Bio lab notes

Cellular Respiration and Photosynthesis

Overview of Autotrophs and Heterotrophs

  • Autotrophs: Organisms that produce their own food from inorganic substances.

    • Examples: Bacteria, Algae, Plants.

    • Specific type: Photautotrophs (e.g., plants) use light energy for photosynthesis.

    • Process: Using sunlight, they convert CO2 and water into glucose and oxygen.

  • Heterotrophs: Organisms that cannot produce their own food and rely on consuming autotrophs.

    • Example: Animals, such as deer, that eat plants to obtain glucose.

    • Dependence on autotrophs for energy.

Photosynthesis

  • Definition: The process through which photautotrophs convert light energy into chemical energy.

    • Main reactants: CO2 (carbon dioxide) and H2O (water).

    • Main products: C6H12O6 (glucose) and O2 (oxygen).

  • Chemical Reaction:

    • Formula: CO2 + H2O + light energy → C6H12O6 + O2.

  • Chloroplasts: Organelles in plant cells where photosynthesis occurs.

    • Contains pigments that absorb light energy, primarily Chlorophyll a (blue-green pigment).

    • Accessory pigments include Chlorophyll b, Carotenoids, etc.

  • Light Absorption:

    • Absorbs specific wavelengths of light.

    • Reflects other wavelengths, which determines the color we see in plants.

    • Example: A red car absorbs all colors except red, which it reflects.

  • Seasons:

    • Autumn leaf color change due to chlorophyll degradation, revealing accessory pigments.

    • Compounds such as carotenoids reflect yellow, orange colors.

Chromatography in Photosynthesis

  • Definition: A technique to separate different pigments based on polarity.

    • Types of chromatography include affinity, size, charge, and polarity.

  • Procedure: In paper chromatography, photopigments are separated when a nonpolar solvent moves up polar paper.

  • RF Value Calculation:

    • Formula: RF = Distance traveled by pigment / Distance traveled by solvent front.

    • Example calculations provided.

    • Usage: Used to identify pigments by their polarity based on RF values.

Cellular Respiration

  • Definition: The process by which cells convert glucose into usable energy (ATP) using oxygen.

    • Overall Reaction:

    • Formula: C6H12O6 + O2 → CO2 + H2O + ATP.

  • Stages of Cellular Respiration:

    1. Glycolysis

    2. Acetyl CoA (Bridge Reaction)

    3. Krebs Cycle

    4. Electron Transport Chain.

  • Glycolysis:

    • Occurs in the cytosol.

    • Converts glucose (6-carbon) into 2 pyruvate molecules (3-carbon each).

    • Net products: 2 NADH and 2 ATP (4 total ATP produced, 2 ATP invested).

    • Process involves breaking bonds to release electrons, which are captured by NAD+ to become NADH.

  • Bridge Reaction:

    • Converts pyruvate to acetyl CoA.

    • Releases CO2 and produces NADH from the remaining electrons.

  • Krebs Cycle:

    • Occurs in the mitochondrial matrix.

    • Main reactants: Acetyl CoA combines with oxaloacetate (OOA) to form citrate.

    • Products per glucose: 6 NADH, 2 FADH2, 2 ATP, and 4 CO2 (after two turns for each acetyl CoA).

Electron Transport Chain (ETC)

  • Key step for ATP production occurring in the inner mitochondrial membrane.

  • Uses NADH and FADH2 generated in previous steps to transport electrons through protein complexes (Complexes I-IV).

  • Hydrogen Ion (H+) Pumping: Electrons create a proton gradient used to power ATP synthase.

    • ATP synthase generates ATP when H+ ions flow back through it.

  • Final Electron Acceptor: Oxygen combines with electrons and protons to form water.

    • Essential for aerobic respiration.

Importance of Oxygen

  • Oxygen is required for the full progression of cellular respiration and serves as the final electron acceptor in the ETC.

  • Lacking oxygen leads to fermentation (produces lactic acid or ethanol), which does not yield much energy compared to aerobic respiration.

Implications and Applications

  • Understanding these biochemical processes is crucial for comprehending how energy is transferred within ecosystems.

  • Knowledge applicable in fields like agriculture (crop yield) and medicine (metabolic disorders).

  • Understanding cellular respiration's efficiency is crucial in bioenergetics and bioengineering contexts.

  • What is chromatography technique? 

  • Looks at Rf values are determining which one is more polar or more non-polar

  • Calculating the Rf value

    • You will not be provided with the Rf value equation.

  • Photosynthesis general equation

  • Most abundant photopigment

  • In what scenario would accessory pigments be needed?

  • What colors are absorbed or reflected based on a photopigment I give?

    • Will be provided a graph to solve

  • Cellular Respiration 

    • OIL RIG

    • Where does glycolysis occur?

    • What are the reactants and products of glycolysis?

    • Where does the bridge reaction occur?

    • What are the reactants and products of the bridge reaction?

    • Where does the Kreb Cycle occur?

    • How many rounds of the Kreb cycle happens per 1 glucose molecule?

    • What are the major reactant and products?

    • Explain what happens in the Electron Transport Chain (in full detail).

      • Reducing electron transport carriers, electrons shuttled through protein complexes, O2 collects remaining electrons from Complex 4 to make H2O. Because of the complex shuttle system... we can Hydrogen having a larger concentration in the inner membrane space. Thus, Hydrogens will go down its concentration gradient into ATP synthase resulting in the most ATP made.

  • Be able to read Oxygen and CO2 levels on a graph and explain if it is going through cellular respiration or photosynthesis (AKA the graphing assignment)