Vesicular Transport

What is endocytosis

The process by which large substances or bulk materials enter the cell without crossing the membrane

How does endocytosis work

The cell membrane invaginates (folds in) to form a flask-shaped pocket that traps extracellular material.
This pocket then pinches off to form an intracellular vesicle containing the material

What are the two main types of endocytosis

Phagocytosis and Pinocytosis

What is phagocytosis

The process by which the cell engulfs solid particles (like bacteria or cell debris). The vesicle is usually sent to a lysosome for digestion

What is pinocytosis

The process by which the cell takes in liquids or dissolved substances. It allows for faster uptake than through individual protein channels

What is receptor-mediated endocytosis

A selective form of endocytosis that uses specific receptor proteins on the membrane to recognise and capture target molecules

What are clathrin-coated pits

Specialised membrane regions lined with the protein clathrin, which help form vesicles during receptor-mediated endocytosis

Why is receptor-mediated endocytosis important

It allows the cell to control what enters, ensuring specific substances (like hormones or nutrients) are taken in.

What is exocytosis

he process by which large substances (or bulk amounts of smaller ones) exit the cell without crossing the membrane.

How does exocytosis occur

Vesicles (usually from the Golgi apparatus) fuse with the plasma membrane and release their contents into the extracellular environment

What happens to the vesicle membrane after exocytosis

The vesicle’s phospholipids become part of the cell membrane, replacing those lost during endocytosis

Why is exocytosis important

It allows the cell to secrete materials (like hormones, enzymes, or waste) and helps maintain the cell membrane’s surface area