New
New
Year 11
OCR
Foundation

Using a microscope to observe effects of osmosis in plant cells: practical

I can use a light microscope to observe effects of osmosis in plant cells.

New
New
Year 11
OCR
Foundation

Using a microscope to observe effects of osmosis in plant cells: practical

I can use a light microscope to observe effects of osmosis in plant cells.

Lesson details

Key learning points

  1. Use a light microscope to observe effects of osmosis in plant cells (including: shrinking/crenation, swelling/bursting)
  2. The parts of a light microscope and their functions.
  3. The sequence of steps for setting up a light microscope to observe cells, including changing magnification and focus.
  4. Explaining observations from microscopy using ideas about osmosis and net movement of water into/out of cells.

Common misconception

The process of osmosis, the direction of movement from high to low water concentration, and the effect that this has on plant cells in terms of turgidity and flaccidity are frequently confused.

Errors are explored, explained and questioned, and clear demonstrations of turgidity and flaccidity and the effects that these have on a plant are demonstrated. This will be reinforced by observation of these processes using a light microscope.

Keywords

  • Light microscope - an instrument that uses visible light and lenses to magnify viewed objects

  • Selectively-permeable membrane - a membrane that will only allow some substances through and not others

  • Osmosis - the net movement of water molecules from high to low concentration through a selectively-permeable membrane

  • Turgid - a cell which is swollen with water and firm

  • Flaccid - a cell which has lost a lot of water and is soft and limp

You could model the process of the vacuole filling or emptying by using a balloon which is filled with water to become firm, then pin-pricked and allowed to empty showing flaccidity and plasmolysis.
Teacher tip

Equipment

light microscope, slides with onion epidermis in states of turgor and plasmolysis

Content guidance

  • Risk assessment required - equipment

Supervision

Adult supervision required

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
What is the process by which water moves into the roots of a plant?
diffusion
condensation
evaporation
Correct answer: osmosis
active transport
Q2.
True or false? Osmosis is a type of diffusion.
Correct answer: true
false
Q3.
Match the cell part to its function.
An image in a quiz
Correct Answer:A,provides support and structure

provides support and structure

Correct Answer:B, controls what enters and leaves the cell

controls what enters and leaves the cell

Correct Answer:C,the site of photosynthesis

the site of photosynthesis

Correct Answer:D,contains cell sap (water and other substances)

contains cell sap (water and other substances)

Q4.
Which tissue inside a plant transports water?
Correct Answer: Xylem, xylem tissue, xylem vessel, xylem vessels
Q5.
Which three of the following statements about diffusion are true?
Correct answer: The particles are constantly moving in random directions.
There is an overall net movement of particles from a low to high concentration.
Diffusion requires energy.
Correct answer: Diffusion is a passive process.
Correct answer: There is an overall net movement of particles from a high to low concentration.
Q6.
A concentration is a measurement of how the concentration of something changes from one place to another.
Correct Answer: gradient

6 Questions

Q1.
Match the part to its function.
An image in a quiz
Correct Answer:a,eyepiece lens: viewing lens with ×10 magnification

eyepiece lens: viewing lens with ×10 magnification

Correct Answer:b,objective lenses: three lenses with different magnifications

objective lenses: three lenses with different magnifications

Correct Answer:c,stage: specimen on a slide is placed here

stage: specimen on a slide is placed here

Correct Answer:d,light source: illuminates the specimen so that it can be observed

light source: illuminates the specimen so that it can be observed

Correct Answer:e,coarse focus wheel: for adjusting the focus in larger increments

coarse focus wheel: for adjusting the focus in larger increments

Correct Answer:f,fine focus wheel: for adjusting the focus in smaller increments

fine focus wheel: for adjusting the focus in smaller increments

Q2.
Put these steps in the right order to show how to use a light microscope.
An image in a quiz
1 - Select the lowest power objective lens.
2 - Place the slide on the stage.
3 - Turn on the light source.
4 - Look from the side, turn the coarse focus wheel to move the stage up.
5 - Look into the eyepiece lens, turn the coarse focus wheel to move the stage away.
6 - Look into the eyepiece lens, turn the fine focus wheel to make the image clear.
Q3.
What is plasmolysis?
water moving from a high to a low concentration
Correct answer: when a cells membrane pulls away from the cell wall
when a cells membrane pushes against the cell wall
water moving from a low to a high concentration
Q4.
When plant cells gain water, the vacuole fills up and becomes....
An image in a quiz
flaccid
Correct answer: turgid
wilted
Q5.
is the movement of water from an area of high water concentration to an area of low water concentration through a selectively-permeable membrane.
Correct Answer: osmosis
Q6.
What is the net direction of movement when the concentration of water molecules is greater inside the cell compared to outside the cell?
into the cell
Correct answer: out of the cell
no net movement

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