Cell - The Unit of Life

Study Notes

Cell Wall:
- Algae have cellulose, galactans, mannans, and CaCO3.
- Fungi have peptidoglycan.
- Plants have cellulose and pectin.
- Animal cells lack a cell wall.
Mitochondria:
- Divide by fission and budding.
- Contain DNA and 70S ribosomes.
Smooth Endoplasmic Reticulum (SER):
- Doesn't synthesize glycoproteins or glycolipids.
- Functions include lipid synthesis, steroid hormone synthesis, and detoxification.
Vacuoles:
- Usually occupy 90% of a plant cell's volume.
- Membrane is called the tonoplast.
- Sap is typically alkaline and hypertonic.
- Contractile vacuoles are involved in osmoregulation.
Chlorophyll:
- Found in grana, specifically thylakoids.
Perinuclear Space:
- Approximately 0.5-1 µm in diameter.
Mitochondria characteristics:
- 0.2 µm to 1 µm in diameter.
- Double membrane-bound organelle.
- Known as the power house of the cell.
- Part of the endomembrane system.
Cytoplasmic Bridge:
- Connects adjacent plant cells.
- Called plasmodesmata.

Chromatin: Contains DNA, RNA, histone proteins, and non-histone proteins.
Polar Molecules: Require carrier proteins to cross the non-polar lipid bilayer.
Hydrolases: Found in lysosomes, active at acidic pH.
Chloroplast and Mitochondria: Possess their own DNA, 70S ribosomes, and are double membrane-bound organelles.
Cilia: Small structures that act like oars, emerge from the basal body, and move the cell or surrounding fluid.
Centrosome: Composed of microtubules.
Centriole: Part of the centrosome and essential for cell division, characterized by cartwheel-like structure.
Axoneme: The core of cilia and flagella.
Nucleolus: A proteinaceous region within the nucleus and the site of ribosome biogenesis.