Page 33 - Biology_F5

Biology for Advanced Level Secondary Schools

Digestion
Phagocytosis

Autophagy
Food vacuole

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Secretion of Lysosomes
hydrolytic
enzymes
Golgi apparatus

Transport vesicle
Plasma membrane

Rough endoplasmic
reticulum

Figure 1.14: Lysosomal functions

Lysosomes are adapted to their functions cells, known as the "garbage disposal"
in different ways. The first way is the or "recycling center" of the cell. Explain
presence of hydrolytic enzymes which how lysosomes maintain cellular
catalyse degradation of unwanted cellular homeostatic condition by digesting
substances. In addition, lysosomes have waste materials and recycling cellular
the membranes that isolate hydrolytic components
enzymes from the rest of the cytoplasm.
This prevents unnecessary autolysis. Microbodies

Microbodies are small, spherical organelles
Exercise 1.8 bounded by a single phospholipid bilayer
membrane which contains a matrix of
1. Why are lysosomes said to be suicide intracellular materials such as catalase
bags? (peroxidase) enzyme and other proteins

2. Describe the structure and functions of (Figure1.15). They are present in almost
lysosomes. all eukaryotic cells and are mostly seen near
3. Giving reasons, mention the parts of the ER, and sometimes near mitochondria
your body which are expected to have and plastids. They can be distinguished
large number of lysosomes. from other cell organelles by their contents.
4. Lysosomes are membrane-bound Microbodies include peroxisomes,
organelles commonly found in animal glyoxysomes, and glycosomes. Peroxisomes

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