Ch 3 Regulation of biochemical pathways

Question 1

What is the definition of biochemical pathway?

Answer 1

series of reactions controlled by enyzmes that convert initial substrate into final product
- interconnected to form multi-step biochemical pathways

Question 2

What are the types of biochemical pathways?

2 types

Answer 2

• anabolic pathways reaction where atoms and simple moleucles are joined together to make complex molecules
• catabolic pathways reaction where complex molecules are broken down into simple molecules

Question 3

What is photosynthesis?

definition, type of biochemical pathway, reactants and products

Answer 3

definition -> process where light energy is used to convert CO2 and H2O into glucose (in chloroplasts)
6H2O + 6CO2 -> C6H12O6 + 6O2
- anabolic reaction
- require **initial input of energy **to get them started
- light energy is absorbed from surrounding and used to form bonds in glucose molecules and is endothermic

Question 4

What is cellular respiration?

definition, type of biochemical pathway, reactants and products

Answer 4

definition -> energy from glucose is converted into energy form (ATP) used by cells (occurs in cytosol and mitochondria)
C6H12O6 + 6O2 -> 6H2O + 6CO2
- catabolic reaction
- does not require initial input of energy
- heat is released to surroundings and is exothermic

Question 5

What is the role of enzymes in biochemical pathways?

funtion & lock and key model & induced fit

Answer 5

catalysts -> enzyme that is used to increase speed of reaction but is not used up
- used as catalysts
- active site is complementary to shape of substrate
- help orientate substates to create/speed up reactions

lock and key -> model of enzyme with the shape of substrate molecule that has exact shape of active site
induced fit -> shape of enzyme’s active site undergoes specific changed induced by substrate

Question 6

What enzymes are used in photosynthesis?

Answer 6

water-oxidising enzyme splits water molecule releasing hydrogen ions and electrons, with oxygen released
rubisco captures inorganic carbon dioxide from air and catalyses into organic carbon dioxide

Question 7

What are coenzymes?

definition, function, loaded and unloaded

Answer 7

definition -> small molecule that assists enzyme activity by carrying groups of atoms to or from reaction
- can accept electrons, protons and chemical groups during reactions and transfer them to another reaction
- loaded carry protons, eletrons or chemical groups needed for anabolic reactions to occur
- unloaded can accept protons, electrons or chemical groups that are released from catabolic reactions

Question 8

What are factors that contribute to enzyme function?

Answer 8

temperature
- too high can result in denature of enzymes
- too low molecular movement and reaction slows down

pH
- too high and low causes protein/enzyme to denature

enzyme and substrate concentration
- better to have an increase in enzyme concentration
enzyme inhibitors
- non-competitive inhibitors does not bind to active site but bind to alternative site called allosteric site which causes active site to permanently change
- competitive inhibitors directly compete with substrates and binds with active site