prokaryotic cells
Prokaryotes are unicellular organisms that lack organelles or other internal membrane-bound structures. Therefore, they do not have a nucleus, but, instead, generally have a single chromosome: a piece of circular, double-stranded DNA located in an area of the cell called the nucleoid. Living things have evoled into three large clusters of closely related organisms, called "domains": Archaea, bacteria, and Eukaryota. ARCHAEA and bacteria are small, relatively simple cells surrounded by a membrane and a cell wall, with a circular strand of dna containing their genes. they are called prokaryotes.
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What's inside a prokaryotic cellThe cell wall provides the cell with both structural support and protection. the cell membrane separates the interior of all cells from the outside environment. Ribosomes are the protein builders or the protein synthesizers of the cell. the chromosomes are made up of DNA tightly coiled many times around proteins that support its structure.
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PROKARYOTIC CELLS:
There are some key ingredients that a cell needs in order to be a cell, regardless of whether it is prokaryotic or eukaryotic. All cells share four key components: The plasma membrane is an outer covering that separates the cell’s interior from its surrounding environment.
Cytoplasm consists of the jelly-like cytosol inside the cell, plus the cellular structures suspended in it. In eukaryotes, cytoplasm specifically means the region outside the nucleus but inside the plasma membrane. DNA is the genetic material of the cell.
Ribosomes are molecular machines that synthesize proteins.
Despite these similarities, prokaryotes and eukaryotes differ in a number of important ways. A prokaryote is a simple, single-celled organism that lacks a nucleus and membrane-bound organelles. We’ll talk more about the nucleus and organelles in the next article on eukaryotic cells, but the main thing to keep in mind for now is that prokaryotic cells are not divided up on the inside by membrane walls, but consist instead of a single open space. The majority of prokaryotic \text{DNA}DNAD, N, A is found in a central region of the cell called the nucleoid, and it typically consists of a single large loop called a circular chromosome. The nucleoid and some other frequently seen features of prokaryotes are shown in the diagram below of a cut-away of a rod-shaped bacterium.
There are some key ingredients that a cell needs in order to be a cell, regardless of whether it is prokaryotic or eukaryotic. All cells share four key components: The plasma membrane is an outer covering that separates the cell’s interior from its surrounding environment.
Cytoplasm consists of the jelly-like cytosol inside the cell, plus the cellular structures suspended in it. In eukaryotes, cytoplasm specifically means the region outside the nucleus but inside the plasma membrane. DNA is the genetic material of the cell.
Ribosomes are molecular machines that synthesize proteins.
Despite these similarities, prokaryotes and eukaryotes differ in a number of important ways. A prokaryote is a simple, single-celled organism that lacks a nucleus and membrane-bound organelles. We’ll talk more about the nucleus and organelles in the next article on eukaryotic cells, but the main thing to keep in mind for now is that prokaryotic cells are not divided up on the inside by membrane walls, but consist instead of a single open space. The majority of prokaryotic \text{DNA}DNAD, N, A is found in a central region of the cell called the nucleoid, and it typically consists of a single large loop called a circular chromosome. The nucleoid and some other frequently seen features of prokaryotes are shown in the diagram below of a cut-away of a rod-shaped bacterium.
cytoplasm
the cytoplasm is the material or protoplasm within a living cell, excluding the cell nucleus. It comprises cytosol (the gel-like substance enclosed within the cell membrane) and the organelles – the cell's internal sub-structures.
ribosome
a minute particle consisting of RNA and associated proteins, found in large numbers in the cytoplasm of living cells. They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins.
flagella
A flagellum is a lash-like appendage that protrudes from the cell body of certain prokaryotic and eukaryotic cells. he primary role of the flagellum is locomotion, but it also often has function as a sensory organelle, being sensitive to chemicals and temperatures outside the cell.
plasmid
a genetic structure in a cell that can replicate independently of the chromosomes, typically a small circular DNA strand in the cytoplasm of a bacterium or protozoan. Plasmids are much used in the laboratory manipulation of genes.
plasma membrane
a microscopic membrane of lipids and proteins that forms the external boundary of the cytoplasm of a cell or encloses a vacuole, and that regulates the passage of molecules in and out of the cytoplasm.
cell wall
a rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria. In the algae and higher plants, it consists mainly of cellulose.