Tag: cell cycle

Questions Related to cell cycle

........... is used for preparing standard solutions in which it is always desired to maintain a constant pH.

  1. Buffer

  2. Plasma

  3. Serum

  4. None of the above


Correct Option: A
Explanation:

A buffer is a solution that resists a change in pH upon the addition of acidic or basic components. To effectively maintain a pH range, a buffer consists of a weak conjugate acid-base pair. It is either a weak acid and its conjugate base, or a weak base and its conjugate acid. Thus the correct answer is option A.

A buffer is a mixture of 

  1. Weak acid and its salt with a strong base

  2. Strong acid and its salt with a strong base

  3. Weak acid and its salt with a weak base

  4. None of the above


Correct Option: A
Explanation:
A buffer is a solution that resists a change in pH upon the addition of acidic or basic components. To effectively maintain a pH range, a buffer consists of a weak conjugate acid-base pair, meaning either a weak acid and its conjugate base, or a weak base and its conjugate acid. An acidic buffer solution is the one which has a pH less than 7. Acidic buffer solutions are commonly made from a weak acid and one of its salts having a strong base. Thus the correct answer is option A.

The proton-pumps provide energy to cells through.

  1. pH gradient and electro potential gradient

  2. ATP and ADP

  3. Auxins and hormones

  4. Carbolwdrates and lipids


Correct Option: A

If the activity of an enzyme is constant over a broad range of pH values,it is likely that

  1. only ionizing groups on the enzyme participate in the reaction

  2. only ionizing groups on the substrate participate in the reaction

  3. ionizing groups on the enzyme and substrate participate in the reaction

  4. the temperature should be changed in order to observe a pH effect


Correct Option: A
Explanation:
Changes in pH may influence the state of a catalyst as well as change the shape or charge properties of the substrate so that either the substrate can not tie to the dynamic site or it can't experience catalysis. In general, protein has a pH ideal. Anyway, the ideal isn't the equivalent for every chemical. 
So, the correct option is 'only ionizing groups on the enzyme participate in the reaction'