By : Professor StudyWiz
Biology Study Notes:
Cell Biology and Genetics
Cell Biology
1.Cell Structure and Function
• Prokaryotic Cells: Simple, single-celled organisms (e.g., bacteria). Lack
membrane-bound organelles and a nucleus.
• Eukaryotic Cells: More complex, can be single-celled or multicellular (e.g.,
plants, animals). Contain membrane-bound organelles.
o Key Organelles:
▪ Nucleus: Contains genetic material (DNA).
▪ Mitochondria: Powerhouse of the cell, site of ATP (energy)
production.
▪ Ribosomes: Site of protein synthesis.
▪ Endoplasmic Reticulum (ER): Rough ER (with ribosomes)
synthesizes proteins; Smooth ER synthesizes lipids.
Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion.
2.Cell Membrane and Transport
• Structure: Phospholipid bilayer with embedded proteins, cholesterol, and
carbohydrates.
• Transport Mechanisms:
o Passive Transport: Movement of molecules across the membrane
without energy (e.g., diffusion, osmosis).
o Active Transport: Requires energy to move molecules against their
concentration gradient (e.g., sodium-potassium pump).
1
Biology Study Notes:
Cell Biology and Genetics
Cell Biology
1.Cell Structure and Function
• Prokaryotic Cells: Simple, single-celled organisms (e.g., bacteria). Lack
membrane-bound organelles and a nucleus.
• Eukaryotic Cells: More complex, can be single-celled or multicellular (e.g.,
plants, animals). Contain membrane-bound organelles.
o Key Organelles:
▪ Nucleus: Contains genetic material (DNA).
▪ Mitochondria: Powerhouse of the cell, site of ATP (energy)
production.
▪ Ribosomes: Site of protein synthesis.
▪ Endoplasmic Reticulum (ER): Rough ER (with ribosomes)
synthesizes proteins; Smooth ER synthesizes lipids.
Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion.
2.Cell Membrane and Transport
• Structure: Phospholipid bilayer with embedded proteins, cholesterol, and
carbohydrates.
• Transport Mechanisms:
o Passive Transport: Movement of molecules across the membrane
without energy (e.g., diffusion, osmosis).
o Active Transport: Requires energy to move molecules against their
concentration gradient (e.g., sodium-potassium pump).
1
