BIOL 221 L2

What advantage is it for biological systems to use hundreds of weak bonds rather than one strong bond to hold two molecules together?

• Weak bonds are better suited to enzyme-catalyzed reactions than strong bonds are

• It takes less energy to make hundreds of weak bonds than to make one strong bond

• Tetrahedral carbon atoms form weak bonds more readily than strong bonds.

• Weak bonds can be broken with less energy input than strong bonds.

• It isn't. Biological molecules are joined more b\ strong bonds than b\ weak bonds.

Which of the following is NOT caused by hydrogen bonding?

• A. protein alpha helices

• B. ice floats in water

• C. DNA double helix

• D. NaCl dissolves in water

• E. Hydronium ions form in water

Weak bonds are caused by

• Isotopes with lighter nuclei than normal

• Electron sharing

• Partial electron sharing

• Charge interactions

• Adding heat to strong bonds

Van der Waals (hydrophobic) interactions occur when . . .

• a polar molecule interacts with an ion

• two molecules get closer together than the\ would in a covalent bond

• a random charge fluctuation sets up a transient dipole in a non

• a polar molecule with a dipole interacts with another polar molecule

• one ion interacts with an ion of opposite charge

Weak bonds are caused by

• Charge interactions

• Partial electron sharing

• Atoms with lighter nuclei than normal

• Electron sharing

• Adding heat to strong bonds

Two molecules with polar covalent bonds are attracted to each other. The resulting bond could be a

• Polar covalent bond

• van der Waals bond

• Nonpolar covalent bond

• Hydrogen bond

• Ionic bond

Which of the following CANNOT participate in hydrogen bond formation?

• the O in O-H

• the N in N-H

• the H in C-H

• the H in N-H

• the C in C=O

Why is it important that most intermolecular interactions in cells are weak bonds?

• Fewer of them are needed to hold molecules together

• Very few strong bonds can occur in an aqueous solution

• They are more easily reversible

• It takes more energy to form them

• More energy is released when the\ are broken

What happens when water hyrates itself?

• H3O+ and OH- ions form

• it can not be transported through aquaporins an\more

• it expands and free]es

• Water can't hydrate itself.

• molecules stick together and become cohesive

Tags

NGSS.HS-ESS2-5

To have a dipole moment (to be polar) a molecule must . . .

• have at least 4 different atoms covalently bonded to a central atom

• be soluble in the lipid phase of a membrane

• have a bond in which one atom has a substantially higher electronegativity than the other

• have a bond in which the electrons spend equal time around each atomic nucleus

• have an ionic charge on at least one atom