Endocytosis and Exocytosis
Cells engulf or release large particles using vesicles.
About this topic
Large particles and bulk materials move in and out of cells inside vesicles. In endocytosis the membrane folds inward to engulf material, forming a vesicle: phagocytosis for solids (white blood cells engulfing bacteria) and pinocytosis for fluids. In exocytosis, vesicles fuse with the membrane to release contents outside, as in hormone secretion and neurotransmitters.
Both processes need energy and keep the membrane area balanced.
When a white blood cell meets a bacterium, it wraps its membrane around it and pulls it inside in a vesicle, which then fuses with a lysosome and is digested. Nerve cells release neurotransmitters using exocytosis: vesicles fuse with the membrane at the nerve ending and empty their contents into the gap. Pancreas cells secrete insulin the same way.
These processes use energy and explain how membranes keep a constant size, since the membrane added by exocytosis is later retrieved by endocytosis. Viruses such as influenza sometimes hijack endocytosis to sneak into cells. Students sometimes mix up the two names; remember that endo means in, as in endoskeleton, and exo means out, as in exit.
Key ideas
- Phagocytosis
- Secretion of hormones
- Membrane folds around cargo
Quick check
Use cases: where Endocytosis and Exocytosis helps
- Homework: review the key idea behind Endocytosis and Exocytosis before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Endocytosis and Exocytosis without notes.
- Visual learning: play with the interactive lab to see how Endocytosis and Exocytosis changes when you adjust its inputs.
- Teaching a friend: explain Endocytosis and Exocytosis in your own words, then compare your version with the key ideas.
Biology underpins medicine, farming, conservation and biotechnology.
Frequently asked questions
What is Endocytosis and Exocytosis?
Cells engulf or release large particles using vesicles.
What will I learn in Endocytosis and Exocytosis?
Phagocytosis. Secretion of hormones. Membrane folds around cargo.
Is Endocytosis and Exocytosis part of Biology?
Yes. It is one of 150 Biology topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Endocytosis and Exocytosis lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Endocytosis and Exocytosis?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.