Microbes in human welfare

Question 1

what is the common name of lactobacillus?

Answer 1

lactic acid bacteria (LAB)

Question 2

how does lactobacillus convert milk to curd?

Answer 2

• LAB produces acids that partially digest the milk proteins.
• A small amount of LAB is added to milk as inoculum(starter) and they multiply at suitable tempratures.

Question 3

how does LAB improve the nutritional quality of milk in converting it to curd?

Answer 3

by increasing vitamin B₁₂

Question 4

how is LAB useful in the stomach?

Answer 4

checks disease causing microbes

Question 5

what is the puffed-up appearance on dosa and idli dough due to?

Answer 5

Co2 from the fermentation caused by bacteria

Question 6

what is the dough for making bread fermented with?

Answer 6

baker’s yeast- Saccharomyces cerevisiae

Question 7

how is ‘Toddy’, a south indian drink, made?

Answer 7

by fermenting sap from palms

Question 8

Microbes influence the ____, ____ and ____ of cheese

Answer 8

texture, flavour and taste

Question 9

large holes in ‘Swiss cheese’ are due to-

Answer 9

Co2 produced by Propionibacterium sharmanii on fermentation

Question 10

How is ‘Roquefort cheese’ ripened?

Answer 10

by growing Penicillium roqueforti on them, which gives them a particular flavour

Question 11

what the foods microbes are used in for household products?

Answer 11

curd, dosa, idli, bread, toddy, cheese, fermented fish, soybean and bamboo shoots

Question 12

What are fermentors?

Answer 12

large vessels used to grow microbes for production on an industrial scale

Question 13

Which microbe is used for making fermented beverages like wine, beer, whisky, brandy and rum?

Answer 13

brewer’s yeast- Sacchromyces cerevisiae

Question 14

brewer’s yeast- Sacchromyces cerevisiae ferments ____ ____ and ____ ____ to produce ethanol

Answer 14

malted cereals and fruit juices

Question 15

drinks produced with distillation-

Answer 15

whisky, brandy and rum

Question 16

drinks produced without distillation

Answer 16

wine and beer

Question 17

what are antibiotics?

Answer 17

chemical substances produced by some microbes which can kill or retard the growth of other(disease-causing) microbes

Question 18

Which was the first antibiotic to be discovered?

Answer 18

Pencillin

Question 19

(by who and how)

Discovery of Pencillin

Pencillin not in italics as its not a microbe, but the product of one

Answer 19

• discovered by Alexand Flemming
• accidental; while working on Staphylococci bacteria (as it would not grow in one of the unwashed culture plates)
• named after mould Pencillium notatum

Pencillin - name of antibiotic, from mirobe- Pencillium notatum

Question 20

Why do Flemming, Chain and Florey share the 1945 nobel prize for the discovery of Pencillin?

Answer 20

Because its full potential as an effective antibiotic was established later by Ernest Chain and Howard Florey

Question 21

Pencillin was used to treat American soldiers during ______

Answer 21

World War 2

Question 22

Name 3 diseases that are treated with antibiotics

Answer 22

• whooping cough (kali khansi)
• diptheria (gal ghotu)
• leprosy (kusht rog)

Question 23

Citric acid is produced by-

Answer 23

Aspergillus niger (fungus)

Question 24

Acetic acid is produced by-

Answer 24

Acetobacter aceti (bacterium)

Question 25

butyric acid is produced by-

Answer 25

Clostridium butylicum (bacterium)

Question 26

lactic acid is produced by-

Answer 26

Lactobacillus (bacterium)

Question 27

Why are lipases (enzymes produced by microbes) used in detergent formulations?

Answer 27

as they remove oily stains from laundry

- break down fat (hydrolysis); triglycerides -> glycerol + fatty acids

Question 28

Why are bottled fruit juices(market) clearer that homemade ones?

Answer 28

they are clarified using pectinases and proteases

pectinases break down pectin, proteases break down proteins and peptides

Question 29

What bacteria is streptokinase produced from? What is it used for?

Answer 29

• produced from Streptococcus
• Used as ‘clot-buster’(after genetic mod.) for patients that underwent myocardial infraction(heart attack)

myocardial infraction is caused by decreased blood flow to myocardium

Question 30

Which fungus produces cyclosporin A and what is it used for?

Answer 30

• produced by Trichoderma polysporum
• used as immunosuppressive agent in organ-transplant patients

Question 31

What produces statins? what are they used for?
how do they work?

Answer 31

• produced by the yeast Monascus purpureus
• used to lower blood-cholestrol levels (commercially)
• inhibit the enzyme required for synthesis of cholestrol

statins are prescription medicine (class of drugs)

Question 32

Microbes in industrial products can be used for-

Answer 32

Beverages, antibiotics, organic acids and enzymes

beverages- ethanol/alchohol

Question 34

Primary treatment of sewage

Answer 34

• involves removal of particles (large and small) through filtration and sedimentation.
  1. Floating debris is removed through sequential filtration,
  2. Grit (soil and pebbles) removed by sedimentation.
• solids that settle from these- supernatant effluent- sent to secondary tank

Question 35

Secondary treatment of sewage (biological treatment)

Answer 35

• primary effluent passed to large aeration taks- constant mechanical agitation and air is pumped into it- growth of flocs- consumes major pt. of organic matter in effluent- reduces BOD- effluent is put into sedimentation tank- flocs sediment (activated sludge)- rest water released into rivers/streams

flocs- aerobic microbe masses- associated fungal filaments- mesh str.

Question 36

What is BOD?

Answer 36

* biochemical oxygen demand
* amount of oxygen consumed if all organic matter in 1 litre of water was oxidised by bacteria.
* measures uptake of O2 by micro-organisms->measure of organic matter in water
* (more BOD = more organic matter = more pollution)

Question 37

what happens to activated sludge(sedimented flocs) after secondary sewage treatment?

Answer 37

1. Part of it is pumped back into aeration tank- inoculum
2. Remainder is pumped into anaerobic sludge digestor tanks-anaerobic bacteria digest sludge- produces gases like methane, hydrogen sulphide(H2S) and CO2-biogas

biogas is used for energy as its inflammable

Question 38

What plans has the Ministry of Environment and Forests initiated to save rivers from water pollution?

water pollution due to growing sewage production but same no. of STPs

Answer 38

Ganga action plan and Yamuna action plan
(propose to build moe STPs- so that only treated sewage is disposed in rivers)

Question 39

What is biogas?

Answer 39

mixture of gases (mostly methane) produced by microbial activity- can be used for fuel

Question 40

What are anaerobic bacteria that produce a large amount of methane with CO2 and H2 called?

for making alc.,chesse etc main byproct prod. y microbes was CO2

Answer 40

Methanogens- eg. Methanobacterium
(found in anaerobic sludge during treatment?)

Question 41

In cattle, methogens are found in the ____. Why?

methanogens are used industrially for biogas production

Answer 41

rumen(pt.of stomach),
bacteria in the rumen breal down cellulosic material from cattle’s food.

bactreia in rumen break down cellulose- nutrition for cattle