Biology · Unit 2 · Paper 3

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 3” 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 36 min 33 points0/17 attempted

Passive transport

Surface area to volume ratio

Mitochondrial structure and function

Lab: Diffusion and Osmosis

Cotransport

Water potential

Cholesterol in membranes

Smooth ER

Sodium-potassium pump

Ribosome

Plasmodesmata

Rough ER

Short answer 1. Define or explain: Hypotonic, hypertonic, isotonic

3 pts

Short answer 2. Define or explain: Nucleolus

3 pts

Short answer 3. Define or explain: Osmosis

3 pts

Short answer 4. Define or explain: Nuclear envelope and pores

3 pts

Free response

9 pts

A student cuts identical cylinders from a single potato, blots and weighs each one, and places one cylinder in each of five sucrose solutions for 60 minutes at 22 °C. After blotting and reweighing, the percent change in mass is: 0.0 M, +12%; 0.2 M, +5%; 0.4 M, −3%; 0.6 M, −11%; 0.8 M, −18%.

Identify the independent and dependent variables, and describe one variable the student must hold constant.

Explain why percent change in mass is reported rather than absolute change in grams.

Using the data, estimate the sucrose molarity at which the potato tissue is isotonic to the bathing solution and justify your estimate.

Calculate the solute potential of the 0.4 M sucrose solution at 22 °C (295 K), using Ψs = −iCRT with i = 1 and R = 0.0831 L·bar·mol⁻¹·K⁻¹.

Predict and explain the direction of net water movement if a cylinder from the 0.4 M beaker were transferred to distilled water.