G Multidrug resistance can make it difficult to treat cancer successfully with chemotherapy. What causes multidrug resistance in cancer cells? Chemotherapy drugs and other toxins are actively pumped out of cancer cells by transmembrane proteins. The smooth endoplasmic reticulum in some cancer cells neutralizes a variety of chemotherapy drugs. The immune system identifies each chemotherapy drug as foreign and develops antibodies to each drug. Some cancer cells phagocytize chemotherapy drugs and use the lysosomes in the cell to destroy the drugs.

Chemotherapy drugs and other toxins are actively pumped out of cancer cells by transmembrane proteins.

Explanation:

Drugs inside the cell can be inactivated by oxidation and / or conjugation with glutathione, such as glutathione S-transferases, playing an important role in detoxification. However, conjugation is not enough for drug elimination. And this is where the GS-X pumps appear. Transporter proteins, such as Mrp protein, act as GS-X pumps. The PgP, Mrp and Bcrp proteins function as expulsion pumps, thus reducing the intracellular accumulation of drugs, causing resistance in cancer cells.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.