Cell Membrane, vacuoles,
vesicles and lysosomes
Cell membrane
 The
“skin” of the cell that controls what
goes in and out of the cell
 Made up of a bi-layer of phospholipids
 Other molecules (proteins and
carbohydrates) impeded in the bi-layer
 Cell has to be small so that the volume
does not out grow the surface area
Vacuoles

Used in cell maintenance
Food vacuoles
 Formed by phagocytosis
 Collects food from outside
Contractual vacuole
 Pumps out excess water
Central vacuole
 Hold materials (waste, access food, harmful
materials)
Vesicles
 Sacs
made of membrane inside of a cell
 Transport products in various stages of
processing from one cisterna to an other
Transport vesicle
 Tiny membrane sacs in a cell’s cytoplasm
carrying molecules produced by the cell
Lysosomes

Membrane-bound sac of hydrolytic enzymes that the cell
uses to digest macromolecules
 Found in the cytoplasm of eukaryotic cells
 Lysosomal enzymes can hydrolyze proteins,
polysaccharides, fats, and nucleic acids
 Carry out intracellular digestion by a process called
phagocytosis
 Lysosomes also use hydrolytic enzymes to recycle the
cell’s own organic material in a process called autophagy
 Lysosomes provide a space where the cell can digest
macromolecules safely
 Formed by budding off the Golgi membrane
Transport vesicles containing
inactive hydrolytic enzymes
buds off the ER membrane
Golgi apparatus
activates hydrolytic
enzymes
Lysosomes containing
active hydrolytic enzymes
bud off the Golgi membrane
Autophagy: a
lysosome engulfs a
damaged organelle
Phagocytosis: a food vacuole
pinches off the plasma
membrane, enclosing food
particle
Food vacuole
fuses with
lysosome
Hydrolytic enzymes digest particles
engulfed by lysosomes ;breakdown
products (monomers) pass across
lysosome membrane into cytosol