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GCSE WJEC triple science Y11 wales > BIOLOGY - Micro-organisms and their applications > Flashcards

BIOLOGY - Micro-organisms and their applications Flashcards

1
Q

what is a nutrient agar

A

a jelly that contains nutrients needed for the growth of microbes

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2
Q

what does inoculate mean?

A

to transfer microbes to nutrient agar or other nutrient medium

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3
Q

what does aseptic technique mean

A

steps taking in microbiology to avoid contamination from unwanted microbes

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4
Q

what does incubate mean

A

allow microbes to grow at a set temperature

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5
Q

what are pathogens?

A

a micro-organism that causes disease

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6
Q

what does colony mean

A

the visible growth of bacteria - one bacterium divides repeatedly to produce one colony

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7
Q

what does serial dilution mean

A

reducing the concentration of a stock solution step by step, by the same dilution factor each time

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8
Q

What is an antimicrobial agent?

A

chemical that kills or halts the growth of microbes

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9
Q

what is penicillium?

A

a fungus that produces the antibiotic penicillin

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10
Q

what is penicillin?

A

an antibiotic produced by a fungus known as penicillium

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11
Q

what is a fermenter?

A

a large industrial container which allows us to control the conditions in which microbes grow.

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12
Q

what is an antibody?

A

a protein molecule produced by plasma cells in response to the presence of a foreign antigen

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13
Q

what does monoclonal antibody mean

A

identical antibodies specific to only one type of antigen

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14
Q

what does hybridoma mean

A

the cell that results from a fusion of activated B - lymphocytes and tumor cells

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15
Q

what does preclinical testing mean

A

testing new medical drugs on human cells, tissues, organs, animals and healthy volunteers

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16
Q

what does clinical testing mean

A

testing new medical drugs on small groups of patients

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17
Q

what is yeast used to make

A

bread and alcohol

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18
Q

what is bacteria used to make

A

yoghurt and cheese

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19
Q

how do we prevent food spoilage by microbes

A

freezing - slow bacteria production
cooking
sealing

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20
Q

what is pasteurisation

A

heating milk to 72 degrees for 15 seconds as it kills most bacteria /9/including some harmful ones like the TB bacterium) but doesnt change the tatse

• heating milk to 72 degrees for 15 seconds
• kills most bacteria
• doesn’t change the taste

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21
Q

why does milk need to be pasteurised

A

to kill bacteria that could be harmful

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22
Q

why does pasteurised milk eventually go off even when kept in a fridge

A

• not all bacteria killed
• some use milk sugars (lactose) in respiration
• produces lactic acid
• turning milk sour

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23
Q

what type of milk can be kept for months

and how is it done

A

• UHT milk - ultra high temp
• jet of steam passed thru milk at 132 degrees for 1 second
• kills all microbes but taste is affected
• once opened, lasts for a few days

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24
Q

why can UHT milk only last a few days once opened

A

microbes in air can get in the milk and contaminate it

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25
Q

what are 4 ways to prevent or slow down growth of microbes

A

removing oxygen
removing water
changing optimum pH
changing optimum temperature

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26
Q

when seeing microbes in milk

why must petri dishes and nutrient agar be sterilised before use

A

to kill any unwanted microbes

27
Q

when you are seeing microbes in milk

an inoculating loop is used to transfer bacteria onto the agar. how do you sterilise this

A

heat it until its red hot

28
Q

when seeing microbes in milk

what steps must be taken at the end of all work, with microbes

A

sterilise all equipment and work surfaces

29
Q

QER
youv been asked to estimate the number of bacteria in a sample of pasteurised milk, write down a method, including ways you would prevent contamination.

A
  1. add 9ml of broth to 6 test tubes using a sterile syringe
  2. use a single sterile syringe to transfer 1ml of sample to test tube 1.
  3. neck of flask and test tubes passed through flame to sterilise.
  4. invert tube to mix thoroughly
  5. use a sterile syringe to transfer 1ml from test tube 1 to test tube 2
  6. repeat steps 3-4 to produce 6 test tubes in total.
  7. use a sterile syringe to transfer 1ml from each test tube to its corresponding agar plate.
  8. tape lids, label dishes, incubate at 25 degrees for 2 days.
  9. count colonies in the plate which has no clumps but enough to give a decent count
  10. use this dilution factor to calculate number of cells per ml of original sample
    11.plate count x dilution factor = cells per ml of sample
30
Q

explain how temperature effects bacterial growth

A

-0 degrees or less is water freezing point, will almost stop bacterial growth
-5 to 60 degrees is danger zone, food in this temp range allows rapid growth of bacteria
-60 to 100 degrees is cooking temperature and will destroy bacteria, but beware of toxins
-100 degrees is water boiling point

31
Q

explain how bacteria affects the concentration of oxygen in milk

A

respiration uses oxygen

32
Q

what are 6 ways we kill microbes

A

-heat
-alcohol
-radiation
-disinfectant
-bleach
-soap

33
Q

the fungus penicillium is grown in huge fermenters made out of stainless steal and are steam fertilised

why is steam preferred rather than disinfectant to fertilise the fugus penicillium

A

disinfectant would kill the fungus

34
Q

what are advantages of growing the fungus in a fermenter

A

large quantities in a short time, cheaper and a lot easier to control the conditions

• large quantities in a short time
• cheap
• easier to control the conditions

35
Q

what nutrients would need to be present in agar for growth of the fungus

A

-amino acids
-glucose
-nitrates
-potassium

36
Q

what does the paddle wheel do in large scale production of penicillin

A

• stirs to makes sure that all cells get nutrients
• maintain temperature throughout.

37
Q

what does a temperature recorder and cold water pump control do in a large scale production of penicillin

A

temperature is monitored and the cooling jacket helps to keep the temperature from rising and enable maximum growth

temperature recorder
• monitors temp

cold water pump control
• a cooling jacket
• helps keep temp from rising
• enable maximum growth

38
Q

why is the air inlet needed in large scale production of penicillin

A

cells need O2 to respire so air inlet provides oxygen

39
Q

What happens in the harvest line in the large scale production of penicillin?

( the page where they show image of how pure penicillin made or some shit )

A

the penicillium fungus secretes the antibiotic into the medium. this is extracted and filtered to obtain pure penicillin.

• penicillium fungus secretes the antibiotic
• into the medium
• it’s extracted and filtered
• to obtain pure penicillin

40
Q

what is the pH control reservoir needed for in large scale production of penicillin

A

• fungus makes waste products
• changes pH
• it’s monitored and altered

41
Q

what happens in the food inlet in the large scale production of penicillin

A

fungus uses carbohydrates for energy and nitrogen for growth

42
Q

what is the steam inlet needed for in large scale production of penicillin

A

in between batches the fermenter must be sterilised with steam to make sure no other microbes compete for resources

• To sterilise in between batches to make sure no other microbes compete for resources

43
Q

what happens in the penicillium inlet in the large scale production of penicillin?

A

starter culture of penicillium fungus is added to a liquid nutrient medium

44
Q

questions about the AIDS disease

cause?
effects?
how is it spread?
how to prevent spread?
treatment?

A

cause - HIV virus infects lymphocytes in the body

effects - infects lymphocytes which decreases the body immunity

spread by - blood to blood contact

prevent spread - use condoms or disposable gloves

treatment - antiviral agent

45
Q

questions about the Chlamydia disease

cause?
effects?
how is it spread?
how to prevent spread?
treatment?

A

cause - Chlamydia trachmatis

effects - S.T.D infecting reproductive organs

spread by - sexual intercourse

prevent spread - condoms during sex

treatment - antibiotics

46
Q

questions about the Malaria disease

cause?
effects?
how is it spread?
how to prevent spread?
treatment?

A

cause - plasmodium

effects - infects red blood cells, ‘causes fever and anaemia, possibly death’

spread - ‘female mosquitos of the genes Anopheles’. Anopheles mosquitos bite humans and inject plasmodium into the blood stream.

prevent spread - kill mosquitos with insecticide, biological control, nets and repellants, possible vaccine in the future.

treatment - kill plasmodium with ‘anti-malarial drugs like paludrine or daraprim’.

47
Q

what are the steps for the process of testing new drugs

A
  1. a new drug is discovered
  2. test the drug on cells in the lab. check if the drug is toxic (poisonous)~
  3. test the drug on tissues (groups of cells) in the lab, check if the drug is toxic to tissues
  4. test the drug on live animals in the lab, check if its toxic to animals, as theyr similar to humans, check for side effects
  5. trial the drug on healthy volunteers, give low doses at the start, check for side effects
  6. if the drug is found to be safe, test the drug on patients who have volunteered to be involved in a trial, increase amount given to find the best/optimum dose for the drug, check for side effects
    7, use patients, conduct a “double blind” trial, some patients given a placebo and some are given the real drug, neither patients nor the doctor knows who has received the real drug until trail is complete.
  7. apply to the government and international health organizations for permission to the market, sell and prescribe the drug.
48
Q

why are healthy humans used in drug testing

A

because they can cope better with side effects

49
Q

which two people found a way of producing monoclonal antibodies, and in which year

A

milstein and kohler found it in 1975

50
Q

what are antibodies

A

protein molecules produced by immune system.

51
Q

how do antibodies normally work in the body

A

they recognise and bind itself to, and destroy a protein antigen on the surface of a target (eg, bacterium, virus, foreign tissue, allergen.)

52
Q

what would monoclonal antibodies be used for in medicine

A

speed up research
diagnosing and treat diseases

53
Q

what is special about a pure monoclonal antibody

A

will attach itself to one specific antigen

54
Q

how are antibodies made visible when they are used to diagnose disease

A

tagged with a fluorescent dye

55
Q

monoclonal antibodies are produced using lymphocytes from mice which have been injected with an antigen, what problem does this cause when the monoclonal antibodies are used in humans

A

the mouse antibodies might cause a reaction from the human immune system

56
Q

what has to be done to the monoclonal antibodies to make them useful in the diagnosis and treatment of human diseases?

A

they need to be humanised - the top of the antibody is kept but the base of it is replaced with a human version

57
Q

name 4 uses of antibodies in medicine

A

• diagnosis of diseases like chlamydia and aids
• tissue typing for transplants
• monitoring the spread of malaria
• supporting chemotherapy for cancers

58
Q

what is it called when a B lymphocyte is fused with a tumor cell

A

hybridoma

59
Q

describe how monoclonal antibodies are produced

A

1) antigen that stimulate specific antibody production injected into mouse
2) mouse immune system (B-lymphocytes) produce antibodies specific to the antigen
3) One of the antibodies fuse with tumour cells using detergent to help
4) forms hybridoma
5) hybridoma divides repeatedly forming clones
6) all producing monoclonal antibodies
7) monoclonal antibodies isolated & used for diagnosis and treatment of disease

60
Q

3 reasons why scientists use antibodies

A

to treat diseases
research and test/diagnose conditions
Theres an endless supply

61
Q

in the production of monoclonal antibodies, why are cancer cells used

A

cancer cells dont die, they repeatedly multiply by mitosis

62
Q

when detergent is added to the cells, the mixture is gently agitated, suggest why

A

detergent breaks down cell membranes helping the B - lymphocyte and tumor cell to fuse.

63
Q

what risk would be associated with injecting monoclonal antibodies from hybridomas into humans

A

causes an overreaction in the immune system, and it attacks its own body tissues

GCSE WJEC triple science Y11 wales (21 decks)

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