Explanation : Proteins will behave similarly to phospholipids in water; the polar groups will form favorable interactions on the surface with water, while the hydrophobic groups will be in the core and away from the water molecules.
Report an Error. Example Question 2 : Hydrophobic Interactions. Possible Answers: Enthalpy; lipid molecules absorb a tremendous amount of heat when they come to associate with each other rather than with water.
Correct answer: Entropy; water molecules acquire more degrees of freedom as a result of nonpolar molecules forming one large aggregate from many smaller ones.
Explanation : In aqueous solutions, lipid molecules are surrounded by a lattice-like ring of water molecules known as a clathrate shell. Example Question 3 : Hydrophobic Interactions. Which of the following is false about hydrophobic effects? Possible Answers: Generally, it is only nonpolar substances which exhibit hydrophobic effects.
Cell membranes are held together in part by hydrophobic effects. Correct answer: They can occur in a non-aqueous environment. Explanation : Hydrophobic effects require water to occur. Example Question 4 : Hydrophobic Interactions.
Possible Answers: Entropy increases because water molecules exclude the nonpolar solute in order to interact with each other and regain a higher state of disorder. Correct answer: Entropy increases because water molecules exclude the nonpolar solute in order to interact with each other and regain a higher state of disorder. Explanation : This is called the hydrophobic effect.
Example Question 5 : Hydrophobic Interactions. What is the major driving force for the formation of a phospholipid bilayer? Possible Answers: Hydrogen bond formation. Correct answer: Hydrophobic interactions. Explanation : Phospholipids are amphipathic - in other words they are simultaneously hydrophobic and hydrophilic. Example Question 6 : Hydrophobic Interactions. Possible Answers: Stronger than covalent and ionic bonds, but weaker than London dispersion forces.
Weaker than London dispersion forces and ionic bonds, but stronger than covalent bonds. Weaker than covalent and ionic bonds, but stronger than London dispersion forces. Stronger than covalent bonds, London dispersion forces, and ionic bonds.
Weaker than covalent bonds and London dispersion forces, but stronger than ionic bonds. Correct answer: Weaker than covalent and ionic bonds, but stronger than London dispersion forces. Explanation : Hydrogen bonds are the strongest of the intermolecular forces. Example Question 7 : Hydrophobic Interactions. Possible Answers: Nonpolar molecules.
Correct answer: Nonpolar molecules. Explanation : Hydrophobic molecules are nonpolar molecules - from the Greek "hydro-" water and "phobic" fearing. Copyright Notice. View Biochemistry Tutors. Jeffrey Certified Tutor. Adeyeni Certified Tutor. The model compound studies predict that the hydrophobic effect of exposing one buried methylene group to bulk water is 0.
The site directed mutagenesis studies yielded a larger number with greater statistical variation: the average hydrophobic effect estimated by SDM for a buried methylene group is about 1. However, when the SDM results for methylene were plotted against the size of the cavity created by the residue substitution, and extrapolated to zero, the result at zero cavity size is 0. In the SDM studies, cavities created by residue substitution have an additional destabilizing effect: the loss of favourable VDWs interactions as compared to the wild-type.
Thus, the "hydrophobic effect" measured by SDM includes both an entropic component due to solvent ordering and a primarily enthalpic component due to loss of VDWs contacts within the protein.
This is smaller than expected c. Click here for a gif showing the cavity and links to the structures. The finding was a strong correlation between the degree of destabilization which ranges from 0.
See figure below. The strength of Hydrophobic Interactions depend on several factors including in order of strength of influence :.
Hydrophobic Interactions are important for the folding of proteins. This is important in keeping a protein stable and biologically active, because it allow to the protein to decrease in surface are and reduce the undesirable interactions with water.
Besides from proteins, there are many other biological substances that rely on hydrophobic interactions for its survival and functions, like the phospholipid bilayer membranes in every cell of your body! Illustration of how protein changes shape to allow polar regions blue to interact with water while non-polar hydrophobic regions red do not interact with the water. Causes of Hydrophobic Interactions American chemist Walter Kauzmann discovered that nonpolar substances like fat molecules tend to clump up together rather than distributing itself in a water medium, because this allow the fat molecules to have minimal contact with water.
Thermodynamics of Hydrophobic Interactions When a hydrophobe is dropped in an aqueous medium, hydrogen bonds between water molecules will be broken to make room for the hydrophobe; however, water molecules do not react with hydrophobe. Formation of Hydrophobic Interactions The mixing hydrophobes and water molecules is not spontaneous; however, hydrophobic interactions between hydrophobes are spontaneous.
Strength of Hydrophobic Interactions Hydrophobic interactions are relatively stronger than other weak intermolecular forces i. The strength of Hydrophobic Interactions depend on several factors including in order of strength of influence : Temperature : As temperature increases, the strength of hydrophobic interactions increases also. However, at an extreme temperature, hydrophobic interactions will denature.
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