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AQA GCSE Biology > Topic 3: Infection and Response > Flashcards

Topic 3: Infection and Response Flashcards

1
Q

What is the definition of a pathogen?

A

Microorganisms that cause infectious disease and depend on host to provide conditions and nutrients needed to grow and reproduce

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2
Q

Name the four types of pathogen and how they are spread

A

Virus, Bacteria, Protists, Fungi
Infect plants and animals and spread by direct contact, water or air

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3
Q

Why are bacteria and viruses dangerous?

A

Can reproduce rapidly in body and produce toxins which damage tissues and makes us feel ill. These toxins cause symptoms of infection which include high temp. , nausea etc. Viruses also live and reproduce in cells, which cause cell damage

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4
Q

What is HIV short for?

A

Human Immunodeficiency Virus

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5
Q

What are the symptoms of HIV?

A

-Flu-like illness
-Enter lymph nodes and attack immune cells
-Can develop into AIDS in which body can no longer deal with infections or cancers

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6
Q

How is HIV spread?

A

-Exchange of body fluids (blood shared from needles)
-Sexual Contact with infected person

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7
Q

How can the spread of disease be reduced?

A

-Hygiene Measures
>Covering Mouth
>Washing Hands
-Destroying Vectors (Mosquitoes vector for malaria)
-Isolation of infected individuals
-Vaccination

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8
Q

How can HIV be prevented/treated?

A

-Don’t share needles
-Protection
-Antiretroviral Drugs

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9
Q

What is measles and what are the symptoms?

A

Viral disease which causes fever and red skin rash

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10
Q

How is measles spread?

A

-Contact with infected person
-Inhalation of droplets from coughs or sneezes

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11
Q

How can measles be prevented/treated?

A

-There is no treatment for measles
-Prevented with the MMR Vaccine (Measles, Mumps, Rubella)
Children are vaccinated early as can be fatal if complications arise

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12
Q

What is TMV and what does it affect?

A

-Tobacco Mosaic Virus
-Only affects plants
- Widespread plant pathogen affecting species including tomatoes

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13
Q

What are the symptoms of TMV?

A
  • Distinct ‘mosaic’ pattern of discoloration on leaves
    -Can’t photosynthesise
    -Stunted Growth which may lead to death
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14
Q

How is TMV spread?

A

-Physical Contact with infected leaves/tools

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15
Q

How can TMV be prevented/treated?

A

-Prevent transmission
-Kill infected tissue/plants
-Disinfect tools between use

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16
Q

What are the symptoms of salmonella?

A

-Fever
-Abdominal Cramps
-Vomiting
-Diarrhoea

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17
Q

How is Salmonella spread?

A

-Bacteria is ingested in food due to being prepared in unhygienic conditions

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18
Q

How can Salmonella be prevented/treated?

A

-Check source of food
-Don’t eat raw/uncooked poultry
-Poultry are vaccinated against it to control spread

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19
Q

Explain why Malaria is special

A

-Classified as protist
-No pathogens are malaria but the pathogens which cause malaria belong to protists plasmodium

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20
Q

What are the symptoms of Malaria?

A

-Recurrent episodes of fever
-Cam be fatal

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21
Q

How can Malaria be spread?

A

-Female, Pregnant, Anopheles Mosquitoes which have previously bitten someone infected

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22
Q

How can Malaria be prevented/treated?

A

-Preventing vector (mosquito) from breeding
-Mosquito nets to avoid getting bitten
-Anti-malaria biotics

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23
Q

Describe the life cycle of Plasmodium

A

-Mosquito bites an infected person
-Gametes for plasmodium enter mosquito
-Plasmodium moves to mosquito’s salivary glands
-Mosquito bites another person
-Injects saliva and plasmodium enters bloodstream
-Plasmodium moves to liver and multiplies
-Moves back into blood and invades red blood cells
-Plasmodium produces gametes in red blood cell
-Bursts cell and gametes enter blood plasma

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24
Q

Non-Specific Defence Systems

A

Ways humans defends itself against entry of pathogens which include: Skin, Stomach acid, Nose, Trachea/Bronchi, Tears, Blood Clots

25
Phagocytosis Brief Description
If pathogen enters body, immune system tries to destroy pathogens with phagocytes which engulf and destroy pathogens. This can include inflammation or ingestion.
26
What are the two main types of drug?
Recreational and Medicinal Drugs
27
What are the two further sections of medicinal drugs?
Painkillers: Reduces pain, relieves symptoms, doesn't kill pathogens, doesn't heal Examples include: Paracetamol, Ibuprofen, Aspirin, Morphine Antibiotics: Kill bacteria without damaging animal cells, Don't kill viruses Examples include: Penicillin, Amoxycillin
28
How was penicillin discovered?
-Alexander Fleming -Came from fungus penicillium -Experiment with bacteria colonies on Petri Dish -Penicillium grew on dish -Killed bacteria on it
29
What are the natural origin of drugs (from plants):
Coffee- Caffeine Cocoa, Tea, Cola- Theophylline Poppy- Codeine Tobacco- Nicotine Mint- Menthol Foxglove- Digitalin Belladonna- Atropine Yew- Taxol Thyme- Thymol
30
What is the first stage of modern day drug development?
Synthesis/Extraction > Identify active ingredient and have an idea of it being a drug
31
What is the second stage of modern day drug development?
Preclinical Testing >Test on cell/tissues to see if drug works and how well it works e.g. toxicity
32
What is the third stage of modern day drug development?
Clinical Trials (Three Phases) 1) Test on healthy volunteers to look for side effects LOW DOSAGE ONLY 2) Test on patients to see strength/potence and side effects LOW DOSAGE ONLY 3) Test on patients with INCREASED dosage to see if it works, suitable dosage, side effects
33
What is the main focus of testing drugs?
1) Side effects / Toxicity 2) Efficacy 3) Dosage
34
What is a placebo?
Drug that has no effect to see difference, control group, COMPARISON
35
What is a double blind trial?
Neither the patient or doctors know who takes the placebo to prevent bias
36
What is peer-review?
When a study has been checked by other scientists in a different lab
37
What are the three types of white blood cell?
-Phagocytes -B-Lymphocytes -T-Lymphocytes
38
What is a T-Lymphocyte?
Recognise antigens and attack them directly or activate B-Lymphocytes
39
What is a B-Lymphocyte?
Produce antibodies and antitoxins
40
What is an antibody?
Special Y-Shaped proteins and bind to antigens on pathogens causing them to clump and be destroyed
41
Why are monoclonal antibodies used compared to normal white blood cell?
White blood cell can only divide if they don't produce antibodies, they don't divide as soon as it does
42
Characteristics of MCA
-Come from cells which have been cloned -Produced and used over long periods of time and are lots of copies of a specific antibody - Produced in lab - Allows white blood cell to divide whilst producing antibodies
43
How is MCA produced?
1) Mouse injected with specific antigen to stimulate lymphocytes to make particular antibody 2) Extracted lymphocytes combine with particular cancerous tumour cell. Detergents are used to help break down cell membrane of both cells to help them fuse 3) Create hybridoma cell, which divides and makes antibodies 4) Single hybridoma cells are cloned to produce identical cell that produce same antibody 5) Large amounts of MCA collected and purified
44
What are MCA's used for?
-Pregnancy Testing Kits -Diagnostic Tool (HIV) -Industrial production interferon (treats cancers) -Specific drug delivery
45
How do pregnancy tests work?
Urine is placed onto strip and urine travels through paper to three zones: Reaction Zone, Test Zone and Control Zone
46
Describe the Reaction Zone of the pregnancy test
Mobilised antibodies attach/bind to hCG with a colour-reacting enzyme
47
Describe the Test Zone of the pregnancy test
Immobile antibodies bind to hCG antibodies and release dye from enzymes
48
Describe the Control Zone of the pregnancy test
Test for mobilised antibodies which didn't bind to hCG to see if test was faulty and release dye from enzymes
49
How is MCA used for identification?
Antibodies attached to dye that will glow under UV light which helps with identification process
50
What are the three possible ways to treat cancer with MCA?
1) Monoclonal antibodies directly stimulate immune system to respond, attack and destroy cancer cell 2) MCA block receptors, preventing them from growing, dividing 3) MCA used to transport toxic drugs or radioactive substances which control growth of cell and attack them
51
What are some possible side effects of MCA?
-Chills or Fever -Itchy Rashes -Nausea -Breathlessness/Wheezing -Headaches -Change in blood pressure
52
What are the factors to tell if a plant is unhealthy / diseased?
- Stunted Growth - Spots on leaves - Plant pests - Decolouration
53
What is chlorosis?
Breakdown of chlorophyll due to lack of magnesium ions which cause yellow on leaves and affects photosynthesis
54
What are examples of mechanical plant defences?
- Thorns and hairs deter animals from eating or touching them - Leaves which droop or curl when touched - Mimicry to trick animals into not eating or laying eggs on leaves
55
What are examples of chemical plant defences?
- Production of anti-bacterial / fungal chemicals - Poisons to deter herbivores
56
What are examples of physical plant defences?
- Cellulose cell walls - Tough waxy cuticle on leaves - Layer of dead cell around cell (bark) which fall off, taking pathogens with them
57
What is rose black spot?
- Fungal disease where purple or black spots develop on leaves, turn yellow and drop early - Spread by water and wind
58
How is rose black spot treated?
- Using fungicides or removing infected leaves
59

AQA GCSE Biology (7 decks)

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