Biology (2nd Quarter)

• What is ATP?

  it is a molecule that transfers energy
• ATP is composed of three parts:

  • Three phosphate groups
  • Adenine (nucleobase)
  • Ribose (simple sugar)
• Molecules of carbohydrates and lipids are broken down through the process of cellular respiration to produce ATP
• What is ADP?


  often converted to ATP, a high-energy molecule used in biochemical reactions
• Process of ATP Cycle

  1. Energy Release

  • When a cell needs energy for processes, ATP is hydrolyzed to release energy
  • The hydrolysis of ATP involves breaking the high-energy bond between the second and last phosphate group, resulting to formation of ADP and Pi
  • The removal of one phosphate-group transitions the Triphosphate to Diphosphate
• General Form of ATP Cycle in Energy Release

  $ATP +$$H2O >ADP +$$Pi +$$Energy$
• What is Hydrolysis?


  it is the process of breaking complex macromolecule. During hydrolysis, water is lysed, and the resulting Hydrogen atom (H+) and hydroxyl group (OH-) are added to larger molecule
• Process of ATP Cycle

  2. Regeneration of ATP

  • cells need to regenerate it from ATP to ADP, to maintain constant supply of ATP
  • ADP is continually converted to ATP by the addition of phosphate during the process of cellular respiration
  • As the cell requires more energy, it uses energy from the breakdown of food molecules to attach a free phosphate group to an ADP molecule in order to make ATP.
• Exergonic - yields energy

  Endergonic - requires energy
• Photophosphorylation is the process of utilizing light energy from photosynthesis to convert ADP to ATP.
• Cyclic is a process that results in the movement of the electrons in a cyclic way to synthesize the ATP molecules
• Non-Cyclic the process in which the electrons that are expelled from the exciting photo center do not return
• Substrate Level Phosphorylation

  • Simply the enzymatic transfer of a phosphate group from an organic molecule to adenosine diphosphate (ADP) to form adenosine triphosphate (ATP).

  • The phosphate group is transferred to ADP from a substrate.

  • Occurs in the cytoplasm of cells (glycolysis) and the mitochondria (Krebs cycle).
• Oxidative Phosphorylation

  • is defined as an electron transfer chain driven by substrate oxidation that is coupled to the synthesis of ATP through an electrochemical transmembrane gradient.

  • a cellular process that harnesses the reduction of oxygen to generate high-energy phosphate bonds in the form of adenosine triphosphate (ATP)
• Chloroplast is an organelle that contains the photosynthetic pigment chlorophyll that captures sunlight and converts it into useful energy. It can be found in mesophyll cells located in the leaves of the plants. A type of plastid absent in animal cells
• Photoautotrophs – capable of photosynthesis
• Functions of Chloroplast

  • synthesize food by the process of photosynthesis.
  • absorbs light energy and converts it into chemical energy.
  • it also plays a role in synthesizing certain amino acids, lipids, and pigments crucial for plant metabolism and function.
• Types of Plastids

  1. Chromoplasts
  2. Chloroplasts
  3. Leucoplasts
• Chromoplasts


  Contains multi-coloured pigments

  found in all flowers, fruits, and are mainly responsible for their distinctive colors
• Chloroplasts

  are green coloured plastids which consist of green-colored pigments within the plant cell called chlorophyll.
• Leucoplasts

  • colorless plastids mainly used for the storage of starch, lipids, and proteins within the plant cell.
• Structure of the Chloroplasts

  1. Outer Membrane
  2. Inner Membrane
  3. Membrane Transporters
  4. Intermembrane Space
  5. Stroma
  6. Thylakoid
  7. Stroma Lamellae
  8. Thylakoid Lumen
  9. Chlorophyll
  10. Chloroplast DNA
  11. Ribosome
• Outer Membrane

  • it is semi-permeable and holds everything together
• Inner Membrane

  • less permeable than the outer membrane
• Membrane Transporters

  • enables transport of nutrients, solutes, and metabolites in and out of the chloroplast o farms a border to the stroma
• Intermembrane Space

  • the thin region between the inner membrane and the outer membrane (10-20 nm thick).
  • It plays a role in oxidative phosphorylation.
• Stroma

  It is a colorless, alkaline, aqueous, protein-rich fluid present within the inner membrane of the chloroplast
• Thylakoid

  • Are membranes sacs suspended in the stroma and carries out the light reactions of photosynthesis.
  • Found in stacks called grana (singular granum)
• Stroma Lamellae

  • increase the efficiency of photosynthesis by keeping grana at a distance.
• Thylakoid Lumen

  • A continuous aqueous phase enclosed by the thylakoid membrane.
  • the compartment where molecular oxygen is produced from water during photosynthesis light-dependent reaction.
• Chlorophyll

  The green photosynthesis pigment that helps in the process of photosynthesis.
• Chloroplast DNA

  • Contains genes that are involved with aspects of photosynthesis
• Ribosome

  It plays a crucial role in protein synthesis.
• Chlorophyll

  A greenish pigment found in the thylakoid membrane inside the chloroplast of a plant cell. Absorbs blue and red light while it transmits and reflects green light
• Pigments

  Are substances that absorb visible light. Different pigments absorb light of different wavelengths.
• Chlorophyll A

  Energy was transferred by the light absorbed by the pigments.
• Chlorophyll B

  • Accessory Pigments
• Carotenoids

  Serve as protection for chlorophyll by dissipating excessive energy that will otherwise be destructive chlorophyll.
• Structure:

  1. Head – a Porphyrin Ring and has a magnesium atom at its center 2. Phytol Tail – a lipid-soluble hydrocarbon tail
• Photosynthesis

  • process by which carbohydrate molecules are synthesized
  • It turns sunlight, water, and carbon dioxide into oxygen and energy, in the form of sugar
  • These sugar molecules contain energy and the energized carbon that all living things need to survive.