Grade achieved: 9
I have put so much hard work into making this set of notes. Achieving grade 9 and constantly getting top grades at school proved that my hard work paid off.
My notes are mostly based on 10+ years of mark schemes from past papers, and some from revision guides + online reso...
How cause? Bacteria • Produce toxins - damage tissues - ill
• Reproduce rapidly in binary fusion
Viruses • Live & reproduce rapidly inside cell - cell damage
How By air • Droplet infection
spread? • Ppl sneeze - expel droplet with pathogens from breathing system - other
ppl breath in
By water • Dirty water - cholera
Direct • Cuts - give excess to blood eg HIV
contact • Shake hands
How 1. Wash hands
prevent? 2. Drink clean water
3. Good hygiene
4. Isolate infected individuals
5. Destroy / control vectors eg mosquitoes
6. Vaccination
What is pandemic? (1)
• A disease affecting ppl in many countries
3.1.2 Viral diseases
Measles
Spread by • Inhalation of droplets from coughs/sneezes
Symptoms • Fever, red skin rash
• (serious - blindness, brain damage, fatal)
Prevention • Vaccination
• Isolate infected individuals
HIV/AIDs
Spread by • Exchange of body fluids eg blood when share needles
• Unprotected sexual contact with infected person
Symptoms • Flu-like illness
• Virus attack & remain hidden in immune system
• AIDs (last stage of HIV) occurs when immune system becomes so badly damaged - X
deal with other infections
Treatment • Antiretroviral drugs to control attack
Prevention • Use condoms
• Don't share needles
2
, AQA GCSE Biology notes Topic 3 – Infection and response
• Use HIV +ve mother bottle to feed children
Tobacco mosaic virus (TMV)
Spread by • Contact between healthy & infected plants & vectors
Symptoms • Give distinctive 'mosaic' pattern of discoloration on leaves coz viruses destroy cells
How affect • Less chlorophyll - less photosynthesis - less glucose
growth of • A) Less respiration - less energy released for growth
plants? • B) Less amino acids/cellulose for growth
Prevention • Good field hygiene
• Good pest control
• Wash tools
All viral diseases - no treatment
3.1.3 Bacterial diseases
Salmonella food poisoning
Caused by • Food prepared in unhygienic condition - food contaminated with salmonella from raw
meat
• Eat uncooked food - bacteria not killed by heat
Spread by • Bacteria ingested in food - disrupt balance of natural gut bacteria
Symptoms • Fever, abdominal cramps, vomiting & diarrhoea
• 8-72hrs
Prevention • Vaccination
• Cook meat thoroughly
• Keep raw meat away from cooked food
• Avoid washing raw meat - spread bacteria around kitchen
Gonorrhoea - sexually transmitted disease (STD)
Spread by • Unprotected sexual contact with infected person
Symptoms • Thick yellow / green discharge from vagina / penis
• Pain on urinating
Prevention • Use condom
• Reduce no of sexual partners
• Antibiotics
Treatment • Antibiotic penicillin
3.1.4 Fungal diseases
Rose black spot
Spread • In environment by wind & water
Symptoms • Purple / black spots develop on leaves
• Weaken plant & affect growth coz reduce area available for photosynthesis - turns
yellow & drop early
Treatment • Use fungicides
3.1.5 Protist diseases
Malaria
Spread by • Mosquitos (act as vectors coz they transmit disease)
Symptoms • Recurrent episode of fever
• Fatal
• Shaking when protists burst out of blood cells
• Headaches, vomiting, diarrhoea
Treatment • Take antimalarial drugs - kill parasites in blood
Prevention • Use mosquito nets - avoid being bitten
• Insecticides - kill mosquitoes
• Remove standing water - prevent mosquitoes breeding
3.1.6 Human defence systems
Non-specific defence system
Skin • Acts as barrier
• Produces antimicrobial secretions - kill bacteria
Nose • Hair & mucus trap & prevent pathogens entering lungs
Trachea & bronchi • Has mucus - trap pathogens
• Cilia waft mucus upwards to throat - shallowed
Stomach • Produce HCl - kill pathogens in food
White blood cell
• Phagocytes (non-specific) & Lymphocytes (specific)
How?
1. Ingest pathogens (phagocytes)
• Phagocytes move towards, changes shape, attack pathogen, engulfs & digest it with enzymes
2. Produce antibodies (protein) (made by lymphocytes)
• Have complementary shape - specific antibody for specific pathogen
• Allow binding with antigens (foreign microorganisms)
• If same pathogen re-enters body, WBC respond quickly, produce correct antibodies, prevent
infection
3. Produce antitoxins - counteract toxins
4
Voordelen van het kopen van samenvattingen bij Stuvia op een rij:
Verzekerd van kwaliteit door reviews
Stuvia-klanten hebben meer dan 700.000 samenvattingen beoordeeld. Zo weet je zeker dat je de beste documenten koopt!
Snel en makkelijk kopen
Je betaalt supersnel en eenmalig met iDeal, creditcard of Stuvia-tegoed voor de samenvatting. Zonder lidmaatschap.
Focus op de essentie
Samenvattingen worden geschreven voor en door anderen. Daarom zijn de samenvattingen altijd betrouwbaar en actueel. Zo kom je snel tot de kern!
Veelgestelde vragen
Wat krijg ik als ik dit document koop?
Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.
Tevredenheidsgarantie: hoe werkt dat?
Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.
Van wie koop ik deze samenvatting?
Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper acer. Stuvia faciliteert de betaling aan de verkoper.
Zit ik meteen vast aan een abonnement?
Nee, je koopt alleen deze samenvatting voor €6,79. Je zit daarna nergens aan vast.
