Lab 2, diffusion and osmosis

Diffusion defintion

Movement of particles from a high concentration gradient to a low concentration gradient

Osmosis defintion

Net flow of H2O across a membrane, from a low solute to high solute

Osmolarity defintion

Total solute concentration in a solution

Hypotonic solution

Inside gradient > outside gradient

Net flow of H2O in cell, causes swelling

Decrease solute

Isotonic solution

Outside gradient = inside gradient

No net flow of H2O

= solute

Hypertonic solution

Outside gradient > Inside gradient

Net flow of H2o out of cell, causes shrinking

Increase solute

How does an increase in temperature affect diffusion rate

Increase diffusion rate

How does an increase in molecular weight affect diffusion rate

Decrease diffusion rate

How does an increase in Concentration gradient affect diffusion rate

Increase diffusion rate

How does an increase in membrane surface area affect diffusion rate

increase diffusion rate

How does an increase in membrane permeability affect diffusion rate

Increase diffusion rate

How does an increase in viscosity affect diffusion rate

Decrease diffusion rate

In which solution does the potato become limp (flexible)

Was the solution isotonic, hypertonic, or hypotonic to the potato cells

10% NaCl

Hypertonic solution

Explain why water would diffuse out of the potato

In hypertonic solutions, the osmolarity of the solution is much higher then the osmolarity of the osmolarity inside, this causes the water to flow out of the potato strip because in osmosis H2O flows from a low solute to a high solute, this causes the potato to shrink

Why would water diffuse into the potato

In hypotonic solutions, the osmolarity of the solution is much lower then the osmolarity of the osmolarity inside, this causes the water to flow into the potato strip because in osmosis H2O flows from a low solute to a high solute, this causes the potato to swell

In what solution does the potato become rigid (stiff)

Was that solution isotonic, hypotonic, or hypertonic

H2O

Hypotonic

How did temp affect diffusion rate in (2% agar 0C) and (2% agar 50C), and (1% agar 0C) and (1% agar 50C)

The warmer ones traveled further, the temp increased the rate of diffusion

How did molecular weight affect diffusion rate (0.1 Congo red MW or 697g/mol) and (0.1 Methylene blue MW 374g/mol)

Methylene blue traveled further, this is because higher molecular weight decreases diffusion

How did concentration gradient affect diffusion rate, 0.1M methylene blue and 1M methylene blue

1M traveled further than 0.1 on average, this is because increased concentration gradient increases diffusion

How did viscosity affect diffusion rate? 2% agar compared to 1% agar, 2% is more viscous

2% didn’t travel as far on average because the increased viscosity decreases diffusion