffraction pattern of DNA and to study cell and their components in a living state. 

Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

Light microscopes

  1. Work by reflecting electrons off the surface of an object being studied

  2. Can generally magnify objects about 10,000 times without blurring

  3. Use light and glass lenses to magnify an image

  4. Provides more resolution than an electron microscope
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The microscope is the instrument used to magnify the image of an object that we cannot see by our naked eyes. It is of two types on the basis of a number of lenses, simple microscope, and compound microscope. A light microscope is a compound microscope that uses focused light and two lenses to magnify a specimen.

Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

If a microscope has a $10\times$ objective lens and $10\times$ ocular lens, it would magnify the object by 

  1. $10\times$
  2. $20\times$
  3. $50\times$
  4. $100\times$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The compound microscope is the instrument used to magnify the image of the object that we cannot see by naked eyes. It uses two lenses or lens systems, one is the objective lens which enlarged the image of the object and the second is an ocular lens which magnifies the image formed by the first. The total magnification is the product of the magnifications of two lens systems. Hence, the microscope which has a 10X objective lens and 10X ocular lens, it would magnify the object by 10 × 10 = 100 times. 

Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

The strength of magnification of oil immersion lens is

  1. $20\times$
  2. $500\times$
  3. $1000\times$
  4. $100\times$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
There are three types of objective lens: 10X (low power objective lens); 40X (high power objective lens) and 100X (oil immersion objective lens). Each objective lens is represented by a particular colour. Oil immersion is the technique used to increase the resolving power of the microscope. In this technique, oil is used to avoid the different refractive index of air and glass which affect the numerical aperture.
Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

Anton van Leeuwenhoek was from

  1. France

  2. Holland

  3. Sweden

  4. Britian
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Antonie Philips van Leeuwenhoek was a Dutch businessman and scientist. He belonged to Holland. He discovered protozoa, a single-celled organisms. He named it as animalcules. He also had contributed in the improvement of the microscope and laid foundation for microbiology. 

Thus, the correct answer is 'Holland.'