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aqa gcse biology free > T3 communicable diseases > Flashcards

T3 communicable diseases Flashcards

1
Q

what is a pathogen

A

disease-causing microorganism

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2
Q

how do bacteria cause disease

A

once inside the body, they divide rapidly by binary fission

kill cells and produce harmful toxins

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3
Q

how do viruses cause disease

A

invade and reproduce inside living body cells, leading to cell damage

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4
Q

give 3 ways in which pathogens can be spread

A

air - flu, tuberculosis and the common cold are spread by droplet infection

water - fungal spores in water spread plant diseases

direct contact - common in plant diseases and STIs

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5
Q

give 4 ways in which the spread of pathogens can be reduced

A

hygiene - handwashing, disinfectants, tissues

reducing contact with infected individuals - quarantine

removing vectors - use of pesticides and insecticides, removal of habitats

vaccination

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6
Q

why is it especially important to prevent the spread of viral diseases

A

scientists haven’t developed cures for many viral diseases

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7
Q

what is measles

A

serious viral disease that can cause blindness and brain damage.

main symptoms are fever and red skin rash

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8
Q

how is measles spread

A

air - inhalation of droplets from coughs and sneezes

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9
Q

what is HIV / AIDS

A

Hiv - virus which attacks and damages the immune system until it can no longer function properly

AIDs - condition resulting from a long-term HIV infection.

no cure or vaccine

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10
Q

how is HIV spread

A

direct sexual contact and the exchange of bodily fluids

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11
Q

how can the spread of HIV/AIDS be prevented

A

condoms

screening of blood for transfusions

not sharing needles

bottle-feeding by HIV-positive mothers

use of antiretroviral drugs to prevent the development of AIDS

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12
Q

what is tobacco mosaic virus

A

plant pathogen which causes lead discolouration when cells are damaged

affected areas cannot photosynthesise, reducing crop yield

no treatment so farmers grow TMV-resistant crop strains to avoid infection

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13
Q

how is TMV spread

A

contact between infected and healthy plants

insects may act as vectors which transfer the virus between different plants

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14
Q

what is salmonella

A

type of bacteria found in raw meat, poultry and eggs

if they enter the body via food poisoning, they can affect natural gut bacteria

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15
Q

symptoms of salmonella food poisoning

A

fever
abdominal cramping
vomiting
diarrhoea

may be fatal in very young or elderly due to risk of dehydration

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16
Q

how can the spread of salmonella be limited

A

vaccinating animals intended for consumption

keep raw meat away from cooked meat

disinfect hands and surfaces after contact with raw meat

thoroughly cook meat

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17
Q

what is gonorrhoea

A

ST bacterial infection caused by unprotected sex with an infected individual

yellow/green discharge from genitals and painful urination

spread can be controlled through antibiotics + condoms

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18
Q

what is rose black spot

A

fungal disease which causes purple or black spots to develop on rose leaves

reduces the area of the lead which is available for photosynthesis and causes leaves to turn yellow and drop prematurely

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19
Q

how is the rose black spot fungus spread

A

fungal spores are spread by the wind and in water

20
Q

how can rose black spot fungus be treated

A

using fungicides

destroying infected leaves

21
Q

what is malaria

A

disease caused by protist pathogens

disease is carried from host to host by mosquitoes, and the protists enter the human bloodstream when they feed

fever and shaking, and it may be fatal in some cases

22
Q

how can the spread of malaria be reduced

A

using insecticides

using insect nets to avoid bites

prevent mosquito breeding by removing stagnant water

antimalarial drugs

23
Q

how does the skin prevent pathogens from entering the body

A

acts as physical barrier

scab formation after skin is cut/wounded

antimicrobial secretions which can kill pathogens

healthy skin flora compete with pathogens and act as an additional barrier

24
Q

how does the respiratory system prevent pathogens from entering the body

A

nose - has hairs and mucus which trap pathogens

trachea and bronchi - mucus that traps pathogens.
Ciliated cells move mucus to the mouth so it can be swallowed

25
Q

how does the stomach prevent pathogens infecting the body

A

secretes hydrochloric acid - kills any pathogens present

26
Q

how does phagocytosis protect us against disease

A

white blood cells (phagocytes) ingest and destroy pathogens so they cannot infect more cells

27
Q

how does antibody production protect us against disease

A

WBCs produce antibodies which are complementary to a specific antigen on a pathogen

binding of antibodies to antigens causes pathogens to clump together, making them easier to destroy

in case of 2nd infection, correct antibodies can be produced rapidly, preventing the person getting the same disease again

28
Q

how does antitoxin production protect us against disease

A

antitoxins bind to toxins released by pathogens and neutralise them

29
Q

what is a vaccination

A

contains a dead or inactivated form of the pathogen which stimulates WBCs to produce complementary antibodies to the pathogen

in case of 2nd infection, memory cells can rapidly produce the correct antibodies and prevent illness

30
Q

what is herd immunity

A

if a sufficiently high proportion of a population are immune to a disease, the spread of this disease will be limited

31
Q

advantages of vaccinations

A

eradicate many deadly diseases

many epidemics can be prevented by vaccinations

herd immunity protects those who cannot have vaccinations

32
Q

disadvantages of vaccinations

A

not guaranteed to work - might not protect against multiple strains of a pathogen

may have side effects or adverse reactions

33
Q

what drugs are used to cure some bacterial diseases

A

antibiotics - they can kill bacterial pathogens inside the body

34
Q

how do antibiotics work

A

kill bacterial pathogens inside the body, but do not kill human cells

whilst some kill a wide range of bacteria, it is important that the right antibiotic is used for specific bacteria

35
Q

why can antibiotics not be used to treat viral diseases

A

have no effect on viral pathogens as they live inside the host’s cells

therefore, it is difficult to design drugs that would kill the virus and not destroy human cells at the same time

36
Q

what is antibiotic resistance

A

occurs when mutations lead to individual bacteria being resistant to an antibiotic

these bacteria are able to survive, reproduce and pass on their alleles, leading to a greater proportion of antibiotic-resistant bacteria

concerning as some types of bacteria are becoming resistant to all known antibiotics, so the diseases cannot be cured

37
Q

how can we prevent antibiotic resistance

A

avoid overuse and unnecessary use of antibiotics

finish antibiotic courses - to ensure all bacteria are killed

38
Q

what effect do painkillers have on infectious diseases

A

only treat symptoms but don’t kill pathogens

39
Q

what plant is the heart drugs digitalis extracted from

A

foxgloves

40
Q

what painkiller originates from a compound found in willow bark

A

aspirin

41
Q

what antibiotic was discovered by Alexander Fleming from a type of mould

A

Penicillin

42
Q

what are the 4 qualities of a good medicine

A

effective
stable
safe
able to be taken in and removed easily

43
Q

3 main factors tested for when developing new drugs

A

toxicity
efficacy
dose

44
Q

how is preclinical testing carried out

A

in a lab - uses cells, tissues and live animals

45
Q

how is clinical testing carried out

A

uses healthy volunteers and patients

drugs is tested at low dose on healthy, then tested on patients and on a larger scale to find the optimum dose

often, 1 group gets placebo and other receive the actual drug, in order to asses efficacy

46
Q

difference between single-blind and double-blind trial

A

S: only doc knows whether the patient is receiving the drug or placebo

D: neither patient nor doctor knows
Helps remove bias on the part of the doctor

47
Q

what is peer review

A

where the results of drug trials are checked over by scientists knowledgeable in this field

aqa gcse biology free (25 decks)

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