Tag: organization of life

Questions Related to organization of life

Which of the following is correct?

biology organization of life the cell structure cytoplasm number and shape of cells

  1. Cells of all living organisms have a nucleus

  2. Both animal and plant cells have a well defined cell wall

  3. In prokaryotes, there are no membrane bound organelles

  4. Cells are formed de novo from abiotic materials

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Correct Option: A

End of prophase is marked by?

biology organization of life the cell structure cytoplasm number and shape of cells

  1. Initiation of condensation of chromosomal material

  2. Complete disintegration of nuclear membrane

  3. Reappearance of ER, Golgi body, nucleolus and nuclear envelop

  4. Alignment of chromosomes at the equator

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Correct Option: A

Cells capable of division are

biology organization of life the cell structure cytoplasm number and shape of cells

  1. Stem cells.

  2. Meristematic cells.

  3. Undifferentiated cells.

  4. All of the above.

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Correct Option: D
Explanation:

Stem cells are totipotent cells that can able to differentiate and divide into any type of cells of the body. meristematic cells are undifferentiated cells of the plants that can able to divide and form tissues, organs of the plant. so cells capable of division are all the cells including stem cells, meristematic cells and undifferentiated cells. Hence option D is correct.

A nucleated differentiated cell that has lost the power to dedifferentiate is ____________.

biology organization of life the cell structure cytoplasm number and shape of cells

  1. Nerve cells.

  2. Kidney cells.

  3. Liver cells.

  4. All of the above.

Show answer
Correct Option: A
Explanation:
A nucleated differentiated cell that has lost the power to division are nerve cells. These are the cells of nervous system and carry electrical messages and signals throughout the body. They have lost their power to division because the existing ones can grow new connections by loosing the old ones and also these cells needs oxygen and nutrients and if it divides rapidly and get packed, it will become difficult to supply and hence will starve.
So, the correct answer is option A.

RBCs are

biology organization of life the cell structure cytoplasm number and shape of cells

  1. Differentiated cells.

  2. Undifferentiated cells.

  3. Dedifferentiated cells.

  4. Dead cells.

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Correct Option: A
Explanation:

Mammalian erythrocytes also called as red blood cells are formed in bone marrow from multipotential hemocytoblast and further converted to erythroblast (normoblast). The nucleus and mitochondria of erythroblast disappear and it is converted to mature erythrocyte with haemoglobin. So RBC's are differentiated cells which lack a nucleus.

Which one of the following is anucleate?

biology organization of life the cell structure cytoplasm number and shape of cells

  1. Sieve tube

  2. Companion cell

  3. Medullary ray

  4. All of the above

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Correct Option: A

Formation of meristems cork cambium from fully differentiated parenchyma cells is an example of :

biology organization of life the cell structure cytoplasm number and shape of cells

  1. Differentiation

  2. Redifferentiation

  3. Dedifferentiation

  4. Regenration

Show answer
Correct Option: C
Explanation:
Cambium is the layer which forms Cork and acts as a secondary meristem from a layer of collenchyma or parenchyma immediately beneath the epidermis. The cells which produce from cork cambium will differentiate and will get mature to perform a specialized function. The living cells which lost the capacity to divide can regain the capacity of the division under certain conditions is called as 'Dedifferentiation.'
So the correct option is 'Dedifferentiation.'

Any specialized plant cell that is dispersed among cells of a different kind is called a

biology organization of life the cell structure cytoplasm number and shape of cells

  1. Marcophyll

  2. Xenophyte

  3. Normoblast

  4. ldioblast

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Correct Option: D
Explanation:
An idioblast is an isolated plant cell that differs from neighboring tissues. They have various functions such as storage of reserves, excretory materials, pigments, and minerals. They could contain oil, latex, gum, resin, tannin or pigments etc. So, the correct answer is "Idioblast."

Dedifferentiated cells are formed in the region of

biology organization of life the cell structure cytoplasm number and shape of cells

  1. Injury.

  2. Regeneration.

  3. Secondary growth.

  4. All of the above.

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Correct Option: D
Explanation:

An undividable differentiated cell sometimes gains the power to divide. This process is called dedifferentiation. Wound healing after injury and secondary growth in plants are some of the best examples of dedifferentiation. Dedifferentiation is one of the mechanisms of natural regeneration. So answer D is correct.

Which of these statements is/are true?


(i) The surface area available for cellular functions in a prokaryotic cell is less than that in a eukaryotic cell.
(ii) The total genome size of a prokaryotic cell is always less than that of a eukaryotic cell.
(iii) Unlike eukaryotes, no special respiratory organelles are found in prokaryotes. Hence they respire at a much less rate than eukaryotes.
(iv) Eukaryotic cells show various membrane-bound organelles such as chloroplasts and nucleus while ribosomes are the only membrane-bound organelles found in prokaryotes.

biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

  1. (i) and (ii)

  2. (iv) only

  3. (iii) only

  4. (i), (ii) and (iv)

Show answer
Correct Option: A
Explanation:

The cellular and genomic organisation of prokaryotes are fundamentally different from that of eukaryotes. 

  • Prokaryotic cells have a small, simple structure compared to eukaryotic cells. They have less surface area per volume. Prokaryotes have simpler and smaller genomes than eukaryotes. In the majority of prokaryotes, the genome consists of a ring of DNA with few associated proteins. 
  • The eukaryotic genome is larger, organised into chromosomes, and is complexed with histone proteins. 
  • Unlike eukaryotes, prokaryotes do not have membrane-bound organelle for respiration but many enzymes needed for cellular respiration are attached to the plasma membrane, which may fold and extend into the cell. Ribosomes are the only cytoplasmic organelles in prokaryotes and they are not membrane-bound.
So, the correct answer is '(i) and (ii)'.