B3: Infection and Response Flashcards

1
Q

What is a communicable disease

A

A disease caused by a pathogen which can be passed down between animals or plants eg. Flu

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2
Q

What is a pathogen?

A

A disease-causing microorganism e.g. bacteria

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3
Q

How do bacteria cause disease?

A
  • inside the body, they divide rapidly by binary fission.
  • They kill cells and produce harmful toxins
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4
Q

How do viruses cause disease?

A
  • they invade and reproduce inside living body cells, leading to cell damage
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5
Q

Give three ways in which pathogens can be spread and examples

A
  • by air - flu, tuberculosis and the common cold are spread by droplet infection
  • by water- fungal spores in water spread plant disease
  • by direct contact - common in plant diseases and sexually transmitted infections
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6
Q

Give four ways in which the spread of pathogens can be reduced

A
  • Hygiene: handwashing, disinfectants,
  • reducing contact with infected individuals: quarantine
  • removing vectors: use of pesticides and insecticides, removal of habitats
  • vaccination
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7
Q

Why is it important to prevent the spread of viral disease?

A
  • scientists have not yet developed cures for many viral diseases
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8
Q

.Define ‘health’.

A

State of physical and mental well-being

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9
Q

What is measles? Give the main symptoms

A
  • Measles is a serious viral disease that can cause blindness and brain damage
  • fever and a red skin rash
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10
Q

how is measles spread ?

A

by air: through the inhalation of droplets from coughs and sneezes

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11
Q

What is HIV?

A
  • A virus which attacks and damages the immune system until it can no longer function properly
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12
Q

What is AIDS?

A

AIDS: condition resulting from a long-term HIV infection

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13
Q

How is HIV spread?

A
  • Direct sexual contact
  • the exchange of bodily fluids e.g. blood, breastmilk
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14
Q

Give 5 ways the spread of HIV/AIDS be prevented?

A
  • use of 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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15
Q

What is tobacco mosaic virus?

A
  • A plant pathogen which causes leaf discolouration when cells are damaged.
  • Affected areas cannot photosynthesise , reducing the crop yield
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16
Q

How is tobacco mosaic virus spread ?

A
  • contact between infected and healthy plants
  • insects may act as vectors which transfer the virus between different plants
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17
Q

What is salmonella?

A
  • 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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18
Q

Give 4 symptoms of salmonella food poisoning?

A
  • fever
  • abdominal cramping
  • vomiting
  • Diarrhoea
    May be fatal in very young or elderly populations due the risk of dehydration
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19
Q

Give four ways 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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20
Q

What is gonorrhoea?

A
  • A sexually transmitted bacterial infection caused by unprotected sex with an infected individual
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21
Q

Give symptoms of gonorrhoea

A
  • yellow/green discharge from genitals
  • painful urination
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22
Q

State 3 long-term effects of gonorrhoea.

A
  • Long-term pelvic pain,
  • infertility
  • ectopic pregnancies
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23
Q

give three ways the spread of gonorrhoea be
stopped?

A
  • Use condom
  • Limit sexual partners
  • spread can be controlled through the use of antibiotics
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24
Q

what is rose black spot?

A
  • A fungal disease which causes purple or black spots to develop on rose leaves
  • it reduces the area of the leaf which is available for photosynthesis and causes leaves to turn yellow and drop prematurely
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25
Q

How is the rose black spot fungus spread?

A
  • fungal spores are spread by the wind and in water
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26
Q

Give two ways the rose black spot fungus can be treated?

A
  • using fungicides
  • destroying infected leaves
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27
Q

.How can we use Agrobacterium tumefaciens
in plants?

A

They cause galls –> genetic manipulation

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28
Q

What is malaria?

A
  • Malaria is a disease caused by protist pathogens
  • the disease is carried from host to host by mosquitoes , and the protists enter the human bloodstream when they feed
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29
Q

Give symptoms of malaria

A
  • fever
  • shaking
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30
Q

Give four ways the spread of malaria be reduced

A
  • using insecticides
  • using insect nets to avoid bites
  • prevent mosquito breeding by removing stagnant water
  • antimalarial drugs
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31
Q

Give four ways the skin prevents pathogens from entering the body

A
  • acts as a 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
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32
Q

Give two ways the respiratory system prevent pathogens from entering the body

A
  • nose - has hairs and mucus which trap pathogens
  • trachea and bronchi- have mucus that traps pathogens. Ciliated cells move mucus to the mouth so it can be swallowed
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33
Q

How does the stomach prevent pathogens infecting the body ?

A
  • secretes hydrochloric acid - kills any pathogens present
34
Q

How does phagocytosis protect us against disease?

A

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

35
Q

State the three ways in which white blood
cells defend the body.

A
  • Engulf pathogens
  • Produce antibodies
  • Produce antitoxins
36
Q

How does antibody production protect us against disease? (3

A
  • white blood cells produce antibodies which are complementary to a specific antigen on a pathogen
  • the binding of antibodies to antigens causes pathogens to clump together, making them to easier to destroy
  • in the case of a second infection, the correct antibodies can be produced rapidly, preventing the person getting the same disease again
37
Q

How does antitoxin production protect us against disease?

A
  • antitoxins bind to toxins released by pathogens and neutralise them
38
Q

What is a vaccination and how does it work

A
  • contains a dead or inactivated form of the pathogen which stimulates white blood cells to produce complementary antibodies to the pathogen
  • in the case of a second infection, memory cells can rapidly produce the correct antibodies and prevent illness
39
Q

What is herd immunity?

A
  • If a sufficiently high proportion of a population are immune to a disease ( through vaccination)
  • the spread of this disease will be limited
40
Q

Give three advantages of vaccinations

A
  • eradicated many deadly diseases
  • epidemics can be prevented
  • herd immunity protects those who cannot have vaccinations
41
Q

Give two disadvantages of vaccinations

A
  • not guaranteed to work as might not protect against multiple strains of pathogen
  • may be side effects or adverse reactions
42
Q

What drugs are used to cure some bacterial diseases?

A

antibiotics - they can kill bacterial pathogens inside the body

43
Q

How do antibiotics work?

A
  • antibiotics kill bacterial pathogens inside the body but not human cells
44
Q

Why are antibiotics ineffective to treating viral diseases

A
  • have no effect on viral pathogens as they live inside the host human cells
  • it is difficult to design drugs that would kill the virus and not destroy human cells at the same time
45
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
46
Q

give two ways to prevent antibiotic resistance

A
  • avoid overuse and unnecessary use of antibiotics
  • finish antibiotic courses to ensure all bacteria is killed
47
Q

What effect do painkillers have on infectious diseases?

A
  • painkillers can only treat the symptoms such as mild to moderate pain but do not kill pathogens
48
Q

Which plant did the heart drug digitalis
originated from?

A

Foxgloves

49
Q

What painkiller originates from a compound found in willow bark?

A

Aspirin

50
Q

What type of antibiotic was discovered by Alexander Fleming from a type of mould?

A

Penicillin

51
Q

What are the 4 qualities of a good medicine?

A
  • efficacy
  • safety
  • stable
  • able to be taken in and removed easily
52
Q

New drugs are tested extensively for three
factors. Name the three factors.

A

Toxicity, efficacy, dose

53
Q

How is preclinical testing carried out?

A

in a lab - using cells, tissues and live animals

54
Q

Describe how clinical testing is carried out (4)

A
  • uses healthy volunteers and patients
  • the drug is tested at a low dose on healthy people
  • then tested on patients and on a larger scale to find the optimum dose
  • one group receives a placebo and the other group receive the actual drug to test efficacy
55
Q

What is the difference between a single-blind and a double blind trial?

A

single-blind trial: only the doctor knows whether the patient is receiving the drug or the placebo
double blind trials: neither the patient nor the doctor knows ; helps remove bias on the part of the doctor

56
Q

Define placebo

A

A medicine that does not contain the active
drug being tested

57
Q

define ‘ peer review’

A
  • where the results of drug trials are checked over by scientists knowledgeable in this field
58
Q

what are monoclonal antibodies (mAbs)?

A
  • antibodies that are clones from one parent cell
  • specific to one type of antigen
59
Q

Describe how monoclonal antibodies are produced

A
  1. Specific antigen injected into an animal
  2. B-lymphocytes producing complementary antibodies extracted
  3. B-lymphocytes fuse with myeloma ( tumour) cells to form hybridoma cells - these cells can divide and produce antibody
  4. Hybridoma cells are cultured
  5. Monoclonal antibodies collected and purifed
60
Q

Outline the 5 uses of monoclonal antibodies

A
  • used in pregnancy tests
  • Disease diagnosis
  • Monitoring chemical levels in blood
  • location of cancer cells and blood clots
  • treatment of Cancer
61
Q

What are myeloma cells?

A
  • type of tumour cells
62
Q

What do pregnancy kits test for?

A

hCG in urine

63
Q

What does a pregnancy test consist of?

A
  • A stick containing monoclonal antibodies (mABs) specific to hCG
  • mABs attached to a blue bead ( free to move)
  • mABs fixed to the test stick
64
Q

Describe what happens to the test stick if a woman is pregnant

A
  • hCG in urine binds to mAbs attached to a blue bead
  • mAbs with hCG diffuse up dipstick
  • mAbs fixed to the stick bind to hCG
  • blue line forms

if not pregnant:
no hCG so a blue line is not formed

65
Q

Give 3 advantages of using monoclonal antibodies to test for pathogens

A
  • specific to one particular antigen
  • very accurate
  • quick results
66
Q

Why can monoclonal antibodies be used to target cancer cells

A
  • cancer cells have specific antigens called tumour markers on their membranes
  • mAbs are specific to one type of antigen so can be targeted to ‘ tumour markers’ without damaging other cells
67
Q

Describe how monoclonal antibodies can be used to diagnose cancer

A
  • mAbs attached to a radioactive substance
  • mAbs injected into the patient’s bloodstream
  • mAbs bind to tumour markers on cancer cells
  • emitted radiation is detected using a specialised scanner enabling doctors to determine the location of cancer cells
68
Q

How can monoclonal antibodies be used to target drugs to cancer cells?

A
  • mAbs attached to an anti-cancer drug
  • mAbs injected into the patient’s bloodstream
  • mAbs bind to tumour markers on cancer cells
  • anti-cancer drug destroys cancer cells
69
Q

Give three reasons why cancer treatments that use monoclonal antibodies favoured over traditional treatments

A
  • radiotherapy and chemotherapy target rapidly dividing cells - no way to differentiate from healthy cells
  • healthy cells (e.g. hair follicle ells ) are damaged as a consequence , producing unpleasant side effects
  • mAbs only target cancer cells, reducing damagee to normal cells
70
Q

How can monoclonal antibodies be used to locate blood clots?

A
  • mAbs attached to a radioactive substance
  • mAbs target and bind to specific proteins in blood clots
  • radiation emitted by mAbs is detected, enabling the location of blood clots to be identified
71
Q

What is a disadvantage to the use of monoclonal antibodies on treatment?

A

More side effects than expected (skin rash)

72
Q

How do aphids damage
plants?

A
  • Feed on phloem sap, so plant loses glucose
    which can be converted to proteins for growth.
    This means less proteins is produced and the
    plants suffer from stunted growth
  • Vectors of pathogens
73
Q

Give two ways we can reduce the number of aphids

A
  • chemical pesticides
  • biological pest control - using ladybirds
74
Q

Why do plants need a good supply of nitrate ions?

A
  • nitrate ions are required to convert sugars ( by joining with glucose) into proteins for growth
  • the growth of the plant will be stunted if there is inadequate supply
75
Q

Why do plants need a good supply of magnesium ions?

A
  • ions are required to synthesise chlorophyll which absorbs light energy during photosynthesis
  • the leaves as a result of a lack of supply cannot photosynthesise properly and they turn yellow ( chlorosis)
76
Q

Give 6 symptoms of disease in plants ?

A
  • stunted growth
  • spotted leaves
  • decay/rotting
  • malformation of stems/leaves
  • discolouration
  • presence of pests
77
Q

Give three ways in which plant disease can be identified?

A
  • reference to a gardening website or manual
  • laboratory testing
  • monoclonal antibody test kits
78
Q

Give 4 examples of physical defence responses used by plants

A
  • cellulose cell walls
  • tough waxy cuticle on leaves
  • outside layer on stems / bark on trees
  • leaf fall
79
Q

Give two examples of chemical defence responses used by plants

A
  • antibacterial chemicals
  • poisons
80
Q

Give three examples of mechanical defence responses used by plants

A
  • thorns and hairs to deter animals
  • leaves that droop/ curl on contact
  • mimicry to trick animals