1. The nature and variety of living organisms Flashcards
Describe the common features of a plant cell.
- multicellular organisms
- contain chloroplasts so photosynthesize
- have cellulose cell walls
- store carbohydrates as starch or sucrose
What are some examples of plants?
- maize
- beans
- peas
Describe the common features of an animal cell.
- multicellular organisms
- NOT able to photosynthesise
- heterotrophic: consume other organisms to obtain nutrients
- no cell walls
- usually have nervous coordination
- often store carbohydrate as glycogen
What are some examples of animals?
- housefly
- dog
- kangaroo
What are the common features of a fungi cell.
- multicellular or unicellular
- no photosynthesis
- feed via saprotrophic nutrition
- composed of mycelium which consists of many hyphae
- contain cell walls
- store carbohydrates as glycogen
What are some examples of fungi?
- Mucor –> has a typical hyphal structure
- yeast –> single celled
Describe the common features of a Protoctista.
- unicellular
- microscopic
- some have features resembling animal cells like amoeba
- others have chloroplasts and cellulose cell walls, so they are more similar to plant cells like chlorella
What are some examples of protoctista?
- plasmodium –> pathogenic which cause causes malaria
Describe the common features of a bacteria cell.
- unicellular, microscopic
- have a cell wall, cell membrane, cytoplasm and plasmids
- cell wall is made of polysaccharides and proteins
- no nucleus but contain a circular
chromosome of DNA - some bacteria have another layer outside the cell wall, called the capsule or slime layer
- some bacteria carry out photosynthesis but most feed off other living or dead organisms
What are some examples of bacteria?
- Lactobacillus bulgaricus –> a rod-shaped bacterium used in the production of yogurt from milk
- Pneumococcus, a spherical bacterium that acts as the pathogen causing pneumonia
Describe the common features of a virus.
- smaller than bacteria
- genetic material (DNA or RNA) surrounded by a protein coat
- some viruses are surrounded by a membrane called an envelope
- they are parasitic and can only reproduce inside living cells
- different types infect different kingdoms
What are some examples of a virus?
- tobacco mosaic virus –> causes discolouring of the leaves of tobacco plants by preventing the formation of chloroplasts
- influenza virus –> causes flu in humans
What is a pathogen?
Microorganisms that cause disease to its host.
What is a prokaryotic cell?
A cell found in the bacteria kingdom that does not contain a nucleus
What is a eukaryotic cell?
A type of cell found in animal, plant, fungi and protoctist cells that contain a nucleus
What does the term unicellular mean?
an organism made up of a single cell (bacteria and Protoctista)
What is amoeba?
Protoctists that live in pond water and resemble animal cells with chloroplasts
What is chlorella?
a protoctist that has features similar to plant cells
What is DNA?
A double stranded molecule made of nucleotides, wound in a double helix shape, carrying the genetic code.
What is HIV?
A virus that weakens the immune system and can lead to acquired immunodeficiency syndrome (AIDS)
What is hyphae?
long filaments of a fungus that contain many nuclei
What does ‘MRS H GREN’ stand for?
Movement
Respiration
Sensitivity
Homeostasis
Growth
Reproduction
Excretion
Nutrition
What is mycelium?
a collection of thread-like hyphae in fungus
What are plasmids?
loops of DNA found in the cytoplasm of prokaryotic cells
