1.4: Enymes and biological reactions

digital reading

5- A(n) ________ is given of the glucose concentration in the sample.

Environmental factors

________, such as temperature and pH, can denature and permanently alter the shape of enzymes.

Non competitive inhibitors

________ can also bind irreversibly and reversibly, irreversibly deactivating the enzyme.

substrate concentration

An increase in the ________ reduces the effect of these inhibitors, as more substrate increases their chances of successfully beating the inhibitor for the enzyme.

excess OH

At a high pH, ________- ions neutralise positive charges.

Percentage increase

________ in mass= (increase in mass (initial mass- final mass) ÷ initial mass) x 100.

Enzymes

________ only catalyse energetically favourable reactions that would happen without their involvement.

They are globular proteins

tertiary structure with hydrophilic R groups on the outside, making them soluble

This is due to the differing behaviour of enzymes

they can fit either model more closely

Activation energy is the minimum energy required for a reaction

to break the existing bonds and form new ones

At this temperature, the increased kinetic energy causes vibration to increase to the point is breaks the hydrogen bonds, denaturing the enzyme

altering the active site so the substrate cannot fit

At a high pH, excess OH

ions neutralise positive charges

Percentage increase in mass = (increase in mass (initial mass

final mass) ÷ initial mass) x 100

Rate of production (mg min-1) = increase in mass (initial mass

final mass) (mg) ÷ time (mins)

The opposite is also true

an increase in inhibitors lowers the reaction rate

These bind to the enzyme at an ‘allosteric site‘

a site other than the active site, therefore they do not compete with the substrate

1

The reactants are allowed through the semipermeable membrane, in glucose detection this is glucose and oxygen

2

Enzyme-substrate complexes are formed between glucose oxidise and glucose

3

The product is made, gluconic acid and hydrogen peroxide

4

This product is detected by the electrode, which converts the chemical energy to electrical

5

A digital reading is given of the glucose concentration in the sample

Inhibition

Decrease in the rate of an enzyme controlled reaction.

Competitive

Inhibition that binds at the active site.

Non-competitive

Inhibition that binds at the allosteric site.

Feedback inhibition

Process where the final product of a metabolic pathways is a non-competitive inhibitor to the first enzyme in the process.

Immobilised

Enzymes that are fixed in position.

Alginate beads

Beads where enzymes can be held in place.

Continuous flow

Technology where enzymes are held in place to constantly catalyse a product, such as lactase and lactose.

Biosensor

When enzymes are used to calculate the concentration of molecules, such as in diabetes detection.

Glucose oxidise

Enzyme used to detect glucose concentration.

Gluconic acid

Product created and detected during glucose detection.

Metabolic pathways

Enzyme controlled reaction sequences.

Anabolic

Reactions that build up molecules.

Catabolic

Reactions that break down molecules

Basal

Metabolic rate when we are at rest.

Enzymes

Biological catalysts that are tertiary proteins and are necessary for organisms to function.

Extracellular

Enzymes secreted by exocytosis and used outside of cells, such as amylase in the mouth.

Intracellular, in solution

Enzymes that act within a solution in a cell, such as glucose synthesis in the stroma.

Intracellular, membrane-bound

Enzymes that act while attached to membranes, such as on the cristae where they transfer molecules necessary for ATP synthesis.

Lock and key model

Enzymes specifically fit one particular substrate perfectly with no alteration needed.

Induced fit

The enzyme is flexible, and changes shape so the substrate can fit and returns to its original shape afterwards.

Activation energy

Minimum energy required for a reaction to occur, lowered by enzymes.

Temperature coefficient

Measure of a reaction’s rate of change if the temperature is raised by ten.