Cell Physiology L4/5: Vesticular Transport Flashcards
What are the 2 functions of vesticular transport?
- Transport unusual or large substances through the membrane for which there isn’t a specific carrier protein
- Store a substance prior to release to the ECF
Materials are transferred between ____ and_____ or between structures within cell in ______, small membranous sacs that form at or fuse with the cell membrane. It also requires energy from _____.
ECF; ICF; vesicles; ATP
What is endocytosis?
Vesticular transport into the cell
What is exocytosis?
Vesticular transport out of the cell
What are the 5 steps of endocytosis?
- Trigger (ligand, presence of object)
- Indentation of the membrane (becomes larger)
- Pouch formed on membrane
- Neck of pouch sealed off
- Vesicle detached from membrane
What are the 2 types of vesticular transport?
- Endocytosis
- Exocytosis
What is receptor-mediated endocytosis?
Uptake of specific substances bound to membrane surface receptors
What is pinocytosis in endocytosis?
“cell drinking”
- Uptake of extracellular fluid
What is phagocytosis in endocytosis?
“cell eating”
- Uptake of solid objects such as bacteria, cell debris, etc.
What are the 3 types of endocytosis?
- Receptor-mediated endocytosis
- Pinocytosis - “cell drinking”
- Phagocytosis - “cell eating”
How does transport via vesicles occur in receptor-mediated endocytosis?
Collection of specific molecules
How does transport via vesicles occur in pinocytosis?
- Cell drinking”- vesicle forms filled with ECF
- Similar process to receptor-mediated
- endocytosis but not as selective
- not initiated by ligand binding
- Target seems to be general ECF contents
- Performed by most cells
How does transport via vesicles occur in phagocytosis?
- Engulfs solid objects - may be as large as the cell itself
- Performed by specialised cells eg. macrophages (WBC)
- Vesicle (called phagosome)
- Fuses with lysosome
- Lysosomal enzymes digest contents
- Remains may be exocytosed
Transport via vesicles in pinocytosis has a similar process to ________.
Receptor-mediated
Transport via vesicles in pinocytosis is endocytosis but ___(more/less) selective and not initiated by ______ binding.
less; ligand
Transport via vesicles in pinocytosis is performed by ____ cells.
Most