Bio

• The 8 life processes


  • Movement
  • Respiration
  • Sensitivity
  • Homeostasis
  • Growth and Development
  • Reproduction
  • Excretion
  • Nutrition
• Movement


  Be able to change position. Muscle actions in animals / Slow growth movement in plants.
• Respiration


  Carry out chemical reactions in cells. Break molecules down to release energy for metabolism.
• Sensitivity


  Be able to respond to surroundings. Detect changes / stimuli in internal + external surroundings. Carry out appropriate responses.
• Homeostasis


  Be able to maintain a steady internal environment. Control internal conditions to maintain a steady state internally.
• Growth and Development


  Increase in size and complexity. Growth: Permanent increase in size + dry mass, by increase in cell number or cell size. Development: An increase in complexity.
• Reproduction


  Be able to produce offspring. Make more of the same kind of organism.
• Excretion


  Remove waste products. Removal of toxic materials, excess substances, and waste products of metabolism.
• Nutrition


  Require and acquire nutrition. Require nutrition. Take in nutrients for energy, growth and repair.
• Cells


  Prokaryotic / Eukaryotic
• Eukaryotic cells


  • Have a nucleus, cytoplasm, plasma membrane & membrane bound organelles
  • Can be both unicellular + multicellular
• Plant characteristics


  • Multicellular (10 - 100 μm)
  • Autotroph (Photosynthesizes)
  • Carbohydrate storage: Starch / Sucrose
  • Examples: Flowering plants (Maize), Herbaceous legume (Peas)
• Animal characteristics


  • Multicellular (10 - 100 μm)
  • Golgi body
  • Lysosomes
  • Has nervous coordination
  • Heterotroph (Consumes other organisms)
  • Carbohydrate storage: Glycogen
  • Examples: Mammals (Humans), Insects (Mosquitoes)
• Fungal characteristics


  • Unicellular (2 - 5μm) / Multicellular (10 - 100μm)
  • Mycelium: Formed from hyphae (Hyphae have many nuclei)
  • Reproductive body: Mushrooms / toadstools
  • Saprotrophic (Consumes dead organisms)
  • Carbohydrate storage: Glycogen
  • Examples: Typical hyphal structure (Mucor), Unicellular (Yeast), Pathogenic (Athlete's foot)
• Protoctist characteristics


  • Unicellular
  • Examples: Animal-like (Amoeba, lives in water), Plant-like (Chlorella, has chloroplasts), Pathogenic (Plasmodium → malaria)
• Prokaryotic cells


  • Have no nucleus & membrane bound organelles
  • Are only unicellular
• Bacterial characteristics


  • Unicellular (1 - 5μm)
  • Slime capsule, Peptidoglycan cell wall, Cell membrane, Flagella
  • Cytoplasm, Nucleoid (Loop of DNA chromosome), Plasmids (Ring of DNA that replicates + moves through cells to share info)
  • 3 shapes: Rod, spherical or spiral shaped
  • Pathogenic: Releases toxins
  • Autotrophic (Photosynthesises), Heterotrophic (Consumes other organisms)
  • Examples: Rod-shaped (Lactobacillus bulgaricus → yoghurt), Rod-shaped (Salmonella → food poisoning), Spherical-shaped (Pneumococcus → pneumonia)
• Pathogens


  Anything that produces disease. Include fungi, bacteria, protoctists, viruses.
• Viruses


  • Non-living microscopic particles (0.01 - 0.1μm)
  • No cell structure
  • Envelope: From the membrane of the host cell
  • Protein coat
  • DNA / RNA
  • Parasitic (Reproduces inside living cells)
  • Hijacks the cell mechanisms to create millions of copies of itself
  • Spreads within the host by cell bursting
  • Examples: Tobacco mosaic virus (Prevents chloroplast formation in tobacco plants), Influenza virus (Causes flu), HIV virus (Causes AIDS)
• Levels of organisation


  • Organelles
  • Cells
  • Tissues
  • Organs
  • Organ systems
  • Organisms
• Organelles


  Membrane-bound subcellular structures (E.G ribosomes), Found in the cytoplasm
• Cells


  The basic functional unit of all living organisms (E.G red blood cell), Contains organelles
• Tissues


  Group of SIMILAR CELLS carrying out specific functions (E.G muscular tissue), Only made up of one type of cell
• Organs


  Group of SIMILAR TISSUES carrying out a specific function (E.G stomach)
• Organ systems


  • Digestive = digest food, absorb digested materials
  • Gas exchange = exchange of CO2 and O2
  • Circulatory = transport of materials
  • Excretory = removal of toxic waste materials
  • Nervous = coordination of the body's actions
  • Endocrine = glands secreting hormones
  • Reproductive = production of eggs / sperms, development of embryo
• Organism


  An individual plant, animal or single celled life form
• Cell organelles


  • Cytoplasm
  • Nucleus
  • Cell membrane
  • Mitochondria
  • Ribosomes
  • Cell Wall
  • Chloroplasts
  • Vacuole
• Cytoplasm


  Where chemical reactions take place, Living, jelly-like material, Supports organelles, Contains enzymes, water and solutes
• Nucleus


  Contains genetic information of a cell, Enclosed in a nuclear membrane, Contains chromosomes, Control the activity in cells by determining the proteins produced
• Cell membrane


  A selectively permeable layer around the cell that controls what enters and leaves, Forms a boundary between cytoplasm and the outside, Holds the cell together, Selectively controls the movement of substances
• Mitochondria


  Site of cellular respiration
• Ribosomes


  Site of protein synthesis, Free within cytoplasm / Attached to membranes within the cell
• Cell Wall


  (Plant cell) Non-living cellulose that supports and protects cells, Porous and freely permeable layer outside cell, Internal pressure = strength and support, Pushes against other plant cells, Helps plants keep their shape
• Chloroplasts


  (Plant cell) Site of photosynthesis, Contains chlorophyll (absorbs light energy)
• Vacuole


  (Plant cell) Large vesicles for storage and structure, Contains cell sap, dissolved sugars, mineral ions and other solutes, Improves the cell's rigidity by keeping the cell turgid (swollen from water uptake)
• Similarities between plant and animal cells

  • Eukaryotic
  • Has membrane bound organelles
  • Carries out respiration
• Differences between plant and animal cells

  • Plant cells have no nervous coordination, Carbs = starch + sucrose, Autotrophic (photosynthesizes)
  • Animal cells have nervous coordination, Carbs = glucose + glycogen, Heterotrophic (consumes organisms), No plant cell organelles, Fixed shape
• Cell differentiation


  The development of new subcellular structures, Allows cells to perform specific functions (specialisation)
• Mitosis


  Cell division that results in two genetically identical daughter cells, Zygote = divides by mitosis as embryo grows, Differentiation = when embryo grows and cells become specialised to carry out particular roles
• Differences in differentiation between plants and animals

  • Plant cells = differentiate throughout life (can create new tissues)
  • Animal cells = differentiate early on in development (in mature animals, cells divide to replace cells, and new tissues are rarely created)