AP BIOLOGY

BIOCHEMISTRY

PROPERTIES OF WATER

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
In living cells, changes in pH:
A
can affect the chemical reactions that happen.
B
can cause proteins to denature.
C
do not affect the cell.
D
can cause high fevers.
Explanation: 

Detailed explanation-1: -Denaturation can also be caused by changes in the pH which can affect the chemistry of the amino acids and their residues. The ionizable groups in amino acids are able to become ionized when changes in pH occur. A pH change to more acidic or more basic conditions can induce unfolding.

Detailed explanation-2: -The change of pH will lead to the ionization of amino acids atoms and molecules, change the shape and structure of proteins, thus damaging the function of proteins. Enzymes are also proteins, which are also affected by changes in pH.

Detailed explanation-3: -A protein becomes denatured when its normal shape gets deformed because some of the hydrogen bonds are broken. Weak hydrogen bonds break when too much heat is applied or when they are exposed to an acid (like citric acid from lemon juice).

Detailed explanation-4: -Proteins change their shape when exposed to different pH or temperatures. The body strictly regulates pH and temperature to prevent proteins such as enzymes from denaturing. Some proteins can refold after denaturation while others cannot. Chaperone proteins help some proteins fold into the correct shape.

Detailed explanation-5: -Heat denaturation of GFP was found to be pH dependent as well, with the denaturation being fastest at pH 6.5 as compared to pH 7.5 or pH 8.5. Like the denaturation studies, renaturation of heat-denatured GFP was most efficient at pH 8.5, followed by pH 7.5, and then pH 6.5.

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