cell bio HW ch 2

indicate why the following property of the carbon atom contributes to make it the most important atom in biological molecules: the carbon atom has a valence of four

Carbon can form 4 bonds due to the presence of 4 valance electrons. These bonds can be formed as single, double, and triple bonds - all are strong due to the sharing of electrons. This is important in making stable molecules.

defend the assertion that all of life as we know it depends critically on the fact that the angle between the two hydrogen atoms in the water molecule is 104.5 º and not 180º

If the bond were linear, then water would be a nonpolar molecule. All of the polar molecules in the cell...DNA, sugars, many proteins, etc would be insoluble and unable to interact at all.

describe a hydrogen bond

In a hydrogen bond, the partial positive charge of a hydrogen found in a polar covalent bond is attracted (electrostatically) with the negative charge of another molecule (often oxygen due to its partial negative charge but it can be other negatively charged molecules as well).

what are the elements that most readily form multiple strong bonds.

Oxygen, nitrogen and carbon

indicate why the following property of the carbon atom contributes to make it the most important atom in biological molecules: carbon atoms can bond readily to hydrogen, nitrogen and sulfur atoms

The presence of these functional groups provide unique characteristics to the diverse shaped hydrocarbons. Of particular importance, these functional groups increase the polarity of these molecules so they can interact in water. Also allows for molecules to form noncovalent interactions with each other which allows molecular interaction.

indicate why the following property of the carbon atom contributes to make it the most important atom in biological molecules: a carbon atom can bond simultaneously to two other carbon atoms

This allows for the formation of hydrocarbons that can be linear, branched, and rings. This allows for the creation of a large variation of molecules.

indicate why the following property of the carbon atom contributes to make it the most important atom in biological molecules: the C-C bond has a bond energy that is above the energy of photons of light in the visible range (400-700 nm)

This means that the carbon-carbon bonds in the molecules that make up living organisms are stable in the presence of the electromagnetic energy that is given off by the sun. We wouldn't be able to make cellular molecules if the bonds kept breaking.

which cellular molecules would you expect to be soluble in a container of benzene? hint: think about the structure of Benzene

Triacylglycerols (fats and oils), cholesterol, and the long chains of fatty acids. All nonpolar molecules, not polar ones. (likes dissolve likes)

Oil droplets coalesce in water to form a separate phase because of what type of forces?

the strong repulsive forces of the water molecules.

true or false Water has a high specific heat compared to most molecules of similar molecular weight.

true