Chapter 3 Movement of substances across a plasma membrane in living organisms and its application in daily life Flashcards
When does passive transport occur in living organisms?
Gaseous exchange between an alveolus and a blood capillary through simple diffusion
Reabsorbtion of water through the renal tubule in the kidney
Absorbtion of water by a plant root hair cell
Absorbtion of fructose molecule in the villus
When does active transport occur in living organisms?
Absorbtion of glucose molecule and amino acids in the villus
Reabsorbtion of glucose through the renal tubule in the kidney
Transport of sucrose from a leaf to a phloem tissue
Absorbtion of mineral ions by a plant root hair cell
What types of solutions are there?
Isotonic
Hypotonic
Hypertonic
Definition of isotonic solution
Both solutions have the same concentration of solutions. Causing both solutions to be isotonic to each other
Definition of hypotonic solution
One of the solution has a low solutes concentration and high water potential
If Solution A is hypotonic to solution B. Water diffuses from A to B
Definition of hypertonic solution
One of the solution has high solutes concentration and low water potential
If solution A is hypertonic to B. Water diffuses from B to A
What is the fluid found in cell and surrounding the cell called
Intracellular fluid
Extracellular fluid
What is haemolysis?
Bursting of red blood cells
Effects of isotonic solution in animal cells
Water diffuses in and out of the cell at the same rate ( Osmosis )
No movement of water across the plasma membrane
Cells maintain their normal shape
Effect of hypertonic solution in animals cells
Water moves out of the cell ( when placed into a hypotonic solution )
Causing cells to shrink
Undergo crenation
Effects of hypotonic solution in animal cells
Water diffuses into the cell, causing the cell to swell and burst ( Haemolysis )
Because cell membrane is too thin to withstand built up osmotic pressure
Effects of hypotonic solution on plant cells
Water diffuses into the vacuoles
Cause the vacuoles to expand and ush the cytoplasm and plasma membrane against the cell wall
Does not burst because the cell wall is rigid and strong
In this condition, cells are turgid.
Turgor pressure provides support and maintains the shape of the plant cell and causes guard cell to swell and allow stomata to remain open for photosynthesis
What is the importance of turgor pressure?
Gives support and maintains shape of plant cell
Causes guard cell to swell and allow stomata to remain open for photosynthesis
Effects of hypertonic solution in plant cells
Water diffuses out of the vacuoles
Causing the vacuoles and cytoplasm to shrink and plasma membrane to pull away from the cell wall
This process is known as plasmolysis and causes the stem to bend downwards and wilt
Plasmolysed plant can regain turgidity when returned to a hypotonic solution immediately (deplasmolysis)
Effects of isotonic solution in plant cells
Water potential between sap of the plant cell and extracellular solution is the same
Movement of water diffusion in and out of cells is the same
Become flaccid
How does the excessive use of fertilisers cause wilting in plants?
Dissolved fertilizers cause soil water to be hypertonic to the sap cell of roots.
Causing water to diffuse by osmosis from roots’ cell sap to the soil and cell to be plasmolysed.
Plasmolysed plants will recover once watered but if the plasmolysis is prolonged, wilted plants will die
Applications of movement of substances across a plasma membrane in our daily lives.
Isotonic drinks to recover loss of water and electrolytes
Saline solutions used in medicine
Liposomes, which protect drugs taken orally from being destroyed by gastric juices
