1.2 – Describe the common features shared by organisms within the following main
groups: plants, animals, fungi, bacteria, protoctists and viruses.
PLANT (e.g. flowering plants, herbaceous legume etc.)
– Multicellular organisms.
– Cells contain chloroplasts and can photosynthesise.
– Cells contain a cellulose cell wall.
– Stores carbohydrate as starch or sucrose.
ANIMAL (e.g. mammals, insects etc.)
– Multicellular organisms.
– Cells do not contain chloroplasts and cannot photosynthesise.
– Cells do not contain a cell wall.
– Stores carbohydrate as glycogen.
FUNGI (e.g. mucor, yeast etc.)
– Both multicellular and unicellular organisms.
– Cannot photosynthesise.
– Body organised into a mycelium made from thread-like structures known as hyphae
which contain many nuclei.
– Cell walls made out of chitin.
– Feed by saprotrophic nutrition (extracellular secretion of digestive enzymes).
– Stores carbohydrate as glycogen.
BACTERIA (e.g. lactobacillus, pneumococcus etc.)
– Microscopic unicellular organisms.
– Have a cell wall, cell membrane, cytoplasm and plasmids with no nucleus but
instead have a circular chromosome or DNA.
– Some are able to photosynthesise. Others feed on dead and living organisms as
decomposers.
– Some are pathogens. Others are helpful.
PROTOCTIST (e.g. amoeba, chlorella, plasmodium etc.)
– Microscopic unicellular organisms.
– Either have animal, plant or pathogenic features.
• Amoeba has animal features.
• Chlorella has plant features.
• Plasmodium is a pathogen (causes malaria).
VIRUS (e.g. tobacco mosaic virus, influenza etc.)
– Microscopic particles that come in a variety of shapes and sizes, but all have a
protein coat and either DNA or RNA.
– Parasites that can only replicate by invading a host cell and infect any living
organism.
1.3 – Recall the term ‘pathogen’ and know that pathogens may be fungi, bacteria,
protoctists or viruses.
– Pathogen: A disease-causing microbe.
– Pathogens could be fungi, bacteria, protoctists or viruses.