Most organisms can be divided into two categories - prokaryotes and eukaryotes. what is the main difference between these two categories?

The main difference between Prokaryotic and Eukaryotic cell is that, eukaryotes contain membrane bound organelles like nucleus where as prokaryotes do not. The genetic material is present at the center and is called nucleoid in prokaryotes.

Explanation:

Example of prokaryotes include bacteria and archea bacteria. Examples of eukaryotes include plants and animals. Prokaryotes lack organelles such as mitochondria, endoplasmic resticulum and lysosomes which are present in eukaryotes. Both the groups contain ribosomes but its 70s ribosome in prokaryotes and 80s ribosomes in eukaryotes.

Eukaryotes possess a well-defined nucleus and genetic material (DNA) is not freely suspended in the cytoplasm whereas prokaryotes lack a well-defined nucleus and genetic material is freely suspended in the cytoplasm.

Explanation:

There are two different kinds of cells.

1- Prokaryotic cells

2- Eukaryotic cells

Organisms possessing Prokaryotic cells are called Prokaryotes.

Organisms possessing Eukaryotic cells are called Eukaryotes.

PROKARYOTIC CELLS:

Greek pro: before and karyon: kernel/nut

1-They don't have a well-defined nucleus and genetic material is freely suspended in the cytoplasm. Genetic material (DNA) is not bounded by a double nuclear membrane.

2- They don't possess most of the membrane bound organelles like Endoplasmic retiuculum, mitochondria etc.

3- They are more primitive cells.

4- They have smaller ribosomes (70S).

5- They reproduce by binary fission.

6- They possess a cell wall. Cell wall is made up of peptidoglycan (murein).

EXAMPLES:

=> Bacteria is a prokaryote as it possesses prokaryotic cells.

EUKARYOTIC CELLS:

Greek Eu: True and karyon: nut/kernel

1- They have a well-defined nucleus. Nucleus is bound by double nuclear membrane. Genetic material (DNA) is not freely floating in the cytoplasm.

2- The possess membrane bound organelles like Endoplasmic reticulum, mitochondria etc.

3- They are more advanced cells.

4- They have larger ribosomes (80S).

5- Somatic cells (cells that form the body of the organism) reproduce by mitosis and gametes (germ cells) reproduce by meiosis.

6- They may or may not possess a cell wall. Cell wall is absent in animal cells whereas it is present in plants, fungi and some protists. Cell wall of plants is made up of cellulose whereas cell wall of fungi is made up of chitin.

EXAMPLES:

=> Humans are eukaryotes because they possess eukaryotic cells.

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products

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