bio

• All living organisms have the following features in common: movement, respiration, sensitivity, nutrition, excretion, reproduction, growth
• Organelles found in both animal and plant cells

  • Cell membrane
  • Cytoplasm
  • Nucleus
  • Ribosomes
  • Mitochondria
• Additional organelles found in plant cells

  • Cell wall
  • Vacuole
  • Chloroplasts
• Nucleus

  Controls the activities of the cell
• Cytoplasm

  Where chemical reactions take place
• Cell membrane

  Controls what enters and leaves the cell
• Ribosomes

  Where protein synthesis takes place
• Cell wall

  Made of cellulose, protects and supports the cell
• Vacuole

  Filled with cell sap, helps maintain cell structure
• Chloroplasts

  Contain chlorophyll, where photosynthesis takes place
• Eukaryotes

  Animal cells, contain membrane-bound organelles
• Prokaryotes

  Viruses and bacteria, contain no membrane-bound organelles
• Bacterial cell

  • Has a cell wall, sometimes a slime capsule and flagellum
  • Contains a circular chromosome (nucleoid) and plasmids
  • Has cytoplasm and cell membranes
• Bacteria can be pathogenic (cause disease) or non-pathogenic
• Pathogenic bacteria

  • Pneumococcus (pneumonia)
  • Tuberculosis
• Non-pathogenic bacteria

  • Lactobacillus bulgaricus (used in yoghurt making)
• Bacteria are unicellular (made of one cell)
• Viruses

  • Much smaller than bacteria
  • Simply made of a protein coat surrounding DNA or RNA
  • Have no organelles
  • Are non-living (do not excrete, respire, or grow)
  • Are always pathogenic
• Characteristics of protoctists

  • Some have animal-like properties
  • Some have plant-like properties (e.g. algae and chlorella have chloroplasts)
  • Use diffusion to obtain nutrients and oxygen
  • Can be unicellular or multicellular
• Protoctists

  • Amoeba
  • Plasmodium (causes malaria)
• Fungi

  • Similar to plant cells but more circular
  • Have a cell wall made of chitin
  • Have hyphae that form a mycelium network
  • Carry out saprotrophic nutrition (secrete enzymes to break down dead matter)
• Fungi

  • Muchor
  • Mushrooms
  • Yeast (used in beer and bread making)
• The five kingdoms are: plants, animals, protoctists, bacteria, and fungi
• Cell

  A group of organelles working together to perform the same function
• Tissue

  A group of cells working together to perform the same function
• Organ

  A group of tissues working together to perform the same function
• Organ system

  A group of organs working together to perform the same function
• Organism

  A group of organ systems working together to perform the same function
• Organ systems in the body

  • Digestive
  • Endocrine
  • Reproductive
  • Circulatory
  • Respiratory
  • Nervous
  • Excretory
• Zygote

  The cell formed when a sperm and egg meet at fertilization
• Differentiation

  The process where cells become specialised
• Stem cell

  A cell with the potential to divide many times without being differentiated
• Types of stem cells

  • Embryonic
  • Adult
• Embryonic stem cells

  • Can differentiate into any cell type
  • Ethical issues with using them from aborted fetuses
• Adult stem cells

  • Can only differentiate into a limited number of cell types
  • Used in treatments like bone marrow transplants
• Stem cell therapy can be used to generate new cells to replace damaged ones, e.g. in leukemia treatment
• Enzyme

  A biological catalyst that speeds up chemical reactions without being used up
• Active site

  The biologically active part of an enzyme where the substrate binds
• Enzyme-substrate complex

  The complex formed when the substrate binds to the enzyme's active site
• Digestive enzymes

  • Amylase (breaks down starch into glucose)
  • Protease (breaks down proteins into amino acids)
  • Lipase (breaks down lipids into fatty acids and glycerol)