yr8cells

Year 8 Science
= Cells =

Cells are the smallest units of life. Some people call them the building blocks of life. We are made up of billions of cells. Some organisms are made of one cell only. Bacteria are single cellular organisms. Although they are small they can reproduce remarkably quickly. E. coli bacteria split into two (asexual reproduction) every 20 minutes. In 8 hours one bacteria can become 20 million. WOW. No wonder you should wash.



As well as learning about cells in this unit, we are also going to look at some. To do this we have to learn about microscopes.

Write up and submit a full prac report for the Prac on p65-68 of your text book. Blank microscope template

Resources:

More Pracs!
 * looking at dental plaque (repeating the original 1680 experiment from Leeuwenhoek) and discovering animicules.
 * looking at a swab of cheek cells
 * looking at dandruff
 * looking at what we have under our finger nails

Mobile Phone Warning!!
Monday, November 07, 2011 - bigpondnews.com //A study by the University of London reveals that one in six mobile phones showed positive culture for the bacteria E coli.// //E coli is found in faeces and in some severe cases can cause vomiting, diarrhoea and even renal failure.// //The warm surfaces of mobile phones often enable various bacteria and diseases, such as hepatitis and influenza,// //to thrive and then spread infection from person to person.// //Infection can be reduced by cleaning your mobile phone with antibacterial wipes and washing one's hands after using the toilet.//

Learn more about cells: [|Biology4kids]

What do the parts of cells do?
Look at the following web site http://upper.usm.k12.wi.us/academics/faculty/rheun/organelle.html

1. Make a table listing the main **organelles**. 2. Write the functions next to each and give an every day comparison (e.g. mitochondria are the power stations of the cell). 3. Find a picture of each of the organelles and add it to your slides. 4. What's the difference between plant and animal cells.

Onion Cell Prac
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Iodine
[|Iodine] is used in [|chemistry] as an indicator for [|starch]. When starch is mixed with iodine in solution, an intensely dark blue colour develops, representing a starch/iodine complex. Starch is a substance common to most plant cells and so a weak iodine solution will stain starch present in the cells. ([|ref])

Methylene blue
[|Methylene blue] is used to stain animal cells, such as human cheek cells, to make their nuclei more observable. Also used to staining the blood film and used in cytology. ( [|ref] )

Cells in my Body
Explore what makes in your own bodies with this microscope activity. You will need a flat toothpick, glass microscope slide and cove slip, as well as food coloring or methylene blue stain.

Cheek Cell Prac: