Key Points
Key Points: Mitochondria
- Mitochondria are double-walled organelles, usually sausage-shaped, with inner folds called cristae.
- They have their own DNA and ribosomes, enabling some self-functioning.
- Known as the powerhouse of the cell, they produce ATP through aerobic respiration.
- Responsible for the release of energy from pyruvic acid formed in the cytoplasm.
- Involved in the synthesis of respiratory enzymes.
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.
