5. Enzymes Flashcards

Question

Describe procedure for Investigating the Effect of pH on Amylase

Answer 1

Place single drops of iodine solution in rows on the tile Label a test tube with the pH to be tested Use the syringe to place 2cm3 of amylase in the test tube Add 1cm3 of buffer solution to the test tube using a syringe Use another test tube to add 2cm3 of starch solution to the amylase and buffer solution, start the stopwatch whilst mixing using a pipette After 10 seconds, use a pipette to place one drop of mixture on the first drop of iodine, which should turn blue-black Wait another 10 seconds and place another drop of mixture on the second drop of iodine Repeat every 10 seconds until iodine solution remains orange-brown Repeat experiment at different pH values – the less time the iodine solution takes to remain orange-brown, the quicker all the starch has been digested and so the better the enzyme works at that pH

Answer 2

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

Answer 3

An enzyme is a protein that functions as a biological catalyst.

Answer 4

Enzymes are necessary to all living organisms as they maintain reaction speeds of all metabolic reactions at a rate that can sustain life.

Answer 5

Enzymes are specific to one particular substrate as the enzyme is a complementary shape to the substrate. The enzyme changes the substrate into new molecules called products.

Answer 6

As temperature increases to the optimum, the kinetic energy of the enzyme and substrate increases, causing more collisions between the enzyme and substrate. This causes the formation of more enzyme-substrate complexes, leading to an increase in enzyme activity.

Answer 7

At very high temperatures above the optimum, the enzymes become denatured and the active site changes shape. This decreases the rate of reaction as enzyme-substrate complexes cannot form.

Answer 8

At low temperatures, enzyme activity is low because the enzyme and substrate molecules have less kinetic energy so there are fewer collisions between them.

Answer 9

Deviating from the optimum pH (too high or too low) causes the enzyme’s active site to become denatured. Hence, it can no longer form enzyme-substrate complexes, leading to a decrease in enzyme activity.

Answer 10

Enzymes are specific because different enzymes have different shaped active sites. The shape of an enzyme’s active site is complementary to the shape of its specific substrate or substrates. This means they can fit together.

Answer 11

A substrate enters the active site of the enzyme. This forms the enzyme-substrate complex. The reaction then occurs, converting the substrate into products and forming an enzyme products complex. The products then leave the active site of the enzyme.

Answer 12

Enzymes are proteins and proteins can be tested by using the Biuret test. Each enzyme matches the complementary shape of a substrate. Enzymes can be used again and again because they are unchanged in a reaction. Enzyme are influenced by temperature. Enzymes are influenced by pH.

Answer 13

The lock and key hypothesis states that the substrate fits perfectly into the active site of an enzyme

Answer 14

A specific region of an enzyme where the substrate binds and the reaction takes place.

Answer 15

A permanent change in the shape of an enzyme’s active site that prevents the binding of a substrate.

Answer 16

Denaturation is irreversible.

Answer 17

In the human body, the optimum temperature is 37⁰C. In plants, the optimum temperature is 28⁰C to 30⁰C.

Answer 18

The optimum pH for pepsin in the stomach is pH 2.0 The optimum pH for amylase and trypsin is pH 7.5

Answer 19

hydrogen peroxide ➡ CATALASE ➡ water and oxygen. starch ➡ AMLYLASE ➡ maltose ➡ MALTASE ➡ glucose. protein ➡ PEPSIN ➡ peptides ➡ TRYPSIN ➡ amino acids (proteases). fats/lipids ➡ LIPASE ➡ fatty acids and glycerol.

Answer 20

Know what a pH scale looks such as what is weak/strong acid and weak/strong alkali.

Answer 21

speeds up the rate of reaction

Answer 22

result of reaction

Answer 23

what is going to react

Answer 24

enzymes catalyse every reaction in our body

Answer 25

Proteins Biological catalysts in metabolic reactions Specific (only a selective substrate they function with) Contain an active site Activity is affected by temperature, pH, and substrate concentration

Answer 26

molecule that an enzyme reacts with

Answer 27

A substrate will fit into an enzymes active site like a lock and a key No other substrate will work with an enzyme Each enzyme has a special shape with an area, the active site onto which the substrate molecules bind Very few amino acids form the active site making it a small component of a large molecule

Answer 28

Biological catalysts that speed up the rate of metabolic reactions without being used up themselves.

Answer 29

Reactions where larger molecules are broken down into smaller molecules by enzymes

Answer 30

Reactions where small molecules are built up into larger more complex molecules by enzymes

Answer 31

Modern interpretations suggest that in the presence of a substrate, the active site of an enzyme may change in order to fit the substrates shape The enzyme will wrap around the substate

Answer 32

Denaturing is the loss of biological properties (enzymes can no longer speed up the rate of reaction) Structure can be altered/denatured in extreme temperature and pH The active site is altered and changes shape which disables the ability for a substrate to bind to it therefore it cannot act as a catalyst Enzymes have an optimum temperature where it is the most efficient and when the temperature is higher than the optimum temperature the enzymes may denature stopping the reaction Enzymes have an optimum pH where it is the most efficient. pH level that is too high or too low will lead to the denaturing of enzymes

Answer 33

Uncatalysed reaction/reaction without enzyme should be higher than the catalysed reaction Height from peak of the graph to the beginning of the reaction is the activation energy. Enzymes catalyse reactions by lowering activation energy so catalysed graph should have smaller activation energy Start of reaction is at the peak Smart and end at the same place If the graph is under the original beginning of the graph, it is exothermic reaction which is releasing heat and thermal energy, if it is above it is an endothermic reaction which absorbs heat and thermal energy The y-axis of the start of the graph to the end of the graph is the overall change in energy Free energy (all energy involved with reaction) against course of reaction

Answer 34

Chemical reactions need energy to start them off called activation energy Energy is needed to break the existing chemical bonds inside molecules In the body, enzymes lower the activation energy of a reaction and so reduce the input of energy needed and allow reactions to take place at lower temperature

Answer 35

A protein catalyst which speeds up the rate of the reaction without undergoing any change itself

Answer 36

They bond specifically to a substrate molecule and convert it to a product molecule. They are not used up in a reaction and so can be recycled.

Answer 37

Enzymes reduce the amount of energy required to begin the reactions

Answer 38

Enzymes are made of proteins that have been folded so that they have a specific active site which binds to its substrate.

Answer 39

Enzyme and substrate are available Substrate binds with enzyme Substrate is converted to product Products are released

Answer 40

Enzymes work best at 37 degrees However at high temperatures the enzymes protein structure is permanently changed so that the substrate can no longer bind to the active site.It becomes denatured

Answer 41

The temperature at which the enzyme works best at

Answer 42

Each enzyme works best at a particular pH Enzymes can dénature by extreme pH changes.

Answer 43

More collisions between enzymes and substrate

Answer 44

At optimum pH and optimum temperature

Answer 45

By altering pH and temperature

Answer 46

It denatures the enzyme

Answer 47

The enzyme can be inactive

Answer 48

It will denature the enzyme and if below it can be inactive

Answer 49

They can speed up chemical reactions and break down or build up molecules. Enzymes do not take part in the reactions they catalyse

Answer 50

A chemical that enzymes act upon

Answer 51

They are specialised for certain substrates. E.g amylase always acts on starch and it could never act on a protein or fat molecules

Answer 52

They fit into the active site of the substrate. E.g lock and key

Answer 53

Charbohydrases Proteases Lipases

Answer 54

Starch digested by amylase –> maltose Amylase- salivary or pancreatic

Answer 55

Maltose digested by maltase –> glucose

Answer 56

Protein digested by proteases –> amino acids Proteases e.g pepsin

Answer 57

Protein digested by proteases –> amino acids Proteases e.g pepsin

Answer 58

Lipids digested by Lipases –> fatty acids & glycerol

Answer 59

H2O2 (hydrogen peroxide) digested by catalase –> water + oxygen

Answer 60

Ingestion -> digestion -> absorption -> assimilation -> egestion

Answer 61

The process by which food material is taken into the body, the material is taken into the mouth and chewed up into smaller pieces by teeth

Answer 62

Can be either mechanical (teeth) or chemical (enzymes). It is the process by which larger complex molecules are broken down into smaller more simple molecules

Answer 63

The process by which the smaller molecules produced by digestion are passed into the blood supply of the ileum. The molecules pass across to the blood by diffusion and defines by active transport

Answer 64

The process by which the small molecules absorbed into the blood are passed into body cells and are then used to make the chemicals needed by the body. For example the amino acids from a plant protein can be arranged to make muscle protein in your body

Answer 65

The process by which undigested material (fibre) and dead cells and bacteria are removed from the body. E.g faeces POOO

Answer 66

Substances that increase the rate of chemical reaction without being changed by the reaction

Answer 67

proteins that are biological catalyst that speed up chemical reactions

Answer 68

particular substrate is broken down.

Answer 69

bind to on the pathogen body

Answer 70

break larger molecules into smaller ones build large molecules from smaller ones convert one small molecule to another

Answer 71

they are biological catalysts they speed up reactions they are proteins they are reusable can be denatured influenced by PH and temperature

Answer 72

enzymes are specific to its one specific substrate - the shape of the active site matches the shape of the substrates, allowing two molecules to bind during chemical reactions - active site specifically matches the shape of substrate -1) substrate enters active site enzyme and the enzyme-substrate and bonds in substrate and weakened and then products are formed

Answer 73

maltose ( two glucose molecu;es) the maltose is further broken down by maltase to get two single units of glucose

Answer 74

fatty acids and glycerol

Answer 75

pepsin into peptide and is then digested by trypsin to get amino acids

Answer 76

1) optimal pH 2) optimum temperature 3) orientation of the enzyme and the substrate

Answer 77

some enzymes work best in acidic conditions and some in basic conditions and some in neutral conditions. Wrong pH damages enzymes

Answer 78

for human enzymes is 37 - 40* C - lower than this, enzymes are inactivated. Higher than this enzymes start to denature ○ Enzymes are folded into a shape that accepts the substrate molecule. This is determined by the sequence of amino acids that form it ○ As you approach the optimum temp, enzymes gain kinetic energy, and so collisions with substrates are more frequent. As a result, the rate of reaction is highest ○ As you go beyond the optimum temp, bonds holding enzymes break down, the shape of the active site changes. So it is denatured

Answer 79

change in a protein that results in a loss (usually permanent) of its biological properties.

Answer 80

is a substance that increases the rate of a chemical reaction and is not changed by the reaction.

Answer 81

proteins that are involved in all metabolic reactions, where they function as biological catalysts.

Answer 82

necessary reaction rate to sustain life.

Answer 83

collide. Enzyme and substrate fit together. Substate binds with Enzymes active site. Enzyme substrate complex forms. Because enzyme is Complementary to its substrate. This results in the formation of a product.

Answer 84

Substate fits into the active site of an enzyme. Therefore, the shape of the enzyme and substrate must be complementary

Answer 85

enzymes gain kinetic energy and enzymes move faster, the frequency of effective collisions increases. If the temperature increases above the optimum temperature, the enzyme loses its shape and the enzyme denatures. The substrate no longer fits into the enzyme’s active site. And the enzyme can not catalyze the reaction anymore.

Answer 86

enzymes lose kinetic energy and move slower, frequency of effective collisions decrease. Therefore, the rate of reaction decrease. Enzymes do not denature in this process.

Answer 87

denature the enzyme