Tag: number and shape of cells

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

The members of algae found in littoral zone is

  1. Volvox

  2. Spirogyra

  3. Ectocarpus

  4. Ulothrix.
Reveal answer Fill a bubble to check yourself
C Correct answer
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.
Multiple choice biology cell - the structural and functional unit of life number and shape of cells unicellular and multicellular organisms diversity and classification in animals

Which one of the following pairs is not correctly matched?

  1. Spirogyra- Conjugation

  2. Volvox - Oogamy

  3. Oedogonium - Cap cell

  4. Ulothrix - Heterocyst
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ulothrix reproduces via zoospores or isogamy/anisogamy, not heterocysts. Heterocysts are specialized cells found in certain cyanobacteria like Nostoc or Anabaena for nitrogen fixation.

Multiple choice botany caskets of life the cell structure multicellular organisms number and shape of cells
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.
  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. $(iii)\rightarrow (ii)\rightarrow (i) \rightarrow (iv)$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The size order is: Mycoplasma (smallest, ~0.1-0.3 micrometers) < Bacteria (~1-2 micrometers) < Human RBCs (~7-8 micrometers) < Ostrich egg (largest, macroscopic).

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

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

  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)
Reveal answer Fill a bubble to check yourself
A Correct answer
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.
Multiple choice botany caskets of life the cell structure multicellular organisms number and shape of cells

An organism made of many cells is called a

  1. unicellular organism

  2. multicellular organism

  3. microorganism

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

As the size of the cell increases 

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
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.'

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

Which of the following is not a cell?

  1. Red Blood Corpuscle (RBC)

  2. Bacterium

  3. Spermatozoa

  4. Virus
Reveal answer Fill a bubble to check yourself
D Correct answer
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'