Science Q1 module 5

• Leaves


  • Main organs for photosynthesis
• Parts of the leaves and their functions


  • (diagram provided)
• Plants are considered self-feeders or autotrophs because they produce their own food and sustain themselves without consuming other organisms in order to survive
• Plants are in the bottom parts of the food chain and are considered the primary source of food for all consumers like animals including humans
• Plants have cell parts such as cell wall, large vacuoles, and chloroplast to help them harness and store energy through the process of photosynthesis
• Photosynthesis primarily takes place in the leaves
• Cellular respiration


  The total chemical processes taking place within the living system
• Autotrophs


  Organisms that can produce their own food and sustain themselves without consuming other organisms in order to survive
• Food chain hierarchy


  Plants are at the bottom as the primary source of food for all consumers like animals including humans
• Plant cell parts


  • Cell wall
  • Large vacuoles
  • Chloroplast
• Photosynthesis


  The process by which plants use light energy from the sun and carbon dioxide to produce glucose, the sugar molecules and oxygen that they use for growth and nourishment
• Photosynthesis primarily takes place in the leaves, which are the main organs for photosynthesis
• Molecules involved in photosynthesis

  • NADP
  • NAD
  • ATP
  • PGAL
  • FAD
  • ADP
• Parts of a leaf

  • Upper epidermis
  • Cuticle
  • Mesophyll cells
  • Stoma
  • Lower epidermis
  • Outer membrane
  • Inner membrane
  • Thylakoid
  • Stroma
  • Chloroplasts
  • Vascular bundle (vein)
  • Bundle sheath channel
  • Interconnecting thylakoids
  • Granum (stack of thylakoids)
• Photosynthesis


  1. Chlorophyll absorbs light energy

  2. Carbon dioxide enters through stomata

  3. Plants absorb water and nutrients through vascular tissues

  4. Carbon dioxide + water -> glucose + oxygen
• Light-dependent reaction


  1. Chlorophyll in Photosystem II absorbs light

  2. Electrons become energized and move to electron transport chain

  3. Water is split, releasing oxygen, hydrogen ions and electrons

  4. Electrons move to Photosystem I

  5. NADPH is produced

  6. ATP is produced by ATP synthase
• Calvin cycle (light-independent reaction)

  1. Carbon fixation: CO2 captured and combined with RuBP

  2. Carbon dioxide reduction: 3PGA converted to PGAL using ATP and NADPH

  3. Regeneration of RuBP: PGAL used to regenerate RuBP
• Cellular respiration


  The process of extracting energy in the form of ATP from the glucose in the food
• Aerobic cellular respiration


  1. Glycolysis

  2. Krebs cycle

  3. Electron transport chain
• Mitochondrial structure


  • Outer membrane
  • Inner membrane
  • Intermembrane space
  • Matrix
  • Cristae
• Glycolysis


  Glucose is split into two 3-carbon pyruvate molecules, producing 2 ATP
• Krebs cycle


  1. Pyruvate enters mitochondrial matrix and combines with CoA to form acetyl-CoA

  2. Acetyl-CoA enters Krebs cycle, releasing CO2 and high-energy electrons captured in NADH
• Glycolysis


  1. Pyruvate enters the mitochondrion

  2. One carbon atom is removed via decarboxylation

  3. CO2 is removed using NAD+

  4. Coenzyme A becomes attached to the remaining carbon atoms, creating Acetyl-CoA

  5. Acetyl-CoA enters the Krebs cycle
• Krebs Cycle


  1. Acetyl-CoA enters the cycle

  2. Acetyl-CoA combines with oxaloacetate to make the six-carbon compound citrate

  3. During the eight steps of the Krebs cycle, citrate undergoes a number of reactions, releasing CO2 and energy in a number of steps

  4. Oxaloacetate is eventually converted back into so it can be used again during the Krebs cycle
• Products of the Krebs cycle

  • CO2 is released as waste
  • NADH and FADH2 move to the next stage of cellular respiration
  • Energy is released in the form of ATP. A glucose molecule produces two molecules of ATP because two molecules of pyruvate are created from each molecule of glucose
• Electron Transport Chain


  1. In Complex I, NADH from glycolysis and Krebs cycle are oxidized to NAD+

  2. It passes off 2 electrons and H+ ions are pumped into the intermembrane space

  3. Coenzyme Q picks up electron from complex I and complex II and transport to complex III

  4. After that, four protons pumped from matrix to inter-membrane space, carrier C transports electrons to complex IV

  5. Then, two protons pumped from matrix to inter-membrane space, formation of H2O

  6. ATP synthase action pumps protons from inter-membrane space to matrix, produces ATP from ADP + Pi + energy
• The electron transport chain is a series of protein complexes located at the inner membrane of the mitochondria
• Photosynthesis


  Process where plants use carbon dioxide, water and light energy to produce glucose and oxygen
• Cellular respiration


  Process where cells break down glucose and oxygen to release energy in the form of ATP
• How photosynthesis and cellular respiration are dependent on each other

  Photosynthesis produces the glucose and oxygen needed for cellular respiration, while cellular respiration produces the carbon dioxide and water needed for photosynthesis
• Photosynthesis and cellular respiration are important biological processes needed by organisms to carry out their life processes
• Oxygen diffuses from the alveoli into the bloodstream via the capillaries that surround them.