1.2-2.4 The Nature and Variety of Life Flashcards
Why do livings organisms respire?
Release energy from their food
Why do livings organisms excrete their waste?
Need to remove waste products e.g., carbon dioxide and urine
What do livings organisms respond to in their surroundings?
Can react to changes in their surroundings
Why do livings organisms move?
Move (including plants) towards things like water and food, and away from things like predators and poisons
What do livings organisms control of their internal conditions?
Internal conditions include temperature and water content
Why do livings organisms reproduce?
Have to produce offspring for their species to survive
Why do livings organisms grow and develop
Have to grow and develop into their adult form
Describe eukaryotic organisms
Complex
Plant, animal, fungi and protocists are eukaryotic organisms
Describe the features of plants
Multicellular
Have chloroplasts can photosynthesise
Cells have cell walls of cellulose
Plants store carbohydrates as sucrose or starch
What is an example of a plant
Flowering plants
- cereals (e.g. maize)
- herbaceous legumes (e.g. peas and beans)
Describe the features of animals
Multicellular
Don’t have chloroplasts and can’t photosynthesise
Don’t have cell walls
Nervous coordination - can respond rapidly to changes in environment
Move around
Store carbohydrate in the form of glycogen
What are examples of animals?
Mammals e.g. humans
Insects e.g. houseflies and mosquitos
Describe the features of fungi
Single celled
Multicellular have a body called mycelium - made up of hyphae (thread-like structures)
Hyphae contain lots of nuclei
Can’t photosynthesise
Cell walls of chitin
Most feed by saprotrophic nutrition - secrete extracellular enzymes into the area outside their body to dissolve their food, absorb the nutrients
Store carbohydrate as glycogen
Give an example of a fungi
Yeast - single celled
Mucor - multicellular and has a mycelium and hyphae
Describe the features of protoctists
Single celled and microscopic
Some have chloroplasts and similar to plant cells
Others more like animal cells
Give an example of protoctists
Chlorella (plant cell like)
Amoeba (animal cell like) lives in pond water
Plasmodium - causes malaria
Describe the features of prokaryotic cells
Smaller and simpler
Bacteria is a prokaryotic organism
Describe the features of bacteria
Single celled and microscopic Don't have a nucleus Circular chromosome of DNA Some cam photosynthesise Most bacteria feed off other living and dead organisms
What are some examples of bacteria
Lactobacillus bulgaricus - turn milk into yogurt (useful)
Pneumococcus - causes pneumonia
Describe the features of viruses
Particles rather than cells
Smaller than bacteria
Can only reproduce inside living cells, example of a parasite - depends on another organism to grow and reproduce
Infect all types of living organisms
Come in different shapes and sizes
Don’t have a cellular structure - have a protein coat around some genetic material (either DNA or RNA)
What are some examples of viruses
Influenza virus - causes ‘flu’
HIV - causes AIDS
Tobacco mosaic virus - stops leaves of tobacco plants from producing chloroplasts and discolours them
What is a pathogen
Organisms which cause disease
Include some fungi, bacteria and protoctists - viruses are also pathogens
What is the function of the nucleus
Contains genetic material that controls the cell’s activities
Surrounded by its own membrane
What is the function of cytoplasm
Gel- like substance where most of the cell’s chemical reaction happen
Contains enzymes which control these reactions
