Tag: botany

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Questions Related to botany

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

Unstained living cells can be best studied by

  1. Phase contrast microscope

  2. Electron microscope

  3. Fluorescent microscope

  4. Polarising microscope
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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.

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

Robert Hook's observations were published in __________________.

  1. Zerographia

  2. Micrographia

  3. Bioraphia

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Living beings or organisms are made up of one or more cells. Cell is a basic unit of structure and function of organisms. It was discovered by Robert Hooke in 1665 when he saw empty box-like compartments in a very thin slice of cork under his microscope. He wrote the book "Micrographia" and coined the term cellula which was later changed into the cell. Robert Hooke thought-cells to be passages for conducting fluids.
So, the correct answer is 'Micrographia'.
Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

The distribution of two or more specific molecules within a cell can be studied by using

  1. Dark field microscope

  2. Fluorescent microscope

  3. Phase contrast microscope

  4. Interference contrast microscope
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

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.

Thus, the correct answer is option B.

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

The cell, as a basic unit of structure of living things, was discovered by 

  1. Aristotle

  2. Robert Hooke

  3. Schleiden and Schwann

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

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".

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

Which one of the following can be visualized under fluorescent microscope?

  1. Chloroplast

  2. Actin filaments

  3. Nucleus

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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.

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

Very high wavelength rays are used in one of the following microscope.

  1. Fluorescent

  2. Polarising

  3. Ultraviolet

  4. Phase contrast
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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.

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

Fluorescent microscope is used

  1. To localize cell structure as chlorophyll stained with fluorochromes.

  2. To study living cells.

  3. To study smallest organelle.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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.

So, the correct answer is 'To localize cell structure as chlorophyll stained with fluorochromes'.

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

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. 

Binding of specific proteins on regulatory sequences of DNA will generate specific diffraction pattern of X rays which can help to identify specific proteins binding to specific regulatory regions in DNA.

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

Separation of chromatids during metaphase and behaviour of chromosomes during mitotic and meiotic divisions can be best studied by

  1. Phase contrast microscope

  2. SEM

  3. X-ray microscope

  4. Cell-fractionation method
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Phase contrast 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.

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

The distribution of two or more specific molecules within a cell can be studied by using 

  1. Dark field microscope

  2. Fluorescent microscope

  3. Phase contrast microscope

  4. Interference contrast microscope

  5. Bright field microscope
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Fluorescent microscope is useful in detecting those components which show autofluorescence, e.g., chlorophylls, collagen fibrils, vitamin A. Others can be made fluorescent by coating with fluorochrome dyes like acridine orange and coriphosphine. This is called as secondary fluorescence and is useful in detecting specific biomolecules.