Basics of Cell(Life form)

 Lecture 1 Basics of Cell(Life form) 

Cells 

The cell is the basic structural and functional unit of life forms. It was discovered by Robert Hooke in 1665.

Cells are of two types

Endosymbiosis- One organism live inside another organism. The endosymbiosis helped in evolution of Eukaryote. As Archean engulfing bacterium resulted in evolution of eukaryote cell. 

Non-Cells Agent

Able to carry biological information in form of DNA and RNA(mainly viruses). 

Viruses- Protein coated DNA or RNA agents present in host cell. Discovered by Dmitri Ivanovsky in 19th century. Viruses are of four types

DNA viruses- Single Stranded, Double Stranded

RNA viruses- Single Stranded, Double Stranded

RNA virus has higher mutation rate because of high replication rate and lack of proofreading mechanism. 

Virions- independent viral particles outside cell. 

Pirions- Protein(Non nucleus agent) that cause protein infection. 

Bacteriophage- A virus that infects and replicates within bacteria and archaea.

Viriods- Smaller in comparison to viruses and mainly infect plants. Viriods are short strands of circular and single-stranded RNA without the protein coats. Discovered by T.O. Diener in 1971.

Obelisks- Virus like entities present in the human body(discovered in 2024).It comprises a class of diverse RNAs. It falls between Viriods and viruses. 

           Viriods → Obelisks → Viruses

Dysbiosis- Imbalance within a community of microorganisms living together(microbiome). The misuse of Antibiotics in human kills beneficial bacteria also leading to imbalance in microbiome in human body thus causing Dysbiosis. 

Eukaryotic cells

Cell Wall- Dead and Permeable in nature. 

               Cell Wall = Cellulose + Lignin

High lignin → Wood, Low lignin → Grass

Cell membranes- living and selectively permeable in nature. 

High Cholesterol → Low permeability

High Temperature(upto 45 °C) → High permeability

Increase or decrease in Ph → decrease in permeability

High permeability of neutral molecules compared to charged molecules

Cytoplasm- Cytoplasm is the gelatinous liquid that fills the inside of a cell. It is composed of water, salts, and various organic molecules. 

Mitochondria- Also known as Power House of The Cell, a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy.

Ribosomes- Perform protein synthesis

Endoplasmic Reticulum- Perform transportation of synthesized proteins

Nucleus- Cell nucleus provides a site for genetic transcription and also known as brain of cell. Nucleus was discovered by Robert Brown in 1831.

Nucleus not present in mature RBC(mammals) and platelets cell. 

Location of DNA in cell- Chloroplast, Mitochondria, Nucleus

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