Chapter 1.2 Variety of living organisms - Summary Edexcel International GCSE Biology Student Book Second Edition - Biology

1.2 Variety of living organisms


Eukaryotic (真核生物)

● Plants
○ multicellular
○ contain chloroplasts (carry out photosynthesis)
○ have cellulose cell wall
○ store carbohydrates as starch/sucrose (蔗糖)
○ ***E.g.: maize, legumes (peas, beans)


● Animals
○ multicellular
○ no chloroplasts (no photosynthesis)
○ no (cellulose) cell wall
○ store carbohydrates as glycogen
○ have nervous coordination + ability of locomotion
○ ***E.g.: humans, housefly, mosquito


● Fungi (菌類)
○ ***unicellular (e.g.: yeast), multicellular (e.g.: mucor [毛黴])
○ no photosynthesis
○ have chitin (甲殼素) cell wall
○ made up of thread-like hyphae (菌絲), containing many nuclei, organized
into a mycelium (菌絲體), e.g.: mucor
○ feed by secreting extracellular (細胞外) digestive enzymes outside the
mycelium onto the food, then absorbing the digested molecules
○ Saprotrophic (腐生) (feeding on decaying matter)
■ SOME parasitic (寄生) (feeding on living material)
● SOME pathogenic (causes diseases)
○ MAY store carbohydrates as glycogen


● Protoctists (原生生物)
○ ***MOSTLY unicellular, some multicellular
○ Rather diverse group of organisms, ***do not fit in any of the 3 groups above
○ Microscopic
○ USUALLY aquatic
○ SOME have features like animal cells, e.g.: Amoeba (aquatic), plasmodium
(pathogenic, causes malaria)
○ SOME have features like plant cells, e.g.: chlorella, algae



1