Eukaryotic cell

Introduction:

Eukaryotes (with well-developed nuclei) are described as organisms that contain a well-defined nucleus and show the presence of membrane-bound organelles.
Eukaryotic cells are comparatively larger in size.
They consist of two envelope system.
Eukaryotic cells contain a well defined nucleus and other membrane bound cellular organelles.
The genetic material is ds linear DNA present in the well-defined nucleus.
These cells are mostly multicellular on the basis of cell structure with a few exceptions of unicellular cells.
The eukaryotes include protists, plants, fungi and animals.

Topics covered:

Plant cell vs Animal cell

Detailed Explanation:

Eukaryotic cells:

The eukaryotic cells contain the well defined membrane-bound nucleus which consists of the genetic material of the organism in the form of cell chromosomes.
The eukaryotic cells are made up of two envelope systems as they are surrounded by the plasma membrane and also consist of membrane-bound cell organelles.
Membrane-bound organelles are responsible for the different functions inside the cells like endoplasmic reticulum, Golgi apparatus, lysosomes, microtubules, microfilaments, and centrioles.
Plants and fungi possess cell walls made of cellulose and chitin respectively.
However, animal cells do not possess cell walls.
The reserved stored material in plants is starch and in animals is glycogen.
Eukaryotic flagella show a 9+2 organization and are composed of microtubules.
Ribosomes can be attached to the endoplasmic reticulum or lie free in the cytoplasm and are 80S type as compared to 70S type in the prokaryotes.
The 70S ribosomes are also present in the cell organelles like chloroplast and the mitochondria present in the eukaryotes.
The process of transcription takes place in the nucleus whereas the process of translation occurs in the cytoplasm.
Cytoskeleton, a network of protein filamentous structures, is present in eukaryotes.
Generally, they show the process of formation and fusion of gametes (sexual reproduction).
Spindle apparatus (a subcellular structure that helps in distribution of duplicated chromosomes to daughter cells during cell division) is found in eukaryotes.
Centrioles are found in animals but absent in higher plants.
Examples: Protists, Plants, fungi and animals.

You may also want to know what are plantlings.

Plant cell vs Animal cell

Introduction:

The organisms comprising prokaryotic cells are called prokaryotes whereas the organisms comprising eukaryotic cells are called eukaryotes.
The eukaryotes consist of both plant and animal cells that form the respective plant and animal bodies.
Both the plant and the animal cells contain a well-defined nucleus.
These cells also contain the membrane-bound organelles which are suspended in the cytoplasm of the cell.

Detailed Explanation:

Some common eukaryotic features shared by both plant and animal cells are as follows-

The eukaryotic cells contain the membrane-bound nuclei which consist of the genetic material of the organism in the form of cell chromosomes.
They are made up of two envelope systems as they are surrounded by the plasma membrane and also consist of membrane bound cell organelles.
Membrane-bound organelles which are responsible for the different functions inside the cells.
Ribosomes can be attached to the endoplasmic reticulum or found freely and are the 80S type.
The 70S ribosomes are also present in the cell organelles like chloroplast and the mitochondria found in the eukaryotes.
The process of transcription takes place in the nucleus whereas the process of translation occurs in the cytoplasm.
They both show the presence of microfilaments and microtubules.
Peroxisomes are found in both plant and animal cells.
In plants the reserve food material is in the form of starch while in animal cells it is glycogen.
In plants due to absence of centriole the type of spindle formed during cell division is of anastral type while in animals the spindle formed is of amphiastral type.
In plants the adjacent cells are connected by plasmodesmatal connections while in animals cell junctions are found.
In plants cytokinesis during cell division occurs by cell plate formation while in animals it occurs by cell furrow method.
Presence of cell walls, plastids and large vacuoles is characteristic of plant cells.
Animal cells are demarcated by the presence of centrioles, lysosomes and many small vacuoles. Whereas centriole is absent in higher plants and the function of the lysosomes is taken over by the vacuoles and spherosomes in plants.

Difference between plant cell and animal cell:

Plant cell	Animal cell
The plant cell shows the presence of a surrounding cell wall.	The animal cell shows the absence of a cell wall.
The cell possesses a definite form or shape.	These cells show a less firm structure as compared to the plant cell.
The plant cell is larger in size as compared to other cells.	An animal cell is comparatively smaller in size.
The plant cells show the presence of plastids.	Plastids are usually absent.
Plant cells contain plastids called chloroplasts which are responsible for photosynthesis.	These cells show the absence of Chlorophyll.
The matured cells show the presence of a large central vacuole.	An animal cell may have many smaller vacuoles.
Nucleus is generally shifted to one side in the peripheral cytoplasm due to the central large vacuole.	The cells show the central location of the nucleus.
Mitochondria are comparatively fewer.	Mitochondria are generally numerous.
The higher plants do not have centriole	The animal cells show the presence of centriole.
The matured cells show the presence of a large central vacuole.	An animal cell may have many smaller vacuoles.
Plant cells do not burst if placed in a hypotonic solution, due to the presence of a plant cell wall.	The animal cell when placed in hypotonic solution bursts up due to the gain of water inside the cell, through the process of osmosis.
Golgi apparatus consists of dictyosomes which are a number of distinct or unconnected units.	Golgi apparatus organelle in the animal cell is a well-connected single complex.
Spindle is anastral.	Spindle is amphiastral.
Lysosomes are rarely present.	The animal cells contain lysosomes
Starch is the reserve material.	Glycogen is the reserve material.
Glyoxysomes may be present.	These structures are absent in an animal cell.
Plasmodesmata are the junctions present between the adjacent animal cells.	Different cell junctions connect various adjacent animal cells.
Cytokinesis results from cell plate formation.	Cytokinesis occurs by the process of cleavage.

Frequently Asked Questions (FAQs)

Q1. What are mesokaryotes?
Ans:

Mesokaryotes are the organisms that were used to be considered as intermediates between the prokaryotes and eukaryotes.
As the mesokaryotes show the presence of a well-defined nucleus but the absence of histone proteins.
For example, Dinoflagellates.

Q2. What do you mean by a well-defined nucleus?
Ans:

The structure of the nucleus of a eukaryotic cell is well defined and is made up of a nuclear envelope, nucleoplasm, nucleolus, and chromatin network.
A nuclear envelope is a double-walled delimiting membrane of the nucleus.
The nucleoplasm or karyolymph contains various substances like nucleic acids, protein molecules, minerals, and salts.
It contains a chromatin network and nucleolus.
The nucleolus is made up of rRNA (ribosomal RNA) and ribosomal proteins

Q3. What are the similarities between the plant and animal cells?
Ans: Both plant and animal cells are eukaryotic cells that share the following characteristics:

The eukaryotic cells contain the membrane-bound nuclei which consist of the genetic material of the organism in the form of cell chromosomes.
They are made up of two envelope systems as they are surrounded by the plasma membrane and also consist of membrane-bound cell organelles.
Membrane-bound organelles which are responsible for the different functions inside the cells.
Ribosomes can be attached to the endoplasmic reticulum or found freely and are the 80S type.
The 70S ribosomes are also present in the cell organelles like chloroplast and the mitochondria found in the eukaryotes.
The process of transcription takes place in the nucleus whereas the process of translation occurs in the cytoplasm.
They both show the presence of microfilaments and microtubules.
Peroxisomes are found in both plant and animal cells.

Q4. What is a spindle apparatus?
Ans:

Spindle apparatus is a subcellular structure which helps in distribution of duplicated chromosomes to daughter cells during cell division and is found in eukaryotes.

Q5. Differentiate between cell plate formation and cell furrow.
Ans:

The presence of the solid cell wall in the plant cell is known as Plant cytokinesis.
It takes place by two methods which are the cleavage method and cell plate formation method.

(i) Cell furrow or cell cleavage method:

A viscous fibrous dense mid body is formed in the centre.
Constriction of peripheral microfilaments takes place toward the centre (Centripetally) and finally both sides meet and two daughter cells are formed e.g. Animal cell.

(ii) Cell plate method:

In the case of plant cells, some spindle fibers exist that form phragmoplast.
Golgi vesicles and some ER vesicles deposit in the central part of phragmoplast and their deposition proceeds towards the peripheral part (centrifugally) and finally a cell plate is formed followed by the formation of middle lamella.
Now primary wall deposits at each side of middle lamella and ultimately both cells get separated to form two daughter plant cells.

Q6. How can we differentiate an anastral spindle from that of an amphiastral spindle?
Ans:

Amphiastral spindle arrangement is found in animals which consists of the spindle with two asters, one at each pole.
Anastral spindle arrangement is found in plants in which the spindle has no aster due to the absence of centrioles in them.