8.1 Metabolism

Question 1

state difference between competitive and non competitive inhibitors

Answer 1

Competitive inhibitor then Non-competitive inhibitor

-It is chemically quite similar to the substrate.
It has no similarity to the substrate.

-It binds to the active site of the enzyme.
It binds to the enzyme at a site other than the active site.

-Binding of the inhibitor to the enzyme does not modify its active site.
Binding of the inhibitor to the enzyme modifies its active site, hence preventing binding of substrate (if it does bind, the enzyme will not be able to catalyse the reaction).

-As the concentration of substrate is increased, the effect of the inhibitor on the reaction is reduced.
Increasing the concentration of the substrate does not decrease the impact of the inhibitor. Therefore, the rate of reaction is lower than normal at all substrate concentrations.

Question 2

metabolism

Answer 2

the sum of all chemical reactions that occur within an organism

Question 3

metabolic pathway

Answer 3

cycles or chains of enzyme catalyzed reactions

Question 4

types of metabolic pathways and examples

Answer 4

metabolic chain - glycosis

metabolic cycle - calvin cycle

Question 5

activation energy

Answer 5

the initial input of energy that is required to trigger a chemical reaction

Question 6

inhibitor

Answer 6

a molecule that binds to an enzyme and slows down or stops the enzymes function

Question 7

overcoming alchoholism

Answer 7

example of competitive inhibitiors:

• ethanol to acetaldehyde to acetic acid using enzyme acedehyde oxide
• antabuse is the inhibitor

Question 8

ACE inhibitors: helping to control blood pressure

Answer 8

• angiotensin I goes to angiotensin converting enzyme in heart capillaries, turns into angiotensin II which causes vasoconstriction
• ace inhibitor prevent increase in blood pressure
• non-competitive and reversible
• angiotenson II is harmfull to people with heart failure

Question 9

end product inhibition

Answer 9

end product become non-competitive inhibitor for one of the enzymes in its metabolic pathway

Question 10

isoleucine

Answer 10

is an approach whereby multiple research groups can add information to a database enabling other groups to query the database

Question 11

bioinformatics had facilitated research

Answer 11

into metabolic pathways is reffered to as chemogenomics

Question 12

chemogenomics

Answer 12

• sometimes when a chemical binds to a target site, it can significantly alter metabolic activity.
• Massive libraries of chemicals are tested individually on a range of related organisms
• for each organism a range of target sites are identified
• a range of chemicals which are known to work on those sites are tested

Question 13

example of databases being used to find new anti-malarial drugs

Answer 13

• Malaria is a disease caused by the pathogen plasmodium falciparum
• this protozoan uses mosquitos as host as well as humans and hence can be passed on by mosquito bites
• an increasing drug resistance to anti-malarial drugs has lead to the use of bioinformatics and chemogenomics to try and identify new drugs
• in one study, 300,000 chemicals wee screened against a chloroquine-sensitive 3D7 strain and the chloroquine resistant k1 strain of P.falciparum
• 19 new chemicals that inhibit the enzymes normally targeted by anti-malarial drugs were identified
• 15 chemicals that bind to malarial proteins were identified