7. Microbes

Question 1

Name three types of microorganisms

Answer 1

Bacteria, fungi (yeast) and viruses.

Question 2

Where do we find micro-organisms

Answer 2

They are what we call ‘ubiquitous’ this means we find them everywhere on earth even in harsh environments. Specifically they can be found on surfaces, soil, water, are and even in and on us.

Question 3

What makes micro-organisms useful?

Answer 3

The fact that they grow/multiply very quickly is a very useful property of microorganisms. We can use them for a wide variety of food sources and make a wide variety of products with them.

Question 4

Why are microorganisms essential to life?

Answer 4

They can form partnerships with other living things to ensure that important processes, such as digestion and waste recycling, can continue

Question 5

Why do microbes have a bad reputation?

Answer 5

Because some are capable of causing disease. But we do know that not ALL bacteria are harmful.

Question 6

What are bacteria?

Answer 6

They are a very small, single-celled organism, we find them everywhere, like soil water, surfaces and air. They get around via contact, air or in water.

Question 7

How quickly can bacteria replicate?

Answer 7

Very quickly. Given ideal conditions their numbers can double every 20 minutes.

Question 8

How do bacteria replicate?

Answer 8

Bacteria cells divide into two cells in a type of reproduction called binary fission.

Question 9

What are fungi?

Answer 9

Yeast is an example of a single-celled fungi. We find them everywhere but especial on the surface of fruits and in very damp places. Fungi get around by producing spores which travel in the air. (Spores can then grow into mature fungi).

Question 10

What are viruses?

Answer 10

Viruses are sub-microscopic infectious agents. Again the are found everywhere on Earth . Viruses need a host as they can only replicate inside living cells. They can spread from once cell to the next, travel in veins or can be passed on via contaminated surfaces or through the air.

Question 11

What is aseptic techniques?

Answer 11

Aseptic techniques is a method to prevent the contamination by microorganisms. We use aseptic technique when patients are in hospital, in the food and pharmaceutical industry or when working with microorganisms in the lab.

Question 12

List some aseptic techniques used in hospitals when working with patients

Answer 12

1. Sterile clothing, such as gowns, gloves and masks.
2. Use of sterile equipment and instruments
3. Maintaining a sterile environment requires keeping doors closed during an operation. Only necessary health personnel should be at the procedure.
4. Having contact guidelines (HAND WASHING etc)

Question 13

List some aseptic techniques we can use in a lab when working with microbes.

Answer 13

1 Cleaning and disinfecting lab surfaces prior to use.
2. Limiting the duration that cultures or media are uncapped and exposed to the air.
3. keeping petri dishes closed whenever possible.
4. Flaming loops.
5. Use of fume cupboard

Question 14

What is a streak plate?

Answer 14

The purpose of the streak plate is to get isolated colonies (a single wee circle of growth) from an inoculum by creating areas of increasing dilution on a single agar plate.

Question 15

When making a streak plate what do we do between streaks.

Answer 15

Flame the loop

Question 16

In yeast industries what products can we make with yeast?

Answer 16

Bread, wine and beer.

Question 17

Why do we use yeast in bread making?

Answer 17

During the fermentation of yeast the yeast produce carbon dioxide, this makes the dough/bread rise. Bread is not alcoholic because the alcohol evaporates during baking.

             yeast glucose-------------> alcohol + carbon dioxide

Question 18

Where does yeast obtain its food from?

Answer 18

Sugars such as glucose. Yeast breaks down the sugar in a process called fermentation,

           yeast glucose-------------> alcohol + carbon dioxide

Question 19

Why do we use yeast in brewing?

Answer 19

During the fermentation of glucose the yeast produce alcohol ( makes our beer and wine alcoholic), and the carbon dioxide produced makes the beer fizzy.

            yeast glucose-------------> alcohol + carbon dioxide

Question 20

if we are producing alcohol on a massive scale what do we use (what kind of vessel)?

Answer 20

Fermenters: These are containers used to grow bacteria and fungi in large amounts, eg Penicillium mould for producing penicillin (an antibiotic). Or Yeast in brewing.

Question 21

What is the advantage of using fermenters?

Answer 21

Better for large scale because of…………
1. Low fermentation cost
2. Better yield of product
3. Easy maintenance of ideal conditions for microbes, e.g. temperature and, nutrient concentration such as glucose.
4. Substances can be added without opening the vessel, this prevents contamination of the product.

Question 22

Name three diseases caused by yeast and describe how we treat them

Answer 22

1, Athletes foot - use a antifungal cream or power such as daktarin or Lamisil.
2, Ring worm - Use an antifungal cream such as Daktarin or Clotrimazole
3, Oral thrush - Antifungal tablets (fluconazole) or moth wash such as Corsodyl.

Question 23

I bacteria Industries what do we use bacteria for.

Answer 23

We can use bacteria for the production of Cheese and yoghurt

Question 24

Where do the bacteria obtain their food?

Answer 24

They obtain their food from sugars such as lactase (in milk or glucose

Question 25

How do we make yoghurt?

Answer 25

Milk is carefully soured during yoghurt production. During this lactase sugar in the milk is converted into acid by bacteria. (Just put one teaspoon of bio-yoghurt containing bacteria into fresh milk). The lactic acid thickens the milk changing it’s taste from milk to yoghurt.

Question 26

How do we make cheese?

Answer 26

Cheese is made from milk. The enzyme rennin is added to milk, this separates the solid and liquid parts of the milk (curds and whey). Bacteria is then added to flavour the cheese. The cheese is is then compressed, matured and cut.

Question 27

Enzymes are used in cheese production. What are enzymes?

Answer 27

Enzymes are proteins that act as biological catalysts by speeding up <accelerating> chemical reactions.</accelerating>

Question 28

List some characteristics of enzymes

Answer 28

_ They speed up chemical reactions by lowering the energy needed for that reaction
- Enzymes do not take part or are changed by the chemical reaction they speed up, meaning they can be reused
-Enzymes are specific - each enzyme only acts upon one molecule <SUBSTRATE>
- Enzymes are denatured at extremes of temperature and pH.</SUBSTRATE>

Question 29

Why do we find enzymes in biological washing powders

Answer 29

Biological washing powders contain enzymes that are extracted from bacteria. The enzymes help breakdown some of the chemicals that may stain clothes, such as egg yolk, grass or sweat.