Diffusion Osmosis And Active Transport Flashcards
(27 cards)
What is diffusion?
The net (overall) movement of particles from an area of higher concentration to an area of lower concentration
Diffusion is the natural tendency for substances to spread out.
In which states of matter does diffusion occur?
Diffusion occurs in both liquids and gases
This is because particles in these substances are free to move about randomly.
What types of molecules can diffuse through cell membranes?
Only very small molecules can diffuse through cell membranes, such as glucose, amino acids, water, and oxygen
Big molecules like starch and proteins cannot fit through the membrane.
Define osmosis.
The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
Osmosis can also be described as movement from lower solute concentration to higher solute concentration.
What is a partially permeable membrane?
A membrane with very small holes that allows tiny molecules like water to pass through, but blocks larger molecules like sucrose
This selective permeability is crucial for osmosis.
How do water molecules behave during osmosis?
Water molecules pass both ways through the membrane, but there is a net flow into the region with fewer water molecules
This is due to the random movement of water molecules.
What effect does osmosis have on solute solutions?
The solute solution gets more dilute as water moves into it
Water acts to even up the concentration on either side of the membrane.
What is active transport?
The movement of particles across a membrane against a concentration gradient using energy transferred during respiration
Active transport differs from diffusion as it requires energy.
How does active transport work in the digestive system?
Active transport allows nutrients to be taken into the blood when there is a lower concentration of nutrients in the gut than in the blood
This is essential for nutrient absorption and preventing starvation.
True or False: Active transport moves particles down a concentration gradient.
False
Active transport moves particles against a concentration gradient.
Fill in the blank: Diffusion is a _______ process.
passive
Unlike active transport, diffusion does not require energy.
What is the purpose of the osmosis experiment described?
To see the effect of different water concentrations on potato cylinders in sucrose solutions
The experiment investigates how varying sucrose concentrations affect the mass of potato cylinders.
What happens to the water concentration as sucrose concentration increases?
The water concentration decreases
Higher sucrose concentration means lower water concentration in the solution.
What is the first step in the osmosis experiment?
Prepare sucrose solutions of different concentrations ranging from pure water to very concentrated sucrose solution.
What tool is used to cut potato cylinders for the experiment?
Cork borer
What should be the diameter of the potato pieces used in the experiment?
About 1 cm
How should the potato cylinders be grouped before the experiment?
In groups of three
What is the unit of concentration represented by ‘M’?
mol dm⁻³
What is the concentration of the solution that is pure water?
0.0 M
After leaving the potato cylinders in the sucrose solution for forty minutes, what is the next step?
Remove the cylinders, pat dry gently, and weigh them again.
What must remain constant in the experiment to ensure valid results?
Volume of solution, size of potato cylinders, type of potatoes, and amount of drying
How do you calculate the percentage change in mass?
Using the formula: percentage change = (final mass - initial mass) / initial mass × 100
If a group of cylinders weighed 13.2 g initially and 15.1 g after, what is the percentage change in mass?
14.4%
What does a positive percentage change in mass indicate about the potato cylinders?
They gained mass
