Cells

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• Created by: mve3
• Created on: 06-11-22 14:31

Eukaryotic Cells

Eukaryotic Cells

• Found in Plants, animals, fungi and protists.
• They are 10 - 100 micrometres in size.
• A eukaryote is an organism made up of eukaryotic cells.
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Prokaryotic Cells

Prokaryotic Cells

• Prokaryotic cells are 0.1 - 5.0 micrometres in size.
• A prokaryote is an organism made up of prokaryotic cells.
• Bacteria are prokaryotes.
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Properties of Prokaryotic cells

The key features of prokaryotic cells are:

• No mitochondria or chloroplasts
• No nucleus - instead most of the genetic material is stored in a single DNA loop in the cytoplasm
• Plasmids - some cells contain small rings of dna called plasmids. These can replicate and move between cells so that genetic information can be shared
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Binary Fission

What is Binary Fission?

• Prokaryotic cells such as bacteria reproduce by a process called binary fission
• In binary fission a cell makes a copy of its genetic material (dna and plasmids) before splitting into two daughter cells
• In the right conditions bacteria can divide every 20 minutes
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Binary Fission

How does binary fission work?

1. Genetics in parent cell duplicates

2. The cytoplasm splitis into two

3. Two daughter cells are formed

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Mean Division Time

Mean Division Time

If we want to estimate the number of bacteria in a population we need the mean division time.

Mean division time= average time taken for one bacterial cell to divide into two.

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Mean Division Time Worked Example

A bacterial cell has a mean division time of 30mins. How many cells will be produced after 2.5hrs?

1. Convert 2.5hrs into mins (2.5 x 60 = 150mins)

2. Divide the total time they have been producing cells by the mean division time- this gives you the number of divisions (150mins / 30mins = 5 divisions)

3. Multiply 2 by itself for the number of divisions. This gives you the number of cells (2x2x2x2x2 or 2^5 = 32 cells)

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