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58 Cards in this Set

  • Front
  • Back

What are drugs

Chemical substances that affect the central nervous system

4 kinds of drugs

Depressants,stimulants,painkillers and hallucinogens

Deppressant drugs

They decrease the activity of the brain,which slows down the responses of the nervous system causing slow reactions

Stimulamt drugs

E.g nicotine,caffeine. They increase the activity of the brain by increasing the amount of neurotransmitter at some neurone synapses which increases the speed of reactions.


E.g narcotics like morphine. These decrease the feeling of pain. Some work by blocking the nerve impulses in the brain.


E.g LCD. They disort whats seen and heard by altering the pathways nerve impulses normally travel along

What is a reaction time

The time it takes to respond to a stimulus

Why is tobacco dangerous

It contains carbon monoxide which combines with Haemoglobin in red blood cells causing the blood to carry less also contains carcinogens like tar.

Why is tobacco addictive

Tobacco smoke contains nicotine

Short term affects of alcohol

-Slow reactions because its a depressent so it slows responses of the nervous system

-Blurred visions and can lower inhibitions

Long term effects of alcohol

Excessive drinking can cause the death of liver cells which forms scar tissue that starts to block blood flow through the liver- this is called cirrhosis

-Can lead to brain damage

What is a carcinogen

Chemicals/substances that can lead to cancer

What is an infectious disease

A disease that can be transmitted from one person to another

What is a pathogen

A microorganism/microbe that causes disease

Ways pathegons can be spread

-Through water




-Body fluids

-Animal vectors

How can pathogens spread through water

By drinking dirty/contaminated water

What is cholera

A bacterial infection that causes diarrhoea and dehydration,its spread when water is contaminated with the diarrhea of other sufferers

How do pathogens spread through food

Picked up by eating contaminated food e.g salmonella

What is salmonella

Salmonella Bacteria cause food poisening

How are pathegons spread through air

Airborn pathogens are carried in droplets produced when you cough or sneeze,then other people breathe them in.

What is the influenza virus

A viruses that causes flu and is spread by airborn pathogens

How are pathogens spread through contact

They are picked up by touching contaminated surfaces including skin e.g athletes foot

What is athletes foot

A fungus which makes skin itch and flake off.its commonly spread by touching the same things as an infected person e.g shower floors

How are pathogens spread through body fluids

Spread by body fluids such as blood e.g sharing needles, through breast milk e.g breastfeeding, or through semen e.g sex

What is HIV

A virus spread through body fluids that causes aids,a disease that stops the immune system from working properly

What are animal vectors

Animals that spread disease e.g anopheles mosquite and the house fly

The house fly

Carries bacterium that cause dysentery. It spreads the disease by carrying bacteria onto food.

Anopheles mosquito

Carries protozoan that causes malaria (a disease that can damage the brain kidneys or even be fatal) spreads disease by biting other organisms.

Two types of barriers that stop pathogens entering the body

Physical and chemical.

Physical barriers against pathogens

-The skin,if it gets damaged blood clots quickly seal cuts and keep microorganims out

-The respiratory system

The respiratory system as a physical barrier against pathogens

The whole respiratory tract is lined with mucus and cilia. The mucus catches dust and bacteria before they reach the lungs and the cilia push the gunk-filled mucus away from the lungs.

Chemical barriers for pathogens

-The eyes produce a chemical called lysozyme in tears which kill bacteria on the surface of the eye

-The stomach has hydrochloric acid that kills most pathogens in food

How is carbon removed from the atmosphere

Through photosynthesis-plants use it to make carbohydrates,fats and protein.

How do plants defend themselves

When plants are attacked by pathogens they produce chemicals

Tea tree oil

The tea tree is a large austrailian shub,its leaves produce an oil that kills bacteria.the purified oil is used in all sorts of antibacterial products

What are antisceptics

They are chemicals that destroy bacteria or stop them growing. Antisceptics are used outside the body to clean wounds and surfaces.they prevent infection rather than treat it

What are antibiotics

They are drugs used inside the body. They treat patients who are infected with bacteria or fungi.they dont destroy viruses.

Two types of antibiotics

-Antibacterial antibiotics e.g penicilin work by killing bacteria or stopping them from growing

-Antifungal antibiotics e.g nystatin kill fungi or stop them from growing.

How do bacteria become resistent to antibiotics

Bacteria can mutate which can cause them to be resistant. The individual resistant bacteria will reproduce and the population of the resistant bacteria will increase (an example of natural selection). This resistent strain could cause a serious infection that cant be treated by antibiotics

Practical to investigate antibiotics and antisceptics

Pour hot steralised argar jelly into a sterile petri dish. When the jelly is cooled and set transfer the bacteria onto it. Then take three paper discs,,soak one in antibiotic,one in antisceptic and another in sterile water. (label the dish so you know which is which). Place the disks onto the jelly and tape the disc shut. Leave the dish for 24 hours at 25 degrees celcius. After that time look at the results. The bigger the inhibition lines,the more effective the drugs were.


How much the creatures at each level of the food chain would weigh if you put them all together

Mutualistic relationship

Both species benefit

Parasitic relationship

Only one benefits


Are insects that live in the fur and bedding of animals. They feed by sucking the blood of their hosts.

Head lice

Insects that live on human scalps,they suck blood for food.


Tapeworms attatch to the intestinal wall of their hosts. They absorb lots of nutrients from their host,making them suffer from malnutrition.


Oxpeckers are birds that live on the back of a buffalo. They eat ticks,flies,maggots etc of the buffalo. They also alert the animal if any predators are near,by hissing. These are an example of cleaner species.

Cleaner fish

They eat dead skin and parasites off large fish e.g groupers.

Nitrogen fixing bacteria in legumes

Leguminous plants carry the nitrogen fixing bacteria in nodules in their roots. The bacteria get a constant supply of sugar from the plant.

Chemosynthetic bacteria in deep sea vents

Some chemosynthetic bacteria live inside giant tube worms. The tube worms supply the bacteria with chemicals from the seawater which the bacteria turns into food.

Problems with a bigger human population

Raw materials including non renewable energy sources are being used up

More waste is being produced

More pollutants are being produced e.g phosphates,nitrates and sulfur dioxide.

How do nitrate fertilisers help

Crops take nitrates out from the soil and these need to be replaced.

Too much fertiliser can result in...



Excess nitrate washes into river causing rapid growth of algae

Some plants start to die due to lack of light

Microbe numbers increase as they feed on the dead material

Microbes use up all the oxygen. Fish and other aquatic animals suffocate

Practical to show the effects of pollutants

Put moist cotton wool soaked in water in one jam jar and put 20 cress seeds on top

Set up a second jar the same way but replace the water with nitrate

Seal each jar with its lid

After 5-7 days measure the length of the shoots and work out the average length for each jar

Recycable materials include




Problems with recycling

-Still uses up energy

-Some waste materials can be difficult and time consuming to sort

-The equiptment needed for recycling can be expensive

-Some materials can only be recycled a limited number of times

Indicator species

Some organisms cant live in areas where there is polluted air or water,but others can. Both of these types of organisms can be monitored and used as indicators of pollution.