2.4 enzymes Flashcards
what is the effect of aspirin?
inhibits the enzyme that makes nerve cells more sensitive to pain and swelling
what is the effect of ATPase inhibitors?
allow more calcium ions to enter the cell, increasing mucles contraction, strengthening heeart beat
what is the effect of ACE inhibitors?
lower blood pressure
what is the effect of protease inhibitors?
prevent the replication of virus particles in host cells.
what is the effect of nucleoside reverse transcriptase inhibitors?
inhibit the enzyme involved in making DNA with viral RNA as a templeate. Used to treat patients with HIV
What is the effect of snake venom?
paralysis and suffocation
what is the effect of cyanide?
produces a very toxic gas that inhibits the final stages of aerobic respiration
what is end-product inhibition?
yhe product molecule stays bound to the enzyme are the reaction is completed, to prevent more product forming
what is an inactivator?
a competive inhibitor that binds irreversibly to the emzymes active site
what is the allosteric site?
the region of the enzyme that the non-competitive inhibitor binds to.
what is a competivive inhibitor
a substance that has a similiar shape to the substrate, it bind/blocks to the active site so the substrate cant fit
what is an inhibitor?
a substance that reduces or stops a reaction
what effect does increasing enzyme concentrstion have on enzyme activity?
as enzyme concentration increases, more active sites become available so more ES complexes can form, increasing rate of reaction.
what is enzyme degredation?
breaking down enzymes into amino acids and synthesising new enzymes from the amino aicds.
what is enzyme synthesis?
the making of enzymes
what effect does increasing substrate concentration have on enzyme activity?
more ES complexes form so rate of reaction increases.
how can an excess of hydrogen ions affect enzymes?
too many hydrogen ions can interfere with hydrogen bonds and ionic forces, causing the active site to change shape.
what happens to the enzyme if there is a small change in pH?
rate of reaction is reduced as the shape of the active site is disrupted. If the normal pH is restored the active site can be fixed, so small changes are reversible
what is a buffer?
something that resists a change in pH
what is a thermophile?
an organism that is adapted to living in very hot environments
what is Q10?
the temperature coefficient
what is the Q10 equation?
Q10= rate at higher temperature / rate at lower temperature
what factors affect enzyme activity?
temperature
pH
enzyme concentration
substrate concentration
inhibitors
how do you calculate initial rate of reaction?
draw a tangent at 0, then calculate the gradient
what is a metabolic pathway?
a series of consecutive reactions
what are metabolites?
reactants
products
intermediates
what is a catabolic pathway?
metabolites are BROKEN DOWN into smaller molecules, releasing emergy
what is an anabolic pathway?
energy is use to MAKE larger molecules from smaller ones
what coenzyme is derived from vitamin B3?
NAD and NADP
What is a vitamin B3 deficiency called, and its symptoms?
PELLAGRA
- diarrhoea
- dermatitis
- dementia
what coenzyme is derived from vitamin B6?
coenzyme A
what aare the symptoms of a vitamin B6 deficiency?
elevated blood plasma triglyceride levels
what coenzyme is derived from vitamin B12?
cobalamin coenzymes
what is a vitamin B12 deficiency called?
PERNICIOUS ANAEMIA
what are coenzymes?
small organic non-protein molecules that bind temporarily to the enzymes active site.
Why must coenzymes be recycled back to their original state?
they are chemically changed during the reaction
what do enzymes do to the activation energy of a chemical reaction?
they lower activation energy by bringing the subsstrate molecules close enough to the active site to react
what is the ‘induced fit’ hypothesis?
when the substrate molecule fits into the active site, the active site changes shape slightly to mould around the substrate molecule
what is the ‘lock and key’ hypothesis?
the idea that an enzymes active site represents a ‘lock’ and the ‘key’ is the substrate molecule. The shape of the active site is complementary to the specific substrate
what is the enzyme-substrate complex?
an enzyme moleucle with substrate moleucles in its active site
what is the enzyme-product complex?
an enzyme moleulce with product molecules in its active site
what are 2 examples of complex metabolic pathways?
- respiration
- photosynthesis
what is a cofactor?
a substance that has to be present to ensure that an enzyme- catalysed reaction takes place at an appropriate rate
what are examples of cofactors?
- prosthetic group
- mineral ion
- organic coenzymes
what is an example of an enzyme with a cofactor?
CARBONIC ANHYDRASE has the cofactor ZINC.
it enables carbon dioxide ton be carried from respiring tissues to the lungs.
what coenzyme is derived from folic acid?
tetrahydrofolate
what is folic acid deficiency called, and what are its symptoms?
MEGALOBLASTIC ANAEMIA
- large and irregularly shaped erythrocytes
what coenzyme is derived from vitamin B1?
thiamine pyrophosphate
what is a vitamin B1 defieciency called, and what are its symptoms?
BERI BERI
- mental confusion
- irregular heartbeat
- muscular weakness
- paralysis
- heart failure
what is an active site?
the indented area on the surface of an enzyme molecule, with a shape that is complementary to the substrate molecule
what is a catalyst?
a chemical that speeds up the rate of reacttion and remains unchanged and reusable at the end of the reaction
what is a product?
a molecule produced from substrate molecules by an enzyme-catalysed reaction
what is a substrate?
a molecule that is altered by an enzyme-catalysed reaction
what is metabolism?
the chemical reactions that take place inside living cells or organisms
what is turnover number?
the number of reactions that an enzyme molecule can catalyse per second
what might prevent an enzyme from functioning?
a mutation or change to a codon- this changes the tertiary structure so the active site also changes
what affects an enzymes ability to catalyse reactions?
- pH
- temperature
they change the shape of the active site by breaking the bonds holding the tertiary structure
what are the extracellular enzymes?
- amylase
- trypsin
where is amylase made?
the pancrease and salivary glands
what reaction does amylase catalyse?
starch –> maltose
what reaction does trypsin catalyse?
proteins –> peptides
where is trypsin made?
the pancreas
what is an example of an intracellular enzyme?
catalase
where reaction does catalase catalyse?
hydrogen peroxide –> water + oxygen
where is catalase found?
in peroxisomes in eukaryotes
