Biology · Unit 2 · Paper 2

Cell Structure & Function 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 1 Paper 2 Paper 3

Each paper is built from this unit’s 37 terms and is the same for everyone, so a teacher can assign “Unit 2, 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

Cholesterol in membranes

Golgi apparatus

Tight junctions, desmosomes, gap junctions

Nucleolus

Water potential

Rough ER

Sodium-potassium pump

Nuclear envelope and pores

Surface area to volume ratio

Selective permeability

Ribosome

Peroxisome

Short answer 1. Define or explain: Contractile vacuole

3 pts

Short answer 2. Define or explain: Hypotonic, hypertonic, isotonic

3 pts

Short answer 3. Define or explain: Lab: Diffusion and Osmosis

3 pts

Short answer 4. Define or explain: Osmosis

3 pts

Free response

4 pts

Aquaporins are integral membrane proteins that form channels through which water molecules cross the plasma membrane. Some cells of the kidney insert aquaporins into their membranes in response to a hormone.

(a) Explain why water requires a protein channel to cross the membrane rapidly despite being a small molecule.

(b) Identify the type of transport carried out by aquaporins, and justify your identification.

(c) Predict the effect on urine concentration of a mutation that prevents aquaporins from being inserted into kidney cell membranes.

(d) Justify your prediction in (c).