2.1 Metabolic pathways

• Describe the term anabolic reaction and give an example of a reaction that would be considered this type of reaction.

  Anabolic reactions build up large molecules from smaller molecules and requires energy.

  e.g Protein synthesis, Photosynthesis
• Describe the term catabolic reaction and give an example of a reaction that would be considered this type of reaction.

  Catabolic reactions break down large molecules into smaller molecules and releases energy.

  e.g Aerobic respiration, Digestion.
• State the different types of proteins that can be found within the cell membrane and describe their function.

  Protein pores, pumps, and enzymes are embedded in membranes.

  -Protein molecules found in the cell membrane can act either as enzymes or pores.

  -Protein pores allow passive transport of molecules across the membrane.

  -Protein pumps are responsible for actively transporting ions/particles across the cell membrane.

  -Enzymes catalyse specific biochemical reactions.
• Explain how enzymes speed up chemical reactions.

  An enzyme lowers the activation energy required to start the reaction.
• Explain the term 'induced fit' when describing how the active site of an enzyme complements the substrate.

  As the substrate attached onto the active site, the enzyme undergoes a shape change with the enzyme folding around the substrate making the active site fit very closely around the substrate molecule.
• Explain the difference between competitive inhibitor and non-competitive inhibitors.

  -Competitive inhibitors bind at the active site preventing the substrate from binding. This can be reversed by increasing substrate concentration.

  -Non-competitive inhibitors bind away from the active site but changes the shape of the active site. This prevents the substrate from binding and cannot be reversed by increasing substrate concentration.
• State what negative feedback is and state its importance.

  In negative feedback, the response will reverse or cause the opposite effect of the original stimulus