B4. Enzymes

 (0654) Coordinated Sciences 2023/2024

Subheadings and Key concepts

• enzyme, substrate, active site, enzyme-substrate complex, products
• factors affecting enzymes:
• temperature
• pH

5.1. Enzymes

Many chemical reactions in living things are helped along by enzymes. Enzymes are proteins that function as biological catalysts.

A catalyst = a substance that increases the rate of a chemical reaction and is not changed and not used up by the reaction.

03. Enzymes pdf

#28 Summary of Enzymes

Enzymes are specialized protein molecules facilitating most of the body’s metabolic processes – such as, supplying energy, digesting foods, purifying your blood, ridding the body of waste products. Enzymes are vital to our health and change the rate at which chemical reactions happen, but without any external energy source added or by being changed themselves.

#27 Use of microorganisms to manufacture antibiotic penicillin

Three colonies of a Penicillium mold growing on an agar medium. 

Antibiotics are substances which kill bacteria without harming human cells. They help to cure bacterial infections. Penicillin is made by growing the fungus Penicillium in a large fermenter.

#26 Use of microorganisms and fermenter to manufacture enzymes

We obatain many enzymes from microorganisms. The enzymes that are used in industry are usually obtained from microorganisms. These include bacteria and microscopic fungi, such as yeast. The microorganisms are grown inside large vessels called fermenters.

#25 Use of enzymes in the food industry

Enzymes are an integral component of modern fruit juice manufacturing and are highly suitable for optimising processes. Fruit juices are extracted using an enzyme called pectinase.

#24 Use of enzyme in biological washing powders

Biological washing powders contain protease and lipase to remove protein stains and fat/grease from clothes. The enzymes break down proteins or fats on the fabric, forming water-soluble substances that can be washed away.

# 23 Role of enzymes in germinating seeds

Seeds contain stored food in the cotyledons to provide energy and materials for growth. This is usually in the form of starch – a large, insoluble molecule (long chain of glucose), that keeps the food immobile. The starch needs to be changed into a soluble molecule (sugar) with help of enzymes for the seeds to make use of.

#22 Enzymes - 'Lock and key' model

Enzymes are very specific, each kind of enzyme catalyse one kind of reaction only. To catalyse a reaction, enzyme molecule and substrate molecule need to meet and joint together by a temporary bond.

#21 Enzymes and reactions

Many chemical reactions can be speeded up by substances called catalysts. Within living organisms, these reactions (metabolic reactions) are controlled by catalysts called enzymes. Enzyme molecules are proteins.