Cellular Energy Production and Photosynthesis

Cellular Energy Production

• Cellular energy production is the process by which cells generate energy in the form of ATP (adenosine triphosphate)
• There are two main types of cellular energy production:
  • Aerobic respiration: occurs in the presence of oxygen and produces a net gain of 36-38 ATP molecules
  • Anaerobic respiration: occurs in the absence of oxygen and produces a net gain of 2 ATP molecules

Photosynthesis

• Photosynthesis is the process by which light energy is converted into chemical energy in the form of glucose
• Occurs in chloroplasts of plant cells and some microorganisms
• Equation: 6 CO2 + 6 H2O + light energy → C6H12O6 (glucose) + 6 O2

Mitochondrial Function

• Mitochondria are organelles found in eukaryotic cells responsible for generating energy through cellular respiration
• Mitochondrial function involves:
  • Cellular respiration: generation of ATP through the electron transport chain
  • Regulation of cellular metabolism: mitochondria play a role in regulating cellular metabolism through the regulation of ATP production

Cellular Metabolism

• Cellular metabolism refers to the set of chemical reactions that occur within a cell to maintain life
• Includes:
  • Catabolism: breakdown of molecules to release energy
  • Anabolism: synthesis of molecules to store energy
  • Energy metabolism: generation of ATP through cellular respiration

Glycolysis

• Glycolysis is the first stage of cellular respiration and occurs in the cytosol of cells
• Breaks down glucose (C6H12O6) into pyruvate (C3H4O3) releasing a net gain of 2 ATP molecules
• Equation: C6H12O6 → 2 C3H4O3 + 2 ATP

Cellular Energy Production

• Cellular energy production generates energy in the form of ATP (adenosine triphosphate)
• Two main types of cellular energy production: aerobic respiration and anaerobic respiration

Aerobic Respiration

• Occurs in the presence of oxygen
• Produces a net gain of 36-38 ATP molecules

Anaerobic Respiration

• Occurs in the absence of oxygen
• Produces a net gain of 2 ATP molecules

Photosynthesis

• Converts light energy into chemical energy in the form of glucose
• Occurs in chloroplasts of plant cells and some microorganisms
• Equation: 6 CO2 + 6 H2O + light energy → C6H12O6 (glucose) + 6 O2

Mitochondrial Function

• Mitochondria are organelles responsible for generating energy through cellular respiration
• Mitochondrial function involves cellular respiration and regulation of cellular metabolism
• Generates energy through the electron transport chain

Cellular Metabolism

• Refers to the chemical reactions that occur within a cell to maintain life
• Includes catabolism, anabolism, and energy metabolism
• Catabolism: breakdown of molecules to release energy
• Anabolism: synthesis of molecules to store energy
• Energy metabolism: generation of ATP through cellular respiration

Glycolysis

• First stage of cellular respiration
• Occurs in the cytosol of cells
• Breaks down glucose (C6H12O6) into pyruvate (C3H4O3) releasing a net gain of 2 ATP molecules
• Equation: C6H12O6 → 2 C3H4O3 + 2 ATP

Cellular Energy Production

• Cellular energy production is the process by which cells generate energy from nutrients.
• Energy from nutrients is converted into ATP (adenosine triphosphate), the energy currency of the cell.
• Major energy-producing pathways include:
  • Cellular respiration (aerobic and anaerobic)
  • Fermentation (anaerobic)

Photosynthesis

• Photosynthesis is a light-dependent process by which plants, algae, and some bacteria convert light energy into chemical energy.
• The overall equation for photosynthesis is: 6 CO2 + 6 H2O + light energy → C6H12O6 (glucose) + 6 O2.
• Photosynthesis occurs in chloroplasts, organelles found in plant cells.
• Light-dependent reactions involve:
  • Light absorption by pigments (chlorophyll, others)
  • Electron transfer, proton pumping, and ATP synthesis
• Light-independent reactions (Calvin cycle) involve:
  • CO2 fixation, reduction, and regeneration of RuBP

Mitochondrial Function

• Mitochondria are organelles found in eukaryotic cells, responsible for energy production.
• Mitochondrial functions include:
  • Generating ATP through cellular respiration (oxidative phosphorylation)
  • Regulating cell growth, differentiation, and apoptosis
  • Involvement in cellular signaling, calcium homeostasis, and redox balance
• Mitochondrial structure consists of:
  • Outer and inner membranes, intermembrane space, and mitochondrial matrix

Cellular Metabolism

• Cellular metabolism is the network of biochemical reactions that occur within a cell.
• Major metabolic pathways include:
  • Catabolism: breakdown of molecules to release energy
  • Anabolism: synthesis of molecules to store energy
• Key metabolic pathways include:
  • Glycolysis
  • Citric acid cycle (Krebs cycle, tricarboxylic acid cycle)
  • Fatty acid metabolism
  • Amino acid metabolism

Glycolysis

• Glycolysis is the first stage of cellular respiration, occurring in the cytosol.
• Glycolysis converts glucose (6-carbon sugar) into pyruvate (3-carbon molecule).
• Net ATP production is 2 ATP, 2 NADH.
• Glycolytic reactions involve:
  • Glucose phosphorylation
  • Aldolase and triosephosphate isomerase reactions
  • Pyruvate kinase reaction
• Regulation of glycolysis involves:
  • Allosteric control by ATP, ADP, and NAD+
  • Feedback inhibition by ATP