Starter Flashcards
Basics (53 cards)
What are microbes
they are tiny living organisms
What instrument do you need to see Microbes
you need a microscope
Where are microbes found
they are found everywhere and in everything
4 types of microbes
bacteria viruses fungi protists
How big is bacteria
bacteria is single celled organisms, they are much smaller than a human cheek cell 1-5um
Describe Different types of fungi
some are microscopic And single cell e.g yeast. Some are microscopic and made of threads with many cells e.g bread mould. Some are huge e.g mushrooms and toad stools
Why is fungi important to humans
fungi can be used to bake bread, brewing but some cause disease
Why is fungi important in eco systems
they are vital as decomposers
What are viruses, how do they reproduce
there are many types and are found where there are cells to attack some are useful but many cause diseases,
Viruses can only reproduce inside other living cells meaning they are more like chemicals than living organisms
What do you need to see a virus
Viruses are tiny 0.2-0.4um so you can only see them with an electron microscope
What are protists
Protists are all single celled organisms with a true nucleus that are not fungi e.g single celled algae, single celled animals such as amoeba
Where does the fungus yeast need to grow
A place with warm temperatures, moisture suitable ph levels
What’s an agar plate
agar plates are Petri dishes that are filled with a jelly called agar, which contains all the nutrients (food) needed by the microbes
Why do Agar plates need to be sterile
so you only grow what you need to e.g yeast, and nothing else
How to grow yeast on an agar plate
wash your hands open the lid at the last possible second, use a clean Cotten swab to transfer the yeast. Label the agar plate so you know what you’re growing. Never open it in case it contains harmful chemicals
How is yeast important to humans
yeast is used for brewing and baking, it produces carbon dioxide to make bread rise and produces alcohol from sugar
Foods made from bacteria
bacteria is used to make cheese and yoghurt
How’s yoghurt made
pour sterile uht milk into a clean container, add a spoonful of live natural yogurt containing bacteria, leave it in a warm place for 24hours then refrigerate
Why is food preserved
foods need to be protected from attack microbes otherwise they will rot making the, inedible, foods can be treated or kept in particular storage conditions to keep them fresh for longer
Food presentation techniques
pasteurisation seal food in an airtight container then heat to sterilise = milk and yogurt. Chilling/freezing kept at a low temperature to reduce enzymes action and growth of microbes = butter and vegetables. Vacuum packing remove air from the packaging to remove oxygen then seal = tretelia
What’s a yeast colony
yeast combines made of millions of yeast cells that grew from the ones already made
Why must agar plates never be opened again
so that other microbes don’t get in
Why do microbe populations grow so quickly
microbes grow by deviding into 2 new cells meaning the double in size
What causes population growth to level out
as the microbes run out of food or growth is stopped by the build up of poisonous waste products
