Question 1

Write the characteristics of prokaryotic cell.

Accepted Answer

The characteristics of prokaryotic cells are:Membrane bound cell organelles such as Mitochondria, Golgi apparatus, Chloroplasts are absent.A membrane bound well defined nucleus is absent.Genetic material is circular DNA and occurs naked in the cell cytoplasm. It is attached to the cell membrane and called nucleoid.The cell size ranges from 0.1 to 5.0 micrometre in size.The cell wall is a rigid structure which is made up of polysaccharides.

Question 2

How is a prokaryotic cell different from a eukaryotic cell?

Accepted Answer

Differences between prokaryotic and eukaryotic cell Prokaryotic cell Eukaryotic cell 1. They are generally small in size (1-10 micrometer). 1. Eukaryotic cells are comparatively larger in size. 2. Nuclear matter is undefined without any nuclear membrane and is called as nucleoid. 2. A true nucleus with nuclear membrane is present.  3. Single chromosome is present as genetic material. 3. More than one chromosome is present. 4. It lacks any membrane bound organelles, i.e., ER, Golgi body, mitochondria etc, are absent. 4. It is characterized by presence of membrane bound organelles.  5. 70S type ribosome is present. 5. 80S type ribosome is present. 6. Cell division occurs by fission, budding or fragmentation. 6. It exhibits mitosis and meiosis as cell division processes.

Question 3

Which one of the following structures is not found in a prokaryotic cell?

Accepted Answer

Prokaryotic cells lack membrane-bound organelles and well-organized nucleus. The nuclear membrane is absent in a prokaryotic cell. The nuclear membrane is a double membrane layer which surrounds the nucleus. It is made up of lipids, that encases the genetic material.Hence, the correct answer is 'Nuclear membrane'.

Question 4

What is a mesosome in a prokaryotic cell? Mention the functions that it performs.

Accepted Answer

Mesosome is a convoluted membranous structure formed in a prokaryotic cell by the invagination of the plasma membrane. Its functions are as follows :(1) These extensions help in the synthesis of the cell wall and replication of DNA. They also help in the equal distribution of chromosomes into the daughter cells.(2) It also increases the surface area of the plasma membrane to carry out various enzymatic activities.(3) It helps in secretion processes as well as in bacterial respiration.

Question 5

Which of the following structure is not found in prokaryotic cells?

Accepted Answer

Prokaryotic cells are characterized by the absence of a membrane-bound true nucleus and other membrane-bound organelles such as mitochondria, Golgi apparatus, E.R. etc. Their DNA fibrils are present in the center of the cell, i.e., in the nucleoid. It consists ribosomes which are the site of protein synthesis and have two subunits; large and small. Prokaryotic ribosomes have 30S and 50S subunits that together make a 70S ribosome. Thus, the correct answer is option C.

Question 6

Which structure is present in both prokaryotic and eukaryotic cells?

Accepted Answer

Unlike the eukaryotes, the prokaryotic organisms are devoid of membrane-bound organelles. Nucleus, chloroplast and mitochondria are membrane bound sub-cellular structures found in the eukaryotes only. Cell wall is found in the plants as well as bacterial cells, which are prokaryotes.Hence the correct option is A.

Question 7

Distinguish between :Prokaryotic and Eukaryotic cells.

Accepted Answer

Prokaryotic cells Eukaryotic cellsThe cell size is usually small.The cell size is comparatively larger.A prokaryotic cell has one envelope organisation.A eukaryotic cell has two envelope orgsnisation.An organised nucleus is absent. Instead a nucleoid is found.An organised nucleus is found. It is differentiated into nuclear envelope, chromatin, one or more nucleoli and nucleoplasm.Cell wall, if present, possesses muramic acid.Cell wall, if present, without muramic acid.DNA is naked, that is, without histones.Nuclear DNA is associated with histones.Protein synthesis occurs only in cytoplasm.Protein synthesis takes place in cytoplasm, mitochondria and plastids.Respiratory enzymes are associated with plasma membrane.Respiratory enzymes are present in both cytoplasm as well as mitochondria.Membrane bound organelles like ER, mitochondria, Golgi apparatus, centrioles, lysosomes and other microbodies are absent.Mitochondria, ER, Golgi apparatus and microbodies including lysosomes, centrioles are present in cells of organisms in which motile stage is present in the life cycle.

Question 8

Select the correct option:Mesosomes are the infoldings of cell membrane, which(i) are present in both prokaryotic and eukaryotic cells.(ii) help in cell wall formation, DNA replication and respiration.(iii) increase the surface area of plasma membrane.

Accepted Answer

Mesosomes are present only in prokaryotes.So, the correct answer is '(ii) and (iii)'

Question 9

The type of ribosomes found in prokaryotic cells is

Accepted Answer

Prokaryotes are unicellular organisms that lack membrane-bound cell organelles. Ribosomes are the organelles made up of proteins and RNA molecules called subunits. These are involved in protein synthesis. The prokaryotic ribosomes are of 70S type, unlike the eukaryotic ribosomes which are of 80S type. The 70S ribosomes are made of 50S and 30S subunits. Thus the correct answer is option D.

Question 10

Draw a diagram of a prokaryotic cell and label at least four parts in it.

Accepted Answer

Labelled diagram of a prokaryotic cell.

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Prokaryotic cell