Transport in Cells

• What is diffusion?

  Diffusion is the movement of particles from a high to lower concentration.
• What is osmosis?

  Osmosis is the diffusion of water across a membrane.
• What does active transport do?

  Active transport moves particles from low to higher concentration.
• What are the key concepts of diffusion, osmosis, and active transport?

  • Diffusion: Movement from high to low concentration.
  • Osmosis: Diffusion of water across a membrane.
  • Active Transport: Movement from low to high concentration.
• How do particles in a liquid and gas behave in terms of movement?

  Particles in a liquid and gas move continuously and spread evenly throughout the medium.
• What happens to particles when they are in a higher concentration?

  Particles will move from the region of higher concentration to a region of lower concentration.
• What is a concentration gradient?

  A concentration gradient is the difference in the concentration of a chemical across a membrane.
• What is the net movement of particles during diffusion?

  The net movement of particles is from high to low concentration.
• What happens to particles during diffusion in terms of direction?

  Particles will move in both directions but will have a net movement from high to low concentration.
• What occurs when a crystal of potassium manganate(VII) is placed in water?

  The particles of potassium manganate(VII) spread out and mix with the water particles.
• What is the solute in a solution?

  The solute is the dissolved substance in a solution.
• What is the solvent in a solution?

  The solvent is the liquid in which the solute dissolves to form a solution.
• What is the result of mixing a solute and a solvent?

  The result is a solution, which is a mixture formed by a solute and a solvent.
• How does diffusion occur across membranes?

  Diffusion occurs across membranes between the outside and inside of cells.
• What are some examples of diffusion in biological systems?

  • In a leaf: Gas exchange occurs.
  • In the lungs: Oxygen and carbon dioxide exchange.
  • In liver cells: Nutrient uptake and waste removal.
• What is diffusion?

  Diffusion is the movement of particles from a high to lower concentration.
• What is osmosis?

  Osmosis is the diffusion of water across a membrane.
• What does active transport do?

  Active transport moves particles from low to higher concentration.
• What are the three main types of transport in cells?

  • Diffusion
  • Osmosis
  • Active transport
• What is the formula for calculating the rate of diffusion according to Fick's law?

  The rate of diffusion is calculated by $\text{rate of diffusion} \propto \frac{\text{surface area} \times \text{concentration difference}}{\text{thickness of membrane}}$.
• How does the concentration gradient affect the rate of diffusion?

  The greater the difference in concentration, the quicker the rate of diffusion.
• How does temperature affect the rate of diffusion?

  The higher the temperature, the more kinetic energy the particles will have, so they will move and mix more quickly.
• How does the surface area of the cell membrane affect the rate of diffusion?

  The greater the surface area, the faster the rate of diffusion.
• How do substances diffuse in bacteria?

  Substances diffuse into and out of the bacterial cell across its surface.
• What is osmosis defined as?

  Osmosis is the movement of water molecules across a selectively permeable membrane from a region of higher water concentration to a region of lower water concentration.
• How do simple organisms take in substances?

  Simple organisms take in substances over their body surface.
• How does the surface area to volume ratio change as organisms increase in size?

  As organisms increase in size, their surface area does not increase at the same rate as their volume.
• What are the factors that affect the rate of diffusion?

  • Concentration gradient
  • Temperature
  • Surface area of the cell membrane
• What is diffusion?

  Diffusion is the movement of particles from a high to lower concentration.
• What is osmosis?

  Osmosis is the diffusion of water across a membrane.
• What does active transport do?

  Active transport moves particles from low to higher concentration.
• What is the definition of osmosis?

  • Movement of water molecules across a selectively permeable membrane
  • From a region of higher water concentration to a region of lower water concentration
• What is a molecule?

  A molecule is a collection of two or more atoms held together by chemical bonds.
• What does concentration refer to in a solution?

  The concentration of a solution tells us how much of a substance is dissolved in water.
• What is a dilute solution?

  A dilute solution contains a high concentration of water molecules.
• What is a concentrated solution?

  A concentrated solution contains a low concentration of water molecules.
• What does the term 'net movement' refer to?

  Net movement refers to the overall effect of something when all additions and deductions are calculated.
• What happens when the concentration of water is the same on both sides of a membrane?

  The movement of water molecules will be the same in both directions, resulting in no net movement.
• What is a solute?

  A solute is the dissolved substance in a solution.
• What is the role of root hair cells in plants?

  Root hair cells increase the surface area of the root epidermis to improve the uptake of water and minerals.