Movement in and out of Cells Flashcards
What makes up matter?
Particles (Atoms, molecules).
What are the properties of a solid?
- Particles vibrate in fixed positions
- Almost no Kinetic Energy
- Packed tightly in a regular arrangement
- Strong bonds
- Constant shape, volume and mass.
What are the properties of a liquid?
- Particles move past each other slowly
- Some Kinetic Energy
- Have an irregular arrangement
- Weaker bonds than solids
- Constant volume and mass but no fixed shape.
What is diffusion?
Diffusion is the net movement of particles from an area of high concentration to an area of lower concentration (down a concentration gradient) until dynamic equilibrium is reached.
What is dynamic equilibrium?
When particles are evenly spread out but still moving.
What are the properties of a gas?
- Particles move quickly and randomly
- A lot of Kinetic Energy
- Have an irregular arrangement
- Very weak bonds
- Constant mass but no fixed volume or shape.
What states of matter does diffusion happen in?
Liquid and Gas because particles in a solid are not free to move.
What five factors affect the rate of diffusion?
Distance, Surface Area, Temperature, Concentration Gradient, Molecule Size.
How does surface area affect the rate of diffusion?
The larger the surface area, the higher the rate of diffusion
How does distance affect the rate of diffusion?
The larger the distance needed to travel, the slower the rate of diffusion.
How does temperature affect the rate of diffusion?
The higher the temperature, the more energy the particles have, so they move faster and the rate of diffusion increases.
How does the concentration gradient affect the rate of diffusion?
The larger the concentration gradient, the faster the rate of diffusion.
How does molecule size affect the rate of diffusion?
The smaller molecules can diffuse more easily than the large molecules.
What is Active Transport?
The movement of particles against their concentration gradient (low concentration to higher concentration). This requires ATP energy
Large, insoluble molecules are broken into smaller, soluble molecules outside the cell so…
So they can diffuse through the cell membrane.
What is Osmosis?
The net movement of water from an area of high water concentration to an area of lower water concentration through a partially permeable membrane.
What is an example of Active Transport?
The uptake of glucose from the small intestine to the blood.
What is ATP energy’s function?
It acts as the main energy carrier at a cellular level (in cells).
What is an example of a partially permeable membrane typically used in experiments?
Visking tubing.
What is a partially permeable membrane?
A membrane which allows small, uncharged molecules through, but not large, charged molecules (ions).
What is it called when water leaves a cell because the water concentration inside the cytoplasm is higher than the water concentration outside the cell. (Salty solution)
Plants: The cell becomes plasmolyzed because the cell membrane detaches from the cell wall.
Animals: The cell becomes crenated.
What is it called when water both enters and leaves the cell because the water concentration in the cytoplasm and surroundings are isotonic (the same).
Plants: The cell is flaccid.
Animals: The cell is normal because there is no net movement of water.
What is it called when water enters the cell because the water concentration outside is higher than that in the cytoplasm. (Pure water)
Plants: The cell becomes turgid, and the membrane pushes towards the cell wall.
Animals: The cell becomes lyses, and could burst.
Why don’t plant cells burst when they become turgid?
Plant cells don’t burst because they have a cell wall.
Describe the Agar Jelly practical.
- Collect 3 agar cubes of different sizes: 2cm, 1cm and 0.5 cm
- Place all three cubes in the same beaker and cover with 20ml of 0.1 hydrochloric acid
- Start the stopclock immediately
- Time how long it takes for each cube to turn colourless.
Describe the Osmosis in Potatoes practical.
- Make 5 potato slices of potato, each of the same mass
- Blot each on a tissue
- Record the initial mass
- Put each chip in a different test tube, and label the tubes 0, 0.1, 0.2, 0.3 and 0.5
- Pour solution in every tube, covering the chip
- Put distilled water in the 0 tube, and 0.1, 0.2, 0.3 and 0.5 sucrose solution in the others. making sure you put them in the correct tubes
- Cover the tubes with cling film to prevent evaporation
- Leave for 1 day
- Remove the chips, blot dry with the tissue and record each final mass.
