The Nature And Variety Of Living Organisms Flashcards
(20 cards)
What are the 7 characteristics of living organisms?
Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition (MRS GREN)
What is the definition of a eukaryotic organism?
An organism whose cells contain a nucleus and other membrane-bound organelles.
What is the definition of a prokaryotic organism?
An organism whose cells do not contain a nucleus or membrane-bound organelles (e.g. bacteria).
Name the five main groups of living organisms.
Animals, Plants, Fungi, Protoctists, Bacteria
Give two features of animal cells.
Multicellular, no cell wall or chloroplasts, store carbohydrates as glycogen.
Give two examples of animals.
Humans (Homo sapiens), Mosquitoes (Anopheles)
Give two features of plant cells.
Multicellular, have cell walls and chloroplasts, store carbohydrates as starch.
Give two examples of plants.
Maize (a cereal), Pea plant (a legume)
Give two features of fungi.
Some are single-celled, others have a mycelium made of hyphae; cell walls made of chitin.
How do fungi feed?
Saprotrophic nutrition – they secrete enzymes onto food and absorb the digested nutrients.
Give two examples of fungi.
Yeast (single-celled), Mucor (multicellular with hyphae)
What are protoctists?
Microscopic single-celled organisms; some are like animal cells, others like plant cells.
Give one example of a protoctist that causes disease.
Plasmodium – causes malaria.
What are the features of bacteria?
Single-celled, no nucleus, have a cell wall, cell membrane, cytoplasm, plasmids.
How do bacteria feed?
Some photosynthesise; others feed off other organisms (living or dead).
Give two examples of bacteria.
Lactobacillus (used in yogurt), Pneumococcus (causes pneumonia)
What are viruses?
Non-living particles that infect living cells; they have a protein coat and contain DNA or RNA.
How do viruses reproduce?
They hijack the host cell’s machinery to replicate themselves.
Give two examples of viruses.
Influenza virus (causes flu), HIV (causes AIDS)
Are viruses considered living? Why or why not?
No – they do not show all seven characteristics of life unless inside a host.
