B5 Flashcards

Communicable diseases

1
Q

What is a communicable disease and how does someone suffer from one ?

A
  • transmissible disease
  • spread by pathogens
    [] airborne
    [] waterborne
    [] vectors
    [] direct contact
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2
Q

What is a pathogen ?

A

disease-causing microorganism
- bacteria
- fungi
- protists
- viruses

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3
Q

How do bacteria make you ill ?

A
  • once the bacteria have got inside the body, they reproduce mitotically very fast (binary fission)
  • produce toxins that are poisonous and make you feel ill, sometimes directly damaging cells
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4
Q

How do viruses make you ill ?

A
  • once inside the body, they occupy cells, using cellular resources for their own reproduction and growing in number
  • once cell is too full, it bursts and the viruses spread throughout the body, repeating the process with nearby cells
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5
Q

Describe how to grow bacteria in the lab (RQP)

A
  • disinfect working surface and wear gloves
  • gather equipment
    [] bunsen burner
    [] inoculating loop
    [] agar gel
    [] petri dish + lid
    [] incubator
    [] bacteria suspension
  • melt + pour the agar gel into the petri dish and wait for it to cool/set
  • sterilise the inoculating loop by heating until red hot in the bunsen burner roaring flame
    [] do not set down or blow on it whilst it cools
  • once cool, dip the loop in the bacteria suspension
  • partially open the petri dish’s lid and draw zigzags on the gel with the inoculating loop
  • close the lid and tape shut (not all the way around so oxygen can still get in)
  • place upside down in the incubator so condensation doesn’t fall on the bacteria and contaminate the colony
    [] incubate at 25 degrees and no higher, or else risk of culturing dangerous bacteria
    [] allow to grow for a week
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6
Q

What is the formula for calculating bacterial growth ?

A
  • first calculate number of divisions in the total time period
    [] if time period is 2h, and bacteria divide every 30 minutes, they divide 2 times every hour and thus there are 4 divisions in total
  • then, calculate the bacterial growth:

bacteria at end of growth period = start bacteria x 2^(no. division)

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7
Q

Describe how to investigate the effect of different chemicals on bacterial growth in the lab (RQP)

A
  • disinfect working surface and wear gloves
  • gather equipment
    [] 3 filter paper circles
    [] chemical A and chemical B
    [] bunsen burner
    [] inoculating loop
    [] agar gel
    [] petri dish + lid
    [] incubator
    [] bacteria suspension
  • melt + pour the agar gel into the petri dish and wait for it to cool/set
  • soak a filter paper circle in chemical A and another in chemical B; leave the third with no chemical as a control
  • place these filter paper circles on the agar gel
  • sterilise the inoculating loop by heating until red hot in the bunsen burner roaring flame
    [] do not set down or blow on it whilst it cools
  • once cool, dip the loop in the bacteria suspension
  • partially open the petri dish’s lid and draw zigzags on the gel with the inoculating loop
  • close the lid and tape shut (not all the way around so oxygen can still get in)
  • place upside down in the incubator so condensation doesn’t fall on the bacteria and contaminate the colony
    [] incubate at 25 degrees and no higher, or else risk of culturing dangerous bacteria
    [] allow to grow for a week
  • observe the zones of inhibition, if any, surrounding the filter paper circles with chemical
  • calculate the area of these zones of inhibition and note for the two chemicals
    [] determine which chemical is a better preventor of bacterial growth by which’s zone of inhibition has the greater area
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8
Q

What conditions are needed for bacterial growth ?

A
  • nutrients (minerals + sugars)
  • oxygen
  • warmth (usually upwards of 25 degrees)
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9
Q

Describe the effects of 2 common plant pests

A
  • aphids
    [] pierce phloem of plant with SHARP MOUTHPIECE
    [] suck out sugars from the phloem
    [] derive plant of products of photosynthesis thus, and inhibit proper growth of plant, synthesis of proteins etc.
    [] act as vectors of disease
    [] natural predators are ladybirds
  • nematode worms
    [] feed on plant roots
    [] damages root hair cells and prevents plant from taking in water and valuable mineral ions from the soil
    [] plant loses turgor pressure in cells (flaccid), loses structure, loses ability to photosynthesise effectively and form proteins and other compounds
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10
Q

Describe ways to prevent the spread of disease

A
  • proper personal hygiene as well as proper handling of food
  • destroying vectors of disease
  • getting vaccinated against a disease
  • isolating infected individuals
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11
Q

Describe the symptoms, spread, cause and treatment for measles

A
  • symptoms:
    [] red rash/bumps
    [] high fever
    [] coughing/sneezing
    [] can cause blindness and death if untreated or complicated
  • spread:
    [] airborne in water droplets expelled from the body when coughing/sneezing
  • cause:
    [] virus
  • treatment:
    [] no cure, so infected individuals must be isolated to stop the spread of the disease
    [] there is a vaccination however that can be taken prior to getting measles
    [] antibiotics cannot be taken as it is a viral infection
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12
Q

Describe the symptoms, spread, cause and treatment for HIV/AIDS

A
  • symptoms:
    [] initially, only mild, flu-like symptoms
    [] when AIDS becomes active, can cause death
  • spread:
    [] direct sexual contact
    [] sharing of needles/bodily fluids (including breastfeeding)
  • cause:
    [] virus
  • treatment:
    [] antiretroviral drugs (only work before HIV becomes AIDS)
    [] prevention via condom use, not sharing needles/blood transfusions/HIV positive mothers bottle-feeding instead of breastfeeding
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13
Q

Describe the symptoms, spread, cause and treatment for TMV (tobacco mosaic virus)

A
  • symptoms:
    [] mosaic pattern of discolouration on leaves, disallowing the plant from photosynthesising properly
    [] can greatly reduce the crop yield
  • spread:
    [] direct contact
    [] insects acting as vectors
  • cause:
    [] virus
  • treatment:
    [] good hygiene
    [] good pest control
    [] isolating infected plants and the surrounding plants
    [] growing TMV-resistant plant strains
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14
Q

Describe the symptoms, spread, cause and treatment for salmonella

A
  • symptoms:
    [] diarrhoea
    [] vomiting and nausea
    [] abdominal cramps
  • spread:
    [] improperly cooked meat or eggs which contain the salmonella bacteria
    [] spread of the bacteria around kitchen due to poor hygiene, sanitation or washing the infected meat with a lack of care for splashing
  • cause:
    [] bacteria
  • treatment:
    [] UK poultry vaccinated against salmonella
    [] cook chicken thoroughly
    [] practice good hygiene when preparing raw chicken
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15
Q

Describe the symptoms, spread, cause and treatment for gonorrhoea

A
  • symptoms:
    [] pain on urination
    [] thick yellow discharge from genitals
    [] long-term pelvic pain
    [] infertility
    [] ectopic pregancy
  • spread:
    [] sexual contact
  • cause:
    [] bacteria
  • treatment:
    [] antibiotics
    [] barrier methods of contraception
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16
Q

What does bacterial disease look like in plants ?

A
  • very few bacterial diseases
  • some cause crown galls (abnormal growths)
17
Q

Describe the symptoms, spread, cause and treatment for fungal diseases in humans

A
  • skin fungi can be treated with anti-fungal topical medicines
  • deep seated fungal infections can damage heart valves, muscle etc. and are hard to treat in humans
  • usually spread through direct contact, though spores may also be ingested through water or air
18
Q

Describe the symptoms, spread, cause and treatment for rose black spot

A
  • symptoms:
    [] purple/black spots on rose leaves
    [] leaves eventually turn yellow and drop off early, limiting photosynthesis and stunting flower growth
  • spread:
    [] water/airborne (carried by the wind then get picked up by rain as it falls, splashing onto the rose plants)
  • cause:
    [] fungus
  • treatment:
    [] burning affected plants/dead leaves
    [] chemical fungicides
    [] resistant strains of roses
    [] still no prevention or cure 100% though
19
Q

Describe the symptoms, spread, cause and treatment for malaria

A
  • symptoms:
    [] high fever
    [] shaking
    [] weakens person’s immune system and body generally if doesn’t kill them
  • spread:
    [] mosquitoes as vectors
  • cause:
    [] protist
  • treatment:
    [] if diagnosed early, can be overcome with a varied regiment of drugs
    [] insecticide impregnated mosquito nets in windows/over beds
    [] removing standing/still water and spraying water with insecticides to kill larvae and stop the mosquitoes from breeding
    [] antimalarial drugs before being bitten to prevent protists infecting you if you are bitten
20
Q

Describe how your skin protects from disease/infection

A
  • acts as a physical barrier to pathogens trying to enter the body
    [] if barrier is broken, platelets in blood patch up the wound to seal it again whilst the skin heals beneath the scab
  • skin produces antimicrobial secretions to kill pathogens before they enter the body
  • covered in microorganisms, acting as an extra barrier to pathogenic entry
21
Q

Describe how your respiratory/digestive system protects from disease/infection

A
  • nose:
    [] hairs and mucus that trap particles in the air that may contain/host pathogens or are irritants to your lungs
  • bronchi/trachea:
    [] secrete mucus, trapping pathogens in the air
    [] mucus is wafted up to the back of the throat to be swallowed (and any pathogens destroyed in stomach acid) by the cilia
  • stomach acid destroys ingested pathogens
22
Q

Describe how your immune system protects from disease/infection

A
  • phagocytosis
    [] white blood cells ingest and destroy pathogens so they can’t infect you
  • producing antitoxins
    [] combat the bacterial toxins that poison surrounding cells/tissues
  • producing antibodies
    [] target specific bacteria and destroy them by locking onto and then unravelling their external proteins to destroy them
    [] memory cells store which antibodies work against which bacteria, so that your body can fight the infection quickly if you get it again
23
Q

What is an example of non-communicable disease in plants ?

A

mineral deficiencies

24
Q

Why are nitrate ions needed in plants, and what are the symptoms of deficiency in this mineral ?

A
  • protein synthesis
  • deficiency means lack of protein synthesis and thus stunted growth and improper production of fruit/crop
25
Q

Why are magnesium ions needed in plants, and what are the symptoms of deficiency in this mineral ?

A
  • chlorophyll production
  • yellowing leaves/chlorosis; lack of photosynthesis
    [] growth slows
26
Q

How can mineral deficiencies in plants be cured/treated ?

A

using fertilisers with the needed mineral ions to replenish natural levels in the soil

27
Q

Give 7 common symptoms of plant disease

A
  • visible pests like aphids
  • discolouration in leaves or petals
  • black/purple spots
  • stunted growth
  • areas of decay/rotting
  • abnormal growths like crown galls caused by bacterial infection
  • malformed stems/leaves (most likely due to pests)
28
Q

How can people identify plant disease ?

A
  • comparison of infected plant to disease descriptions in a gardening manual/online
  • lab tests using samples of the diseased plant and techniques like DNA analysis
  • monoclonal antibody testing kits
29
Q

Describe some physical plant defence methods

A
  • cellulose cell wall provides an extra barrier against infection
  • tough waxy cuticle on top of leaf
  • bark on trees/layer of dead cells surrounding stem, acting as added physical barriers
    [] when dead cells lost/shed, pathogens fall off with them
  • leaf fall, preventing diseases on the leaves from spreading to the rest of the tree/bush/plant
30
Q

Describe some chemical plant defence methods

A
  • producing antibacterial chemicals in petals and leaves
    [] mint and witch hazel, as well as tea tree
  • can be extracted and used as antibiotics
  • poisons
31
Q

Describe some mechanical plant defence methods

A
  • drooping/curling leaves/stem to frighten predators when touched
  • produce chemical compounds when attacked to warn other members of the population, which can then activate defence genes, making them less susceptible to attack
  • thorns
  • hairs
  • mimicry of insects or unhealthy plants to discourage predation