transport

• Diffusion deffenition


  Movement of molecules from an area of higher concentration to an area of lower concentration.
• osmosis defenition


  osmosis is the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a cell's partially permeable membrane.
• what factors affect diffusion?

  Temperature, concentration gradient, surface area, and distance
• what is the xylem


  Transports water and minerals (transpiration)
• what is the phloem?

  Transports sugars (translocation).
• what is translocation?


  Translocation is the movement of sugars and other nutrients through the phloem in plants.
• what are the xylem and phlox part of?

  The xylem and phloem are part of the plant’s vascular system, which is responsible for transporting water, nutrients, and sugars throughout the plant.
• what is Transpiration?


  Transpiration is the process where water vapor is lost from the plant, primarily through tiny pores called stomata in the leaves.
• why did the mass of of a potato increase when in water? what conclusion can we make?

  (mass increased because) water entered by osmosis from a dilute solution in the beaker to a more concentrated solution in the egg (cell). we can infer The water outside the potato had a higher water potential than the inside of the potato cells
• Active Transport definition?


  Movement of substances against a concentration gradient (from low to high concentration) using energy from respiration.
• Name the process by which water molecules enter the root hair cell.

  osmosis
• Water is taken in by the roots, transported up the plant and lost from the leaves. Which scientific term describes this movement of water?

  transpiration stream
• Which change would decrease the rate of water loss from a plant’s leaves?

  Increased humidity
• Compare the structure and function of xylem tissue and phloem tissue. [6 marks]

  Structure:

  • xylem is made of dead cells and phloem is made of living cells

  • both made of cells

  • xylem is hollow or xylem does not contain cytoplasm

  • both tubular

  Function:

  • xylem transports water / mineral ions and phloem transports (dissolved) sugars

  •xylem transports unidirectionally and phloem transports bidirectionally
• arteries vs veins

  
• Describe how water moves from roots to the leaves.


  by transpiration stream in xylem
• osmosis-movement from high to low

  ----------------------------------------------------

  diffusion- movment from high to low (until equilibrium)

  ----------------------------------------------------

  Active Transport- movment from low to high concentration (against the concentration gradient)
• name the 2 main substances that strengthen xylem tissue?

  Lignin and cellulose.
• what are features of the xylem?

  • One-Way Flow – Water moves only upwards

  • made of dead cells 

  • strengthened with lignin

  • transport water and minerals
• what are the features of the phloem?

  • transports sugars and amino acids

  • transport in both directions up and down

  • made of living cells

  • Has Sieve Plates
• what process does water being absorbed by the roots involve?

  osmosis
• what does active transport require?

  ATP, the energy source for active transport
• The walls of xylem cells contain cellulose.

  Name one other substance that strengthens xylem tissue.

  lignin
• what is hypertonic solution?

  A hypertonic solution has a higher concentration of solutes (like salt or sugar) than inside the cell.

  • Water moves out of the cell by osmosis.
  • The cell shrinks (in animals) or the membrane pulls away from the wall (in plants – called plasmolysis).
• what is hypotonic solution?

  A hypotonic solution has a lower concentration of solutes than inside the cell.

  • Water moves into the cell by osmosis.
  • The cell swells and may burst (in animals).
  • In plant cells, the vacuole swells and pushes against the cell wall – this is called turgid (which is good for plants).
• what is an isotonic solution?.

  An isotonic solution has the same concentration of solutes as inside the cell.

  • Water moves in and out of the cell at the same rate.
  • There is no net movement of water.
  • The cell stays the same size — it doesn’t swell or shrink.
• what is Turgor Pressure in Plant Cells?

  Turgor pressure is the pressure exerted by the cell membrane against the cell wall in plant cells. This pressure is created when the cell fills with water, causing the vacuole to expand.
• How is Turgor Pressure Maintained?

  • Turgor pressure is maintained through osmosis:
  • If a plant cell is placed in pure water (hypotonic solution), water enters the cell, filling the vacuole and exerting pressure on the cell membrane.
  • The cell wall is strong and prevents the cell from bursting (unlike in animal cells), allowing it to become turgid (firm and swollen).
• Why is Turgor Pressure Important?

  • Keeps plant cells firm and rigid: Turgor pressure helps plant cells maintain their shape. Without it, the cells would be flaccid and the plant would wilt.
  • Supports the plant structure: Turgor pressure plays a key role in keeping plant structures, like leaves and stems, upright to absorb sunlight and carry out photosynthesis.
  • Prevents wilting: When a plant cell has enough turgor pressure, it can resist the inward pressure from the surrounding environment and prevent wilting.
• Effects of Osmosis on Turgor Pressure:

  • Hypotonic solution: Water enters the cell → increased turgor pressure → the cell becomes turgid.
  • Isotonic solution: No net movement of water → stable turgor pressure.
  • Hypertonic solution: Water leaves the cell → decreased turgor pressure → the cell becomes plasmolysed(shrinks and pulls away from the wall).
• Turgidity vs. Plasmolysis:

  • Turgid: A healthy, swollen plant cell with high turgor pressure.
  • Flaccid: A plant cell that has lost some turgor pressure and is no longer firm.
  • Plasmolysis: When the cell loses so much water (in a hypertonic solution) that the cell membrane pulls away from the cell wall.
• osmosis definition.

  'OSMOSIS IS 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'