8.1 - metabolism

Question 1

what are metabolic reactions?

Answer 1

• a complex network of chemical reactions within cells
• a series of smaller steps with specific enzymes that catalyse each step of the reaction

Question 2

what is a metabolic pathway?

Answer 2

• a series of steps of a metabolic reaction
• involve a chain of reactions in a linear path but some form a cycle as the end product of reaction starts the rest of the pathway.

Question 3

how are substraits converted into products?

Answer 3

with metabolic reactions with a specific enzyme

Question 4

what is activation energy? (BIO)

Answer 4

• a molecule has to gain enough energy to reach the transition state
• needed to break or bonds in the substrates

Question 5

how do enzymes effect activation energy?

Answer 5

• enzymes speed up the rate of biochemical reactions by lowering the activation energy
• the active site of enzyme stresses and destabilises the bonds to reach the transition state faster

Question 6

what is exergonic?

Answer 6

• when reactants have more energy than the products the free energy is released into the system
• usually a catabolic reaction

Question 6

what is Endergonic?

Answer 6

• when the reactants have less energy than the products the free energy is lost to the system
• usually an anabolic reaction

Question 7

how to calculate rate of reaction?

Answer 7

rate of reaction (S-1) =
1/time taken(s)

Question 8

what is an inhibitor?

Answer 8

• molecule that can bind to enzymes and reduce the activity of an enzyme
• competitive and non-competitive

Question 9

what is a competitive inhibition?

Answer 9

• substrate and competitive inhibitors are structurally and chemically similar and compete for the same active site on enzyme
• when binded it occupies active site of enzyme and prevents substrate from binding
• eg. Relenza

Question 10

what is Relenza?

Answer 10

• antivirus drug designed to treat Flu A virus
• Relenza is synthesised to completely bind to the NA active site and prevents HA from binding, so less spread of Flu in body
• also prevents new virions forming

Question 11

what is non-competitive inhibition?

Answer 11

• substate and inhibitor are not structurally or chemically similar so do not bind to active site
• binds to other sites called allosteric site
• when binded it changes shape of active site and prevents the substrate from binding to enzyme
• eg. cyanide

Question 12

how can the effect of competitve inhibitors be reversed?

Answer 12

• when a substrate concentration begins to exceed the concentration of inhibitor
  -however, it requires a much higher substrate concentration

Question 13

how can the effect of non-competitive inhibitors be reversed?

Answer 13

it cant.

Question 14

what is an end-product inhibition?

Answer 14

• the product of the last reaction in the pathway inhibits the enzyme that catalyses the first reaction
• forms negative feedback
• end-product binds to an allosteric site and is a type of temporary non-competitive inhibition.
• is reversible
• excess end-product switches pathway off so intermediate products dont build up

Question 15

what is chemogenomics?

Answer 15

• a bioinformatics technique used to develop a new drug
• when chemical binds to active site it can change metabolic activity, they test drugs on range of related organisims.

Question 16

what is malaria?

Answer 16

• malaria is a mosquito-borne infectious disease caused by protist pathogens, common in tropical areas
• symptoms are fever, fatigue, nausea, headaches, seizures, coma or death
• there is a resistance to the malaria drug containing chloroquine

Question 17

chemogenomics and malaria.

Answer 17

• resistance to chloroquine
• using genomes from mosquitos they can screen new chemicals to see if they inhibit metabolic reactions
• using chemogenomics scientists can chemically modify identified compounds to improve binding affinity and lower any toxicity