IB Biology: B1.2-Effects of Temperature and pH on Proteins

Can a denatured protein return to its former structure?

• Yes, denaturation is reversible.

• No, denaturation is usually permanent.

• It depends on the type of protein.

• Yes, but only under specific conditions.

How can extremes of pH cause denaturation?

• By breaking or forming ionic bonds within the molecule, changing the 3-D structure of the protein.

• By increasing the temperature of the protein, leading to unfolding.

• By altering the primary sequence of amino acids in the protein.

• By enhancing the solubility of the protein in water.

What happens when vibrations break the bonds between R-groups of amino acids?

• It results in a change to the 3-D conformation called denaturation.

• It causes the amino acids to become non-polar.

• It leads to the formation of peptide bonds.

• It results in the amino acids being hydrolyzed.

Do all proteins denature at the same temperature?

• Yes, all proteins denature at the same temperature.

• No, temperatures at which proteins denature may vary.

• Only some proteins denature at high temperatures.

• Proteins denature only at low temperatures.

What happens to soluble proteins when they denature?

• They remain soluble and function normally.

• They often become insoluble and form a precipitate.

• They increase in solubility and dissolve completely.

• They change color and become more viscous.

What causes vibrations within a protein molecule?

• Extreme temperature, out of the heat tolerance of a protein.

• High pressure, exceeding the protein's structural limits.

• Chemical reactions, altering the protein's bonds.

• Radiation exposure, affecting the protein's stability.

What is denaturation in proteins?

• Denaturation is when a protein begins to unfold and lose its capacity to function as intended.

• Denaturation is the process of proteins gaining additional functional groups.

• Denaturation refers to the synthesis of new proteins from amino acids.

• Denaturation is the process of proteins folding into their native structure.

What causes soluble proteins to become insoluble during denaturation?

• The hydrophobic R-groups in the center of the molecule become exposed to water.

• The protein structure becomes more compact and rigid.

• The ionic bonds between amino acids are strengthened.

• The temperature of the solution decreases significantly.

What changes in the molecule cause pH-induced denaturation?

• Changes in the charges of the positive and negative charges on the R-groups.

• Alterations in the molecular weight of the protein.

• Increased hydrogen bonding between R-groups.

• Modification of the peptide bonds in the protein.