Slide sets

Free Activation energy-Metabolism-Enzymes

Overview of Metabolism-Khan academy credit

Photosynthesis

Cellular Respiration

Fitness

1. Enzyme Structure

   1. Describe the properties of enzymes.

      1. The structure of enzymes includes the active site that specifically interacts with substrate molecules

      2. For an enzyme-mediated chemical reaction to occur, the shape and charge of the substrate must be compatible with the active site of the enzyme

2. Enzyme Catalysis

   1. Explain how enzymes affect the rate of biological reactions

      1. The structure and function of enzymes contribute to the regulation of biological processes:

         1. Enzymes are biological catalysts that facilitate chemical reactions in cells by lowering activation energy.

3. Environmental Impacts on Enzyme Function

   1. Explain how changes to the structure of an enzyme may affect its function

      1. Changes to the molecular structure of a component in an enzymatic system may result in a change of the function or efficiency of the system

         1. Denaturation of an enzymes occurs when the protein structure is disru[ted, eliminating the ability to catalyze reactions

         2. Environmental temperatures and pH outside the optimal range for a given enzyme will cause changes to its structure, altering the efficiency with which it catalyzes reactions.

      2. In some cases, denaturation is reversible, allowing the enzyme to regain activity

   2. Explain how the cellular environment affects enzyme activity

      1. Environmental pH can alter the efficiency of enzyme activity, including through disruption of hydrogen bonds that provide enzyme structure

         1. pH=-log[H+]

            1. Do not need to do this equation, but do need to know what it represents.

      2. The relative concentrations of substrates and products determines how efficiently an enzymatic reaction proceeds.

      3. Higher environmental temperatures increase the speed of movement of molecules in a solution, increasing the frequency of collisions between enzymes and substrates therefore increasing the rate of reaction.

      4. Competitive inhibitor molecules can bind reversibly or irreversibly to the active site of the enzyme. Noncompetitive inhibitors can bind allosteric sites, changing the activity of the enzyme.

4. Cellular Energy

   1. Describe the role of energy in living organisms.

      1. All living systems require constant input of energy

      2. Life requires a highly ordered system and does not violate the second law of thermodynamics

         1. Energy input must exceed energy loss to maintain order and power cellular processes

         2. Cellular processes that release energy may be coupled with cellular processes that require energy

         3. Loss of order or energy flow results in death

            1. Do not need to know the equation for Gibbs free energy but do need to know the concept of energy.

      3. Energy-related pathways in biological systems are sequential to allow for a more controlled and efficient transfer of energy. A product of a reaction in a metabolic pathway is generally the reactant for the subsequent step in the pathway.

5. Photosynthesis

   1. Describe the photosynthetic processes that allow organisms to capture and store energy

      1. Organisms capture and store energy for use in biological processes

         1. Photosynthesis captures energy from the sun and produces sugars.

            1. Photosynthesis first evolved in prokaryotic organism

            2. Scientific evidence supports the claim that prokaryotic (cyanobacteria) photosynthesis was responsible for the production of an oxygenated atmosphere

            3. Prokaryotic photosynthetic pathways were the foundation of eukaryotic photosynthesis

      2. The light-dependent reactions of photosynthesis in eukaryotes involve a series of coordinated reaction pathways that capture energy present in light to build ATP and NADPH, which power the production of organic molecules.

   2. Explain how cells capture energy from light and transfer it into biological molecules for storage and use

      1. During photosynthesis, chlorophylls absorb energy from light, boosting electrons to a higher energy level in photosystems I and II.

      2. Photosystems I and II are embedded in the internal membranes of chloroplasts and are connected by the transfer of higher energy electrons through and electron transport chain (ETC)

      3. When electrons are transferred between molecules in a sequence of reactions as they pass through the ETC, an electrochemical gradient of protons (hydrogen ions) is established across the internal membrane.

      4. The formation of proton gradients is linked to the synthesis of ATP from ADP and inorganic phosphate via ATPsynthase

      5. The energy captured in the light reactions and transferred to ATP and NADPH powers the production of carbohydrates from carbon dioxide in the Calvin cycle, which occurs in the stroma of the chloroplast.

         1. Do not need to know the steps in the Calvin cycle, structure of the molecules, and names of enzymes (except ATP synthase).

6. Cellular Respiration

   1. Describe the processes that allow organisms to use energy stored in biological macromolecules

      1. Fermentation and cellular respiration use energy from biological macromolecules to produce ATP. Respiration and fermentation are characteristic of all forms of life.

      2. Cellular respiration in eukaryotes involved a series of coordinated enzyme-catalyzed reactions that capture energy from biological molecules.

      3. The electron transport chain transferred energy from electrons in a series of coupled reactions that establish an electrochemical gradient across membranes

         1. Electron transport chain reactions occur in chloroplasts, mitochondria, and prokaryotic plasma membranes

         2. In cellular respiration, electrons delivered by NADH and FADH2 are passed to a series of electron acceptors as they move toward the terminal electron acceptor, oxygen. In photosynthesis, the terminal electron acceptor is NADP+. Aerobic prokaryotes use oxygen as a terminal electron acceptor, while anaerobic prokaryotes use other molecules.

         3. The transfer of electrons is accompanied by the formation of a proton gradient across the inner mitochondrial membrane or the internal membrane of chloroplasts, with the membranes(s) separating a region of high proton concentration from a region of low proton concentration. In prokaryotes, the passage of electrons is accompanied by the movement of protons across the plasma membrane.

         4. The low of protons back through membrane-bound ATPsynthase by chemiosmosis drives the formation of ATP from ADP and inorganic phosphate. This is known as oxidative phosphorylation in cellular respiration and photophosphorylation in photosynthesis.

         5. In cellular respiration, decoupling oxidative phosphorylation from electron transport generates heat. This heat can be used by endothermic organisms to regulate body temperature.

            1. Do not need to know names of specific electron carriers in ETC.

   2. Explain how cells obtain energy from biological macromolecules in order to power cellular functions

      1. Glycolysis is a biochemical pathway that releases energy in glucose to form ATP from ADP and inorganic phosphate, NADH from NAD+ and pyruvate.

      2. Pyruvate is transported from the cytosol to the mitochondria, where further oxidation occurs.

      3. In the Krebs cycle, carbon dioxide is released from organic intermediates, ATP is synthesized from ADP and inorganic phosphate, and electrons are transferred to the coenzymes NADH and FADH2.

      4. Electrons extracted in glycolysis and Krebs cycle reactions are transferred by NADH and FADH2 to the ETC in the inner mitochondrial membrane.

      5. When electrons are transferred between molecules in a sequence of reactions as they pass through the ETC, an electrochemical gradient of protons (hydrogen ions) across the inner mitochondrial membrane is established.

      6. Fermentation allows glycolysis to proceed in the absence of oxygen and produces organic molecules, including alcohol and lactic acid, as waste products

      7. The conversion of ATP to ADP releases energy, which is used to power many metabolic processes.

         1. Do not need to know specific steps, names of enzymes and intermediates of pathways in glycolysis, Krebs cycle and ETC.

7. Fitness

   1. Explain the connection between variation in the number and types of molecules within cells to the ability of the organism to survive and/or reproduce in different environments

      1. Variation at the molecular level provides organisms the ability to respond to a variety of environmental stimuli.

      2. Variation in the number and types of molecules within cells provides organisms a greater ability to survive and/or reproduce in different environments.