Chemistry paper 1 notes, entire summary (2025)

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• Uploaded on May 17, 2025
• Number of pages 14
• Written in 2024/2025
• Type Summary

Subjects

• chemistry
• chemistry practicals
• chemistry paper 1
• summarized notes
• gcse
• science notes
• revision

• notes

• summary

Written for

• Institution GCSE
• Education GCSE
• Module Biology
• School year 200

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Infection and disease -
Communicable diseases -
Pathogens - organisms that can cause disease
Communicable diseases can be spread from one organism to another.
Pathogens can be waterborne, airbourne, contaminated food, bloodborne, direct contact
Stop it spreading by :
1. Good hygiene
2. Kill the vectors - organisms that carry the disease
3. Vaccinations
4. Isolation

Viruses -
Viruses - non living organisms that can use a cell's mechanisms to create copies of selfs. This causes
the cells to burst and the copies of the virus continue the pattern of invading to replicate.
Measles - Airborne - spread by droplets from coughs and sneezes. Causes people to develop a red
rash across the body and fever. Prevented through vaccinations.
HIV ( human immunodeficiency virus ) - Sexually transmitted and weakens the immune system.
Originally develop flu like symptoms that seem to improve but as the virus further damages cells the
person will start to catch unusual infections. This develops into aids which is a life long disease.
Antiretroviral drugs are used to stop the virus from replicating.
Tobacco mosaic disease - Affects plants. Causes patches of discolouration on leaves which prevents
photosynthesis taking place.

Bacteria -
Salmonella - causes food poisoning. Symptoms include fever, stomach cramps, vomiting, diarrhoea.
Gonorrhea - sexually transmitted disease. Symptoms are pain when urinating, green discharge.
Prevention is done by avoiding unprotected sex and treatment includes antibiotics such as penicillin

Protists and fungi -
Rose black spot - affects plants. Causes black and purple spots to form on leaves. The leaves then
start to turn yellow and drop off. This reduces the plants ability to photosynthesise. It is spread
through water and particles in the air moved by the wind. To treat it, chop off infected areas or use a
fungicide.
Protists are often spread by vectors
Malaria - spread by mosquitoes. Symptoms include fevers, headaches that are recurrent.
To prevent malaria vector numbers can be reduced, or use mosquito nets to prevent the vectors from
reaching people to infect with protists.

Immune system and defences -
Physical and chemical barriers -
Skin - stops bacteria entering our body. Also secretes oils and antimicrobial substances which can kill
pathogens
Mucus - traps pathogens and prevents them from traveling further through the body
Cilia - tiny hair like structures that move mucus towards the back of the throat where it can be
swallowed to the stomach
Stomach acid - pH of 2. Kills pathogens

Immune system -

, White blood cells - patrol the body and have 3 main functions :
1. Phagocytosis - white blood cells engulf pathogens
Carried out by a specific white blood cell called a phagocyte which tracks down the antigen
and then binds to it. The phagocyte then engulfs the pathogen and the enzymes in the
phagocyte will break down the pathogen.
2. Producing antitoxins - small molecules that can bind to and counteract the toxins produced by
the pathogen.
3. Producing antibodies - small proteins that can bind to a particular antigen and tell the white
blood cells to come and destroy the pathogen

Vaccinations and immunisations -
Vaccines expose a person to an inactive form of pathogen which tells the body to create antibodies
for this specific antigen. This means that when the person is exposed to the pathogen their white
blood cells are able to recognize the pathogen and create antibodies specific to it quickly as they have
already been created

Pros :
1. Protection from diseases
2. Control common diseases
3. Prevent outbreaks

Cons :
1. Don't always work
2. Bad reactions to vaccines

Drugs and medicine -
Relieve symptoms : aspirin, paracetamol
Treat problem : antibiotics - only works on bacteria. Can form antibiotic resistance

Developing new medicine -
Aspirin - developed from a chemical found in willow tree bark
Digitalis - used to treat heart problems - developed from chemical found in foxgloves
Penicillin - developed from a fungus
Testing -
1. Stage 1 - drug is tested on human cells and tissues in a lab. Means we can easily and
cheaply test multiple substances.
2. Stage 2 - testing on live animals. The first 2 stages can be classed as preclinical
3. Stage 3 - clinical testing - give drugs to healthy volunteers with a low dose. The dosage is
then slowly increased . The drug is next given to those suffering with the illness. The clinical
trials are considered blind trials as some patients will receive placebos but patients nor
doctors will know. This is done to avoid any bias.
Efficacy - how well the drug works
Toxicity - how harmful the drug is
Dosage - how much of the drug should be given

Monoclonal antibodies -
Monoclonal antibodies - antibodies from a single clone of cells. Combine lymphocytes with fast
growing tumor cells which forms a hybridoma. To get the lymphocytes an animal like a mouse is
injected with the antigen that we want the antibodies to bind to. This means that as a response loads
of lymphocytes will be produced and then these lymphocytes are extracted

Pregnancy tests -
Pregnant women produce the hormone HCG which is excreted in urine