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a level biology flashcards - bb > 11 Disease > Flashcards

11 Disease Flashcards

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AP® Biology flashcards
1
Q

what is the definition of health?

A

being free from disease

having physical, social and mental wellbeing

having good nutrition

being suitably housed

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2
Q

what is the definition of disease?

A

a malfunction of the body and/or mind that adversely affects the health of an individual and leads to impairment of normal functioning

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3
Q

what is a communicable disease?

A

a disease or infection capable of being transmitted or communicated to another living organism

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4
Q

what is required for a disease to be communicated successfully?

A

the pathogen must:

  • enter the host (i.e. pass the first line of defence)
  • colonise affected tissue
  • leading to development of symptoms
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5
Q

what is virulence?

A

a measure of the ability of a pathogen to cause disease

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6
Q

how do bacteria cause harm? give an example

A

production of toxin –> symptoms

e.g. streptococcus produces a pyrogenic toxin, causing a rash and high temperatures

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7
Q

how do viruses cause harm?

A

enter host cell and inhibit normal DNA/RNA/protein synthesis

then use these mechanisms to produce new viral particles

once sufficient have been formed, the cell ruptures and the virus spreads

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8
Q

how do fungi cause harm?

A

secretion of enzymes that causes an allergic reaction and allows the spread of pathogens through tissues

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9
Q

what is the difference between a pathogen and a parasite?

A

a pathogen always causes disease, whereas a parasite doesn’t always

a parasite gains energy from the host, whereas a pathogen does not

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10
Q

how does TB cause disease?

A

inhibits the action of lysosomes in phagocytic leucocytes

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11
Q

what happens during the 1° infection of TB?

A

bacteria multiply inside lung tissue and destroy it

a healthy immune system should be able to deal with it

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12
Q

what happens during the 2° infection of TB?

A

phagocytic cells accumulate round infected cells, causing a tubercule (granuloma)

lung tissue is damaged and sputum becomes blood-stained

can spread to immune system, bones, gut and kidneys

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13
Q

how is TB communicated?

A

inhalation of inhaled droplets (T)

long term contact (T)

contaminated meat/unpasteurised milk (B)

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14
Q

how is TB diagnosed?

A

microscopical analysis of sputum and chest xrays

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15
Q

how can TB be prevented?

A

reduce over-crowding

improve ventilation

testing of cattle

pasteurising milk

improve general health

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16
Q

give four symptoms of TB

A

fever

night sweats

coughing up blood

tiredness

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17
Q

what is latent TB?

A

no symptoms ∴ treatment not required but must be monitored

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18
Q

how is TB treated?

A

isolation during infectious period

intensive care and antibiotics

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19
Q

how are antibiotics used to treat TB?

A

2 antibiotics daily for 6 months

2 antibiotics daily for 2 months

n.b. if infection spreads outside lungs, used for 12 months

20
Q

what are the consequences of developing MDR-TB or XDR-TB?

A

require 18 months’ treatment with up to 4 antibiotics and a treatment team

21
Q

what is a retrovirus?

A

a virus that contains RNA and reverse transcriptase

22
Q

which types of cell does HIV infect?

A

T helper cells, macrophages and brain cells

23
Q

how does HIV cause disease?

A

reverse transcriptase creates a DNA copy of viral genome

becomes part of the cell (a provirus)

provirus activates viral DNA –> synthesis of viral RNA and viral proteins

T helper cell ruptures to prevent immune system resistance

24
Q

how is HIV transmitted?

A

direct contact of contaminated body fluids, e.g.:

  • blood
  • semen
  • mother’s milk/across placenta
25
Q

what are the symptoms of HIV infection?

A

presence of other opportunistic diseases (e.g. TB; pneumonia)

weakened immunity

weight loss

26
Q

how can HIV transmission be prevented?

A

testing ‘at risk’ groups

contraceptives

blood screening

monogamy

education

27
Q

what is the function of a capsid in a virus/bacteria?

A

surrounds and protects enzymes and RNA

28
Q

what is the function of reverse transcriptase?

A

creates double-stranded DNA copy of viral RNA

29
Q

what are features of an acellular particle?

A

cannot:

  • grow
  • reproduce/divide (on its own)
  • transform energy
  • synthesise proteins
30
Q

what are the features of aseptic technique?

A

washing hands

bunsen flame

flaming the inoculating loop

flaming the neck

streaking the plate

incubating at 25.C

31
Q

outline the procedure of Gram staining

A

stained with crystal violet for 30s

washed briefly with deionised water

flooded with iodine (mordent)

rinsed with water again

alternating 95% alcohol and water until no further colour change is observed

counterstain (safranin) applied

32
Q

explain the results of Gram staining

A

Gram +ve: thick peptidoglycan wall takes up crystal violet and binds to it ∴ it is purple

Gram -ve: thin peptidoglycan wall takes up crystal violet, but the alcohol washes it away ∴ counterstain taken up ∴ pink

33
Q

give two strengths and two weaknesses of Gram staining

A

+ distinct colour difference
+ quick + relatively straightforward

  • easy to make method error
  • does not identify individual species
34
Q

what are the four aspects of colony morphology?

A

shape

colour

edges

surface features

35
Q

give two strengths and two weaknesses of colony morphology as a means of identifying bacterial species

A

+ many clear features
+ easy to see contamination

  • many different types have similar colony morphology ∴ it is not a reliable means of identification
36
Q

what are the three shapes of bacterial morphology?

A

cocci = spherical

bacilli = rod-shaped

spirilla = corkscrew

37
Q

what is meant by the ‘incidence rate’?

A

the number of new cases in a population each year

38
Q

what is the definition of an endemic?

A

an infectious disease being constantly present in a population

39
Q

what is the definition of an epidemic?

A

a sudden increase in the incidence of an infectious disease in a confined area

40
Q

what is the definition of a pandemic?

A

an increase in the incidence of an infectious in several countries

41
Q

what is the definition of morbidity?

A

the number of people who have a certain disease

42
Q

what is the definition of mortality?

A

the number of people who have died from a certain disease within a population

43
Q

what are the control measures implemented to reduce the spread of disease?

A

control of population movement

improving hygiene standards

vaccination programmes

improving housing

isolation

provision of drugs

improving nutrition

education of population on prevention methods and symptoms

44
Q

what is a notifiable disease?

A

a disease that, upon diagnosis by a doctor, must be reported to the local authorities and Public Health England

45
Q

give an example of a notifiable disease

A

MMR

whooping cough

viral hepatitis

TB

anthrax

malaria

cholera

food poisoning

a level biology flashcards - bb (35 decks)

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