Using Microorganisms

Question 1

special types of bacteria called … can convert milk into …
the same bacteria can also turn milk into …
even the holes in Swiss cheese are made by …
blue cheese is blue because it it … types of fungi are added into the cheese to make the blue veins

Answer 1

lactobacillus
yoghurt
cheese
bacteria
mouldy

Question 2

… is a type of fungus.
when it is added to … and oxygen it produces water and … in a process called aerobic …
this process is used to make …

Answer 2

yeast
glucose
carbon dioxide
respiration
bread

Question 3

when yeast respires in the absence of …, it produces carbon dioxide and … (ethanol). This process is called … (anaerobic respiration) and is used to make alcoholic drinks such as wine and …

Answer 3

oxygen
alcohol
fermentation
beer

Question 4

… is a thick sticky brown paste made from … extract and is a product of beer-making

Answer 4

marmite

yeast

Question 5

in some countries like Brazil alcohol made from sugar can can be used instead of … in cars

Answer 5

petrol

Question 6

certain bacteria can turn alcohol into an acid called acetic acid which is the scientific name for … Bacteria can turn all types of alcohol into vinegar including wine and code. vinegar can be used to make … in order to preserve food.

Answer 6

vinegar

pickles

Question 7

a type of fungi is used to make … the fungi are grown in large chambers; collected and compressed together to form the blocks of … which is a health alternative to meat because it is high in … but low in … and as it is made from microbes, not animals, it is suitable for …

Answer 7

Quorn
Quorn
protein
fat
vegetarians

Question 8

bacteria also carries out a process called … they break down dead plants, animals and animal waste into harmless products. this process can be used in … works where bacteria breaks down the sewage in order to turn it into clean water. bacteria also breaks down plant material to make … which is used in gardening to add … to the soil.

Answer 8

decay
sewage
compost
nutrients

Question 9

some bacteria give out a gas called … when they carry out decay. this can be used as a fuel for … or making electricity. it is also the gas we have in our school …

Answer 9

methane
cooking
bunsen
burners

Question 10

the fungus … produces a chemical called …. which acts as an … killing …

Answer 10

penicillium
penicillin
antibiotic
bacteria

Question 11

finally, bacteria can be genetically modified (i.e. their genes altered), so that they make useful products, such as … this process is called …

Answer 11

insulin

genetic engineering

Question 12

aerobic respiration yeast equation

Answer 12

glucose + oxygen –yeast–> carbon dioxide + water + energy

Question 13

anaerobic respiration (fermentation)

Answer 13

glucose –yeast–> carbon dioxide + alcohol + some energy

Question 14

how to measure respiration is occurring aerobically

Answer 14

one test tube with a bung have yeast and sugar solution

then a connecting test tube have limewater to detect CO2 levels

Question 15

how to measure respiration is occurring anaerobically

Answer 15

one test tube with a bung have yeast and sugar solution with liquid paraffin on top with a connecting tube to the other test tube with limewater to detect CO2 levels

Question 16

what does yeast use for fermentation of beer etc

Answer 16

ie barley grains during digestion of their starch to simple sugars, they then germinate producing an enzyme called maltase which breaks down the starch into maltose which the yeast can use for fermentation

Question 17

most fungi are made from thread-like structures called … and have … made of chitin. they also have lots of the organelle called a … in their cytoplasm. the fungus used to make beer is single-celled and is called … this fungus uses a process called … respiration to convert a sugar called … into ethanol and a gas called …

Answer 17

hyphae
cell walls
mitochondria
yeast
anaerobic
glucose
carbon dioxide

Question 18

describe an experiment you cold do to find out the effect of pH on the growth of yeast

Answer 18

Control - vary pH –> acid/alkali
Organisms involved - same species –> mass/number/concentration
Repetition - repeat each pH
Measurement 1 - mass/number/bubbles/carbon dioxide/alcohol
Measurement 2 - time period stated
Standard - same temp/volume of water/same nutrients/concentration of nutrients/oxygen –> don’t talk about light

Question 19

how to make yoghurt with bacteria (type of respiration)

Answer 19

anaerobic respiration/lactic fermentation

Question 20

bacteria making yogurt equation

Answer 20

lactose (milk sugar) –bacteria–> lactic acid + some energy

Question 21

lactic acid makes milk go …
the low … causes milk proteins to … and … is formed
the low … also prevents … bacteria from growing

Answer 21

sour
pH
curd
clot
pH
harmful

Question 22

steps of making yogurt

Answer 22

1) milk is pasteurised at 85-95 degrees (to kill off bacteria)
2) milk is homogenised (to make sure fat is mixed in)
3) milk is cooled and inoculated with Lactobacillus (so that Lactobacillus’ enzymes does not denature)
4) milk is incubated for several hours (optimum temperature for enzymes so they respire as much as possible)
5) flavourings and fruit are added

Question 23

why add nutrients and glucose to a fermenter

Answer 23

healthy growth and respiration

Question 24

why and how is pH controlled in a fermenter

Answer 24

as pH will affect wroth of microbes you need to stop enzyme damage, add acid/alkali

Question 25

why control temperature in a fermenter

Answer 25

too hot –> enzymes denature

too cold –> work less effectively

Question 26

why stir the contents of the fermenter

Answer 26

keeps a consistent environment for pH, temp and sensors wouldn’t work as well, microbes reach all the nutrients

Question 27

how big are normal fermenters

Answer 27

can hold up to 200000 litres

Question 28

examples of need for fermenters

Answer 28

penicillin, insulin, quorn

Question 29

how can contamination of the fermenter be avoided

Answer 29

sterilise fermenter, anything going in should be sterilised (even the air), be careful which microbes are added

Question 30

what is the importance of the water jacket around fermenters

Answer 30

to stop enzymes denaturing or working less efficiently, to maintain a constant temperature

Question 31

why is steam used to clean the fermenters

Answer 31

no chemical contamination, but completely cleans and sterilises