Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology Module 2 > 4. Enzymes > Flashcards

4. Enzymes Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is an enzyme?

A

Biological catalyst that speeds up the rate of chemical reaction without being used up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Anabolic

A

forms 1 product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Catabolic

A

1 substance broken into 2 products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What do globular proteins have

A

Complex tertiary structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is controlled by enzymes

A

Metabolic pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How are enzymes produced

A

via protein synthesis inside cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Affect of high temperature on enzymes

A
  • more kinetic energy = more successful collisions
  • initial rate faster = more enzyme substrate complexes form
  • enzymes eventually denature and less product formed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do non competitive inhibitors work

A
  • inhibitor binds to allosteric site
  • active site no longer complementary to substrate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

37

A
  • non competitive inhibitor
  • ROR doesn’t continue to rise as substrate conc rises
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Affect of low temperature on enzymes (29b)

A
  • less kinetic energy = less successful collisions
  • rate of reaction is slower = fewer enzyme substrate complexes form
  • not all substrate reacted after x mins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Affect of temperature on active site

A
  • high temp affects bonds involved in tertiary structure
  • change in shape of active site = prevents substrate binding to active site
  • effects of high temp irreversible = results in denaturing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Lock and key hypothesis

A

shape of substrate and
enzyme’s active site are complementary and so enzyme is specific

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Induced fit hypothesis

A

enzyme active site changes
shape to accommodate substrate once substrate binds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Types of catalysts

A

Intracellular or Extracellular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are intracellular enzymes

A

produced and function inside the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are Extracellular enzymes

A

secreted by cells and catalyse reactions outside cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Examples of Extracellular protein

A

digestive enzymes in the gut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Example of intracellular enzyme

A

Catalase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Function of catalase

A

converts hydrogen peroxide into water and oxygen, preventing any damage to cells or tissues.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Named example of Extracellular enzymes

A

Amylase and trypsin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Function of amylase

A

Involved in the carb digestion
• hydrolyses starch into simple sugars

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why is digestions usually carried our by extracellular proteins

A

Because macromolecules being digested are too large to enter cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where is amylase secreted from

A

Salivary glands + pancreas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

If amylase is secreted from the salivary gland where is it digesting starch

A

Mouth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

If amylase is secreted from the pancreas where is it digesting starch

A

Small intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Where is trypsin secreted from

A

Pancreas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Where does trypsin go

A

Small intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Function of trypsin

A

Breaks down proteins into peptides + amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Which organisms only use extracellular digestion

A

Fungi / hyphae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How do some organisms only use extracellular digestion

A

secrete the necessary enzymes directly onto the food they are consuming (e.g. wood) so that the food is digested into smaller, simple molecules that the fungi can then absorb through the walls of the hyphae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Where do substrates bind on the enzyme

A

Active site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Main feature of active site

A

Specific shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What does the active site having a specific shape mean

A

Can only bind to a specific substrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How can the active site be denatured

A

pH / temp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How does an enzyme substrate complex form

A

substrates collide with enzyme active site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Metabolism

A

sum of all different reactions and reaction pathways happening in a cell or an organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How is the shape of active site determined by DNA

A

shape of active site = determined by complex tertiary structure
o proteins = formed from chains of amino acids
o order of amino acids = determined by DNA
o change DNA / amino acids = change 3D shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Enzyme substrate complex

A

forms when an enzyme and substrate join

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Key point about enzyme substrate complex

A

only formed temporarily before enzyme catalyses reaction + products released

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Enzyme product complex

A

Substrate(s) then react, and products) are formed = enzyme-product complex formed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Active site

A

an area within the tertiary structure of the enzyme that has shape which is complementary to shape of a specific substrate molecule.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

How are substrates held in enzymes

A

Temporary Hydrogen and ionic bonds between active site and substrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Activation energy

A

Minimum amount of energy required to start a reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How do enzymes speed up chemicals reactions

A

reduce the stability of bonds in the reactants
o The destabilisation of bonds in the substrate makes it more reactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

How do enzymes work

A

providing an alternative energy pathway with a lower activation energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

How do enzymes help organisms

A

Without enzymes, extremely high temperatures or pressures would be needed to reach the activation energy for many biological reactions
o Enzymes avoid the need for these extreme conditions(that would otherwise kill cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

How does changing pH denature an enzyme

A

o Hydrogen and ionic bonds hold the tertiary structure of the protein (ie. the enzyme) together
o Below and above the optimum pH of an enzyme, solutions with an excess of H+ ions (acidic solutions) and OH- ions (alkaline solutions) can cause these bonds to break
o The breaking of bonds alters the shape of the active site, which means enzyme-substrate complexes form less easily

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What holds the tertiary structure together in enzyme

A

Ionic bonds between positively and negatively charged r groups
Disulphide bonds (cysteine only)
Hydrogen bonds
Hydrophobic/ hydrophilic interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Where’s pepsin located

A

Stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What does pepsin being found in the stomach indicate

A

Suited to an acidic environment at pH 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Why does the stomach have a pH of 2

A

Presence of hydrochloric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What are buffer solutions

A

Solution = Have a specific pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Purpose of buffer solutions

A

maintain pH through reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

When we are investigating the effect of pH on enzymes - what should we test it kn

A

Use the enzyme amylase to breakdown starch at a range of pH values,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What does amylase don

A

digests starch (a polysaccharide of glucose) into maltose (a disaccharide of glucose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What would we use to test for presence / lack of starch

A

Iodine

57
Q

Cokour change of iodine in pH practical + what that means to breaking down
starch

A
58
Q

Method - Investigating the effect of pH on enzyme reaction rates for starch

A

Place single drops of iodine solution in rows on the tile
• Label a test tube with the oH 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 the mixture on the first drop of iodine, which should turn blue-black o This test indicates whether starch is still present
• Wait another 10 seconds and place another drop of the mixture on the second drop of iodine
• Repeat every 10 seconds until iodine solution remains orange-brown
• Repeat experiment at different pH values

59
Q

Iodine solution colour

A

Orange-brown

60
Q

How do we control variables

A

Equal volume and concentration of enzyme should be used in each test tube
o Equal volume and concentration of the substrate (starch) should be used

61
Q

What does it mean when the solution remains orange brown

A

amylase has broken down all of the starch so nothing is left to react with the iodine

62
Q

How to interpret results from - Investigating the effect of pH on enzyme reaction
rates

A

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

63
Q

Limitations of starch + iodine = pH = practical

A

Colour = difficult to distinguish = use a colorimeter

64
Q

How can this practical be adapted to control temperature

A

using a water bath at 35°C

65
Q

How does increased temp denature enzymes

A

• increased kinetic energy of = puts a strain on enzymes = causing the weaker hydrogen and ionic bonds to break
• breaking of bonds causes the tertiary structure of the protein (i.e. the enzyme)
to change
• The active site is permanently damaged and its shape is no longer complementary
Denaturation has occurred if the substrate can no longer bind

66
Q

What temp do enzymes denature at in humans

A

Most denature at temps over 60

67
Q

Temp coefficient formula

A

Temperature coefficient = (rate of reaction at (X + 10) °C) / (rate of reaction at x
°C)

68
Q

Effect of increasing enzyme concentration

A
  • higher enzyme concentration
  • greater amount of active sites
  • more successful collisions per second
  • greater the likelihood of enzyme-substrate complex formation
69
Q

How does the initial rate of reaction increase =
enzyme conc

A

As long as there is sufficient substrate available, the initial rate of reaction increases linearly with enzyme concentration

70
Q

Why would the rate of reaction be limited at some point

A

amount of substrate is limited, at a certain point any further increase in enzyme concentration will not increase the reaction rate as the amount of substrate becomes a limiting factor

71
Q

Enzyme concentration x rate of reaction

A

As enzyme concentration increases, so does rate of reaction AS
• LONG AS
SUFFICIENT
SUBSTRATE IS
AVAILABLE

72
Q

State how substrate concentration effect rate of
reaction

A

• The greater the substrate concentration, the higher the rate of reaction

73
Q

Explain why substrate concentration effects rate of reaction

A

As the number of substrate molecules increases, the likelihood of enzyme-substrate complex formation increases

74
Q

Why does the graph eventually plateau off substrate concentration

A

If the enzyme concentration remains fixed but the amount of substrate is increased past a certain point, however, all available active sites eventually become saturated and any further increase in substrate concentration will not increase the reaction rate

75
Q

Reversible inhibitor

A

Temporarily stops / reduces enzyme activity

76
Q

Two types of reversible inhibitor

A

Competitive + non competitive

77
Q

Competitive inhibitor

A

similar shape to that of the substrate molecules and therefore compete with the substrate for the active site

78
Q

How do reversible inhibitors effect reaction rate

A

Reduce ROR

79
Q

What happens if you increase concentration if inhibitor

A

reduces rate further = eventually stop the reaction

80
Q

How do you counter an increase in competitive inhibitors

A

can counter increase in inhibitor concentration by increasing substrate
concentration = more substrate molecules mean they are more likely to collide
with enzymes and form enzyme-substrate complexes

81
Q

Does the way to counter competitive work for non competitive

A

No

82
Q

Why does the way to counter competitive not work for non competitive

A

as the shape of the active site of the enzyme remains changed and enzyme-substrate complexes are still unable to form

83
Q

Does the amount of product change with competitive

A

no

84
Q

Why does the amount of product not change with competitive

A

lower the initial rate of reaction (by occupying some of the available active sites)
= eventually same amount of product will be produced as would have been produced without the competitive inhibitor (the maximal rate is not affected)

85
Q

Do non competitive inhibitors lower the amount of product formed

A

YES

86
Q

Draw a graph - rate of reaction against substrate concentration - do normal enzyme / competitive inhibitor and non - competitive

A
87
Q

Describe end product inhibition

A

when the last product of the last enzyme can go back to the first enzyme of the cycle and act as an inhibitor to it therefore the cycle stops. Non competitor inhibitor but it is reversible

88
Q

How is the end product inhibitor a negative feedback
Loop

A

The end-product can then detach from the enzyme and be used elsewhere, allowing the active site to reform and the enzyme to return to an active state
o This means that as product levels fall, the enzyme begins catalysing the reaction once again, in a continuous feedback loop

89
Q

What are non reversible inhibitors

A

Some inhibitors can form covalent bonds with enzymes, inhibiting them
permanently = non-reversible

90
Q

What do non reversible inhibitors result in

A

complete inactivation of the enzyme

91
Q

Why is non reversible inhibition dangerous

A

the biological reaction the enzyme is catalysing to be completely stopped

92
Q

How does the cell avoid this danger of non reversible inhibition

A

the cell or organism to produce more of the enzyme being inhibited

93
Q

Why is producing more of the enzyme not as easy as it sounds

A

only be achieved by transcribing and translating the gene(s) for that enzyme = relatively slow process

94
Q

What can irreversible inhibitors also be known as

A

metabolic poisons

95
Q

Example of metabolic poison

A

Cyanide

96
Q

What is a temperature coefficient

A

shows how much the rate of reaction changes when the temperature increases by 10 degrees Celsius.

97
Q

Cyanide

A

inhibits an enzyme used in respiration so it stops which leads to death

98
Q

Snake venom

A

inhibits an enzyme called acetylcholinesterase which causes organisms to be paralysed

99
Q

Aspirin

A

prevents the formation of prostaglandins which means it acts as a painkiller.

100
Q

Cofactors

A
  • inorganic ions
  • non proteins
101
Q

.what are cofactors needed for

A

enzymes require them to function properly

102
Q

Cofactors function

A

help stabilise the structure of an enzyme or take part in a reaction at active site

103
Q

Example of cofactors

A

chloride ions act as a cofactor for amylase

104
Q

How do cofactors actually work

A

may accept hydrogen ions, electrons or other small molecules that enable the main reaction to occur

105
Q

What are coenzymes

A

• larger organic cofactors = coenzymes
• non-protein

106
Q

Are co enzymes permanent or temporary

A

some = permanently bound to the enzyme = in / near active site
some = bind temporarily

107
Q

Are cofactors permenatly or temporarily blind

A

Typically permanently

108
Q

How do coenzymes work

A

often changes the shape of the active site to allow the binding of a substrate

109
Q

Cofactors are from inorganic ions. Where are co enzymes from

A

often vitamins / derived from vitamins = especially vitamin B

110
Q

What are co enzymes involved in

A

Electron transfer reactions

111
Q

Prosthetic group

A

cofactors are actually a permanent part of the structure of the enzyme they assist = prosthetic group

112
Q

Why are prosthetic groups important

A

essential to the enzyme functioning properly, as they help to form the final 3D shape of the enzyme

113
Q

How to investigate enzyme activity using water

A

The rate of product formation is used to measure the rate of enzyme controlled reactions

114
Q

How to investigate enzyme activity using water

A

Hydrogen peroxide is a common but toxic by-product of metabolism o This means it must be broken down quickly
o Catalase is an enzyme found in the cells of most organisms that breaks down hydrogen peroxide into water and oxygen
o Hydrogen peroxide and catalase are combined and the volume of oxygen generated is measured in a set time o The rate of reaction can then be calculated

115
Q

Cofactor for amylase

A

Cl-

116
Q

Prosthetic group for carbonic anhydrase

A

Zn 2+ = carbonic anhydrase transports co2 around the body

117
Q

Name 3 cofactors

A

Prosthetic group, coenzymes, ions

118
Q

Serial dilutions

A
  • start with a stock solution and take 1 cm^3 and add 9 cm^3 of water which makes it 1/10 diluted
  • Then take 1cm^3 this solution and add 9cm^3 water to this which makes it 1/100 diluted and repeat
119
Q
A
120
Q
A

C

121
Q
A

B

122
Q
A

C

123
Q
A
124
Q
A
125
Q
A

A

126
Q

ii

A
127
Q
A
128
Q
A
129
Q
A
130
Q

ii

A
131
Q
A
132
Q
A
133
Q
A
134
Q
A
135
Q
A
136
Q
A
137
Q
A
138
Q

What can be concluded from the results in Table 4.1 about the optimum temperature for lipase activity?

A

(the optimum temperature) is between 30°C and 35°C J

139
Q

The normal maximum rate of malate dehydrogenase activity is 100 mmol dm-3 s-1.
The data in Table 19.1, on the Insert, were obtained in the presence of latrotoxin.
What can be deduced from these results about latrotoxin’s mode of action as a poison? Justify your answer.

A

Biology Module 2 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions