Transcript SQAEnzymes - MrMcKennaBiologyPage

Enzymes
SQA Questions
What you should know - ENZYMES
atalyst
• A c________
is a substance which helps to
s______
up a chemical reaction. It remains
peed
u________
nchanged at the end of the reaction.
• An enzyme is a p_______
which can act as a
rotein
iological
catalyst inside l_____
(b_______
iving c_____
ells
c_________).
atalysts
• Enzymes are important for the functioning of living
cells because w_______
the aid of e________
the
ithout
nzymes
chemical reactions would take place too s______
to
lowly
maintain life.
• Enzymes in a cell are used in ‘b________’
reakdown or
‘s_______’
ynthesis
• Breakdown is when an enzymes breaks down a
arge
l______
s________
ubstrate molecule into s______
maller ones
• Synthesis is when an enzyme j_____
oins s______
maller
substrate molecules t_________
to make a
ogether
larger one
• P_______
and c__________
are examples of
epsin
atalase
breakdown enzymes
hosphorylase
• P______________
is a synthesis enzyme
pecific
• Enzymes are s________
– they will act only on
ne s__________
ubstrate
o___
roteins
• Enzymes are p________
emperature and __.
pH
• Enzymes are affected by t__________
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 activityoptimum temperature
Enzyme is being denatured
the temperature at which the enzyme has
greatest activity
the pH at which the enzyme has greatest
activity
catalase
pepsin
1
2
4
7
9
11
8. Pepsin
pH4
pH1 to _____.
• has a working range of ____
is active between ph 1 and 4
• This means it ______________________
pH2
• Pepsin has an optimum pH of ____.
This
maximum ________
activity
means it has ________
at pH 2
9. Catalase
pH7 to _____.
pH11
• has a working range of ____
is active between ph 7 and 11
• This means it ______________________
pH9
• Catalase has an optimum pH of ____.
This
maximum ________
means it has ________
activity at pH 9
1
2
catalase
5
starch
3
breakdown
6
phosphorylase
7
8
synthesis
9
Fatty acids +
10
Fat
11
glycerol
12
4
breakdown
13
14
breakdown
15
breakdown
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
specific
pH
Control experiment
ontrol
• A c______
experiment is set up to prove
esults
actor
that the r______
are due to the f______
nvestigation
(v_________)
under i___________
ariable
Aim: An investigation is set up to prove that starch is
digested by amylase enzyme to maltose sugar
Draw and describe the control tube
Test tube containing 2ml amylase(5% concentration)
+ 5ml starch solution(10% concentration)
Experiment carried out in a water bath at 37ºC
Q. In this investigation, what is the purpose of
the control experiment
The control p______
roves that starch digestion
o___
nly occurs when a_______
mylase is present
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
• 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 phosphorylase enzyme (1%)
experiment carried out at room temperature (25ºC)
1cm3 glucose 1 phosphate (3%)
1cm3 distilled water
experiment carried out at room temperature (25ºC)
AND
1cm3 phosphorylase enzyme (1%)
1cm3 distilled water
experiment carried out at room temperature (25ºC)
Reliability
epeating
ncreases
• R_________
an experiment i_________
eliabilty
esults
R R R
r________
of r_______
(__,__.__)
• This shows that results are not
nrepresentative or a ‘o___
ne o___’
ff
u___________
verage
• Often an a________
is then calculated
Averages
Temperature (°C)
Bubbles (number/s)
10
20
30
40
50
4
8
14
4
0
To find the average number of bubbles …
1.
Find the total number of bubbles
2.
= 30
4 + 8 + 14 + 4 + 0
Divide the total by the number of items
There are 5 items in the table
30  5 = 6
3.
Don’t forget units in your answer
Average = 6 bubbles/s
Try this example …
Temperature (°C)
Bubbles (number/s)
Click here for answer
10
20
30
40
50
0
2
8
3
2
15 ÷ 5 = 3 bubbles/s
Percentages
Temperature (°C)
Bubbles (number/s)
10
20
30
40
50
4
8
16
4
0
To find the percentage of bubbles at 20ºC …
1.
Find the total
total number of bubbles
2.
4 + 8 + 16 + 4 + 0
= 32
Divide the number of bubbles at 20ºC by the total number

8  32 = 0.25 this is the decimal fraction
3.
Multiply the decimal fraction by 100 to get the percentage
0.25 x 100 = 25%
25% of the bubbles are produced at 20ºC
What percentage of bubbles are produced at
30ºC?
16  32 = 0.5 x 100 = 50%
10ºC?
4  32 = 0.125 x 100 = 12.5%
Ratios
Temperature (°C)
Bubbles (number/s)
10
20
30
40
50
4
8
14
4
2
To find the simple whole number ratio of bubbles at 10 degrees
compared to bubbles at 20 degrees …
1.
Write down the ratio of the numbers
10ºC
4 bubbles
2.
:
:
Find a number that will divide into both numbers to give a whole number –
in this case 2
4 bubbles  2
= 2 bubbles
3.
20ºC
8 bubbles
:
:
8 bubbles  2
4 bubbles
Repeat step 2 until you cannot divide again without getting a fraction
2 bubbles  2
= 1 bubble
:
:
4 bubbles  2
2 bubbles
Ratios
Temperature (°C)
Bubbles (number/s)
10
20
30
40
50
4
8
14
4
2
To find the simple whole number ratio of bubbles at 20 degrees
compared to bubbles at 30 degrees …
1.
Write down the ratio of the numbers
20ºC
8 bubbles
2.
30ºC
14 bubbles
Find a number that will divide into both numbers to give a whole number –
in this case 2
8 bubbles  2
= 4 bubbles
3.
:
:
: 14 bubbles  2
:
7 bubbles
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
Optimum pH
specific
6
√
30
55 - 60
specific
45