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Cells (now part of microscopes)

Using a model of a cell and various slides to explain what a cell is, about how different cells are specialized for their function, and how bacterial cells are different.
Useful information
Kit List: 

Microscope (not dissecting), slides with cell spreads, fabric model of animal cell.


Ideas to explain...

Younger children

- Introduce to the idea of a cell by using model, and looking at cells down the microscope
- Use the model to explain what's inside a cell (nucleus is the 'control centre', mitochondria 'make' energy)
- Cells are very small (typically 10 um for an animal cell... that's 1000 times smaller than 1 cm (you can use the ruler to show 1 cm)
- Not all cells are the same - you can look at red blood cells (the reason why blood looks red when you cut yourself!), and the columnar epithelium slide has lots of different shaped cells visible.
- Bacteria are also cells, but they are smaller and don't have a nucleus (associate bacteria with disease e.g. food poisoning caused by E. coli). Bacteria can be lots of different shapes (look at E. coli, Staphylococcus, Spirillum).


Older children

(in addition to the above)
- Other internal components of cells e.g. DNA in the nucleus (can relate to kiwi fruit experiment if they've already done this), ribosomes, endoplasmic reticulum, golgi and what they do
- Plant cells - cell walls and chloroplasts (we have a root tip squash slide where the cell walls are visible and the nuclei are nicely stained, but they don't have chloroplasts because it's a root so it doesn't need to photosynthesise! If they want to see more plant cells, there's a whole demo on plants...)
- Specialization - red blood cells, nerve cells, epithelium in intestine, liver cells, muscle cells etc (see below for photos of our slides)
- Fungi - also eukaryotic cells - yeast are unicellular. Penicillium grows as mycelium. (See below)
- Cell division - chromosome spread, mitosis (see below)


Possibly useful background information and ideas on how to explain things:

What are cells?

- Cells are analogous to a building brick - houses are built of lots of bricks, like people are built of lots of cells (50-75 trillion!)
- Cells aren't just bricks - they are alive, and make things, use things, and process information
- They do that because inside their fatty outer membrane, they contain lots of other things
- The nucleus is the 'control centre' of the cell
- It contains lots of instructions on how to make things called proteins, from which the rest of the cell is made
- The instructions are written in a 4-letter code on very long molecules called DNA (see Kiwi DNA experiment)
- You can see DNA in the nucleus in the model
- Cells need to make the proteins using instructions from the DNA in the nucleus
- A copy of the instructions for a single protein are made (RNA) and transported out of the nucleus into the cytoplasm
- Ribosomes 'translate' the language of RNA into the language of protein (ribosomes = buttons on model)
- Proteins that are going to be exported by the cell pass into the ER (endoplasmic reticulum) (ER = very folded bit near nucleus on model!)
- Proteins then move to the Golgi apparatus (other side of nucleus on model) and then on to the cell membrane
- Cells need energy - this is supplied by mitochondria (they convert energy from sugars into ATP, the energy currency of the cell)

Looking at slides

- Show scale using ruler (eukaryotic (animal/plant/fungal) cell is roughly 10 um in length, bacteria are often smaller than 1 um)
- The nuclei are stained in many of our cells
- We have a variety of different cell types - you can discuss why the cells have particular shapes or features (some background info in the pictures below)
- Cell division - look at chromosome spreads, and slides of dividing cells (by mitosis). Look for different stages of division.

This is just some background info and ideas about what you might want to say; you probably don't want to go through all of this with one set of children (unless they are super-keen and know some of it already!), but choose things to look at guided by what you and they are interested in!

Risk Assessment
Date risk assesment last checked: 
Wed, 25/12/2013
Risk assesment checked by: 
Date risk assesment double checked: 
Wed, 01/01/2014
Risk assesment double-checked by: 
Risk Assessment: 

Looking at a range of pre-made slides down a microscope
Looking at a fabric model of a cell

1)Electrical hazard (microscope), especially near sources of water.
2)Using thin glass slide could result in broken glass with risk of cuts
3)The light fitting under the microscope becomes hot, and could cause burns
4)Injury from swallowing parts of fabric model cell e.g. buttons
5)Grazing from velcro on fabric model cell

1a)See separate electrical parts risk assessment
1b)Keep microscope away from water as it is not required for this experiment
2)If slides are broken, carefully collect/sweep up broken pieces, wrap in paper and dispose of carefully.
3)Warn children to be careful, turn of lamp when not in use, if it's getting hot put a cardboard shield around (but not touching) the lamp to prevent accidental contact.
4)Ensure small parts of model are securely attached (e.g. buttons stitched on)
5)Ensure children handle model carefully under supervision

In case of accident, call first aider. Run burns under cold water for at least 10 minutes.

This experiment contains mains electrical parts, see separate risk assessment.