Lysosomes are digestive compartments'

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Lysosomes are digestive compartments.
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Lysosomes

• Phagocytosis - Digesting food
• Digesting damaged organelles
• Development
• Function at pH 5

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Phagocytosis
Digested products released
Fuses with lysosome
Food vacuole
Taken up
Food particle
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Digestion of Damaged Organelles
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Lysosome Syntheses
Released
Packaged in a vesicle
Transported to Golgi
Enzymes Synthesized in Rough ER
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Lysosomes and Disease

• Tay-Sachs disease - lack enzymes that digest
  lipids
• Pompes disease - lack enzymes that digest
  glycogen

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Vacuoles - Cell Maintenance

• Food vacuoles
• Contractile vacuoles
• Plant vacuoles

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Plant vacuole

• Storage
• Proteins in seeds
• Potassium and chloride ions
• Waste products
• Plant growth
• Contain colored pigments
• Protection - poisonous substances

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Relationships Among Endomembranes
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Other Organelles

• Microbodies
• Energy-transforming organelles
• Mitochondria - respiration
• Chloroplasts - photosynthesis

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Peroxisomes

• React with oxygen and produce hydrogen peroxide
  later break down hydrogen peroxide
• Liver - detoxify alcohol
• Fat metabolism

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Mitochondria
Power house of the cell - Respiration - ATP
Double-membraned organelle
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Chloroplasts

• Photosynthesis - absorb light--gtglucose
• Double-membraned organelle

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Endosymbiosis

• Mitochondria and chloroplasts may have once been
  free-living
• and were swallowed by other organisms.

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Endosymbiosis
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Endosymbiosis

• Evidence for
• Double membrane systems
• Have DNA ribosomes
• Can synthesize some proteins
• Evidence against
• Can not synthesize all proteins

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Why are cells microscopic? - surface to volume
ratio
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Next step - multicellularity

• Allows greater size of organisms
• Allows cell specialization
• But ---

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New Challenges

• Differentiation development
• Communication
• Hormones
• Nervous system

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Specialized Cells - Red Blood Cell
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Nerve cell
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Muscle