Enzymes

SQA Questions

What you should know - ENZYMES• A c________ is a substance which helps to

s______ up a chemical reaction. It remains u________ at the end of the reaction.

•  An enzyme is a p_______ which can act as a catalyst inside l_____ c_____ (b_______ c_________).

• Enzymes are important for the functioning of living cells because w_______ the aid of e________ the chemical reactions would take place too s______ to maintain life.

• Enzymes in a cell are used in ‘b________’ or ‘s_______’

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peed

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iving ells iological

atalysts

ithout nzymes

lowly

reakdown

ynthesis

• Breakdown is when an enzymes breaks down a l______ s________ molecule into s______ ones

• Synthesis is when an enzyme j_____ s______ substrate molecules t_________ to make a larger one

• P_______ and c__________ are examples of breakdown enzymes

• P______________ is a synthesis enzyme• Enzymes are s________ – they will act only on

o___ s__________• Enzymes are p________• Enzymes are affected by t__________ and __.

arge ubstrate maller

oins maller

ogether

epsin atalase

hosphorylase

pecific

ne ubstrate

roteins

emperature pH

Enzymes revision 1

ells

hemical eactions

ynthesis

lucose

tarch

egradation

atalase

xygen

ock ey

pecific

changed

emperature

ptimum

enatured

epsin

7

Effect of temperature on enzyme activity

Enzyme activity increases rapidly

Maximum enzyme activity- optimum temperature

Enzyme is being denatured

the temperature at which the enzyme has greatest activity

the pH at which the enzyme has greatest activity

1 42 7 119

pepsin catalase

8. Pepsin

• has a working range of ____ to _____.

• This means it ______________________

• Pepsin has an optimum pH of ____. This means it has ________ ________ at pH 2

9. Catalase

• has a working range of ____ to _____.

• This means it ______________________

• Catalase has an optimum pH of ____. This means it has ________ ________ at pH 9

pH1 pH4

is active between ph 1 and 4

pH2

maximum activity

pH7 pH11

pH9

is active between ph 7 and 11

maximum activity

catalase breakdown

starch

synthesis

FatFatty acids +

glycerol

breakdown

breakdown

breakdown

1 23 4

5 6

phosphorylase78 9

10 11

12 1314 15

Enzymes revision 2

Speed up reactions

Unchanged at the end of reaction

Lower the energy needed for a reaction

biological

Chemical reactions

Unchanged at end of reaction

synthesis degradation

temperature pH

specific

Control experiment• A c______ experiment is set up to prove

that the r______ are due to the f______ (v_________) under i___________

ontrol

esults actor

ariable nvestigation

Test tube containing 2ml amylase(5% concentration)

+ 5ml starch solution(10% concentration)

Experiment carried out in a water bath at 37ºC

Aim: An investigation is set up to prove that starch is digested by amylase enzyme to maltose sugarDraw and describe the control tube

Test tube containing

• equal volume of water (2ml)

•equal volume of starch solution (5ml)

•equal concentration of starch solution

( 10% concentration)

Same temperature ( 37ºC), same type of test tube etc

The control p______ that starch digestion o___ occurs when a_______ is present

rovesnly mylase

Q. In this investigation, what is the purpose of the control experiment

1cm3 glucose 1 phosphate (3%) 1cm3 phosphorylase enzyme (1%) experiment carried out at room temperature (25ºC)

• Aim: An investigation is set up to prove that starch is synthesised by phosphorylase enzyme from glucose 1 phosphate

• Draw and describe two control tubes

1cm3 glucose 1 phosphate (3%) 1cm3 distilled water experiment carried out at room temperature (25ºC)

1cm3 phosphorylase enzyme (1%) 1cm3 distilled water experiment carried out at room temperature (25ºC)

AND

Reliability• R_________ an experiment i_________

r________ of r_______ (__,__.__)

• This shows that results are not u___________ or a ‘o___ o___’

• Often an a________ is then calculated

epeating ncreases

eliabilty esults R R R

nrepresentative ne ff

verage

Averages

1. Find the total number of bubbles

Temperature (°C) 10 20 30 40 50

Bubbles (number/s) 4 8 14 4 0

Try this example …

4 + 8 + 14 + 4 + 0 = 30

2. Divide the total by the number of items

There are 5 items in the table

30 5 = 6

Average = 6 bubbles/s

3. Don’t forget units in your answer

To find the average number of bubbles …

Temperature (°C) 10 20 30 40 50

Bubbles (number/s) 0 2 8 3 2

Click here for answer

15 ÷ 5 = 3 bubbles/s

Percentages

1. Find the total number of bubbles

Temperature (°C) 10 20 30 40 50

Bubbles (number/s) 4 8 16 4 0

What percentage of bubbles are produced at

30ºC?

4 + 8 + 16 + 4 + 0

1. Find the total

= 32

2. Divide the number of bubbles at 20ºC by the total number

8 32 = 0.25 this is the decimal fraction

0.25 x 100 = 25%

To find the percentage of bubbles at 20ºC …

3. Multiply the decimal fraction by 100 to get the percentage

25% of the bubbles are produced at 20ºC

16 32 = 0.5 x 100 = 50%

10ºC? 4 32 = 0.125 x 100 = 12.5%

Ratios

10ºC : 20ºC4 bubbles : 8 bubbles

Temperature (°C) 10 20 30 40 50

Bubbles (number/s) 4 8 14 4 2

1. Write down the ratio of the numbers

To find the simple whole number ratio of bubbles at 10 degrees compared to bubbles at 20 degrees …

2. Find a number that will divide into both numbers to give a whole number – in this case 2

4 bubbles 2 : 8 bubbles 2= 2 bubbles : 4 bubbles

3. Repeat step 2 until you cannot divide again without getting a fraction

2 bubbles 2 : 4 bubbles 2= 1 bubble : 2 bubbles

Ratios

20ºC : 30ºC8 bubbles : 14 bubbles

Temperature (°C) 10 20 30 40 50

Bubbles (number/s) 4 8 14 4 2

1. Write down the ratio of the numbers

To find the simple whole number ratio of bubbles at 20 degrees compared to bubbles at 30 degrees …

2. Find a number that will divide into both numbers to give a whole number – in this case 2

8 bubbles 2 : 14 bubbles 2= 4 bubbles : 7 bubbles

3. You cannot divide any more without getting a fraction so …

the simple whole number ratio is: 4 : 7

apple

liver

Equal mass of tissue Same temperature

Equal concentration of hydrogen peroxide

Same apparatus with dead tissue

Improves reliability

3 5

1 6

Optimum pH

specific

√

30 45

55 - 60

specific