STPM Biology Structure of Cell and Organelle (Part 10)

Mitochondria

Distribution:

• Mitochondria are found in almost all cells except for red blood cells of mammals and mature sieve tube elements of plants.
• Mitochondria are randomly distributed in cytoplasm.
• Mitochondria are abundant in muscle cells, pancreatic cells, liver cell, sperms and meristematic cells of plants.

  

  Structure of mitochondrion
  

Structure:

• Shape: Mitochondria exist in different shapes. Usual shapes are oval or rod.
• Size: Varies. General size 1μm (diameter) and 2.5μm (length).
• Mitochondria are bounded by a double membrane. The inner membrane is folded; each fold is called crista (plural = cristae).
• Embedded in the inner membrane of mitochondria are many stalked particles. These stalked particles are ATPase enzymes.
• The watery matrix inside the mitochondria contains DNA, ribosomes, RNA, enzymes, proteins and granules.

Functions:

• Mitochondria are the main site for aerobic respiration.
• Mitochondria carry out fatty acid metabolism.