iGCSE Biology Revision Blog: living organisms

2.3 recall the term ‘pathogen’ and know that pathogens may include fungi, bacteria, protoctists and viruses.

Pathogens are harmful microorganisms that can cause diseases.

Pathogens may include fungi, bacteria, protoctists and viruses:

Fungi

Athlete's foot Thrush

Bacteria
Tuberculosis: lung infection

Salmonella: food poisoning

Whooping cough: highly contagious bacterial disease that causes uncontrollable, violent coughing, making it hard for the patient to breath

Viruses

Chicken pox: develops itchy blisters all over the patient's body
Influenza: flu

HIV: leading up to aids

Measles: highly respiratory disease

2.2 describe the common features shared by organisms within plant, animal, fungi, bacteria, protoctist and virus kingdoms

ORGANISMS	CHARACTERISTIC
Plants	● multicellular ● contain chloroplasts: help carry out photosynthesis ● cells walls made of cellulose ● store glucose instead of starch: starch is not water soluble, more compact for storage
Animals	● multicellular ● consumer: gain nutrition by feeding on animals or plants ● move by their nervous system ● store carbohydrates in the form of glycogen
Fungi	● eg: mushroom, toadstools, mould ● mycelium, which is made of thread like filaments called hyphae
Bacteria	● microscopic ● unicellular: single celled ● genetic information is stored in cytoplasm, no nucleus ● decomposer: recycle dead organisms and waste products in the soil and elsewhere ● bacillus: any rod shaped bacteria ● coccus: any sphere shaped bacteria
Viruses	● microscopic ● infectious → contagious, likely to be transmitted to people ● protein coat: protein assembled together to protect the virus. DNA and RNA ● HIV: virus that causes aids ● DNA: Deoxyribonucleic Acid ● RNA: Ribonucleic acid
Protoctista	● microscopic ● unicellular ● amoeba: similar to animal cells ● chlorella: similar to plant cells ● plasmodium: organism that causes malaria