Tag: cell and cellular organization
Questions Related to cell and cellular organization
Observe the table and answer a, b.
S. No. | Scientist | Invention |
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1 | Robert Hooke | a |
2 | b | Nucleus |
3 | Schleiden, Schwann | Cell theory |
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a- Cell b- Robert Brown
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a- Cell wall b- Robert Brown
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a- Cell wall b- Schleiden
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a- Cell membrane b- Robert Brown
- Robert Hooke had discovered plant cells more precisely, he saw the cell walls in cork tissue. In fact, it was Hooke who coined the term "cell" and also discovered cell wall.
- Robert Brown had discovered the plant cell nucleus.
In 1665, Robert Hooke first observed cells in
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Leaf
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Cork
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Intestin
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Liver
The first cell was observed and named by Robert Hooke in 1665. He described that it looked like cellula, small rooms which are inhabited by monks hence derived the name 'cell'. The cell he actually saw was the dead cell walls of the plant (cork) under a microscope. Hooke described the characteristics of a cell he observed in his book 'Micrographia'.
Unstained living cells can be best studied by
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Phase contrast microscope
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Electron microscope
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Fluorescent microscope
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Polarising microscope
Phase contrast microscopy is a type of microscopic technique which converts phase shifts in light passing through a transparent specimen to brightness changes in the image. This technique made possible to study living cells without staining.
Robert Hook's observations were published in __________________.
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Zerographia
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Micrographia
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Bioraphia
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None of these
The distribution of two or more specific molecules within a cell can be studied by using
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Dark field microscope
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Fluorescent microscope
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Phase contrast microscope
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Interference contrast microscope
The fluorescence microscope can localize and quantify specific molecules in the cells. It is the most versatile and powerful technique for localizing proteins within a cell by light microscopy, is fluorescent staining of cells and the observation in the fluorescence microscope.
The cell, as a basic unit of structure of living things, was discovered by
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Aristotle
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Robert Hooke
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Schleiden and Schwann
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Gregor Mendel
Robert Hooke discovered cell in the year 1665. He observed cork cell in the bark of Spanish oak tree under a simple microscope and was able to see the empty structures surrounded by walls and named it a cell. He elucidated his observation in a book called "Micrographia".
Which one of the following can be visualized under fluorescent microscope?
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Chloroplast
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Actin filaments
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Nucleus
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Both A and B
Fluorescent microscope is a modification of ultraviolet microscope, which was made by Coons in 1945. The instrument uses long wave ultraviolet rays for illumination. It has complementary filters, which allow the viewer to observe directly with the eyes. The microscope is useful in detecting those components which show autofluorescence, e.g., chlorophylls, collagen fibrils, actin filaments, vitamin A, etc. Others can be made fluorescent by coating with fluorochrome dyes like acridine orange and coriphosphine and minerals, eg., proteins, lipids, starch, glycogen, cellulose, etc. The light emitted by them is red, orange, yellow, or green against dark field. It is called as secondary fluorescence. The technique is also useful in diagnosis of viruses, bacteria and protozoans. Immunofluorescent antibody labelling techniques is used in diagnosis of specific molecules like antigens and antibodies. it involves conjugating specific fluorochromes with specific antibodies.
Very high wavelength rays are used in one of the following microscope.
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Fluorescent
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Polarising
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Ultraviolet
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Phase contrast
Fluorescent microscope is a modification of ultraviolet microscope which was made by Coons in 1945. The instrument uses long wave ultraviolet rays for illumination. It has complementary filters which allow the viewer to observe directly with the eyes. The microscope is useful in detecting those components which show autofluorescence, e.g., chlorophylls, collagen fibrils, vitamin A, etc. Others can be made fluorescent by coating with fluorochrome dyes like acridine orange and coriphosphine and minerals, eg., proteins, lipids, starch, glycogen, cellulose etc. The light emitted by them is red, orange, yellow, or green against dark field, it is called as secondary fluorescence. The technique is also useful in diagnosis of viruses, bacteria and protozoans. Immunofluorescent antibody labelling techniques is used in diagnosis of specific molecules like antigens and antibodies, it involves conjugating specific fluorochromes with specific antibodies.
Fluorescent microscope is used
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To localize cell structure as chlorophyll stained with fluorochromes.
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To study living cells.
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To study smallest organelle.
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All of the above.
Fluorescent microscope is a modification of ultraviolet microscope which was made by Coons in 1945. The instrument uses long wave ultraviolet rays for illumination. It has complementary filters which allow the viewer to observe directly with the eyes. The microscope is useful in detecting those components which show autofluorescence eg. Chlorophylls, collagen fibrils, vitamin A etc.
Binding of specific proteins on regulatory DNA sequences can be studied by means of
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Electron microscope
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Light microscope
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Centrifugation
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X-ray crystallography
X-ray crystallography is a technique to study the structural details of crystallizable proteins and nucleic acids. X-ray microscope developed by Kirkpatrick is useful in studying detailed structures of chemicals present in solid state, e.g., haemoglobin, insulin, DNA, RNA etc. due to diffraction of X rays by different atoms of the substance.