Key Points
Key Points: Plant Cell Vs Animal Cell
| Feature | Animal Cell | Plant Cell |
|---|---|---|
| Cell Wall | Absent | Present |
| Chloroplasts | Absent | Present |
| Vacuole | Small or absent | Large central vacuole |
| Shape | Generally round and irregular | Generally rectangular and regular |
| Lysosomes | Present | Present (though less common) |
| Centrioles | Present | Generally absent in most plant cells |
| Plasmodesmata | Absent | Present |
| Microvilli | Present | Generally absent |
| Golgi Apparatus | Present | Present |
| Mitochondria | Present | Present |
| Rough Endoplasmic Reticulum | Present | Present |
| Smooth Endoplasmic Reticulum | Present | Present |
| Ribosomes | Present | Present |
| Nucleus | Present | Present |
| Nucleolus | Present | Present |
| Plasma Membrane | Present | Present |
| Peroxisome | Present | Present |
| Cytoplasm | Present | Present |
| Middle Lamella | Absent | Present |
| Microtubules | Present | Present |
Key Points: Mitochondria
- Structure - Double membrane-bound organelle. The outer membrane is smooth; the inner membrane has infoldings called cristae. Inner space is called the matrix.
- Shape & Size - Sausage-shaped or cylindrical. Diameter: 0.2–1.0 µm; Length: 1.0–4.1 µm.
- Function - Site of aerobic respiration; produces energy as ATP. Called the 'Powerhouse of the Cell'.
- Matrix Contents - Contains circular DNA, RNA molecules, and 70S ribosomes for protein synthesis.
- Reproduction - Divides by fission.
Key Points: Golgi Apparatus
- The Golgi apparatus, also called dictyosomes in plant cells, is found as stacks of flattened membrane sacs.
- It consists of cisternae, vesicles, and vacuoles.
- Involved in the synthesis and secretion of enzymes, hormones, and other substances.
- Plays a role in the packaging and transport of cellular products.
- In animal cells, it helps form the acrosome of sperm cells.
Key Points: Lysosomes
- Lysosomes are membranous sacs formed from the Golgi body.
- They contain around 40 different types of digestive enzymes.
- Responsible for intracellular digestion and destruction of foreign substances.
- Help break down worn-out organelles—hence known as "suicide bags".
- Aid in digesting cartilage during bone formation.
Key Points: Centrosome
- The centrosome is found only in animal cells and is located near the nucleus.
- It consists of one or two centrioles surrounded by microtubules.
- It is the region that surrounds the centrioles.
- Initiates and regulates cell division.
- Helps form spindle fibres during cell division, aided by asters.
Key Points: Endoplasmic Reticulum (ER)
- ER is a network of double-membraned tubules that extend between the plasma and nuclear membranes.
- It occurs in two forms: Rough ER (RER) with ribosomes and Smooth ER (SER) without ribosomes.
- RER is involved in protein synthesis and transport because it contains attached ribosomes.
- SER is responsible for fat (lipid) synthesis and transport.
- ER provides a supportive internal framework within the cell.
