The Cell Theory.

Cells

Introduction.

The Term cell is derived from Greek word kytes (cyto) means cell ( cell means hollow space ) it was discovered by " Robert hook" In 1665 during his investigation on the structure of cork.

Definition of the cell.

"Cell is the basic structural and functional unit of life or living organisms. Some terms as or called the building block of life.

Cell theory.

The cell theory first developed in 1830 by botanist Matthias Schleiden and zoologist Theodor Schwann

• State that the all organism is composed of one or more cells. 
• All cells come from pre-existing cells vital function occurs of an organism within cells. 
• Have all content and heredity information necessary for the regulation cells function for the next generation of cells.

Prokaryotic Cell.

• Prokaryotes defined as simple, single-celled organisms without membrane-bound organelles or a nucleus.
• The term “prokaryote” is derived from two Greek words, 'pro' meaning 'before' and 'karyon' meaning 'nucleus'. This type of cell doesn't have a true nucleus.
• They do not contain a true nucleus nuclear membrane and nucleus. So instead of the nucleus, the genetic material is found in the cytoplasm.
• The cells also do not have those organelles which are covered by a membrane such as mitochondria w bodies lysosome and chloroplast.
• The pancreatic cells found in a simple living organism like blue-green algae bacteria the most common example is prokaryotic cell is "Escherichia coli " (E. coli).

Eukaryotic Cell.

• Eukaryotic cells are cells which contain a complete nucleus or true nucleus covered by plasma Membrane.
•  The term or Eukaryotic is taken from Greek EU, "well," and karyon, "nut or kernel, Eukaryotic cells have a nucleus enclosed by a plasma membrane and all double-bound membrane organelles. 
• These (eukaryotic ) cells are larger than prokaryotic. Having complex cells in which the genetic material is organized into membrane-bound nuclei.
•  The cells are present in an animal, Animal Plants, Fungi, Algae protozoa. All multicellular organisms.

Plant Cell.

• Plant cells are the basic unit of life in the organism of kingdom Plantae.
•   They are Eukaryotic cell which has a true nucleus along with the specialised structure called Organelles that carry out different functions.
•  Plant cells are a basic building block of plant life and carry out all the functions necessary for survival like photosynthesis the food making process from light energy carbon dioxide and water occurs in the chloroplast.
•  The cell energy ATP Adenosine triphosphate is produced through cellular respiration in mitochondria and many more function plant cell do.
• A plant cell has an outer layer of the cell Cell wall as compared to an animal cell which doesn't have a cell wall.

Animal Cell.

• The Animal cells are the basic unit of life in organisms of the kingdom Animalia.
•  They are also eukaryotic cells, means that they have a true nucleus and specialized structures called organelles that carry out different functions like plants. 
•  But Animal cells do not have plant-specific organelles like cell walls, which support the plant cell, or chloroplasts this is main Difference between plant cell and Animal Cell.

Cell parts And Their Functions.

Cell wall. 

The first layer of the cell is the cell wall. 

The cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. 

The most important chemical composition of a plant cell is cellulose. 

Along with cellulose molecules, groups into fibre and helps maintain the shape of the cell. Its function to maintain cell pressure and present over expansion and give mechanical support to the cell.

Cell Membrane or Plasma Membrane.

•  The cell membrane is the thin layer made up of protein lipids and fats. It forms a protective wall around the organelles contained within the cell. 
• Which selectively permeable and regulate the transfer of materials needed for the survival of the organelles of the cell.
•  Its function is to protect the cell from its surrounding and maintain all kind of transport active or passive.

• Cytoplasm. 
• The cytoplasm forms the jelly-like substance that holds the organelles in the cell. 
• It is the colourless substance that is made up of mainly water salt and organic molecules.
•  It also contains a protein that is Make Up The cytoskeleton is the stage where all the function takes place or is the home of organelles of the cell. 
• Serves as I the site of multiple cell process including cell metabolism.

• Vacuole. 
• The vacuole is essentially a sac filled.  It helps maintain the shape of the cell.
•  It stores nutrients and water products its function including isolating materials harmful to the cells maintaining turgor within the cell and exporting unwanted materials away from the cell. 
• Regulate the internal environment.

• C centrosomes.
•  The centrosomes are located in the nucleus and are the small body made up of radiating tubules.
•  It is responsible for producing and organising the microtubules. In a plant cell.
• The centromere is also called microtubules organising centre. Regulate cell cycle progression.

Chloroplast. 

• The chloroplast is organisms that resemble the structure of the mitochondria.
• Tt is plastids that trap the energy from sunlight it contains chlorophyll molecules that carry on the process of photosynthesis or as well as give lush green colour to plant. 

• Golgi Bodie. 
• Known as the Golgi Complex of the Golgi apparatus. It is located near the nucleus.
• It is the stock of membrane-bound structure that is involved in the transportation of lipids and modified modification of protein it is crucial in segregation and transporting material within the cell.
• It is also called the packaging factory of the cell. Transport the protein produced in the endoplasmic reticulum after Protein synthesis after synthesis of protein has been in ER transition in vesicles or sac is formed then floats to the Golgi apparatus into which it is observed.
•  After that as secretary vesicles are formed and released into cytoplasm move to the cell membrane.

 

Mitochondria. 

• Mitochondria are usually known to be n the "powerhouse" of the cell or "storehouse" of the energy of the cell the mitochondria play an important role in the cell. 
• They are made up of cristae of finger-like structure which convert the sugar into Adenosine triphosphate ATP store and release energy required for them to function.
•  It is responsible for regulating cellular metabolism and produce energy and converts it. 

Ribosomes. 

• They are small pockets or granule of RNA that converts the amino acid into a protein.
• It is served is a site of protein synthesis and these are termed protein factory it builds and synthesis proteins. 

Endoplasmic reticulum (Rough) 

• The rough endoplasmic reticulum or rough ER are inter-connected membrane system located close to Nucleus.
•  The presence of ribosome on it makes it rough surface appearance and hence the name of ER accord with the Golgi body to send new protein in their proper direction. 
• These network transport material through the cell and produce protein in track known as Casternae manufacture the lysosomal enzymes facilitate translating folding proteins. 

Smooth ER. 

• Similar to the structure of rough ER the smooth is a separate inter-connected network membrane.
• This is free from ribosome the SER transports material through the cell.
• It is also crucial in producing and digesting lipids and proteins and manufacture and transport the lipids. 

lysosomes and peroxisomes. 

• Both lysosomes and peroxisomes are essentially bags of enzymes. Lysosomes contain enzymes that break down large molecules, including old parts of the cells and foreign material. 
• Peroxisomes contain enzymes that destroy toxic materials, including peroxide.

Cytoskeleton. 

• The cytoskeleton can be considered the scaffolding of the cell. It helps it maintain the correct shape. 
• However, unlike regular scaffolding, the cytoskeleton is flexible; it plays a role in cell division and cell motility the ability of some cells to move.
•  Such as sperm cells, for instance, The cytoskeleton also helps in cell signalling through its involvement in the uptake of material from outside the cell (endocytosis) and is involved in moving materials around within the cell.

Microtubules. 

• Hollow Rod that functions primary help support and shape to the cell. 
• They are important for chromosome Movement in mitosis and meiosis as well as cytosol movement within the cell. 

Nucleus. 

• The nucleus is the control centre of the cell. the cell nucleus control all activity of the cell regulating protein synthesis within the cell. 
• Each cell is surrounded cone could say enclosed by nuclear membrane also known as nuclear envelope inside the nuclear membrane it contains DNA genetic material in the form of gene and nucleolus

Nucleolus. 

• Inside the cell, the nucleus is located within the nucleus.
•  The site of synthesis transfer RNA ribosomal RNA and ribosomal subunits. 

Nuclear membrane.

•  The nuclear membrane is also known as the nuclear envelope and enclose the content of the nucleus separating from the resting cell. 
• Nuclear pore in membrane enables various substance like nutrients and waste of cells in and out of the cell.