CELL
Md. Masud Rana
RN, MSN
Definition
• A cell is the basic structural and
functional unit of living
organisms.
• In other words, cells make up
living things and carry out
activities that a living thing
alive.
• In 1965, Robert Hooke first
discovered cell.
Structure of Human Cell
• Human cell basically
divided into 3 parts:
1. Cell membrane
2. Cytoplasm
3. Nucleus
Cytoplasm
Cytoplasm is the jelly-like substances inside the
plasma membrane that surrounds the
nucleus.
Contents:
1. Organelles
a) Membranous:
b) Non-membranous
2. Inclusion: Fat droplets, glycogen granules,
Lipofuscin, Hemosiderin
Membranous organelles
Mitochondria
Endoplasmic reticulum
Golgi complex or
apparatus
Lysosomes
Peroxisomes
Non-membranous
organelles
Ribosomes
Centrosome
Proteasomes
Cytoskeleton
•Micotubules
•Imicrofilaments
•Intermediate filaments
Nucleus
• Nuclear envelope
• Chromatin
• Necleolus
Cell membrane
• Extremely delicate,
thin, elastic & semipermeable
phospholipids belayed
membrane that
surround a cell.
Nucleus
• Nucleus is the most prominent and largest
cellular component, which is the command
centre of the cell.
• Nucleus is present in all cells in the body
except the red blood cell (RBC)
Functions
• Controls of all the cell activities that include
metabolism, protein synthesis, growth and
reproduction (cell division)
• Synthesis of RNA
• Formation of subunits of ribosomes
• Sending of genetic instruction to the cytoplasm
for protein synthesis through messenger
RNA(mRNA)
• Storage and transformation of hereditary
information from one generation to the next.
Lysosome
• Lysosomes are
membranous vesicles
formed by the Golgi
apparatus.
• They contain digestive
enzymes
Functions
• They destroy and digest foreign material such
as-harmful bacteria, virus.
• In dead cell perform autolysis lysosomes.
That’s why lysosome are called as ‘suicidal
bugs’ or ‘atom bomb of the cell’.
Golgi complex
• Is a membrane bound organelle, involved in
the processing of protein.
• Composed of four or more stacks of closely
folded flattened membranous sacs lying near
the side of nucleus.
• Packaging house of cell
Functions
• Complete post-translational modifications of
proteins synthesized in the RER and then
• Packages and addresses these proteins to
proper destinations.
• Produce vacuoles and secretary vesicles
• They help in production of some hormone and
enzymes
Types
• Rough endoplasmic reticulum: contains
ribosomes and is involved in protein synthesis
• Smooth endoplasmic reticulum: does not
contain ribosomes. It is involved in lipid
synthesis and carbohydrate metabolism
Ribosomes
• Ribosomes are small electron-dense particles
found in the cytosol
• They are the Protein factories of cell
• They are made of protein and RNA
• They found in the both ER & Cytoplasm
Function: Synthesis of protein