3.1 metabolic concepts and cellular energy

Question 1

what does metabolic pathway involves

Answer 1

involved series of steps catalyzed by enzymes

Question 2

what is anabolic and catabolic pathways

Answer 2

• Catabolic pathways break down molecules, releasing energy
• Anabolic pathways build up molecules, consuming energy

Question 3

what are the rules of thermodynamics (4)

Answer 3

Reactions all obey rules of thermodynamics

1. They must create chaos (heat) to be spontaneous (exergonic) (negative G)
2. They run towards equilibrium
3. If endergonic, an energy input is required to drive the reaction
4. The ratio of substances to products affects the dynamic

Question 4

what is exergonic and endergonic reactions

Answer 4

Exergonic reactions - Reactions that release energy and occur spontaneously

Endergonic reactions - Reactions that require an input of energy to proceed

Question 5

when gibbs energy is negative, 0 and positive, whats the differences

Answer 5

• If gibbs energy is negative, the reaction is exergonic
• If gibbs energy is 0, the reaction is in equilibrium
• If gibbs energy is positive, the reaction is endergonic

Question 6

what are enzymes

Answer 6

They are proteins which bind their substrates (sometimes called ligands) at the active site, converting them into products

Question 7

what is allosteric regulation

Answer 7

Allosteric regulation

• Allosteric enzymes have regulatory sites separate from the active site of the enzyme
• Small molecules bind to the regulatory site changing the conformation of the protein, increasing or decreasing the activity of the enzyme

Question 8

what is the reversible covalent attachment

Answer 8

• The covalent attachment of a small molecule to an enzyme is often used as a regulatory mechanism
  • The most common small molecule used is an inorganic phosphate -> phosphorylation or dephosphorylation of the regulated metabolic enzymes, affecting their activity (stimulating or inhibiting)

Question 9

what enzymes perform phosphorylation

Answer 9

kinases

Question 10

what enzymes perform dephosphorylation

Answer 10

phosphatases

Question 11

where does glycolysis operates

Answer 11

Glycolysis operate in most tissues, more controlled in liver and muscle

Question 12

what methods control liver glycolysis

Answer 12

mass action and allosteric regulation

Question 13

what is mass action

Answer 13

substrate to product ratio