Transport in cells

• What is diffusion?

  the spreading out of the particles of any substance in a solution or a gas resulting in the net movement from an area of high concentration to lower concentration.
• What are the factors affecting diffusion?

  • concentration gradient (difference in concentration)
  • the temperature
  • the surface area of the membrane
• What are two examples of substances are transported in and out of cells by diffusion and in what other process?

  Oxygen and carbon dioxide in gas exchange
• What is osmosis?

  the diffusion of water from a dilute solution to a concentrated solution through partially permeable membrane.
• What is active transport?

  movement of substances from a more dilute solution to a more concentrated solution against a concentration gradient.
• Why does active transport require energy from respiration?

  because it is against a concentration gradient.
• What does active transport allow to happen in plants?

  allows mineral ions to be absorbed into plant root hairs from very dilute solutions in the soil for healthy growth
• What does active transport allow in the body (gut)?

  allows sugar molecules to be absorbed from lower concentrations in the gut into the blood which has a higher sugar concentration (against a concentration gradient) which is used for respiration.
• Why is the potato peeled in the osmosis required practical?

  because the potato skin can affect osmosis.
• What is the equation for percentage change?

  change in value

  --------------- x 100

  original value