Tag: biology

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Questions Related to biology

Multiple choice biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

In view of the current status of our knowledge about the cell structure, which of the following statement(s) about cell theory is/are correct?
(i) The cell theory does not hold good since all living organisms are not cellular in organisation.
(ii) The cell theory in its modified form means that all living objects are composed of cells capable of reproduction.
(iii) The cell theory means that all living objects consist of cells, whether reproducing or not.
(iv) The cell theory needed modification due to the discovery of sub-cellular structures such as chloroplasts and mitochondria.

  1. (i) and (ii)

  2. (i), (ii) and (iii)

  3. Only (i)

  4. (ii) and (iii)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The cell theory is one of the basic principles of biology. Credit for the formulation of this theory is given to German scientists Theodor Schwann, Matthias Schleiden and Rudolph Virchow.
The cell theory states-

1) All living organisms are composed of cells. They may be unicellular or multicellular.
2) Cells arise from pre-existing cells.
3) All living organism like virus are not formed by cells. 

Multiple choice biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

Which of the following statements is related to the cell theory?

  1. All organisms are made up of one or more cells.

  2. All organisms must be able to reproduce.

  3. Cells have organelles to carry on their functions.

  4. Cells evolved from a primordial soup on early Earth.

  5. Cells are able to regulate their external environment.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cell theory has 3 basic points: All living things are made of one or more cells. The cell is the smallest living thing that can perform all the functions of life. All cells must come from pre-existing cells through cellular division.

Multiple choice biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

Choose the correct statement with respect to cell theory

  1. All organisms are made up of one or more cells.

  2. All organisms must be able to reproduce.

  3. Cells have organelles to carry on their functions.

  4. Cells evolved from a primordial soup on early earth.

  5. Cells are able to regulate their external environment.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • The generally accepted parts of the cell theory include: All known living things are made up of one or more cells. 
  • All living cells arise from pre-existing cells by the division and cell is the basic unit of life.

Thus, the correct answer is option A. 

Multiple choice biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

Who initiated cell concept?

  1. Robert Hooke

  2. Leeuwenhoek

  3. Grew

  4. Schleiden and Sohwann
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Nehmiah Grew initiate cell concept when he found that plant tissues contain minute elementary structures or cells. Thus, it was a 'basic generalization' extended to all the plants by Schleiden. Schleiden by himself neither discovered cell nor described their structure but extended the cell concept to all plants.

Therefore C is the correct option. 

Multiple choice biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

"Omnis cellula e cellula" is a generalization, given by

  1. Lamarck.

  2. Dutrochet.

  3. Leeuwenhoek.

  4. Virchow.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Rudolf Virchow explained that cells divided and new cells are formed from pre-existing cells. "Omnis cellula e cellula" is also attributed to the Cell Theory, that works on a similar principle. The cell theory asserts that every organism is formed of the same units of the organisation, known as cells.

So, D is the correct option.

Multiple choice biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

An individual has a number of different type of cells was first stated by ______________.

  1. Dujardin.

  2. Robert Brown.

  3. Dutrochet.

  4. Schleiden and Schwann.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Leeuwenhoek was the first to see 'free-living cells' under his microscope. In 1809, Lamarck concluded that all living beings are formed of cells. Living substance was first observed by Corti in 1772 and was named sarcode by Dujardin in 1835. Dutrochet believed in the individuality of cells, i.e., living organisms are made up of a number of individual cells. The nucleus was discovered by Robert Brown and Schleiden and Schwann are credited with the formulation of the cell theory. 

Thus, the correct answer is option C.

Multiple choice biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

Cell theory was propounded by

  1. A botonist.

  2. A zoologist.

  3. Both a botanist and a zoologist.

  4. A psychlologist.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Matthias Schleiden was a German botanist, and Theodor Schwann was a British zoologist. Together, they formulated the cell theory, which states that all living organisms are composed of cells.

Multiple choice biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

New cells generate from

  1. Bacterial fermentation.

  2. Regeneration of old cells.

  3. Pre-existing cells.

  4. Abiotic material.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
New cells generate from pre-existing cells. Rudolf Virchow (1985) first explained that cells divide and new cells are formed from pre-existing cells (omnis cellula-e cellula). He modified the hypothesis of Schleiden and Schwann to give cell theory a final shape.
Cell theory now is understood as:
All living organisms are composed of cells and the product of cells.
All cells arise from pre-existing cells.
Multiple choice biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

New cells generate from :

  1. Bacterial fermentation

  2. Regeneration of old cells

  3. Pre-existing cells

  4. Abiotic materials
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

New cells generate from pre-existing cells. Rudolf Virchow (1985) first explained that cells divide and new cells are formed from pre-existing cells (omnis cellula-e cellula). He modified the hypothesis of Schleiden and Schwann to give cell theory a final shape.
Cell theory now is understood as:

  1. All living organisms are composed of cells and the product of cells.
  2. All cells arise from pre-existing cells.