I/GCSE Biology - Food Production Using Yeast and bacteria

In this post, we'll talk about the food production using yeast and bacteria in I/GCSE Biology. Let's get started! 😆

• Yeast is a single celled organism, each of which have a Nucleus, Cytoplasm and a Membrane surrounded by a cell wall.
• Do you remember what mitosis is in I/GCSE Biology?
• The way in which they reproduce is by asexual Mitosis.

• When yeast cells have plenty of Oxygen they respire Aerobically.
• When the yeast cells break sugar down Anaerobically, they produce Ethanol and Carbon Dioxide.
• This process is called Fermentation. The Carbon Dioxide makes dough rise when making bread.

Making Yoghurt

• Traditionally, yoghurt is fermented whole milk but now we can make it from semi-skimmed, skimmed and even soya milk.
• Yoghurt is formed by the action of bacteria on the Lactose (Milk Sugar) in the milk.
• A starter culture is added to warm milk, and then the culture reproduce, grow, and ferment.
• As the bacteria break down the Lactose In the milk, they produce Lactic Acid which gives yoghurt its sharp tangy taste.
• This is known as Lactic Fermentation. It also clots the milk to a smooth, thick texture.

In I/GCSE Biology, make sure you can understand the term of lactic fermentation!

Cheese Making

• Like yoghurt making, cheese making depends on the reaction of bacteria with the milk.
• Like yoghurt making, you add a starter culture of bacteria to warm milk. The difference is the type of bacteria.
• The bacteria in cheese making also converts Lactose to Lactic Acid, but makes much more of the acid.
• As a result the solid curds are much more solid.
• Enzymes are also added to increase the separation of the milk.
• When it has curdled you can see the separate Curds and Whey.
• The curds are used for cheese making. Then other bacterium can be added to alter the flavour of the cheese.

And we're done with this topic! Well Done!

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Drafted by Alyssa (Biology)

References:  

1. "Simple diagram of yeast cell (en).svg", https://upload.wikimedia.org/wikipedia/commons/thumb/4/48/Simple_diagram_of_yeast_cell_%28en%29.svg/2560px-Simple_diagram_of_yeast_cell_%28en%29.svg.png
2. "discuss the process of reproduction in yeast", http://images.topperlearning.com/topper/tinymce/imagemanager/files/biology/cbse_7/198842_Budding_Yeast.png
3.    "Aerobic and Anaerobic Respiration (Part 1 of 2)", https://i.ytimg.com/vi/GhsxnXGojqc/maxresdefault.jpg
4. "Biotechnology", https://v1.nitrocdn.com/kDXDIJNDOaszRbpagqNqUtquAQQkiLpO/assets/static/optimized/rev-ddee88e/wp-content/uploads/2020/01/Yeast-bread.png
5. "Lactic Acid Fermentation Process Scheme", https://thumbs.dreamstime.com/z/lactic-acid-fermentation-process-scheme-labeled-vector-illustration-diagram-biological-stages-glucose-pyruvate-lactate-169878458.jpg
6. "The Genealogical World of Phylogenetic Networks", http://1.bp.blogspot.com/-Naonn4wwhPA/U90X-a6fn-I/AAAAAAAAC8U/SvHN9GU_BSY/s1600/CheeseMaking.gif