66 Flashcards
(11 cards)
What are lysosomes?
Lysosomes are membrane-bound cell vesicles found in the cytoplasm of all animal cells. They contain hydrolytic enzymes capable of breaking down biological polymers such as nucleic acids, proteins, carbohydrates, and lipids.
What is the function of lysosomes?
When activated, lysosomes function as the cell’s digestive system that destroys invading viruses and bacteria, repairs worn-out cells, and participates in programmed cell death or apoptosis.
What happens if lysosomes are absent in a cell?
If lysosomes are absent, cells tend to gather unwanted substances and become poisonous. They are hence called the ‘trash can’ or the ‘recycle bin’ of the cell.
What is the structure of lysosomes?
Lysosomes are dense spherical vacuoles bounded by a single membrane. The area within the membrane (the lumen) houses all the hydrolytic enzymes.
What is the pH of the lysosomal lumen?
The pH of the lysosomal lumen lies between 4.5 and 5.0, making it acidic.
What are the functions of lysosomes?
Lysosomes are responsible for the digestion of macromolecules, intracellular transport by endocytosis, phagocytosis, autophagy, and signaling.
How do lysosomes digest macromolecules?
Lysosomes contain about 50 hydrolyzing enzymes that digest macromolecules by hydrolysis, releasing energy for cellular activities.
What is phagocytosis?
Phagocytosis is the process where specialized antigen-presenting cells, like macrophages, take up and degrade large molecules that need immediate removal from the body.
What are peroxisomes?
Peroxisomes are membrane-bound organelles primarily involved in lipid metabolism and the conversion of reactive oxygen species into safer molecules.
What is the structure of peroxisomes?
Peroxisomes are made of a phospholipid bilayer with many membrane-bound proteins. They can vary in shape, size, and number depending on the energy needs of the cell.
How do peroxisomes relate to mitochondria and chloroplasts?
Peroxisomes are more similar to mitochondria and chloroplasts in that the enzymes involved in detoxification and lipid metabolism are synthesized on free ribosomes and imported into peroxisomes.
