Tag: number and shape of cells

Questions Related to number and shape of cells

True nucleus is absent in?

biology cell - the structural and functional unit of life number and shape of cells unicellular and multicellular organisms diversity and classification in animals

  1. Volvox

  2. Anabaena

  3. Mucor

  4. Vaucheria

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Correct Option: A

Which organism lacks archegonium ?

biology cell - the structural and functional unit of life number and shape of cells unicellular and multicellular organisms diversity and classification in animals

  1. Funaria

  2. Pteris

  3. Cycas

  4. Spirogyra

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Correct Option: D

The members of algae found in littoral zone is

biology cell - the structural and functional unit of life number and shape of cells unicellular and multicellular organisms diversity and classification in animals

  1. Volvox

  2. Spirogyra

  3. Ectocarpus

  4. Ulothrix.

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Correct Option: C
Explanation:
Ectocarpus is widely distributed massive alga which grows on rocks or larger seaweeds in littoral and supra-littoral zone.
Thus, the correct answer is option C.

Which one of the following pairs is not correctly matched?

biology cell - the structural and functional unit of life number and shape of cells unicellular and multicellular organisms diversity and classification in animals

  1. Spirogyra- Conjugation

  2. Volvox - Oogamy

  3. Oedogonium - Cap cell

  4. Ulothrix - Heterocyst

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Correct Option: A
Different cells have different sizes. Arrange the following cells in an ascending order of their size and select the correct option.
(i) Mycoplasma (ii) Ostrich egg (iii) Human RBCs (iv) Bacteria.
botany caskets of life the cell structure multicellular organisms number and shape of cells

  1. $(i)\rightarrow (iv)\rightarrow (iii) \rightarrow (ii)$

  2. $(ii)\rightarrow (iii)\rightarrow (i) \rightarrow (ii)$

  3. $(ii)\rightarrow (i)\rightarrow (iii) \rightarrow (iv)$

  4. $(iii)\rightarrow (ii)\rightarrow (i) \rightarrow (iv)$

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Correct Option: A

Different cells have different sizes. Arrange the following cells in ascending order of their size and select the correct option:


(i) Mycoplasma                  (ii) Ostrich egg
(iii) Human RBCs              (iv) Bacteria

botany caskets of life the cell structure multicellular organisms number and shape of cells

  1. (i) $\rightarrow$ (iv) $\rightarrow$ (iii) $\rightarrow$ (ii)

  2. (i) $\rightarrow$ (iii) $\rightarrow$ (iv) $\rightarrow$ (ii)

  3. (ii) $\rightarrow$ (i) $\rightarrow$ (iii) $\rightarrow$ (iv)

  4. (ii) $\rightarrow$ (ii) $\rightarrow$ (i) $\rightarrow$ (iv)

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Correct Option: A
Explanation:
  • The smallest cell is Mycoplasma (0.1-0.5$\mu m$). 
  • Bacterial cell measures 3-5$\mu m$ in length. 
  • Erythrocytes are 6-8$\mu m$ in diameter. 
  • The larges cell is the egg of Ostrich.

Mice and elephant have

botany caskets of life the cell structure multicellular organisms number and shape of cells

  1. The same cell number

  2. Different cell numbers

  3. The same cell number but different cell sizes

  4. The same cell number and same cell sizes

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Correct Option: B
Explanation:

The body size of the organism is directly related to the cell number, not the cell size. The bigger the body, the more will the number of cells.

An organism made of many cells is called a

botany caskets of life the cell structure multicellular organisms number and shape of cells

  1. unicellular organism

  2. multicellular organism

  3. microorganism

  4. None of the above

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Correct Option: B
Explanation:

An organism which is made of more than one cell is called a multi-cellular organism. Humans, animals and plants are some multi-cellular organisms which are made of millions to trillions of cells.

As the size of the cell increases 

botany caskets of life the cell structure multicellular organisms number and shape of cells

  1. The total surface area decreases at the same rate as the volume

  2. The volume increases at the same rate as the total surface area

  3. The total surface area increase faster than the volume

  4. The volume increases faster than the total surface area

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Correct Option: C
Explanation:

As the cell becomes larger, the activity of DNA is increased since large number of activities take place in the same cell. The cell membrane increases its size because as the cell enlarges, more and more ions and gases and other molecules are exchanged between the cells and external environment. Therefore, the cells surface area has to increase faster than the volume of the cell or else the cell membrane could rupture.

Thus, the correct answer is 'The total surface area increase faster than the volume.'

Which of the following is not a cell?

botany caskets of life the cell structure multicellular organisms number and shape of cells

  1. Red Blood Corpuscle (RBC)

  2. Bacterium

  3. Spermatozoa

  4. Virus

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Correct Option: D
Explanation:

A cell is defined by definitive structures of the cell membrane and cytoplasm and its capacity of performing the vital metabolic activities. The viruses do not have a defined cellular structure. They are made of a protein coat in which a genetic material (either DNA or RNA) is present. They are unable to perform their cellular activities. They are obligate parasites that depend on the machinery of the host cell to perform their multiplication as well as metabolism.

A. Red blood corpuscles are proper cells that have the nucleus at the young stage. Later, on maturity, they perform their metabolic activities through different pathways.
B. The bacterial cell is a prokaryotic cell which is capable of sustaining on its cellular machinery.
C. Spermatozoa are the haploid cells that do not have a long life but are provided with cellular machinery to carry out vital activities.
D. The virus is acellular. They need the cellular machinery of the host cell to perform the vital activities.
Hence, the correct answer is 'Virus'