Biology B2.3 : Enzymes

What is a protein molecule made up from?

Long chains of amino acids, different arrangements of amino acids give you different proteins

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What are the functions of proteins in the body?

-they act as structural components such as muscles and tendons -hormones eg. insulin -antibodies, which destroy pathogens -catalysts in the form of enzymes

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What is a catalyst?

A catalyst is a chemical known to speed up chemical reactions within the body, that are not used up in the reaction and can be used over and over again

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What controls the chemical reactions in the body?

Enzymes are biological catalysts that speed up reactions

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What are enzymes?

Large protein molecules

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What is an active site?

An active site is the region of an enzyme where a substrate binds and a chemical reaction occurs. It is the structural element of a protein that determines whether the protein is functional when undergoing a reaction with an enzyme.

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What produces an active site?

Long chains of amino acids are folded to produce a molecule with a specific shape, this shape allows other molecules (substrates) to fit into the enzyme protein (the active site).

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What are some of the reactions that enzymes are involved in?

-building large molecules from lots of smaller molecules -changing one molecule into another -breaking down large molecules into smaller ones

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What do enzymes do to a reaction?

Enzymes speed up a reaction (THEY DO NOT CHANGE THE REACTION)

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Give an example of a. way enzymes build large molecules from smaller ones b.change molecules c.break down molecules

a.making glycogen from glucose and proteins from amino acids 2.converting sugars eg. glucose to fructose 3.breaking down food molecules into small soluble molecules eg.glucose

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How do enzymes work? key words: substrate/enzyme/active site

The substrate (reactant) of the reaction binds to the enzyme's active site, the reaction takes place forming an enzyme substrate complex. The products are then released from the surface of the enzyme.

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What are the functions of proteins?

-Structural (muscle) -Hormones (chemical messengers eg. oestrogen) -Antibodies (help destroy pathogens) -Enzymes (speeds up reactions)

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Why does milk go off (in terms of enzymes)

Enzymes in bacteria break down the protein structure, causing the milk to go off.

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What factors affect the rate of reaction for enzymes as biological catalysts?

- Concentration, temperature and surface area

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How does temperature affect an enzyme as a biological catalyst?

As temperature increases, the rate of enzyme-controlled reactions increases. However, this is only true up to the optimum temperature of the enzyme, after that the protein structure of the enzyme is affected by the higher temperature.

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What happens to the active site when the temperature increases above the enzymes optimum temperature?

The amino acid chains unravel and the active site of the enzyme changes shape, this means the enzyme has denatured and can no longer act as a catalyst which causes the rate of reaction to drop dramatically.

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What is meant by the optimum temperature?

The optimum temperature is the temperature at which the enzymes work best at and the reaction works as fast as possible.

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What does the shape of the active site come from?

The shape of the active site comes from forces between the different parts in the protein molecule, the forces hold the folded chains in place.

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How does pH affect the forces between the protein molecules in enzymes?

A change in pH affects these forces, it changes the shape if the molecule, changing the shape of the active site, so the enzyme no longer acts as a catalyst.

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What would happen if the bodies temperature increased above 37 degrees celsius?

The enzymes in the bodies active sites would change shape as a result of the increased temperature, the enzymes would denature and none of the chemical reactions would be able to occur as the enzymes would no longer be able to act as catalysts.

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What is the chemical breakdown of food controlled by?

Digestive enzymes

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What happens during digestion?

Large insoluble food molecules that cannot be absorbed by the body need to be broken down or digested by the digestive enzymes into smaller soluble molecules that can be absorbed by the body into the blood stream and used by the cells.

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How are the digestive enzymes different from the rest of the enzymes in the body?

Most enzymes work inside the body cells, controlling the rate of chemical reactions. Digestive enzymes work outside the cells, they are produced by specialised cells in the glands and in the lining of the gut.

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What is the function of the gut?

A muscular tube that squeezes food, helping break up food into small pieces with a large surface area for your enzymes to work on. It mixes the food with digestive juices so the enzymes come into contact with as much food as possible.

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State the organs involved in the digestive system?

-Mouth (teeth, tongue and salivary glands) -Gullet -Diaphragm -Stomach -Liver -Gall bladder -Bile duct -Pancreas -Large intestine -Small intestine -Rectum -Anus

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What is the name of the enzyme that breaks down carbohydrates?

Carbohydrases

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What is the most common carbohydrate that you eat?

Starch, it is broken down into sugars in your mouth and small intestine

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What is the enzyme that breaks down starch into sugars? Where is it produced?

Amylase, it is produced in your salivary glands, the pancreas and the small intestine.

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What is the name of the enzyme that breaks down proteins? Where are they produced?

The breakdown of protein is catalysed by protease, produced by the stomach, pancreas and small intestine.

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Where does the breakdown of amino acids take place?

The break down of amino acids takes place in the stomach and the small intestine.

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What is another name for the fats an oils that you eat? What are they broken down into and where?

Lipids are the fats and oils that you eat, they are broken down into fatty acids and glycerol in the small intestine.

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What is the enzyme that breaks down fatty acids and glycerol? Where are they made?

The enzymes that catalyse the break down of fatty acids and glycerol are called lipase enzymes, made in the small intestine and pancreas.

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What happens once the food molecules have been broken down into soluble substances?

Once your food has been digested into soluble glucose, amino acids, fatty acids and glycerol, they leave your small intestine and pass into your bloodstream and are carried around the body to the cells that need them.

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Why does your body need a variety of different chemicals to help keep conditions ideal for the enzymes in your body?

Different enzymes in the body need different pH's, as different enzymes work best in different conditions, some enzymes need acidic conditions and some need alkaline conditions.

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What do glands secrete?

Glands secrete protease enzymes to digest the protein eaten, these enzymes work best at an acidic pH, so the stomach produces a concentration solution of hydrochloric acid from the glands, allowing the protease enzymes to work effectively

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Why does the stomach produce a thick layer of mucus?

The thick coating of mucus coats your stomach walls and protects them from being digested by the acid and enzymes.

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What condition do the enzymes made in the pancreas and small intestine work best at?

They work best in an alkaline environment

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What does the bile added to the stomach do?

The bile neutralises the stomach and makes the semi-digested food in the small intestine alkaline. Providing idea conditions needed for the enzymes in the small intestine.

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Why do fat molecules make it difficult for lipase enzymes to act?

Fats do not mix with all the watery liquids in the gut, they stay as large globules making it difficult for the lipase enzyme to act upon them.

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What does the bile from the stomach do to the fat molecules?

Bile emulsifies the fats in food, it physically breaks large drops of fat into smaller droplets, providing a larger surface area for the lipase enzymes to act on.

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How does a larger surface area of fat molecules, help lipase enzymes?

A larger surface area helps the lipase chemically break down the fats more quickly into fatty acids and glycerol.

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What are biological detergents?

Biological detergents remove stains eg. grass/sweat/food They contain proteases and lipases, breaking down proteins and fats in the stains, they work best at lower temperatures as at too high a temperature, the enzymes denature.

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What are proteases used for in the industry?

-they are used in baby foods, to predigest some of the protein in the food, as babies cannot digest food properly, so the protease enzymes makes it easier for a baby's digestive system to cope with it.

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What are carbohydrases used for in the industry?

Carbohydrases are used to convert starch into sugar (glucose) syrup, that can be used in huge quantities for food production.

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How can enzymes be used to provide cheap sources of sugar?

Starch made by plants like corn is very cheap and enzymes can convert this plant starch into sweet sugar, providing a cheap source of sweetness for food manufacturers.

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What is the isomerase enzyme used for?

Isomerase is used to change glucose syrup into fructose syrup

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What is the advantage of converting glucose to fructose?

They both have the same amounts of energy, but smaller amounts of fructose are needed to make food taste sweet and is wildly used to make food taste sweet especially in slimming foods.

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What are some advantages of using enzymes?

-they can catalyse reactions at low temperatures and normal pressures, so enzyme based processes are often cheap to run -they do not need a lot of energy and expensive equipment

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What are some disadvantages of using enzymes?

-they are denatured at high temperatures so the temperature must be kept down and the pH must be carefully controlled to suit the enzyme, this costs money to control the conditions -enzymes are expensive to produce

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Advantage of biological detergents?

-they are effective at cleaning in general and are effective at low temperatures, use less electricity, they are good for the environment and are cheaper for the consumer.

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What are some disadvantages of biological detergents?

-low temperatures used for enzymes may not be as good at killing pathogens on clothes -used to cause allergies and received bad publicity -people are worried about the amount of biological detergents in the waste water from washing machines

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How could enzymes diagnose disease?

-if your liver is damaged or diseased, some of your liver enzymes leak into your bloodstream. If your symptoms suggest your liver isn't working properly, doctors can test for these enzymes and will tell if your liver is damages.

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How can enzymes diagnose and control disease?

-People with diabetes have too much glucose in their blood, so glucose gets in urine. By getting a urine sample, an enzyme on the sample ***** react and change the ***** colour, identifying the glucose present in the sample

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How can enzymes be used to cure disease?

-extra enzymes can be taken (lipase) to allow food to be digested if the pancreas is damaged and cannot make enzymes -after a heart attack,an enzyme can be injected into the blood dissolving clots in the arteries of the heart wall and reduces damage

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How can enzymes be used to treat blood cancer?

Cancer cells cannot make a particular type of amino acid, they take it from the body fluids, the enzyme speeds up the breakdown of this amino acid, if the cancer cells cannot get any they die and your normal cells are not affected,

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Biology B2.3 : Enzymes

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