lysososmes Flashcards
Lysosomes (20 cards)
What are lysosomes?
Membrane-bound sacs containing hydrolytic enzymes that digest macromolecules.
Function best in an acidic environment; enzymes are inactive in the cytosol due to its near-neutral pH.
What can excessive lysosomal leakage lead to?
Cell self-destruction.
How are lysosomal enzymes and membranes formed?
Made by the rough ER and modified in the Golgi apparatus before budding off.
What is phagocytosis?
The process where unicellular organisms engulf food particles or smaller organisms, forming a food vacuole that fuses with a lysosome for digestion.
What is autophagy?
The process where damaged organelles or cytoplasmic material are enclosed by a double membrane and degraded by lysosomes.
What is an example of a lysosomal storage disease?
Tay-Sachs disease.
What are vacuoles?
Large vesicles derived from the ER and Golgi apparatus that store and maintain cellular components.
What are the types of vacuoles and their functions?
- Food Vacuoles: Formed by phagocytosis, fuse with lysosomes for digestion.
- Contractile Vacuoles: Pump out excess water in freshwater unicellular organisms.
- Hydrolytic Vacuoles: Perform enzymatic hydrolysis in plants and fungi.
- Storage Vacuoles: Store proteins, toxic compounds, and pigments in plants.
What is the role of the cytoskeleton?
Provides mechanical support, maintains cell shape, and acts as an anchor for organelles and enzymes.
What are microtubules?
Hollow rods made of tubulin proteins that provide shape, support, and track for organelle movement.
What are centrosomes?
Structures near the nucleus from which microtubules originate, containing two centrioles.
What is the structure of cilia and flagella?
Cilia have a ‘9 + 2’ microtubule arrangement, while non-motile cilia have a ‘9 + 0’ arrangement.
What are microfilaments?
Thin, solid rods made of actin proteins that provide tensile strength and support microvilli.
What is the function of intermediate filaments?
Provide mechanical strength and tensile support, and anchor organelles in place.
What are tight junctions?
Cell junctions that create a watertight seal between neighboring cells.
What are desmosomes?
Anchoring junctions that fasten cells together into strong sheets and provide mechanical stability.
What are gap junctions?
Communicating junctions that allow direct cytoplasmic communication between adjacent cells.
Fill in the blank: The process where damaged organelles are enclosed by a double membrane is called _______.
Autophagy.
True or False: Intermediate filaments are frequently assembled and disassembled.
False.
What is the primary function of contractile vacuoles?
To pump out excess water in freshwater unicellular organisms.
