What is the second biggest organelle? Its main purpose is to recycle and decompose.
Lysosomes act as the recycling and decomposing centers for animal cells, whereas vacuoles are the organelle that serves a similar purpose in plant cells.
Lysosomes are membrane-bound organelles and contain hydrolytic enzymes (acid hydrolases) that work most effectively in acidic pH, due to which the internal pH of the lysosome is maintained at about 4.8. Lysosomes break down various molecules that are no longer useful for the cell, including DNA, RNA, carbohydrates, proteins, lipids, etc. The byproducts and waste materials are brought to the lysosomes, where they are broken down into simpler molecules and are sent back to act as new building materials (recycling). The molecules that are no longer useful for the cell are excreted outside the cell (disposal).
Vacuoles serve a similar purpose in plant cells and share many properties of the lysosomes. They have an acidic pH, contain degradative enzymes and are recycling and disposal centers of plant cells.
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