i need help please as soon as possible
Answers
Answer:
Lysosomes are organelles found inside all cells. In this lesson, you will learn about the structure and function of lysosomes to gain a better understanding of them.
Function
Cells produce waste like all living things. The lysosomes are the garbage disposals of the cell. When a part of the cell becomes damaged or obsolete, it is moved to the outer edge of the lysosome. The membrane of the lysosome opens and the molecule is moved into the lysosome. Once inside, the digestive enzymes produced by the lysosome break down the molecule. After it is has been completely .
Some of the main functions of Lysosomes are as follows:
1. Intracellular digestion:
The word lysosome is derived from (lyso lytic or digestive; and soma body) thus helping in digestion.
Pinocytic vacuoles formed as a result of absorption of fluid substance into cell or phagocytic vacuoles formed by absorption of solid particles into cell, carry protein material to lysosomal region.
Phagocytosis and pinocytosis are active mechanisms in which cell requires energy for their operation. During phagocytosis by leucocytes oxygen consumption, glucose uptake and glycogen breakdown all increase significantly.
In endocytosis contraction of microfilaments of actin and myosin present in the peripheral cytoplasm occurs. It causes plasma membrane to invaginate and form the endocytic vacuole. Ingested particles enclosed in membranes derived from the plasma membrane and forming vacuoles are sometimes celled phagosomes.
After the entrance of a particle or large body into the cell by endocytosis and the formation of a phagosome, the membranes of the phagosome and a lysosome may fuse to form a single large vacuole. Within this vacuole the lysosomal enzymes begin the process of digestion of the foreign material.
Initially the lysosome, known as a primary lysosome containing the complex of enzymes in an inactive state, but after fusion with the phagosome produces a secondary lysosome with a different morphology and active enzymes.
After enzymatic digestion the digested material diffuses out into the hyaloplasm of the cell. Some material may remain in the enlarged lysosome vacuole. This remnant vacuole is the residual body, since it contains the residue of digestive process. During starvation also, lysosomes digest stored food materials, i.e., proteins, lipids and glycogen of cytoplasm and provide energy required by the cell.
Digestion of proteins usually ends at the level of dipeptide, which can pass through the membrane and be further digested into amino acids.
2. Removal of dead cells:
Hirsch and Cohn (1964) told that lysosomes help in the removal of dead cells in tissues such as white blood cells with engulfed bacterium in blood, cells in the outer layer of skin and mucous membrane linings of the body. Lysosomal membrane ruptures in these cells, releasing enzymes into body of cell, so that whole cell may be digested. Lysosomes contain a sufficient complement of enzymes to digest most types of biological or organic materials and the digestive process (autolysis) occurs quite rapidly in dead cells. This process of tissue degeneration (necrosis) is due to this lysosomal activity.
3. Role in metamorphosis:
Recently lysosome’s role has been discovered in the metamorphosis of frog. Disappearance of tail from tadpole larva of frog is due to lysosomal action as described by Weber.
4. Help in protein synthesis:
Novikoff and Essner have suggested the possible role of lysosomes in protein synthesis. Recently, correlated lysosomal activity with the protein synthesis. In liver and pancreas of some birds, lysosomes seem to be more active and, showing possible relationship with cell metabolism.
5. Help in fertilization:
During fertilization, sperms head secrete some lysosomal enzymes which help in the penetration of sperm into vitelline layer of ovum. Acrosome contains prease and hyaluronidase and abundant acid phosphatase. Hyaluronidase disperse the cells around the oocyte and protease digests the zona pellucida making a channel through which sperm nucleus penetrates.
6. Role in osteogenesis:
ageing of cells and parthenogenetic development are related with the lysosome activity.The osteoclasts (multinucleated cells) which remove bone, do so by the release of lysosomal enzymes which degrade the organic matrix. This process is activated by the parathyroid hormone.
7. Malfunctioning of lysosomes:
Lysosomal malfunction may lead to diseases. Ruptures of lysosomes in skin cells exposed to direct sun light leads to pathological changes following sunburn. The enzymes liberated by these lysosomes kill cells in the epidermis, causing blistering and later to ‘peeling’ of a layer of epidermis.
8. Autolysis in cartilage and bone tissue:
The excess of vitamin A causes cell poisoning. It disrupts the lysosomal membrane, causing release of enzymes into the cell and producing autolysis in cartilage and bone tissue.