genbio

• Enzymes: biological catalysts that increase the reaction rate of biochemical reactions by lowering the activation energy without being consumed in the reaction
• Energy of Activation (EA): The energy used to break the bonds in the reactants so they can be reformed in the products
• The active site can lower an EA barrier by:

  • Orienting substrates correctly

  • Straining substrate bonds

  • Providing a favorable microenvironment

  • Covalently bonding to the substrate
• Factors Affecting Enzyme Activity

  • Temperature

  • pH

  • Regulatory Molecule
• Cofactor: nonprotein enzyme helpers
• Coenzyme: organic cofactor
• Inhibitor: chemicals that inhibit the action of enzyme
• Competitive inhibitor: binds to the active site competing with the substrate
• Noncompetitive inhibitor: binds to any other site in the enzyme, resulting to the enzyme’s change in shape and making it less effective
• Feedback inhibition prevents a cell from wasting chemical resources by synthesizing more product than is needed.
• Energy coupling: Energy coupling occurs when the energy produced by one reaction or system is used to drive another reaction or system.
• Endergonic: Describing a reaction that absorbs (heat) energy from itsenvironment.
• Exergonic: Describing a reaction that releases energy (heat) into itsenvironment.
• Free energy: Gibbs free energy is a thermodynamic potential that measures the useful or process-initiating work obtainable from a thermodynamic system at a constant temperature and pressure (isothermal, isobaric).
• Hydrolysis: A chemical process of decomposition involving the splitting of a bond by the addition of water.
• Metabolism: the totality of an organism’s chemical reaction to sustain life
• Catabolism: involves breaking down big, complex molecules into smaller, more manageable ones.
• Anabolism: 

  - Amino acids combine to form polypeptides (protein building blocks).

  - Glucose molecules link up to create glycogen (energy storage).

  - Fatty acids assemble into triglycerides.
• Spontaneous Process: with negative 𝚫G, moving towards equilibrium
• Metabolism is never at equilibrium
• ATP: adenosine triphosphate, the energy currency of the cell. Karl Lohmann was given the credit for its discovery from liver cells.
• ADP: adenosine diphosphate
• Photosynthesis is the process that converts solar energy into chemical energy. This process takes place in the chloroplasts of cells
• Chemical equation of photosynthesis: 6CO2 + 6H2O + light -> C6H12O6 + 6O2
• Autotrophs examples: Fern, kelp, euglena, cyanobacteria
• Heterotrophs obtain their organic material from other organisms
• Why are plants green? Plants are green because they contain chlorophyll, a pigment that reflects green light.
• Stomata: microscopic pores in the leaves of plants where CO2 enters and O2 exits
• Wavelength: is the distance between crests of waves
• Visible light: consists of wavelengths (including those that drive photosynthesis) that produce colors we can see. The range of visible light is 380nm to 750nm
• Chlorophyll A: the main photosynthetic pigment in plants
• Excitation of chlorophyll: When a pigment absorbs light, it goes from a ground state to an excited state, which is unstable. When excited electrons fall back to the ground state, photons are given off.
• 2 Stages of Photosynthesis:

  Light Dependent Reaction

  Calvin Cycle
• Light Dependent Reaction takes place in the thylakoid
• Calvin Cycle takes place in the stroma
• Photosystem: large complexes of proteins and pigments (light-absorbing molecules) that are optimized to harvest light
• primary electron acceptor in the reaction center, accepts an excited electron from chlorophyll a
• Photosystem II: functions first and is best at absorbing a wavelength of 680nm
• Photosystem I: Primary electron acceptor is chlorophyll Ao; special pair is P700
• Electron from PS I fall down the electron transport chain to a protein ferredoxin (Fd) to create NADPH