Biology o’level

• Biology


  study of organisms
• Organism


  A living thing
• Movement


  An action by an organism or part of an organism causing a change of position or place
• Locomotive


  ability to move whole body from one place to another
• Respiration


  The chemical reactions in cells that break down nutrients molecules and release energy for metabolism
• Metabolism


  The chemical reactions that take place in living organism
• Sensitivity


  the ability to detect and respond to changes in the internal or external environment
• Growth


  a permanent increase in size and dry mass
• Dry mass


  The mass of an organism after it has been killed and all water has been removed from it
• Reproduction


  The processes that make more of the same kind of organism
• Nutrition


  Taking in materials for energy, growth and development
• Species


  A group of organisms that can reproduce to produce fertile offspring
• How are species classified into groups?

  By the features that they share
• What do we need to do to have a fertile offspring?

  The 2 parents must be from the same species
• By who were organisms first classified?

  By Swedish naturalist Linnaeus
• In what way did Linnaeus classify living organisms?

  In a way that allows the subdivision of living organism into smaller and more specialized groups
• What happens when species are subdivided?

  The species have more and more features in common
• What is the binomial system?

  It is the where scientific name of an organism is made up of two parts the genus and the species
• What is a kingdom?

  The largest and less restricted group of organisms
• How many kingdoms are there and what are they?

  1. Animal kingdom

  2. Plant kingdom

  3. Fungi

  4. Protoctist

  5. Prokaryote
• What is a fungus?

  an organism whose cells have cell walls, but it doesn't photosynthesise
• What is the fungi cell wall made of?

  chitin
• What is hyphae?


  Microscopic threads, made of cells linked in a long line, that make up the body of the fungus
• Does fungi have chlorophyll and photosynthesise? And if no what do they do?

  No, they feed saprophytically or parasitically on organic matter such as farces, human foods and dead plants or animals
• What are decomposers?


  Organism that break down organic substances outside their bodies, releasing nutrients from them that other organism use
• 3 harmful effects of fungi

  1. Food decay which causes diseases

  2. Ringworm

  3. Athlete's foot
• What is the meaning of saprophytically?

  Act on dead organic matter
• What is the meaning of parasitically?

  They get their food by living host
• Name 4 characteristic features of fungi?

  1. They are usually multicellular but some such as yeast are unicellular

  2. They have a nuclei and cell walls but the walls are not made of cellulose

  3. They do not have chlorophyll

  4. They feed by digesting waste organic material and absorbing in into their cells.
• What is the meaning of unicellular?


  Made up of a single cell
• What is the meaning of multicellular?

  Made up of many cells
• Name 2 facts about protoctist

  They all have cells with a nucleus, but some have plant like cells with chloroplasts and cellulose cell walls, while others have animal-like-cells without these features
• What is a prokaryote? Give an example.


  Organism with no nucleus. (Bacteria)
• Name a protoctist that is multicellular

  Seaweeds
• Name a protoctist that has animal-like-cells and name its features

  Paramecium, it has a cytoplasm, a nucleus and a cell membrane
• Name a protoctist that has plant-like-cells and name its features

  Chlamydomonas, it has a cytoplasm, nucleus, cell membrane, cell wall, chloroplast
• Name 3 characteristic features of protoctist

  1. They are multicellular or unicellular

  2. Their cells have a nucleus and may or may not have a cell wall and chloroplast

  3. Some feed by photosynthesis and others feed on organic substances made by other organisms
• What is the meaning of PRO and KARYOTE

  Before nucleus was developed
• 6 characteristic features of prokaryote

  1. They are unicellular

  2. They have no nucleus

  3. They have cell walls, not made of cellulose

  4. They have no mitochondria

  5. They have a circular loop of DNA, which is free in the cytoplasm

  6. They often have plasmids
• Name 2 groups within the animal kingdom?

  Vertebrates and arthropods