Question

1.Write characteristics of Active transport with example.

2.What do you mean by exergonic and endergonic reactions? Explain with examples.

3.Briefly describe competitive and non-competitive inhibitors.

4.What is the effect of temperature, pH and salinity on enzymes?

Answer 1

Active transport is generally performed against the concentration gradient where solute or ion will take from lower concentration to higher concentration. In thermodynamic principles it is very easy to take higher concentration to lower concentration but if you wish to perform opposite of this than extra energy is required for the process. Similar process is happened in the cells. The best studied example of this is Na⁺-K⁺-ATP pump. In this process Na and K ions balance is made by keeping out the sodium ions out of the cell and taking inside the K ion inside the cell. In this process ATP is used for this reaction. In this process 3 sodium were out and 2 potassium will taken inside.

In general chemical reaction when two reactants mixed and they emit heat while mixing than this process is called exergonic. On the contrary when two reactants mix and temperature is dropped or heat is taken from heat from environment it is called endergonic reaction.

In competitive inhibition, inhibitor is having similar structure like substrate hence it binds to same active site. In such type of enzyme kinetic generally Km of enzyme will incerase the same and Vmax will remain same.

In non competitive inhibition, inhibitor bind to other than active site, these sites are known as allosteric site. These inhibitors reduce the enzyme activity. In such type of inhibition Vmax is changed and Km remains same.

Every enzyme have optimum temperature, pH and salt concentration for their reaction.

As the pH has increase or decrease from optimum their active site residues lose their ionic forma and reduce the interactions. Hence pH increase or decrease from optimum will decrease the enzyme activity. It gives the bell shaped curve.

Similar conditions also applied for the temperature. But here the molecular motion motions of the residues will increase hence the rate of reaction increase but after increasing certain temperature enzyme start denature, hence, enzyme activity is decreasing. In this also obtained bell shaped curve.

Similar case and graph is happed to with salinity. In this case excess of salt initiate the salting our phenomenon, hence, it decrease the rate of reaction due to exposure of hydrophobic residue. Here enzymes lose their core structure.