Biology 1406

List the mass number and atomic number of carbon-12 and carbon-13, respectively.

The mass number and atomic number of carbon-13 is 1313 and 66, while that of carbon-12 is 1212 and 66, respectively

Describe the pH scale and how it relates to living systems. Give an example of how drastic pH changes are prevented in living systems.

The pH scale ranges from 0 to 14, where anything below 7 is acidic and above 7 is alkaline. The bicarbonate system in the human body buffers the blood.

Why can water be a good insulator within the body of endothermic (warm-blooded) animals?

specific heat capacity

What makes ionic bonds different from covalent bonds?

Ionic bond involves the transfer of electrons whereas covalent bond involves the sharing of electrons.

When the temperature of liquid water is reduced, water freezes and becomes less dense. This is a property not seen in most other liquids. Ice floats on liquid water because it is less dense. What molecular property of water allows for this phenomenon?

When water cools, hydrogen bonds between hydrogen atoms push water molecules further apart.

In the diagram shown which is the most recent common ancestor of 1 and 3?

b

Name the three functional groups in the compound pictured.

carbonyl, methyl and carboxyl

Discuss how buffers help prevent drastic swings in pH.

Buffers absorb excess hydrogen and hydroxide ions to prevent increases or decrease in pH. An example is the bicarbonate system in human body.

What property of carbon makes it essential for organic life?

Carbon can form up to four covalent bonds, allowing it to form long chains.

How many neutrons do carbon-12 and carbon-13 have, respectively?

Carbon-12 contains 66 neutrons while carbon-13 contains 77 neutrons.

What property of carboxyl makes carboxyl containing molecules hydrophilic? Which macromolecules contain carboxyl?

Carboxyl groups release H+H+, making its parent molecule hydrophilic. It is found amino acids and fatty acids.

The shape of hair proteins is maintained by a combination of hydrogen bonds and covalent, disulfide bonds. Heat is sufficient to break the hydrogen bonds, but harsh chemicals are required to break the disulfide bonds. Why is it harder to break the disulfide bonds than the hydrogen bonds?

Covalent bonds are stronger than hydrogen bonds.

One of the risks for people with diabetes is diabetic ketoacidosis, a build-up of acid in the blood stream. Explain why this is dangerous to humans.

Diabetic ketoacidosis decreases normal pH (7.35-7.45) to a lower value.

An atom may give, take, or share electrons with another atom to achieve a full valence shell, the most stable electron configuration. Looking at this figure, how many electrons do elements in group 1 need to lose in order to achieve a stable electron configuration? How many electrons do elements in groups 14 and 17 need to gain to achieve a stable configuration?

Elements of group 1 need to lose one electron, elements of group 14 need to gain 4 electrons, and elements of group 17 need to gain 1 electron

Looking at the above figure, can you infer which two groups together will form a strong ionic bond?

Group 1 and Group 17