Biology Y8 B2.2

• Producers

  Organisms that make their own food
• Producers


  • Plants
  • Algae
• Consumers


  Organisms that eat other organisms as food
• Photosynthesis


  The process producers use to make their own food

  
• Photosynthesis

  1. Light

  2. Carbon dioxide + water

  3. Glucose + oxygen

  
• Glucose is the food produced in photosynthesis
• Chloroplasts

  The part of the plant cell where photosynthesis happens

  
• Chlorophyll

  The chemical pigment in chloroplasts that absorbs light and makes plants green
• How carbon dioxide gets to chloroplasts

  Diffuses from air through stomata (tiny holes underneath leaf)
• How water gets to chloroplasts

  Diffuses from soil through root hair cell, root, xylem in stem, into leaf
• How light gets to chloroplasts

  Passes through top of leaf and is absorbed by chloroplasts in palisade layer
• Glucose

  The plant uses it for energy right away or stores it for later use
• How plant gets rid of oxygen

  Oxygen diffuses from stomata (tiny holes underneath leaf) into the air
• Leaves

  • Thin, wide and flat, have veins, and are green
• Leaves are green because of chlorophyll
• Leaves are greener on top than bottom because more chloroplasts on top due to more sunlight
• Waxy cuticle layer

  Prevents water inside leaf from evaporating
• How gases get into and out of leaf

  Diffuse through stomata
• Stomata

  Open to allow gases in/out for photosynthesis, close to prevent water loss
• How stomata open and close

  Guard cells change shape to open during day, close at night
• Palisade layer

  Has lots of chloroplasts for photosynthesis
• Spongy layer

  Has lots of air spaces for diffusion
• Minerals

  Dissolved in water in soil, absorbed by root hair cells, transported by xylem
• Main minerals plants need

  • Nitrates
  • Phosphates
  • Potassium
  • Magnesium
• Nitrates

  Made from nitrogen and oxygen
• Phosphates

  Made from phosphorus and oxygen
• Magnesium is Mg, Potassium is K
• Plant nutrient deficiencies

  Nitrates - poor growth, older leaves yellow

  Phosphates - yellow leaves with dead patches

  Potassium - poor root growth, younger leaves purple

  Magnesium - yellow leaves
• Proteins

  Made of amino acids, plants need them for growth
• Nitrates

  Provide nitrogen for plants to make proteins
• How minerals are returned to soil

  Decomposers return minerals from dead plants/leaves
• When farmers sell crops, nutrients are not returned to soil
• Fertilizers

  Add minerals (N-P-K) to soil
• Chemosynthesis

  Process some bacteria use to make food without light, using energy from chemical reactions
• Chemosynthesis usually uses carbon dioxide, photosynthesis always uses carbon dioxide
• Photosynthesis and chemosynthesis both make glucose for food
• Places chemosynthetic bacteria are found

  • Volcanic vents on sea floor
  • Inside tube worms
  • In soil
  • In root nodules of legumes
• Symbiosis/Mutualism

  Close relationship where organisms provide chemicals/food for each other
• Respiration

  Process that releases energy from food for immediate use
• Aerobic

  With oxygen