(Unit 2.1) Metabolic Pathways

• what is cell metabolism?

  thousands of biochemical reactions that occur within a living cell
• what is a catabolic pathway?

  they bring about the break down of complex molecules into simpler ones
• what is an anabolic pathway?

  they bring about the synthesis of molecules from building blocks
• do catabolic pathways release or use energy?

  release energy
• do anabolic pathways release of require energy?

  require energy
• What is a metabolic pathway?

  An integrated series of enzyme-controlled reactions
• What does the term metabolism refer to?

  All the reactions that take place within a cell
• What are the two forms of metabolic reactions?

  Anabolic and catabolic reactions
• What do anabolic reactions do?

  Build up simple molecules into more complex molecules
• What do catabolic reactions do?

  Break down complex molecules into simpler molecules
• What is required for an anabolic reaction to take place?

  Energy
• What do catabolic reactions release?

  Energy
• What is an example of an anabolic reaction discussed in the material?

  Protein synthesis from amino acids
• What is an example of a catabolic reaction mentioned in the material?

  Glucose breakdown during respiration
• What regulates metabolic pathways?

  Enzymes
• How are anabolic and catabolic pathways related?

  The energy generated by catabolic reactions can be used for anabolic reactions
• Can some metabolic reactions be reversed?

  Yes, some can be reversible while others are irreversible
• What is an example of a reversible reaction in metabolism?

  Conversion of pyruvate to lactate and back
• What is an example of an irreversible reaction in metabolism?

  Fermentation of pyruvate to ethanol and carbon dioxide
• What is the structure of the mitochondrion?

  It has two membranes: an outer membrane and a folded inner membrane
• What is the function of the inner membrane of the mitochondrion?

  It is responsible for certain chemical reactions and contains enzymes
• What is the advantage of having compartments in organelles like mitochondria and chloroplasts?

  They allow high concentrations of substrates, leading to high reaction rates
• What are the three forms of membrane proteins mentioned?

  Pores, pumps, and enzymes
• What are enzymes?

  Biological catalysts that speed up the rate of reaction
• How do enzymes affect activation energy?

  They lower the activation energy required for reactions
• What is induced fit in enzyme activity?

  The active site changes slightly to accommodate the substrate
• What does affinity refer to in enzyme-substrate interactions?

  The tendency of a substrate to bind to the active site
• What happens to the affinity of products after a reaction?

  They have a lower affinity for the active site and separate
• What is a metabolic pathway?

  A series of enzyme reactions where the product of one becomes the substrate for the next
• How can mutations affect enzymes?

  They can lead to faulty enzymes that disrupt metabolic pathways
• How can the effect of competitive inhibitors be countered?

  By increasing the concentration of the substrate
• What are competitive inhibitors?

  Molecules that compete with the substrate for the active site
• What is feedback inhibition?

  A process where the final product inhibits an earlier enzyme in the pathway
• What is an inhibitor?

  A substance that decreases the rate of reaction
• What are non-competitive inhibitors?

  Inhibitors that bind to a different area of the enzyme, changing its shape
• What happens when too much of a final product is produced in feedback inhibition?

  The final product may inhibit an earlier enzyme to slow down the pathway
• What are the functions of membrane proteins in cellular metabolism?

  • Pores assist in diffusion of molecules
  • Pumps actively transport ions using ATP
  • Enzymes catalyze reactions within the membrane
• What are the key concepts introduced in key area one of metabolic pathways?

  • Definition of metabolic pathways
  • Types of metabolic reactions: anabolic and catabolic
  • Role of enzymes in metabolism
  • Activation energy and its significance
  • Induced fit and affinity in enzyme activity
  • Types of enzyme inhibitors: competitive, non-competitive, and feedback inhibition
• What is the significance of compartmentalization in organelles like mitochondria and chloroplasts?

  • High surface area to volume ratio
  • High concentrations of substrates
  • Increased reaction rates
• What are the characteristics of the fluid mosaic model of the cell membrane?

  • Composed of a double layer of phospholipids
  • Flexible structure
  • Proteins embedded within the bilayer