Question

3.This experiment explores the concept of osmosis, with a hands on experiment using potatoes and salt water in your kitchen at home. Be sure to read the instructions for the potato experiment

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in the lab handout ahead of time so you can get the materials you need for the lab before you do it!

In your prelab, you explored diffusion through a semipermeable membrane. In that activity, small particles could easily pass through the semipermeable dialysis membrane. But all semipermeable membranes are not equal! Before starting this lab, consider the following.

A living membrane is considered to be semipermeable. Is it permeable to the same substances as the dialysis membrane used in prelab? Which of the following substances do you expect to passively move through the plasma membrane of potato cells? Pick all that apply.  

Group of answer choices

sodium ions

chloride ions

water

4.The passive movement of solutes across a living membrane is called  .

The passive movement of water across a living membrane is called  .

Answer 1

Ans3) A living membrane is considered to be semipermeable. No it is not permeable to the same substances as the dialysis membrane used in prelab. A semipermeable membrane is impermeable to solute molecules and only permeable to solvent, whereas a dialysis membrane is selectively permeable, which allows some molecules and ions to diffuse at different rates.

Substances that are expected to passively move through a plasma membrane of potato cell is:

Water only

Explanation- Although plasma membrane of potato cells is selectively permeable, only water molecules can passively pass through its membrane by a process called osmosis. Charged ions like chloride and sodium cannot diffuse passively through it. Rather facilitated diffusion is involved in passage of ions or molecules across the membrane passing through specific transmembrane integral proteins.

Ans4) The passive movement of solutes across a living membrane is called diffusion.

Explanation- Diffusion is a random movement of molecules (i.e. solutes) along the concentration gradient, from an area of higher concentration to an area of lower concentration by their own kinetic energy. It is spontaneous and passive process

The passive movement of water across a living membrane is called osmosis.

Explanation- Osmosis is a specialised case of diffusion that involves the passive transport of water (i.e. solvent) through a semi-permeable membrane, from a region of its higher concentration to a region of its lower concentration.

Ps- An