Enzymes Notes Andri

Flashcards on Enzymes

Metabolism

A series of enzyme-controlled reactions.

Intracellular Enzymes

Enzymes that act inside the cell.

Extracellular Enzymes

Enzymes that act outside the cell.

Active Site

Specific region of an enzyme where the substrate binds and catalysis occurs.

Induced Fit Hypothesis

A model describing how an enzyme's active site changes shape upon substrate binding for a better fit.

Catalysis

The acceleration of a chemical reaction by a catalyst; enzymes lower the activation energy.

Activation Energy

The energy required to start a chemical reaction; enzymes lower this energy.

Denaturation

Loss of an enzyme's native structure and function due to extreme conditions.

Buffers

Substances that resist changes in pH, maintaining a stable environment for enzyme activity.

Competitive Inhibition

Inhibition where the inhibitor binds to the active site, blocking substrate binding.

Non-Competitive Inhibition

Inhibition where the inhibitor binds elsewhere on the enzyme, changing the active site's shape.

Immobilized Enzymes

Enzymes that are attached to an inert matrix allowing for reuse and increased stability.

Enzymes– lock and key hypothesis

The enzyme combines with substrate molecules at the active site to produce a product.

Enzymes

Biological catalysts that speed up the rate of metabolic reactions.

substrate

Enzymes are specific, Each enzyme reacts with particular _ molecules.

active

The substrate molecule fits into and binds to an _site within the enzyme to form an enzyme-substrate complex.

Anabolic enzymes

build larger products from smaller substrate molecules.

Catabolic enzymes

break large substrate molecules into smaller products.

Lysozyme

An enzyme found in tears and other secretions. Its function is to destroy pathogenic bacteria by breaking down their cell walls.

Induced fit hypothesis

Scientists believe that the substrate molecule changes the shape of the active site; the active site changes to fit the substrate molecule perfectly.

Enzymes are specific

Each enzyme will catalyse only one particular reaction.

Enzymes are very efficient and have a high turnover number

This means that they can convert many molecules of substrate into product per unit time.

activation energy

The energy needed to break existing chemical bonds inside molecules.

kinetic

An increase in temperature gives molecules greater _energy.

optimum

The best temperature is reached.

At 60 oC

The enzymes quickly become denatured as vibrations break hydrogen bonds within the active site of the enzyme, causing the shape of the active site of the enzyme to change.

inactivation

Small changes outside the optimum range can cause reversible changes in enzyme structure; this results in .

Catalase

Breaks down the highly toxic waste, hydrogen peroxide.

Enzyme inhibitor

a substance which decreases the rate of an enzyme catalysed reaction or stops it.

Competitive inhibitors

Are structurally similar to the substrate molecule; it can fit in the active site instead of the substrate molecule.

Non-competitive inhibitors

The substrate molecule can no longer fit into the active site.

Immobilised enzymes

Are fixed, bound or trapped on an inert matrix.

Lactase

Breaks the di- saccharide lactose into glucose and galactose.

Remember immobilised enzymes cannot move.

This reduces the frequency of successful collision as the substrate is the only molecule moving.

Biosensors

Detects a chemical change, as substrate is converted to product, and a transducer converts this chemical change into an electrical signal which can be amplified and viewed on a display.