Tag: number and shape of cells

Questions Related to number and shape of cells

Which one of the following is the smallest in size?

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

  1. Bacteria

  2. Mitochondrion

  3. Mammalian cell

  4. Virus

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Correct Option: D
Explanation:

The average diameter of bacteria is 0.2 to 2 micrometer. 
Mitochondrion size is 0.5 to 10 micrometer. 
The average diameter of a mammalian cell is 20 micrometer. 
Virus diameter ranges from 20 nanometers to 250-400 nanometer. 1000 nanometer = 1 micrometer. Hence, the virus particle is the smallest of all.

Cells of multicellular organism are usually________________

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

  1. Triangular

  2. Rectangular

  3. Polyhedral

  4. None of these

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Correct Option: C
Explanation:

Cells of unicellular organisms are usually spherical due to surface tension. 
Cells of the multicellular organism are usually polyhedral. Because polyhedral cells have more neighbors which means more intercellular exchange can occur. Also, the polyhedral group of cells resists stretching to a more extent. 

The life of .......... organisms start with a zygote.

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

  1. Acellular

  2. Unicellular

  3. Multicellular

  4. All of the above

Show answer
Correct Option: C
Explanation:

In unicellular, reproduction occurs asexually and two new identical daughter cells that are produced. All multicellular start their life from a single cell i.e., zygote which is a product of the fusion (fertilization) of usually two haploid gametes, a female and a male gamete. The zygote (diploid) divide to give rise huge variety of different types of cell, specialized for different functions which in turn forms multicellular organism.

In multicellular organisms, cell size is 

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

  1. 10-100 micrometer

  2. 100-1000 micrometer

  3. 200-500 micrometer

  4. 300-800 micrometer

Show answer
Correct Option: A
Explanation:

Cell size in unicellular organisms is 0.5-10 micrometer whereas, in multicellular organisms, cell size is 10-100 micrometers.

Hence, the correct option is A.

Match the following:
A                                                                                B
A. Barr body                             1   Gives a grey colour to the
                                                          cell body
B. Purkinje cells                       2. Condudion muscles of
                                                        heart.

C. Nissl bodies                           3. Present in neurilemma
D. Schwann cell                          4. Certain neurons having
                                                           flask shaped cylons.

E. Purkinje fibres                          5. Found in cylons of female.
The correct pairing is.

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

  1. 5, 4, 1, 3, 2

  2. 3, 2, 5, 1, 4

  3. 5, 2, 1, 3, 4

  4. 4, 3, 2, 5, 1

Show answer
Correct Option: A

Few genes are found in all types cells

of differentiated multicellular organisms of high

class. It is called

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

  1. Key genes

  2. Core genes

  3. House keeping genes

  4. None of the above

Show answer
Correct Option: B
Explanation:
Core genes refer to the genes present in all the cells of an organism.
Housekeeping genes are those genes which are always expressed in a cell and code for various proteins that are required for the normal functioning and sustenance of cell. These genes are expected to maintain constant expression levels in all cells and at all conditions. Lethal gene is the gene that generally formed by the mutation and causes the death of the organisms.
Thus, the correct answer is option B.

Distinction of individual cells is absent in coenoctic organism such as

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

  1. Ulothrix.

  2. Volvox.

  3. Escherichia.

  4. Rhizopus.

Show answer
Correct Option: D

Who believed in the individuality of cells?

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

  1. Leeuwenhoek

  2. Lamarck

  3. Dutrochet

  4. Malpighi

Show answer
Correct Option: C
Explanation:

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.

So, C is the correct option. 

A multicellular organism possesses

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

  1. Differentiated cells.

  2. Undifferentiated cells.

  3. Dedifferentiated cells.

  4. All of the above.

Show answer
Correct Option: D
Explanation:

A multicellular organism attains its multicellularity from a single cell. Single totipotent cell undergo number of mitotic and meiotic divisions to give rise to a multicellular structure where cells undergo differentiation to a particular function. Some of the cells are undifferentiated such as stem cells which can give rise to any type of cells of the body. Also multicellular organisms undergoes dedifferentiation process where a differentiated cell revert back to totipotent cell and can again differentiate to a particular type of cell witha particular function. So Multicellular organisms posses all these type of cells so Answer D is correct.

Human egg has a volume larger than human sperm by

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

  1. $100,000$

  2. $10,000$

  3. $1000$

  4. $100$

Show answer
Correct Option: A
Explanation:

In short a gamete is an egg cell (female gamete) or a sperm (male gamete). This is an example of anisogamy or heterogamy, the condition in which females and males produce gametes of different sizes. This is the case in humans, the human ovum has approximately 100,000 times the volume of a single human sperm cell. 

Hence A is the correct option.