biology

• Animals


  • Multicellular
  • Heterotrophs
  • Reproduce sexually
  • Estimated 5-10 million species
• Plants


  • Multicellular
  • Autotrophs (get energy from sun via photosynthesis)
• Fungi


  • Some are multicellular, some are unicellular
  • Heterotrophs (get energy from other organisms)
  • Many use saprotrophic nutrition (secrete digestive enzymes outside body)
  • Some have a mycelium body made of hyphae
• Protists


  • Nearly all are unicellular
  • Some are plant-like (have chloroplasts, photosynthesize)
  • Some are animal-like (consume other organisms)
  • Some are pathogens that can cause disease
• Bacteria


  • Single-celled organisms
  • Some can photosynthesize but don't have chloroplasts
  • Most feed off other living or dead organisms
  • Estimated to have more species than all other kingdoms combined
  • Some are pathogens that can cause disease, but most are harmless or helpful
• Viruses


  • Tiny particles, not cells
  • Have a protein coat surrounding genetic material (DNA or RNA)
  • Can only reproduce by infecting and using other living cells
  • All are considered pathogens as they cause harm to host organisms
• Viruses, bacteria, protists, fungi, plants, and animals are the 6 groups of life, with viruses being the only non-living group
• Animals, plants, fungi, and protists are all eukaryotic organisms, while bacteria are prokaryotic
• Eukaryotic cells have DNA in chromosomes and a nucleus, while prokaryotic cells have loose DNA and no nucleus
• Cells


  The basic building blocks of life that can replicate independently
• Multicellular organisms like animals and plants contain many cells that divide to grow or replace dead cells, not to create new organisms</b>
• Bacteria are single-celled prokaryotic organisms
• Subcellular structures common to animal and plant cells

  • Cell membrane
  • Nucleus
  • Cytoplasm
  • Mitochondria
  • Ribosomes
• Plant cells


  • Have a rigid cell wall made of cellulose
  • Contain a permanent vacuole with cell sap
  • Contain chloroplasts for photosynthesis
• Bacterial cells

  • Lack mitochondria and chloroplasts
  • Have a single circular strand of DNA instead of a nucleus
  • May have additional plasmids
  • May have flagella for movement
• Photosynthesis occurs in the chloroplasts of plant cells, using chlorophyll to absorb light energy
• Mitochondria in cells break down glucose through aerobic respiration to provide energy
• Characteristics of living things (organisms)


  • Movement
  • Respiration
  • Sensitivity
  • Growth
  • Reproduction
  • Excretion
  • Nutrition
• Acronym for the 7 key features

  Mrs gran
• Movement


  Ability of organisms to move, either the whole organism or just part of it
• Respiration


  Chemical reactions that break down nutrient molecules to release energy for metabolism
• Sensitivity


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


  Permanent increase in size and dry mass
• Reproduction


  Process that makes more of the same kind of organism
• Excretion


  Removal of waste products of metabolism and substances in excess of requirements
• Nutrition


  Taking in of materials for energy, growth and development
• All living organisms are made up of one or more cells
• Viruses are not considered living organisms because they don't meet all 7 requirements
• Diffusion


  The net movement of particles from an area of higher concentration to an area of lower concentration
• Diffusion


  1. Molecules move about randomly

  2. Molecules spread out over time

  3. Molecules become evenly distributed
• Diffusion can happen in both gases and liquids
• Partially permeable membrane


  Only some molecules can diffuse through, like water, glucose, and amino acids. Larger molecules like proteins and starch cannot fit through.
• Diffusion is a passive process that does not require energy from the cell
• Factors affecting rate of diffusion


  • Concentration gradient
  • Temperature
  • Surface area
• Larger concentration gradient


  Higher rate of diffusion
• Higher temperature


  Higher rate of diffusion
• Larger surface area


  Higher rate of diffusion
• Osmosis


  The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
• Water concentration


  The amount of water as compared to the other molecules like sugars or salts that are dissolved in that water
• Solutes are the dissolving molecules in water