21 / 03 thursday learning objectives: draw and label a bacterial cell

21 / 03 Thursday

Learning objectives:1) Draw and label a bacterial cell2) Classify bacteria according to their

shape

Starter1) Draw a plant cell and label these

parts – nucleus, cell wall, cell membrane, cytoplasm, vacuole

2) Define the term ‘micro-organism’3) What are the three groups of

micro-organisms?

© Boardworks Ltd 20041 of 20 © Boardworks Ltd 20053 of 31

Microbes are very small living things and are sometimes called micro-organisms.

Microbes are so tiny that they cannot be seen with the naked eye. They can only be seen using a microscope.

What are microbes?

Because they are so small, we measure them using a unit called a micrometre.

© Boardworks Ltd 20041 of 20 © Boardworks Ltd 20054 of 31

There are three types of microbes:

Different types of microbes

bacteria viruses fungi

microbes

Bacteria

Bacteria are the most common form of life on earth, they are found everywhere.

Bacteria are very small:Between 0.5 ~ 8.0 micrometresApproximately 1000 bacteria will fit

into 1 mm

Bacteria are made of only one cell = unicellular

(We are multicellular)

Structure of Bacteria

Bacteria come in a variety of shapes

Bacteria come in a variety of shapes:

Spheres (coccus) – Streptococcus (causes sore throats)

Rods – Bacillus (causes typhoid & anthrax)

Spirals – Spirillum (causes syphilis & campylobacter)

Cocci - Spherical

Strep throat is caused by streptococcus

Bacilli – Rod-shaped

Vibrio – Comma shaped

Gone Fishin’

Spirillum – Spiral shaped

22 / 03 Friday

Learning objectives: Describe how bacteria reproduce

(binary fission) Describe and explain the bacterial

growth curves

Bacterial Reproduction – Binary Fission

Starting with a single bacterium which multiplies every 20 minutes, how many bacteria would there be after:i. One hour?ii. Three hours?iii. Six hours?iv. Nine hours?v. One day?

How long would it take for a single bacterium to multiply into…i. One thousand?ii. One million?iii. One billion?iv. One trillion?v. One googol (10100)?

Bacterial Growth Curves