Question

The data table for both of the PL& WU graphs is at the end of the discussion. Read through the directions for completing each graph. PRELAB: Use the Last Digit of your CLASS ID to determine which column to use for data. Fill out the table, complete the calcula- tions for Total Change", and then Graph the "TOTAL CHANGE" for each Sucrose percentage NE DO NOT DRAW for ANY ANSWERS-EXPLAIN I. EXPLAIN two different ways that we have discussed in LECTURE & LAB for how plants and certain protozoa avoid lysis in hypotonic solutions (Do not discuss "Osmoregulation", etc., or use terms such as Turgidity") A) Plants: B) Protozoa: 2. Assume you have a cell with a phospholipid bilayer membrane (NO Proteins). A SMKCI solution is inside the cell and a 5 M Sucrose solution is outside the cell. Describe the Net Movement you would expect to occur across the membrane, for WATER KCh & sucROSE. In Terms Discussed in Lab, EXPLAIN why EACH Compound does or does not move. DO NOT DRAW

Answer 1

1. Plants plant cells have rigid cell wall. When plant cells are exposed to hypertonic solution water rushes into the cell and filled in vacuoles now cell will increase pressure against cell wall making it turgid. Plant cell wall resist further water entry when it is fully turgid which stops the cell from lysis.

Protozoans most of the protozoans have contractile vacuoles.

When excess water is there in the surrounding contractile vacuole swells and move to the edges of the cell and burst which expels its water out of the cell hence prevent them from lysis.

2. Movement of water: water will move inside the cell as 5M KCl is more hypertonic than 5M sucrose. So endosmosis will take place.

Movement of Sucrose: sucrose will not able to move inside as no protein carriers are there in the phospholipid membrane