The clean-up crew
Lysosomes break down waste and damaged parts.
Rubbish in a busy kitchen
A busy kitchen makes rubbish all the time. If nobody cleans up, the kitchen stops working.
How does a cell keep from filling up with waste and worn-out parts?
What this lesson covers
The idea
Lysosomes are single membrane-bound sacs of enzymes that break down unwanted proteins, carbohydrates, fats and damaged cell parts, keeping the cell clean; the products are released into the cytoplasm for reuse.
Rubbish in a busy kitchen
A busy kitchen makes rubbish all the time. If nobody cleans up, the kitchen stops working.
How does a cell keep from filling up with waste and worn-out parts?
- Special sacs of enzymes break them down
- It never makes waste
- It throws away the whole cell
Watch the clean-up
Press + to follow the lysosome, step by step.
Lysosomes
Lysosomes are single membrane-bound sacs filled with enzymes. They break down unwanted proteins, carbohydrates, fats and even damaged parts of the cell, keeping it clean and healthy. The products are released into the cytoplasm and may be reused.
Human sperm cells carry lysosomal enzymes. They help break down the outer layer of the egg so fertilisation can take place.
- Step | What happens
- 1 | a lysosome meets waste or a damaged part
- 2 | its enzymes break the material down
- 3 | the products are released and reused
Notes
Lysosomes are single membrane-bound sacs of enzymes that break down unwanted material and damaged parts. The products are released and reused.
Check yourself
A lysosome is a…
What happens to the products of the breakdown?
Lysosomes help the cell by…
Which of these can lysosomal enzymes break down?
- single membrane-bound sac of enzymes — correct. Yes.
- double-layered nucleus. The nucleus is a different organelle.
- stack of flattened sacs. That is the Golgi apparatus.
- They are released into the cytoplasm and may be reused — correct. Yes.
- They are destroyed. They are reused.
- They stay forever inside the lysosome. They are released.
- breaking down unwanted and damaged material, keeping it clean — correct. Yes.
- making ATP. Mitochondria do that.
- making proteins. Ribosomes do that.
- Proteins, carbohydrates, fats and damaged cell parts — correct. Yes.
- Only water. They digest the materials listed.
- Only the cell wall. They break down unwanted materials and damaged parts.