1 - STRUCTURES AND FUNCTIONS IN LIVING ORGANISMS

The Kingdoms - 


Plants - 

• Multicellular 
• Have chloroplasts - they photosynthesise 
• Cells have cell walls (made of cellulose) 
• Store carbohydrates as sucrose or starch 
• eg: cereals (maize etc.), herbaceous legumes (peas, beans etc.)

Animals - 

• Multicellular 
• No chloroplasts 
• No cell walls 
• Most have a form of nervous coordination (respond quickly to changes in environment) 
• Usually can move around 
• Often store carbohydrates as glycogen 
• eg: mammals (humans etc.), insects (houseflies, mosquitos etc.)

Fungi - 

• Some are single-celled, other have body called a mycelium (made up of hyphae - thread-like structures, contain lots of nuclei) 
• Can't photosynthesise 
• Cells have cell walls (made of chitin) 
• Most feed by saprotrophic nutrition (secrete extracellular enzymes - dissolve the food - absorb nutrients) 
• Store carbohydrates as glycogen 
• eg: yeast (single-celled fungus), nucor (multicellular, mycelium and hyphae) 

Protoctists - 

• Single-celled 
• Microscopic 
• Some have chloroplasts (
• Some are similar to plant cells, others more like animal cells 
• eg: chlorella (plant cell-like), amoeba (animal cell-like, live in pond water) 

Bacteria (prokaryotes) - 

• Single-celled 
• Microscopic 
• No nucleus 
• Have a circular chromosome of DNA 
• Some photosynthesise
• Most feed off other organisms 
• eg: lactobacillus bulgaricus (used to make milk go sour to make yoghurt, rod shaped), pneumococcus (spherical shape) 

Viruses - 

• Particles, not cells 
• Smaller than bacteria
• Only reproduce inside living cells (parasitic) 
• Infect all types of living organisms 
• Different shapes and sizes 
• No cellular structure - protein coat around some genetic material (DNA or RNA) 
• eg: influenza virus, tobacco mosaic virus (makes the leaves of tobacco plants stop producing chloroplasts - discoloured), HIV 

Pathogens - cause disease 
eg:

• Protoctist - Plasmodium, causes malaria 
• Bacterium - Pneumococcus, cause pneumonia 
• Viruses - Influenze virus, causes flu 
• Viruses - HIV, causes AIDS