B3.1 - Exchange of materials Flashcards
Name two factors that affect the rate of diffusion
Temperature
Concentration gradient
Name two examples of diffusion in the human body
Synapse
Oxygen diffusing into blood
How is osmosis different to diffusion
Osmosis only happens with water particles
What is osmosis?
Diffusion of water molecules from an area of high concentration to an area of low concentration across a partially permeable membrane.
When does osmosis stop?
When both sides of the partially permeable membrane have equal amounts of water particles
What is a solute?
Something that is dissolved in water
Give two examples of solutes
Sugar
Salt
What will happen when a cell is placed in a solution of lower concentration?
Solution is more dilute than that of the cell so it will absorb more water, swells and could possibly burst.
What is it called when a cell absorbs more water and swells?
Iysis
What will happen when a cell is placed in a solution of same concentration?
There’s no net movement so the cell will remain the same
What will happen when a cell is placed in a more concentrated solution?
Will lose water because there is less water in the solution. It loses water by osmosis and the cell becomes crinkled/crenated
What happens when you exercise
You respire more, using up glucose
Sweat more, losing electrolytes (mineral ions) and water
Cells will become dehydrated (water leaves by osmosis)
What’s in a sports drink and why
Glucose to replenish glucose that is used in respiration
Electrolytes to replace ions lost when sweating - this keeps cells working well
Mainly water for hydration
What is a hypotonic drink
Concentration of dissolved substances is lower than in the body. This means it is good for hydration
What is an isotonic drink
Concentration of dissolved substances is similar to the levels of dissolved substances in the body. Good for hydration and fuel replenishment
What is a hypertonic drink
Concentration of dissolved substances is higher than in the body. Replaces glucose needed for respiration
What is the job of the lungs?
To transfer oxygen to the blood and remove waste CO2 from it.
How do the lungs transfer oxygen and Carbon dioxide
They contain millions of little air sacs where gas exchange takes place
What are the air sacs in the lungs called
Alveoli
How are the alveoli specialised to maximise the diffusion of oxygen
Large surface area
Very thin walls
Good blood supply
Moist lining for dissolving gases
Where are the villi
Inside the small intestine
How do the villi work
They increase the surface area so digested food can be absorbed into the blood much quicker
How are the villi adapted
A single layer of surface cells
Good blood supply assists quick absorption
What is the definition of diffusion?
Diffusion is the movement of particles from an area of high concentration to an area of low concentration
