1.2 describe the common features shared by organisms within the following main groups

• plants
• animals
• fungi
• bacteria
• protoctists
• viruses

for each group describe examples and their features

(details of lifecycle and economic importance are not required)

Plants

Multicellular organisms

Their cells contain chloroplasts- able to carry out photosynthesis

Their cells have cellulose cell walls

They store carbohydrates as starch or sucrose

Examples include flowering plants, such as a cereal (for example maize), and a herbaceous legume (for example peas or beans)

Animals

These are multicellular organisms
They have no cell walls
They usually have nervous coordination and are able to move from one place to another
They often store carbohydrate as glycogen
Examples include mammals (for example humans) and insects (for example mosquito)

Fungi

Usually organised into a mycelium made from thread-like structures called hyphae, which contain many nuclei

Some examples are single-celled

Their cells have walls made of chitin

They feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products (saprotrophic nutrition)

They may store carbohydrate as glycogen

Examples include Mucor (hyphal example) and yeast (single cell example)

Bacteria

These are microscopic single-celled organisms

They have a cell wall, cell membrane, cytoplasm and plasmids

They lack a nucleus but contain a circular chromosome of DNA

Some bacteria can carry out photosynthesis but most feed off other living or dead organisms

Examples include Lactobacillus bulgaricus (used in the production of yoghurt from milk) and Pneumococcus (pathogen causing pneumonia)

Protoctists

These are microscopic single-celled organisms

Some, like Amoeba, that live in pond water, have features like an animal cell

Some like Chlorella, have chloroplasts and are more like plants

A pathogenic example is Plasmodium, responsible for causing malaria

Viruses

These are small particles, smaller than bacteria

They are parasitic and can reproduce only inside living cells

They infect every type of living organism

They have a wide variety of shapes and sizes

They have no cellular structure but have a protein coat and contain one type of nucleic acid, either DNA or RNA

Examples include the tobacco mosaic virus,  the influenza virus (causes ‘flu’) and the HIV virus (causes AIDS)