OCR Gateway GCSE Biology A global challenges (B6) overview quiz quiz

The total number of individual organisms living in a particular area, regardless of which species they are

The number of plant species only, ignoring all the animals, fungi and microorganisms in the ecosystem

The variety of different species in an ecosystem

The size of the single largest population of one species found anywhere within the whole ecosystem

The countryside has much more rainfall, and lichens can only survive in places that are very wet all year round

Lichens prefer the colder weather found out in the open countryside rather than the warmer air of the town

The town has more predators that feed on lichens, eating them faster than they can possibly regrow there

The town air is more polluted, because lichens are sensitive to air pollution

Energy is lost at each step of a food chain, so feeding crops to animals wastes most of the energy

Plants always contain far more protein than meat does, so they pass much more energy on to the people who eat them

Animals do not need any food at all, so growing crops to feed them to people is a complete waste of land and water

Meat contains no energy whatsoever, while plants are the only food that stores any usable energy for humans

Spraying a chemical pesticide across the whole field so that it kills the pest and many other insects too

Using a natural predator, parasite or disease of the pest to reduce its numbers

Removing the crop entirely from the field so that the pest is left with nothing at all that it can feed on

Adding extra fertiliser to the soil so the crop grows so fast and strong that the pest can no longer harm it

A bacterium, spread in dirty drinking water that has been contaminated with sewage

A virus, spread through the air in tiny droplets when an infected person coughs or sneezes

A protist, spread by a mosquito vector

A fungus, spread by direct skin contact between an infected person and a healthy one

Antibodies that are shaped to fit and destroy one specific type of pathogen and no others

Memory cells left over from a previous infection, ready to respond quickly to that same pathogen

A vaccine that trains the body in advance to fight off one particular pathogen it has not yet met

Mucus and cilia in the trachea trapping and removing pathogens

It introduces dead or inactive pathogen so the body makes antibodies and memory cells, ready to respond fast next time

It cures an infection that the person already has, by directly destroying every single pathogen that is currently present inside the body

It kills all the bacteria in the body at once, including the helpful ones, so that no infection can take hold

It works only against non-communicable diseases such as heart disease, and has no effect on infectious illness

Flu is far too mild an illness to be worth treating, so antibiotics are simply never prescribed for it

Flu is caused by a virus, and antibiotics only kill bacteria

Antibiotics only work inside plants and other crops, so they cannot have any effect at all inside the human body

The flu virus is far too large for any antibiotic molecule to get inside it and destroy it from within

By extracting them directly from a healthy donor's blood and purifying them, since blood already contains every kind of antibody that is needed

By gently heating antigens in the laboratory until they rearrange themselves and turn directly into matching antibodies

By fusing antibody-making lymphocytes with tumour cells to form hybridomas, which are cloned to make identical antibodies

By vaccinating a patient with the antigen and then collecting the many different antibodies that their body produces

Because the study is far too large, and a study with that many people in it is always unreliable and can never be trusted to find any real link

Because heart disease is infectious and spreads from person to person, so exercise has nothing to do with it at all

Because exercise has no effect on health whatsoever, so the pattern seen in the study must be a simple mistake

Because a correlation alone does not prove cause; another factor could be responsible without a mechanism and dose-response evidence

It is a mesh tube that holds a narrowed coronary artery open so blood can flow

It is a drug that lowers the level of cholesterol in the blood to slow the build-up of fatty deposits

It replaces the whole heart with a mechanical pump, taking over the job of the diseased coronary arteries

It is a vaccine for the heart that trains the body to fight off the disease before the arteries narrow

So that the drug being tested actually works faster in the patients than it otherwise would in an ordinary trial

So neither the patient nor the doctor knows who has the real drug or placebo, which removes bias

To make the trial much cheaper to run, because hiding the treatment groups saves money on staff and equipment

So that patients are free to choose for themselves whether they receive the real drug or the placebo treatment