Week 1 RAS live Lecture 1 Flashcards
5) What does biosynthesis require?
5) Energy
6) Where are the precursors of biosynthesis supplied from?
6) From the central catabolic pathways e.g. glycolysis and krebs cycle etc.
7) How is energy conserved?
7) Electron carriers; ATP / NADH / NADPH
8) Why is CO2 special?
8) Because it favours being in the CO2 state, G strongly negative
a) Evolution of CO2 (decarboxylation) gives a strong thermodynamic pull to a reaction because…
b) CO2 is very stable (more stable than reactants)
c) R-COOH ⇌ RH + CO2
It easily escapes from the site of reaction
d) There are more products than reactants
9) Why do anabolic reactions require energy?
9) Because disordered molecules are favoured in terms of entropy. So if we order them, we need energy.
10) Why are reactions that contain water as a product unfavourable?
10) Because the environment the reaction happens in contains lots of water (in the cell)
11) How does carbon enter metabolism?
11) Photosynethesis
Called carboxylation and it uses the enzyme: Pyruvate carboxylase
a) Pyruvate + CO2 oxaloacetate
b) ATP used and ADP is by product
12) How does oxygen enter metabolism?
12) phenylalanine + O2 -> tyrosine
a) enzyme used Phenylalanine hydroxylase
b) Uses NADPH and NADP is by product
13) In biosynthetic reactions which is usually used more NADPH or NADH…
13) NADPH
14) How does nitrogen enter metabolism?
14) Uses Nitrogern rixation or Nitrogenase
a) Uses glutamate deyhydrogenase as an enzyme
b) -ketoglutarate + NH4+ -> glutamate
c) Uses nadph or nadh
15) What properties would you predict for a threshold enzyme?
15) Include;
a) normally tightly controlled
b) have a high affinity for their substrate
c) Non-constitutive
16) Example of a threshold enzyme
16) Glutamate dehydrogenase (GDH)
