G10 Bio

• Chemotropism


  The movement of plants in response to a chemical stimulus
• Thigmotropism


  The directional movement in plants in response to touch
• Thermotropism


  The movement of plant or their parts in response to changes in the external stimulus of temperature
• Nastic movements


  Non-directional movements in plants that are not dependent on the direction of the stimulus
• Nastic movements


  • Leaves of touch me not (Mimosa, Hti-ka-yone) fold up immediately when touched
  • Closing of the lid of pitcher plant (Nepenthes, Ne-ta-gaung) due to the catchment of insects
• Skeletal system


  Semi rigid system with joints that act as hinges
• Muscular system


  System attached to the skeletal system that can pull on the skeleton
• Muscular action


  Produces a change in body shape, which places a force on the ground, the force they exert moves its body forward rapidly
• Muscular and skeletal systems

  Allow movement in animals
• Locomotion in earthworm


  • Fluid-filled central body cavity or coelom encompassed by circular muscles that contract and longitudinal muscles that relax
  • Bristle-like structures called setae on the underside of the body
  • Waves of circular-muscle contraction followed by waves of longitudinal muscle contraction which pass backward

  
• Locomotion in earthworm


  1. Circular muscles contract and longitudinal muscles relax, front end extends forward

  2. Circular muscles contract, longitudinal muscles relax, anterior swells and setae anchor the ground

  3. Body region behind the anterior end is pulled forward, setae prevent slipping backward

  
• Locomotion in grasshopper


  • Flexor and extensor (antagonistic) muscles attached to the internal surface of the exoskeleton
  • Rear legs are long and muscular, adapted for hopping or jumping
• Jumping in grasshopper


  1. Leg is folded in a J-shape and ready for a jump

  2. Extensor muscle contracts, leg jerks backwards, propelling the grasshopper forward and up
• Flying in grasshopper


  Alternate contraction of extensor muscles (elevators) and flexor muscles (depressors) located inside the exoskeleton of the thorax
• Locomotion in fish


  • Streamlined body shape to reduce friction
  • Contraction and relaxation of antagonistic muscles called myotomes on either side of the body and the tail or caudal fin
  • Pectoral fins used for steering, pelvic fins used to prevent the body from diving or rolling
• Locomotion in frog


  • Powerful hind legs adapted for swimming and leaping
  • Extensor muscles of the thigh contract, extending the limb and thrusting the foot against the ground or water
• Swimming and leaping in frog

  Thrust transmitted through the body by the pelvic girdle and spine, pushing the whole animal forward
• Locomotion in birds


  • Approximately 175 different muscles, mainly controlling the upstrokes and strong downstrokes of the wings
  • Antagonistic muscle pair of pectoral and supracoracoideus forms the major wing muscles
• Flying in birds


  1. Pectoral muscles contract to cause downstroke of the wings, supracoracoideus causes the upstroke, providing lift

  2. Circular movement of the wings, forward and then backward, during each downstroke provides thrust that moves the bird forward
• Locomotion in humans


  • About 630 skeletal muscles, most function in antagonistic pairs
• Flexion and extension in humans

  Biceps brachii contracts to flex the forearm towards the upper arm, triceps brachii contracts to extend the forearm away from the upper arm
• Nutrition


  The process of taking food by an organism and utilization of food for energy
• Nutrients


  • Carbohydrates
  • Proteins
  • Fats
  • Vitamins
  • Minerals
• Autotrophic nutrition


  Organisms that can make their own food from simple inorganic materials
• Autotrophic nutrition


  • Photosynthetic plants use energy from the sun to make their own food
  • Chemosynthetic organisms consume simple nonliving chemical nutrients to make their own food
• Heterotrophic nutrition


  Organisms that cannot make their own food and depend on other organisms for food
• Types of heterotrophic nutrition


  • Holozoic (ingesting solid organic matter)
  • Saprophytic (feeding on dead and decaying matter)
  • Parasitic (obtaining nutrients by living on or in the body of another organism)
• Photosynthesis


  1. Absorption of sunlight energy by chlorophyll

  2. Carbon dioxide and water are converted into glucose

  3. Glucose is used as an energy source or converted into other carbohydrates
• Chlorophyll


  The green pigment in plants that traps light energy for photosynthesis
• Photosynthesis occurs in the chloroplasts of plant cells
• Absorption of sunlight energy by chlorophyll

  1. Chlorophyll absorbs sunlight energy

  2. Energy is changed into chemical energy
• Chloroplast


  • Where photosynthesis occurs in plant cells
• Photosynthesis occurs in the chloroplast
• Experiment to demonstrate that starch is formed during photosynthesis
• Starch test with variegated leaf

  1. Boil leaf in water to kill protoplasm

  2. Boil leaf in methylated spirit to remove chlorophyll

  3. Soften leaf by dipping in boiling water

  4. Place iodine solution on leaf

  5. Leaf turns blue-black if starch is present
• Green leaves make starch as food during photosynthesis
• Starch gives a blue-black colour with iodine solution
• Factors affecting photosynthesis


  • Intensity of light
  • Concentration of carbon dioxide in the air
  • Temperature
  • Water
• Macronutrients


  Nutrients needed in relatively large amounts
• Macronutrients


  • Carbohydrates
  • Fats
  • Proteins
  • Fibres
  • Water