Unit 1: Chemistry of Life
Biology · Unit 1 · Paper 2

Chemistry of Life unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Paper 1Paper 2Paper 3
Each paper is built from this unit’s 34 terms and is the same for everyone, so a teacher can assign “Unit 1, Paper 2” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.
Suggested time 31 min 28 points0/17 attempted
1

Why ice floats

2

Protein structure levels

3

Cohesion vs adhesion

4

Hydrolysis

5

Saturated vs unsaturated fat

6

pH scale

7

Peptide bond

8

Carbonic acid–bicarbonate buffer

9

Nucleic acid directionality

10

Buffer

11

R group

12

Carbohydrate structure and function

Short answer 1. Define or explain: Functional groups

3 pts

Short answer 2. Define or explain: Nucleotide structure

3 pts

Short answer 3. Define or explain: Monomers of the four macromolecules

3 pts

Short answer 4. Define or explain: Phospholipid amphipathicity

3 pts

Free response

4 pts

A researcher heated a solution of a globular enzyme from 25 °C to 80 °C and found that its activity fell to zero and did not recover when the solution was cooled back to 25 °C.

(a) Describe the level of protein structure that is disrupted first when a protein is heated.

(b) Explain how the disruption described in (a) causes the loss of enzyme activity.

(c) Identify one type of interaction between amino acid side chains that stabilizes the tertiary structure of a protein.

(d) Explain why the enzyme did not regain activity when the solution was cooled.