➢ Cell Structure and Function
Structure of cell
1. Cell: Basic Unit of Life
• Definition: Structural and functional unit of life
• Types: Prokaryotic (no nucleus, bacteria)
Eukaryotic (has nucleus, plants & animals)
2. Cell Membrane (Plasma Membrane)
• Structure: Phospholipid bilayer with proteins
• Functions:
o Controls entry/exit of substances
o Selectively permeable
o Communication (receptors)
3. Cell Wall (Only in Plants, Fungi, Bacteria)
• Made of:
o Cellulose (plants)
o Chitin (fungi)
o Peptidoglycan (bacteria)
• Function:
o Protection & shape
, o Prevents bursting from water intake
4. Nucleus (Control Center)
• Parts:
o Nuclear membrane
o Nucleolus
o Chromatin (DNA)
• Functions:
o Controls cell activities
o Stores genetic info
o Site of RNA synthesis
5. Cytoplasm
• Jelly-like fluid between nucleus and membrane
• Function:
o Holds organelles in place
o Site of metabolic reactions
6. Cell Organelles (Only in Eukaryotes)
a) Mitochondria
• Powerhouse
• ATP production (energy)
• Has its own DNA
b) Ribosomes
• Site of protein synthesis
• Found free or on RER
c) Endoplasmic Reticulum (ER)
• Rough ER (RER): Has ribosomes → protein transport
• Smooth ER (SER): Lipid synthesis, detoxification
d) Golgi Apparatus
• Modifies, sorts & packages proteins
• Forms lysosomes
e) Lysosomes
Structure of cell
1. Cell: Basic Unit of Life
• Definition: Structural and functional unit of life
• Types: Prokaryotic (no nucleus, bacteria)
Eukaryotic (has nucleus, plants & animals)
2. Cell Membrane (Plasma Membrane)
• Structure: Phospholipid bilayer with proteins
• Functions:
o Controls entry/exit of substances
o Selectively permeable
o Communication (receptors)
3. Cell Wall (Only in Plants, Fungi, Bacteria)
• Made of:
o Cellulose (plants)
o Chitin (fungi)
o Peptidoglycan (bacteria)
• Function:
o Protection & shape
, o Prevents bursting from water intake
4. Nucleus (Control Center)
• Parts:
o Nuclear membrane
o Nucleolus
o Chromatin (DNA)
• Functions:
o Controls cell activities
o Stores genetic info
o Site of RNA synthesis
5. Cytoplasm
• Jelly-like fluid between nucleus and membrane
• Function:
o Holds organelles in place
o Site of metabolic reactions
6. Cell Organelles (Only in Eukaryotes)
a) Mitochondria
• Powerhouse
• ATP production (energy)
• Has its own DNA
b) Ribosomes
• Site of protein synthesis
• Found free or on RER
c) Endoplasmic Reticulum (ER)
• Rough ER (RER): Has ribosomes → protein transport
• Smooth ER (SER): Lipid synthesis, detoxification
d) Golgi Apparatus
• Modifies, sorts & packages proteins
• Forms lysosomes
e) Lysosomes
