Differences Between Prokaryotic and Eukaryotic Cells, Difference Between Unicellular and Multicellular Organisms, Difference Between Plant and Animal Cells

Think of a bacteria and an Amoeba. Are they similar or are they different? Well, the answer is, both! Confused? Let me break it down for you. Bacteria and protozoa are similar as both are unicellular organisms but while bacteria is made up of a single prokaryotic cell, an Amoeba is made up of a single eukaryotic cell. Thus, they have multiple differences too.

Now take an example of the Amoeba and a mushroom. You must be thinking that there can be no similarities between the two as they look so very different. Amoeba is a unicellular protozoan while a mushroom is a multicellular fungus. But did you know that at the cellular level, they share a similarity? They are both composed of eukaryotic cells.

Now let us take examples of a plant and animal cell. Both of these cells are eukaryotic but do they have any differences? Well, we are all aware that plant cells can photosynthesise but animal cells cannot and the secret to this amazing power in plant cells is the presence of chlorophyll in plant cells which the animals lack. But is this the only difference?

Come let us learn more about the differences between the prokaryotic and eukaryotic cells, unicellular and multicellular organisms and plant and animal cells.

Table of Contents

Differences between prokaryotic and eukaryotic Cell
Difference between unicellular and multicellular organisms
Difference between plant and animal cells
Practice Problems
FAQs

Difference Between Prokaryotic and Eukaryotic cells

Prokaryotic cells

These are cells which lack a well defined nucleus bound by a nuclear membrane and all membrane bound organelles, for example, bacterial cells, archaebacterial cells, etc.

A bacterial (prokaryotic) cell

Fig: A bacterial (prokaryotic) cell

Eukaryotic cells

These are cells with a well defined nucleus bound by a nuclear membrane and contain all membrane bound organelles, for example, plant cells and animal cells.

Eukaryotic cells

Fig: A plant (eukaryotic) cell

Differences

Prokaryotic cell	Eukaryotic cell
Genetic material is not enclosed in a nuclear envelope and is present suspended in the cytoplasm in a region called nucleoid.	Genetic material is enclosed within the nucleus by a nuclear envelope and is not present in direct contact with cytoplasm.
Cell wall is made up of peptidoglycan.	Cell wall is made up of chitin in fungi and cellulose in plants.
Ribosomes are of the 70S type.	Ribosomes are of the 80S type.
Nucleolus is absent.	Nucleolus is present.
Transcription and translation occurs in cytoplasm.	Transcription occurs in the nucleus and translation occurs in cytoplasm.
Cytoplasm lacks membrane-bound cell organelles.	Cytoplasm contains all membrane-bound cell organelles.
Examples: Bacteria, cyanobacteria etc.	Examples: All plant cells and animal cells

Difference between Unicellular organisms and Multicellular organisms

Unicellular organisms

The body of such organisms is composed of a single cell. The cell can perform all basic life processes. Hence, it can be called a complete functional unit which is capable of undergoing respiration, excretion, etc.Hence, each unicellular organism is mostly capable of independent existence.

Unicellular organisms

Multicellular organisms

The bodies of such organisms are made up of more than one cell. The number of cells in multicellular organisms usually correlates with the size of the organism. Specialised cells are grouped together into organs and organ systems which perform different physiological functions. These cells then interact with one another to maintain life.

Differences

Unicellular organisms	Multicellular organisms
The body of such organisms is composed of a single cell.	The bodies of such organisms are made up of more than one cell.
A single cell can perform all basic life processes.	Specialised cells are grouped together into organs and organ systems which perform different physiological functions. These multiple specialised cells interact with one another to maintain life.

Difference between Plant and Animal cells

Animal cell	Plant cell
Cell membrane acts as the outermost protective layer.	The outermost protective layer is the cell wall which encloses the cell membrane.
Plastids are absent. Thus chlorophyll is also absent.	Plastids are present. Photosynthetic plant parts contain chloroplasts with the green pigment chlorophyll.
Mitochondria are numerous.	Mitochondria are comparatively fewer.
Vacuoles are fewer and smaller in size.	Central part of the cell is occupied by a large central vacuole which occupies almost 90% of the cell volume.
Nucleus is almost in the centre of the cell.	Nucleus is usually pushed to one side in the cytoplasm.
Stores carbohydrates in the form of glycogen.	Stores carbohydrates in the form of starch.
Centrioles and centrosomes are present.	Centrioles and centrosomes are absent.
Example: Human cheek cells	Example: Cells of an onion peel

Plant cell Vs Animal cell

Fig: Plant cell Vs Animal cell

Practice problems of Prokaryotic and Eukaryotic Cells

Question1. Which of these is a characteristic of prokaryotic cells?

(a) Absence of membrane-bound cell organelles

(b) Absence of nucleus

(d) All of these

Answer: Prokaryotic cells lack a nucleus and their genetic material lies naked in the cytoplasm. They also lack membrane bound cell organelles such as mitochondria, vacuoles, endoplasmic reticulum, etc. They possess 70S ribosomes made up of 30 S and 50S subunits.

Thus, the correct option is (d).

Question2. How is the functioning of an unicellular organism different from that of a multicellular organism?

Answer: In unicellular organisms a single cell can perform all basic life processes and acts as the functional unit of the organism.

In multicellular organisms, specialised cells are grouped together into organs and organ systems which perform different physiological functions.

Question3. Differentiate between prokaryotic and eukaryotic cells with respect to cell wall composition and ribosome structure.

Answer:

Prokaryotic cell	Eukaryotic cell
Cell wall is made up of peptidoglycan.	Cell wall is made up of chitin in fungi and cellulose in plants.
Ribosomes are of the 70S type.	Ribosomes are of the 80S type.

Question4. Choose the statement that describes an eukaryotic cell.

(a) Contains only single membrane bound organelles

(b) Genetic material is enclosed by a nuclear membrane.

(d) both (a) and (b)

Answer: Eukaryotic cell both single and double membrane bound organelles. They can be uni or multicellular. They also contain multiple linear chromosomes which serve as genetic material and remain enclosed within a nucleus bound by a nuclear membrane.

Thus the correct option is (b).

FAQs of Prokaryotic and Eukaryotic Cells

Question1.What are the similarities shared by prokaryotic and eukaryotic cells?

Answer: The characters which are similar between both eukaryotic and prokaryotic cells are - presence of ribosomes, genetic material being composed of DNA, presence of cell membrane and a cytoplasm.

Question2. Is the DNA present in prokaryotic cells different from that found in eukaryotic cells?

Answer: Prokaryotic DNA contains only coding sequences whereas eukaryotic DNA contains both coding and non-coding sequences. Prokaryotic DNA is not associated with histones and is packaged by supercoiling of the DNA into a scaffold-like structure which is stabilised by some non-histone proteins. Eukaryotic DNA is packaged in the form of nucleosomes which contain a core of eight histone proteins around which the DNA is looped in a few turns. This nucleosome structure further coils and supercoils to form compact chromosomes.

Prokaryotic DNA is much smaller and contains much less number of genes when compared to eukaryotic DNA.

Question3. Why is the nucleus in plant cells not centrally placed?

Answer: The vacuoles in plant cells are located centrally and occupy around 90% of the cell volume. Thus the presence of the central vacuole pushes the nucleus to the edge of the cell. Animal cells either lack vacuoles or have very few small vacuoles. The nucleus in these cells are centrally located.

Question4. Does the presence of a cell wall provide any extra advantage to plant cells?

Answer: The cell wall provides rigidity to the plant cell which makes them more resistant to environmental stresses such as water stress. If excess water enters into a plant cell, it swells up and becomes turgid with the cell membrane distended against the cell wall, but it does not burst open. Animal cells on the other hand have a high probability of bursting open if excess water continues to enter the cells,

NCERT Class 11 Biology Chapters

The Living World	Biological Classification	Plant Kingdom
Animal Kingdom	Morphology of Flowering Plants	Anatomy of Flowering Plants
Structural Organization in Animals	Cells: The Unit of Life	Biomolecules
Cell Cycle and Division	Transport in Plants	Mineral Nutrition
Photosynthesis in Higher Plants	Respiration in Plants	Plant Growth and Development
Digestion and Absorption	Breathing and Exchange of Gases	Body Fluids and Circulation
Excretory Products and their Elimination	Locomotion and Movement	Neural Control and Coordination
Chemical Coordination and Integration