Bacteria

This post is an overview of bacteria. The PowerPoint that forms the basis of our learning has excellent diagrams that should be copied into our books/notes. Add any details from these videos etc. that you find useful in building your understanding of bacteria and how they interact with the world around them.

OVERVIEW/STRUCTURE

GROWTH AND REPRODUCTION (Binary Fission)

Growth = getting bigger

Reproduction = making "daughter" cells

Why don't bacteria keep dividing and take over every surface of the world? There are factors that affect bacterial growth and reproduction. This next video gives a very in-depth overview of this:

NUTRITION (Extracellular Digestion)

Bacteria cannot "eat" food the way we do. When they detect suitable nutrition, they release enzymes (biological catalysts) which break the food down into much smaller particles. These smaller particles can be absorbed across the cell wall and cell membrane. Once inside the cell, these nutritious particles can then be used in the biochemical processes in the cytoplasm (and organelles such as mitochondria).

BACTERIA AND FOOD

1. Food Safety

Bacteria can make food spoil. This is because they release enzymes that speed up the break-down (digestion) of food, as part of their own life processes to gain Nutrition. 

Bacteria can also cause food poisoning, making us unwell. Many bacteria also release toxins as part of their waste. Toxins can make us sick. However, the bacteria are not usually making these toxins with the intention of making their host (us) sick. They are just part of their Excretion life process.

We often have an immune response to bacteria inside our body. As bacteria Grow and Reproduce, our immune system tries to kill them. This may cause a fever, for example.

Consider each "Key to Food Safety" from the video. How would each help reduce the risk of food poisoning?

2. Digestion

Bacteria also help our digestion. This is very important for our health.

Think about how the life processes (MRS GREN) are helping humans with their own digestion. Bacteria are not helping us "on purpose" - it is just an added bonus for us, and is probably why our immune system does not kill them off!

3. Food Production

Bacteria are very useful in food production, particularly for the dairy industry.

The first part of this is about a simple fungus, called yeast. The rest of the video is about the role of bacteria in cheese production. Again, try to link the life processes of bacteria to how they are being used to help us (humans).

BACTERIA AND DISEASE

Bacteria cause a lot of diseases in humans, other animals, and in plants. This is because of the toxins they produce (as part of excretion) or because they reproduce so quickly that they harm (or kill) their host.

 

How does the human body fight these pathogens?

What about drugs to help us?