P. americanus produces a small antifreeze protein (AFP) that binds to ice crystals as they form. The structure of AFP has polar
groups on one side and nonpolar groups on the other. Propose a hypothesis to explain how AFP prevents cells from freezing solid. A) AFP binds to ice crystals and forms a nonpolar shell that prevents covalent bonding between water molecules to form a larger crystal. By limiting crystal growth, the cell would not freeze solid.
B) AFP binds to ice crystals and forms a nonpolar shell that prevents covalent bonding between ice crystals to form a larger crystal. By limiting crystal growth, the cell would not freeze solid.
C) AFP can denature in cold water with the discharge of heat, so it melts ice crystals preventing them from becoming larger. By limiting crystal growth, the cell would not freeze solid.
D) AFP binds to ice crystals and forms a nonpolar shell that prevents hydrogen bonding between water molecules to form a larger crystal. By limiting crystal growth, the cell would not freeze solid.
A) AFP binds to ice crystals and forms a nonpolar shell that prevents covalent bonding between water molecules to form a larger crystal. By limiting crystal growth, the cell would not freeze solid
Explanation:
Water is a "polar" molecule, which means that electron density is unevenly distributed. Water has a partial negative charge, near the atom of oxygen due to the unshared pairs of electrons and partial positive charges, near the atoms of hydrogen. Because water is polar and the protein is nonpolar, their molecules are not attracted to each other this is want prevents the ice crystals from forming.
It's important to not touch the sides or the bottom of the test tube with the thermometer because touching it to the sides or bottom of the test tube fractures the glass and does not allow for correct temperature measurements.
