bio

• Characteristics


  • Movement - action made by organism causing change of position/place
  • Respiration - chemical reactions that break down nutrient molecules and release energy for metabolism
  • Sensitivity - ability to detect stimuli and make appropriate responses
  • Growth - permanent increase in size and dry mass by increase in cell number or both
  • Reproduction - process that makes more of the same kind of organism
  • Excretion - removal from organisms of waste products of metabolism, toxic materials and excess substances
  • Nutrition - taking in materials for growth, energy, and development
• Binomial naming system


  Scientific name consists of Genus and Species, written with Genus capitalised and Species lowercase
• Why do we classify organisms? To identify those at risk of extinction, to understand evolutionary relationships
• How do we classify organisms?

  • By studying its morphology (study of form or outward appearance) and anatomy (study of internal structure by dissection)
  • Sequences of DNA and amino acids in proteins are a more accurate way of classification
• Whittaker's Five kingdom Scheme

  • Animal
  • Plant
  • Fungus
  • Prokaryote
  • Protoctist
• Animal


  • Multicellular
  • Divided into vertebrates and arthropods
• Plant


  • Unicellular or multicellular
  • Cell wall made up of cellulose
  • Contains chloroplasts with chlorophyll
• Fungus


  • Unicellular
  • Made up of thread-like hyphae
  • Many nuclei distributed throughout the cytoplasm in their hyphae
• Prokaryote


  • Bacteria
  • Each bacterial cell contains a single chromosome, consisting of circular DNA strands
• Protoctist


  • Unicellular
  • Eukaryotic cells: have nucleus and membrane bound organelles
• Cell Structure in bacterial cells

  • Cell wall
  • Cell membrane
  • Cytoplasm
  • Ribosomes
  • Circular DNA: DNA not in nucleus, in a loop
  • Plasmids: little rings of DNA, contain extra DNA
  • Flagella: helps them move around
• Cell structure in plants only

  • Cell wall: Structural support for plants
  • Chloroplasts: Site of photosynthesis in plants
  • Central Permanent vacuoles: stores/isolates harmful materials, maintains water balance in cell
• Specialised cells


  • Ciliated cells: allow movement of mucus in the trachea and bronchi
  • Neurons/nerve cells: conduction of impulses
  • Root hair cells: increase surface area to maximise absorption
  • Red blood cells: transport oxygen in blood
  • Sperm and egg cells: contain haploid nucleus, acrosome with digestive enzymes, tail for swimming
• Levels of organization

  • Cell - basic functional and structural unit
  • Tissue - groups of cells of similar structure working together
  • Organ - different tissues working on same function
  • Organ system - groups of organs working together to perform specific functions
• Diffusion


  Movement of molecules from high concentration to low concentration through a partially permeable membrane
• Osmosis


  Net movement of water molecules from high water potential (dilute) to lower water potential (concentrated) through a partially permeable membrane
• Active transport


  Movement of particles through cell membrane from lower concentration to high concentration using energy from respiration
• Fats


  Made up of triglycerides (1 glycerol molecule chemically bonded with 3 fatty acid chains)
• Carbohydrates


  • Long chains of simple sugars
  • Glucose is a simple sugar (Monosaccharide)
  • When lots of Glucose join together starch, glycogen or cellulose can form (Polysaccharides)
• Proteins


  • Long chain of amino acids
  • 20 different amino acids
  • Same basic structure but the 'R' is different for each one
• DNA (Deoxyribonucleic Acid)


  • Molecule contains the instructions for growth and development of all organisms
  • Consists of two strands of DNA wound around each other in a double helix
  • Individual units are called nucleotides, with 4 different bases: Adenine, Cytosine, Thymine, Guanine
• Iodine solution test for starch, Benedict's solution test for reducing sugars, Biuret test for proteins, Ethanol emulsion test for fats and oils, DCPIP test for vitamin C
• Enzymes


  • Proteins with specific shape, held in place by bonds
  • Active site's shape ensures substrate can fit and reaction can occur
  • Denaturation occurs if pH is too low or too high, breaking the bonds that hold the enzyme's shape
• Photosynthesis

  • Process in which plants synthesise carbohydrates from carbon dioxide and water, using light energy and chlorophyll
  • End products are glucose and oxygen
• Limiting factors in photosynthesis


  • Light intensity
  • Carbon dioxide concentration
  • Temperature
• Digestive system


  • Ingestion: taking in of substances like food and water
  • Digestion: breakdown of food
  • Absorption: movement of nutrients from the intestines into the blood
  • Assimilation: uptake and use of nutrients by the cell
  • Egestion: removal of undigested food as faeces
• Functions of organs in digestive system

  • Salivary glands
  • Stomach
  • Small intestines
  • Large intestines

  
• A balanced diet needs proper amounts of carbs, protein, lipids, vitamins, minerals, dietary fibre and water
• Scurvy is caused by vitamin C deficiency, rickets is caused by vitamin D deficiency
• Investigating effect of changing carbon dioxide concentration

  1. Place plant in sodium hydroxide to absorb carbon dioxide from surrounding air

  2. Place other plant in beaker with beer
• Chapter 7: Human Nutrition
• Digestive system organs


  • Salivary glands
  • Small intestines
  • Large intestines

  
• Diets and deficiencies
• Digestive System

  
• Balanced diet


  Proper amount of carbs, protein, lipids, vitamins, minerals
• Ingestion


  Taking in of substances like food and water
• Digestion


  Breakdown of food
• Absorption


  Movement of nutrients from the intestines into the blood
• Assimilation


  Uptake and use of nutrients by the cell
• Egestion


  Removal of undigested food in the form of faeces