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What happens if you get corona virus?
What happens if you get corona virus?
Let's begin...
Let's begin...
Look at the diagrams of cells 1, 2 and 3. In each example, explain the net movement of molecules. Use the questions in red as a guide.
Think deeper - Is it important to have differences between two sides? What would happen if there are no differences between the inside and outside of cells?
Check your answers
Check your answers
Net movement: In - because there is a higher concentration of molecules outside the cell compared to inside.
Net movement: Out - because there is a higher concentration of molecules inside the cell compared to outside.
Net movement: Neither - because the concentration of molecules is the same on both sides.
For your notes:
The words 'net movement' refers to the overall movement of particles or molecules.
There will be greater movement in one direction than others if there is a difference in concentration between the two sides.
Notice that the first two diagrams show concentration differences between the two sides, so there is a concentration gradient. On the other hand, there is no concentration gradient for diagram 3.
Concentration gradient is the difference is concentration. We say 'steep or high concentration gradient' if the differences are large.
Concentration gradient is the difference is concentration. We say 'steep or high concentration gradient' if the differences are large.
Next...
Next...
Watch introduction videos to visualise what is happening in your respiratory system.
Bullet point key information about what happens if you get corona virus.
Be ready to share your ideas with the rest of the class
Exchange of substances comprehension task
Exchange of substances comprehension task
GCSE Specification link
GCSE Specification link
Specification requires students to know the following:
Substances may move into and out of cells across the cell membranes via diffusion.
Diffusion is the spreading out of the particles of any substance in solution, or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration.
Some of the substances transported in and out of cells by diffusion are oxygen and carbon dioxide in gas exchange, and of the waste product urea from cells into the blood plasma for excretion in the kidney.
Students should be able to explain how different factors affect the rate of diffusion.
Factors which affect the rate of diffusion are:
the difference in concentrations (concentration gradient)
the temperature
the surface area of the membrane.
Learning objectives
Learning objectives
Context: The key idea to understand is that multicellular organisms have many cells too far away from the outer surface to get substances in and out to meet their needs. Gases and food molecules can no longer reach every cell inside the organism by passive/simple diffusion. Metabolic waste (ammonia/urea/CO₂) cannot be removed fast enough to avoid poisoning cells.
Therefore, large complex organisms solve this problem by having special exchange surfaces and transport systems to ensure that the needs of every cell are met.
By the end of this section, you will be able to do the following:
Explain how the following features increase the efficiency of exchange surfaces.
A large surface area
A thin membrane
An efficient blood supply
Being well ventilated
Learning task 1 Structure of the human gas exchange system
Learning task 1 Structure of the human gas exchange system
Look at a range of images to visualise what is going on in your lungs. https://www.gettyimages.in/videos/alveoli?phrase=alveoli&sort=best
Draw a flowchart to show the journey of oxygen molecules.
Learning task 2 Explain how each of the features of the lungs increases the rate of gas diffusion.
Learning task 2 Explain how each of the features of the lungs increases the rate of gas diffusion.
Student guide:
Start by describing the features, you may want to sketch out some of the diagrams.
Then explain how the features help to move gases in and out of the blood quickly.
"Reach high for stars lie hidden in your soul. Dream deep, for every dream precedes the goal." Pamela Vaull Starr
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