Enzymes

Question 1

What is protein molecule made of?

Answer 1

Long chains of small units called amino acids. Different arrangements of amino acids brings about different proteins.

Question 2

What are the different functions of proteins in our body?

Answer 2

Antibodies
Catalysts( enzymes)
Hormones
Structural components such as muscles and tendons

Question 3

What is the active site?

Answer 3

The special part in the structure of an enzyme where the substrate binds.

Question 4

How do enzymes work?

Answer 4

The reactant( substrate) of the  reaction fits into the active site of the enzyme(like a lock and key as the substrate is the correct shape).Once it is in place, the enzyme and the substrate bind together.
The reaction then takes place rapidly and the products are released from the surface of the enzyme, they leave the active site. The active site is ready to use again.  The enzyme is unchanged.

Question 5

What are enzymes involved in?

Answer 5

Building large molecules from lots of small ones( glycogen from glucose, proteins from amino acids).
Changing one molecule into another (glucose to fructose)
Breaking down large molecules into smaller ones( food molecules into small soluble molecules).

Question 6

What is a substrate?

Answer 6

A substrate is a molecule that is acted upon by an enzyme.It is the reactant.

Question 7

Why do enzymes only catalyse one reaction?

Answer 7

Because a substrate has to be the correct shape to fit into the active site.

Question 8

What effect does increasing the temperature have on the rate of the reaction?

Answer 8

A higher temperature increases the rate at first. But if it gets too hot the bond holding the enzyme breaks and the long chain amino acid chains unravel. As a result, the shape of the active site changes. The substrate no longer fits and the enzyme won’t work. It is said to be denatured. Enzymes in the human body work best at 37 degrees.

Question 9

Explain the effect of temperate in terms of collision and molecules

Answer 9

When enzyme and substrate molecules meet they react. They collide with each other and if the temperature is increased the molecules move faster, causing more meetings, so the rate of reaction increases.

Question 10

What effect does pH gave on enzymes?

Answer 10

The shape of the active site of an enzyme comes from forces between different parts of protein molecules. These forces hold the folded chains of amino acids in place. A change in pH interferes with the bonds holding the enzyme together. This changes the shape of the active site, substrate no longer fits. The enzyme gas denatured.

Question 11

Why does the affect of pH affect different enzymes differently?

Answer 11

Need different pH to work at optimum rate.
For e.g pepsin in the stomach has an optimum of pH of 2, which means it’s well suited to the acidic conditions there.
A lot of enzymes have an optimum pH of neutral 7

Question 12

What are enzymes?

Answer 12

They are large protein molecules that act as biological catalysts.

Question 13

What are biological detergents used for?

Answer 13

To remove biological stains such as grass, sweat and food from their clothes. Biological washing powders contain proteases and lipase to breakdown the protein and fats in the stains. They give a cleaner wash.

Question 14

Why are biological detergents better at lower temperature?

Answer 14

Because they contain enzymes which work better at low temperatures. If the temperature of the water is too high, then the enzymes will denature. Using them at lower temperatures means you need less electricity too, so less fossil fuels need to be burned.

Question 15

What are pros and cons of biological detergents?

Answer 15

Pros:
Low temperatures, less energy, less fossil fuels.

Cons: low temperatures used may not be as effective at killing pathogens on clothes.
They may cause allergies

Question 16

Which is enzyme is used to make baby food?

Answer 16

Proteases are used to make baby food, they ‘pre digest’ some of the protein in the food. As when babies first begin eating solid foods, they are not very good at digesting it. So this makes it easy for the baby’s digestive system to cope and it is easier for them to get the amino acids they need from their food.

Question 17

What are carbohydrases used for?

Answer 17

They convert starch syrup into a tasty sugar syrup. We can use huge quantities of sugar syrup quite cheaply( as starch is made by plants like corn). Cheap source of sweetness for food manufacturers.

Question 18

What is the isomerase enzyme used for?

Answer 18

Change glucose syrup into fructose syrup. Fructose is sweeter than glucose, so you can use less of it for the same amount of sweetness. So it’s used in skimming foods and drinks. Food tastes sweet for less calories.

Question 19

What are the advantages and disadvantages for using enzymes in industry?

Answer 19

Advantages: They’re specific and they only catalyse the reaction you want them to do.
Lower temps…
Enzymes work for a long time, so after the initial cost of buying them, you can continually use them.
They’re biodegradable and cause less environmental pollution.

Disadvantages: enzymes can be denatured by even a small increase in temperature. They’re also susceptible to poisons and pH. This means the conditions in which they work need to be tightly controlled, this costs money.
Enzymes can be expensive to produce
Contamination of the enzyme with other substances can affect the reaction.

Question 20

What are the advantages of immobilised enzymes?

Answer 20

The enzymes don’t contaminate the product
The immobilised enzymes in alginate beads( type of bead) can be used continuous food processing, only the products emerge from column. The enzymes stay fixed in the column.

Question 21

What are immobilised enzymes?

Answer 21

Enzymes that don’t need to be separated out from the mixture after the reaction has taken place.
You can immobilise enzymes by encapsulating them in alginate beads.

Question 22

Why does the stomach contain hydrochloric acid?

Answer 22

The protease enzymes that digest proteins work best in acid pH.
It also kills most of the bacteria you take in with your food.

Question 23

What conditions does the small intestine work best in?

Answer 23

Alkaline

Question 24

What is the function of bile?

Answer 24

Bile( which is stored in the gall bladder and produced by the liver) neutralises the acid from the stomach and makes the semi digested food alkaline, creating ideal conditions for the enzymes in the small intestine.

Because the fats you eat do not mix with watery liquids in the gut. They stay as large globules of fat, that make it difficult for the lipase enzymes to act. So bile emulsifies fats in your food. It breaks the large drops of fat into smaller droplets. This provides a much larger SA for the lipase enzyme to act on. The larger SA helps the lipase enzyme chemically break down fats into fatty acids and glycerol

Question 25

What is your food made of?

Answer 25

Large insoluble molecules that your body cannot absorb. They need to be broken down or digested to form soluble molecules which can be absorbed into the cells.

Question 26

How does your gut help In digestion?

Answer 26

It helps break up your food into small pieces with a large SA for your enzymes to work on. It mixes your food with digestive juices so that the enzyme comes in contact with as much food as possible.. Muscles of gut move food from one area to the next

Question 27

Describe the digestion process of fats:

Answer 27

Mechanical break down of food in mouth. Then the lipase enzyme( produced by pancreas and small intestine) breaks down fats into fatty acids and glycerol. Bile..
Fat digestion occurs in SI.
Small intestine is where digested food is absorbed out of the digestive system and into the blood.

Question 28

Describe break down of starch

Answer 28

Mechanical break down of food in mouth. Amylase in the (produced by small intestines, pancreas, salivary glands) catalyses the break down of starch into sugars( MALTOSE) . Digestion takes place in SI, absorbed out of the digestive system and into the blood.

Question 29

Describe the break down of proteins

Answer 29

Mechanical break down of food in mouth. The enzyme, protease catalyses the break down of proteins into amino acids( produced by stomach, small intestine and pancreas). Called Pepsin in stomach. Final digestion takes place in theSI and digested food is absorbed out of the digestive system and into the blood.