BIO150 Notes Chapter 1 PDF

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Summary

What is enzyme?An enzyme is a substance that acts as a catalyst in living organisms, regulating the rate at which chemical reactions proceed without itself being altered in the process *Key point A biological catalyst Increases the rate of reaction Is not itself consumed in the reaction Lowers the a...

Description

What is enzyme? An enzyme is a substance that acts as a catalyst in living organisms, regulating the rate at which chemical reactions proceed without itself being altered in the process Active site *Key point enzyme • A biological catalyst • Increases the rate of reaction substrate • Is not itself consumed in the reaction • Lowers the activation energy • Reaction will not occur at a rate that supports survival unless enzyme is prese

Metabolism The total of all the chemical reactions occur in cells is known as metabolism.

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Anabolisme Requires energy to grow and build (simpler substances combined to form more complex substance)

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For example:

For example: • Synthesis of gyclogen (glucose + glucose)n→glycogen •

Catabolisme Uses energy to break down (complex substances are broken down to form simpler substance)

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Require a constant input of energy to convert low energy substance into higher energy products

Endergonic reaction (energy need to form chemical bond)*energy is absorbed

Hydrolysis of glycogen (breakdown of glycogen to glucose unit) Involve the breakdown of high energy substances into lower energy products

Exergonic reaction (energy is released) Do you know? •

Products (glycogen)contains more than the reactants (glucose)

Catalysis make possible biochemical reactions •

Endergonic reaction Energy in

Majority of these biochemical reaction do not take place spontaneously.

The “nature of life”-coupling favourable to unfavourable

All chemical reaction require enzyme to work

Catalysts – substance that speed up chemical reaction but stay unchanged at the end of the reactions. Energy out

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The catalysts of biochemical reaction are enzymes.

bringing about almost all of the chemical reaction Exergonic reaction in living organisms. Product (glucose)contains less energy than the reactents (glycogen)

metabolic pathway • • •

Metabolic pathways alter molecules in a series of steps. That begin with a specific molecule and end with a product. That are each catalyzed by a specific enzyme

Enzyme 1

Enzyme 2

A

B Reaction 1

Enzyme 3

C Reaction 2

D Reaction 3

Starting molecule

product

characteristic of enzymes Globular protein • • •

Globular protein with catalytic properties Made a long linear chains of amino acids that fold to produce 3-D shape Mostly tertiary and quartenary structure

Active site • • •

Have active site for substrate binding. active site - location the reaction occurs have active site contains amino acid side chain that are complementary to the substrate.

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catalyzing reaction of enzyme is reversible. which the conversion of reactants to products and the conversion of products to reactants occur simultaneously.

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For any chemical reaction, the reactant that an enzyme acts on is called the enzyme’s substrate The enzyme binds to its substrate, forming an enzymesubstrate complex Those left at the end are the products.

Reaction reversible

Enzyme specificity

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