MRS GREN is an acronym often used by students to help them remember all the features of living organisms.

Choose three of these features and explain what they mean.

COVID-19 an infectious disease caused by a virus. 

Viruses, like the COVID-19 virus, are not classified as living things.

Give three reasons why.

Bacteria can also cause disease in humans, other animals and even plants, but their structure is very different from the structure of viruses.

Name three structures that are present in bacteria but that are not in viruses.

BSE is a disease of cows. BSE damages the cow's brain and spinal cord. 

A cow with BSE lacks coordination, and acts very nervous or violent, which is why BSE is commonly called “mad cow disease”.

BSE is caused by a protein called a prion. 

The body of a sick cow does not recognise the abnormal prion so it is unable to fight off the disease.

Name two ways in which prions are different from viruses.

Humans are organisms from the kingdom Animalia.

 Name two other kingdoms.

Name two characteristics that place humans in the kingdom Animalia.

Animals can be classified as either vertebrates or invertebrates.

In which group would you place humans, and why?

Humans can be further classified as mammals.

Give three characteristics of humans that place them in the Mammalia class.

The platypus is an animal classed as a mammal, but it has some bird and reptile features.

Platypuses have a duck-like bill and webbed feet, lay eggs, and live mostly underwater.

Male platypuses have a pair of venomous spurs on their hind feet.

Suggest why scientists class the platypus as a mammal.

Platypuses resemble ducks. 

Ducks are birds that belong to the family Anatidae, which also includes geese and swans.

Give two characteristics of ducks that place them in the Bird class.

Ladybirds are amongst the best-known beetles.

Some ladybirds have bright red wing cases with black spots, making them easy to spot and recognise.

Ladybirds are a beneficial insect as they feed on aphids and other pests.

Why are ladybirds classed as insects?

Name two features.

Ladybirds belong to the phylum Arthropods.

Arachnids, like spiders, ticks and scorpions, also belong to the phylum Arthropods.

State two differences between arachnids and insects.

Living things are divided into five kingdoms: animals, plants, fungi, protoctists and prokaryotes.

Which kingdom do unicellular eukaryotes belong to?

Which kingdoms do multicellular eukaryotes with a cell wall belong to?

Which kingdom do multicellular eukaryotes without a cell wall or chloroplasts belong to?

Which kingdom do organisms without a nucleus or membrane-bound organelles belong to?