Science lesson plan · 12th grade (Year 13 in England) · 45 minutes
Membrane structure, protein channels and bulk transport
Cells, genetics and evolution
CCSS NGSS.HS-LS1-2CCSS NGSS.HS-LS1-3England: A level Biology: Cell membranes (extension)
Objective and success criteria
Students will: Membrane structure, protein channels and bulk transport.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Diffusion, osmosis or active transport?
Leads to: the next skill in this area.
Materials: Microscope images or slides, Cell diagrams, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Diffusion, osmosis or active transport?). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Which process is this: oxygen entering the blood in the lungs? (diffusion / osmosis / active transport) → diffusionPrompt: Is it water specifically? Is it going against the gradient?
- Glucose is absorbed from the small intestine even when the blood already holds more glucose than the gut. How? (by diffusion down the gradient / by active transport, using energy from respiration / it cannot be absorbed / by osmosis) → by active transport, using energy from respirationPrompt: The glucose is moving against its gradient.
- Transport in cells: which statement is true? (Osmosis is the movement of water molecules. / Active transport only happens in plants. / Osmosis needs energy from respiration. / Water moves by osmosis from a concentrated to a dilute solution.) → Osmosis is the movement of water molecules.Prompt: Which process needs energy?
Hook · 5 min
- Show a microscope image of cells and ask what students think they are looking at.
- Share the objective: Membrane structure, protein channels and bulk transport. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Is this passive or active transport: a gland cell releasing hormone in vesicles (exocytosis)?
- Step 1: Active transport and bulk transport use energy from ATP.
- Step 2: So the answer is: active (uses ATP)
- Answer: active (uses ATP)
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Is this passive or active transport: the sodium–potassium pump? (passive (no ATP needed) / active (uses ATP)) → active (uses ATP)Prompt: Does it go down a gradient by itself?
- Why can oxygen cross the membrane easily but glucose needs a protein? (Oxygen is small and non-polar; glucose is larger and polar / Glucose is a gas / Oxygen is too big for proteins / Glucose dissolves in fat) → Oxygen is small and non-polar; glucose is larger and polarPrompt: The middle of the bilayer is made of fatty tails.
You do: independent practice · 10 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Why is the cell membrane described as a "fluid mosaic"? (Its proteins never move / It is a rigid wall of cellulose / Phospholipids move freely and proteins are scattered through them like tiles / It is made of liquid water) → Phospholipids move freely and proteins are scattered through them like tilesPrompt: Think about both words: fluid and mosaic.
- Is this passive or active transport: osmosis through aquaporin channels? (passive (no ATP needed) / active (uses ATP)) → passive (no ATP needed)Prompt: Does it go down a gradient by itself?
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: Diffusion, osmosis or active transport?.
- Use concrete materials: microscope images or slides.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-12.
Free lesson plan from eurekami.com/lesson-plan-builder