A lysosome is a membrane-bound cell organelle that contains digestive enzymes for breaking down parts of the cell, as well as material that has been taken into the cell by phagocytosis.

Animal cells have a set of organelles not found in plant cells: lysosomes. Lysosomes are a cell’s “garbage disposal.” Hydrolytic enzymes within the lysosomes aid the breakdown of proteins, polysaccharides, lipids, nucleic acids, and worn-out organelles. These enzymes are active at a much lower pH than that of the cytoplasm. Therefore, the pH within lysosomes is more acidic than the pH of the cytoplasm.

Practice Questions

 

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MCAT Official Prep (AAMC)

Sample Test B/B Section Passage 10 Question 52

Practice Exam 2 B/B Section Question 9

Practice Exam 2 B/B Section Passage 9 Question 50

Key Points

• Lysosomes, which are found in animal cells, are the cell’s “garbage disposal.”

• Hydrolytic enzymes within them aid in the breakdown of proteins, polysaccharides, lipids, nucleic acids, and worn-out organelles.

Key Terms

Lysosome: found in animal cells, is the “garbage disposal”, breakdowns molecules and old organelles

Hydrolytic enzyme: enzyme needing water to break chemical bonds of large molecules

Organelles: membrane-bound compartments with specialized functions

Polysaccharides: a carbohydrate whose molecules consist of several sugar molecules bonded together

Cytoplasm: a thick solution that fills each cell and is enclosed by the cell membrane