Answer:
Kupffer cells, also known as stellate macrophages due to their particular structure while viewed under a microscope, were first identified by scientist Karl Wilhelm von Kupffer, after whom the cells were named, in 1876.
These cells, whose origin is in the yolk sack during fetal development, later on move to the liver where they will stay and further differentiate into their mature versions.
These cells are part of the liver cells, and are found particularly on the walls of the sinusoids, where they perform their two most important tasks. First, these cells are part of the immune system, as they are essentially macrophages. However, their role is pretty unique, as they are responsible not just for phagocytosis of invading bacteria, and other pathogens, and initiating immune responses, but also, this cell plays a role in decomposing red blood cells who are dying, and taking up the hemoglobin from them to further break that into reusable globin, and the heme group, from which iron is further extracted to be re-used and also to create bilirrubin, a part of bile.
Finally, these cells have been found to be connected to hepatic cirrhosis, as in their process of detoxifying ethanol, they produce toxins that force the liver cells to produce collagen, and thus to become fibrous.
Answer:
The correct option is
Option (E) All the choices are membrane - bound organelles.
Explanation:
The membrane bound organelle are -
( A ) Lysosome - have digestive and destructive membranes .
( B ) Golgi apparatus - are membrane bound , and are responsible for transporting and modifying lipids and proteins .
( C ) peroxisome -
It is a membrane - bound organelle present in the cytoplasm of the cell, it plays a key role in the oxidation of some biomolecules.
( D ) Endoplasmic reticulum - is a membrane bound organelle , present in the cytoplasm , it usually has ribosomes on its outer surface , which helps in protein and lipid synthesis.
Hence,
all the mentioned organelles are membrane bound,
correct answer is ( E )
Answer:
b. Cellulose acetate
Explanation:
Cellulose acetate is acetate ester of the cellulose.
The material was first prepared in 1865. It is used as film base in the photography as component in coatings and also as frame material for the eyeglasses. Also, it is used as synthetic fiber in the manufacture of the cigarette filters and also in playing cards. It is used because it is far less flammable and also cheaper to produce. <u>It provides support and stiffness to the X-ray film and further helps in producing good results.</u>
