3.1 Biological molecules - carbs, proteins, enzymes, lipids and biochemical tests Flashcards
1
Q
what are carbohydrates used by and what for
A
by cells for respiration and as structural components in membranes and cell walls, storage ( starch and glycogen )
2
Q
what are carbohydrates used by and what for
A
by cells for respiration and as structural components in membranes and cell walls, storage ( starch and glycogen )
3
Q
what are lipids used for?
A
used for respiration, the bilayer of plasma membranes, some hormones
4
Q
what are proteins used for?
A
many cell structures, enzymes, chemical messengers, transport and components of the blood
5
Q
what is water used for?
A
solvent found as the major component of all cells
6
Q
examples of nucleic acids
A
DNA and RNA
7
Q
what do nucleic acids do?
A
carry the genetic code for the production of proteins, RNA is part of ribosome structure
8
Q
what are vitamins and minerals required for?
A
a range of enzyme functions
9
Q
what is a polymer?
A
a long chain molecule made up of large numbers of repeating units linked together e.g. starch, proteins, DNA
10
Q
what is a monomer?
A
one of the molecules linked together in the chain to form a polymer e.g. glucose, amino acids, nucleotides
11
Q
what do 2 monomers make?
A
dimer
12
Q
what do 3 monomers make?
A
trimer
13
Q
glucose formula
A
C6H12O6
14
Q
glucose + glucose
A
maltose + water
15
Q
what is produced when 2 biological monomers are linked together
A
water
16
Q
what is the reaction called when 2 biological monomers are linked together and water is produced
A
condensation reaction
17
Q
what happens to the water molecule in a condensation reaction
A
involve the removal of a water molecule
the removal of water from monomers enables a chemical bond to form between the monomers
18
Q
what happens during a hydrolysis reaction
A
a water molecule is added between two bonded monomers ( within a dimer or polymer ) to break the chemical bond
19
Q
what is a hydrolysis reaction?
A
the opposite of a condensation reaction where water is split
20
Q
what does a condensation reaction involve the removal of?
A
the removal of a water molecule
this removal of water from monomers enables a chemical bond to form between the monomers
21
Q
what is a hydrolysis reaction?
A
the opposite of a condensation reaction
a water molecule is added between the two bonded monomers to break the chemical bond
22
Q
what do carbohydrates do?
A
store energy and can provide structural support to plant cells
23
Q
which carbohydrates are monosaccharides?
A
glucose
fructose
galactose
24
Q
which carbohydrates are disaccharides?
A
maltose
sucrose
lactose
25
which carbohydrates are polysaccharides?
starch
glycogen
cellulose
26
what is the general formula for a monosaccharide?
CnH2nOn
where n = the number of carbon atoms it contains
27
what is the formula for glucose?
C6H12O6
28
what is an isomer?
compounds that have the same formula but the atoms are arranged differently
29
what are the structural isomers of glucose?
beta glucose and alpha glucose
30
what are the difference between the structures of alpha and beta glucose?
the H group and the OH group on carbon 1 swap position
31
where are the H group and OH group on carbon 1 on alpha glucose?
H group is above and the OH group is below carbon 1
32
where are the H group and OH group on carbon 1 on beta glucose?
H group is below and the OH group is above carbon 1
33
what is a disaccharide?
two monosaccharides bonded together by a glycosidic bond, that is formed by a condensation reaction
34
glucose + glucose
maltose
35
glucose + galactose
lactose
36
glucose + fructose
sucrose
37
how does a condensation reaction create a disaccharide?
a water molecule is removed from the OH group on carbon 1 and carbon 4 on the two monosaccharides
the bond that forms is known as a glycosidic bond
will be a 1-4 glycosidic bond if between carbon 1 and carbon 4
38
what reaction takes place to make a disaccharide go back to a monosaccharide?
hydrolysis reaction
39
what are polysaccharides?
polymers made up of many monosaccharides
40
how are polysaccharides created?
through condensation reactions
41
where is starch found?
plants
42
what is starch made from?
the excess glucose created during photosynthesis
43
what type of glucose makes up starch?
alpha glucose
44
what type of glycosidic bonds keep starch held together?
1,4 and 1,6 glycosidic bonds
45
what two polymers make up starch?
amylose and amylopectin
46
in starch what do the 1,4 glycosidic bonds in amylose cause?
a spiral shaped polymer
47
in starch what do the 1,4 and 1,6 glycosidic bonds in amylopectin cause?
result in branches
48
is starch soluble or insoluble?
insoluble due to the fact it is a large molecule
49
what is starch being insoluble an advantage?
it means it can be stored within cells and not dissolve therefore it will not change the water potential of the cell nor cause osmosis to occur
50
why is amylose being spiral shaped an advantage?
it can be readily compacted
51
why is amylopectin being branched an advantage?
it provides a larger surface area for enzymes to attach to meaning starch is readily hydrolysed back into glucose when plant cells are running low on glucose for respiration
52
what is glycogen?
the major carbohydrate storage molecule found in animal cells
53
where are the main glycogen cells stored?
in the liver and muscle cells
54
what is glycogen made from?
the excess glucose that has been eaten and absorbed into the bloodstream
55
why is glycogen mainly stored in the liver and muscle cells?
to ensure they always have access to glucose to respire and release energy
56
what type of glucose is glycogen made up of?
alpha glucose
57
why does glycogen have more of a branched structure than amylopectin?
because it contains more 1,6 glycosidic bonds
58
is glycogen soluble or insoluble?
its insoluble due to the fact its a large molecule
59
why is glycogen being insoluble an advantage?
means it can be stored within cells and not dissolve
therefore it will not change the water potential of the cell nor cause osmosis which would cause cell lysis
60
why is glycogen being highly branched an advantage?
means it has a larger surface areas for enzymes to attach which means it can be readily hydrolysed into glucose
glycogen is more branched than starch so it can be hydrolysed back into glucose more rapidly
61
why is glycogen being more branched than starch essential for animals?
because hey have a higher metabolic rate and therefore need more glucose than plants e.g. running away from a predator
62
what is the function of cellulose?
to provide structural strength in plants
63
where is cellulose located in plants and why?
in the cell wall of plants and therefore prevents cells from bursting if they take in excess water
64
what type of glucose is cellulose made from?
beta glucose
65
what glycosidic bonds is cellulose made up of?
1,4 glycosidic bonds only
66
why is the cellulose polymer unbranched?
because it is only made up of one type of glycosidic bond
1,4 create straight lines whereas 1,6 create branches
67
what is the structure of cellulose like?
the long straight chains of b glucose accumulate and lie parallel to each other
the parallel chains are then held together by many hydrogen bonds which provide strength due to the amount of them
68
what is the structure of cellulose called?
fibril
69
is cellulose soluble or insoluble?
insoluble
70
why is cellulose being insoluble an advantage?
it will not change the water potential of the cell and affect osmosis
71
how is cellulose a very strong polysaccharide?
due to the large number of hydrogen bonds in and between the fibrils
72
what is the method of the reducing sugars test?
1. add benedicts reagent to the sample you re testing
2. heat e.g. using water bath
3. if a colour change of blue to yellow/ green / red is observed then it is confirmation that a reducing sugar is present
4. if the solution remains blue, there is no reducing sugar present
73
what is an example of a non reducing sugar?
sucrose
74
why is sucrose not a reducing sugar?
because it cannot reduce Cu2+
75
how can we prove that sucrose is still a sugar but is just unable to reduce Cu2+?
the glycosidic bond must be hydrolysed to expose the reducing group
76
what is the method for the non - reducing sugar test?
1. mix sucrose with hydrochloric acid and boil
2. cool the solution and then add sodium hydroxide to make the solution alkaline
3. add a few drops of benedicts reagent and heat - if a colour change of blue to yellow, green or red is observed then this is confirmation a non reducing sugar is present.
77
why do we mix the sucrose with the HCl and boiled in the non reducing sugars test?
this is acid hydrolysis and it breaks the glycosidic bond so that sucrose is hydrolysed back into glucose and fructose
78
why in the non reducing sugars test must we cool the solution and add sodium hydroxide to make it alkaline?
cooling is to prevent excessive, dangerous fizzing
the sodium hydroxide is because benedicts only works in alkaline solutions so this stage is essential
79
what does the rustier the red after the reducing or non reducing sugars test mean?
the higher the concentration of sugar present because more copper oxide has been made (rust)
80
what is the method for the test for starch?
add a few drops of iodine
it will turn blue/black if starch is present
81
what is the method for a test for proteins?
add biuret reagent
it will turn from blue to purple if protein is present
82
what is the method for a test for lipids?
your sample must first be dissolved in ethanol e.g. by shaking your sample you are testing in ethanol
once the sample is dissolved add distilled water and shake again
if lipids are present, you will observe a white emulsion
83
are proteins polymers or monomers?
polymers
84
what monomers are proteins made up of?
amino acids
85
what does the general structure of an amino acid include?
a central carbon
an amine group (NH2)
a hydrogen atom
a carboxyl group (COOH)
the variable group (R group)
86
what reaction allows amino acids to join together to make the polypeptide polymer?
Amino acids join together to make the polypeptide polymer via condensation reactions
87
what bonds keep amino acids together to make polypeptide polymers?
peptide bonds
88
what is the first structure that forms in the creation of a protein?
the polypeptide chain
89
what is the primary structure of a protein?
the primary structure is the sequence of amino acids in a polypeptide chain
90
when will the specific order of amino acids alter?
where bonds occur and how the protein folds
91
what does the primary structure determine overall due to the sequence of amino acids?
the primary structure determines the final 3D shape and the protein's function
92
in the secondary structure of a protein what does the sequence of amino acids cause?
causes parts of a protein molecule to bend into an α helix or fold into β pleated sheets
93
what bonds form between the carboxyl groups of one amino acid and the amine group of another in the secondary structure?
hydrogen bonds which hold the secondary structure in place
94
what bonds hold the tertiary structure together?
hydrogen, ionic and disulfide bonds hold the tertiary structure
95
where do disulphide bonds form between in the tertiary structure of a protein?
only form between the R-groups of two amino acids that contain sulfur
96
describe the tertiary structure of a protein (3 marks)
- the further folding of the secondary structure
- to create a unique 3D structure
- held in place by hydrogen, ionic and disulfide bonds
97
what type of protein has a quaternary structure?
a protein that is made up of more than one polypeptide chain has a quaternary structure
98
what is a prosthetic group in the quaternary structure of a protein?
any group that is attached to a protein, but is not made up of amino acids
99
why is the active site specific and unique in shape?
due to the specific folding and bonding in the tertiary structure of the protein
due to this specific active site, enzymes can only attach to substrates that are complementary in shape
100
where are protein polymer chains, or polypeptides created?
on ribosomes in cells and are then further folded and modified in
the Golgi apparatus
101
what do enzymes do to the activation energy?
they can lower the activation energy needed for the reaction to occur, and therefore speed up the reaction
102
what is the lock and key model and what does it suggest?
this model suggests that the enzyme is like a lock and that the substrate is like a key that fits into it due to its complementary shape
the enzyme active site is a fixed shape and due to random collisions, the substrate can collide and attach to the enzyme
this forms an enzyme substrate complex.
once the enzyme-substrate complex has formed, the charged
groups within the active site are thought to distort the substrate
and therefore lower the activation energy
the products are then released, and the enzyme active site is empty
and ready to be reused
103
what is the induced fit model and what does it suggest?
this model suggests that the enzyme is like a glove and the substrate is like your hand; the empty glove is not exactly complementary in shape to your hand, but when your hand enters, it enables the glove to mold around your hand to become completely complementary
the enzyme active site is induced or slightly changes shape, to mould around the substrate
the formation of the enzyme substrate complex involves the enzyme moulding around the substrate, which puts a strain on the bonds and therefore lowers the activation energy
The products are then removed, and the enzyme active site returns to its original shape
104
what is the accepted model for how enzymes work?
the induced fit model is the accepted model for how enzymes function
105
what factors affect the rate of enzyme-controlled reactions?
- temperature
- pH
- substrate concentration
- enzyme concentration
- inhibitors
106
how does temperature the control rate of reaction?
if the temperature is too low, there is not enough kinetic energy for successful collisions between the enzyme and substrate
if the temperature is too high, enzymes denature, the active site changes shape and enzyme substrate complexes cannot form
107
how does pH control rate of reaction?
too high or too low a pH will interfere with the charges in the amino acids in the active site.
this can break the ionic and hydrogen bonds holding the tertiary structure in place and therefore the active site changes shape.
therefore the enzyme denatures and fewer
enzyme-substrate complexes form.
108
what happens to the active site when the enzymes are insufficient?
then the enzyme active sites will become saturated with substrate and unable to work any faster
109
what shape are competitive inhibitors?
the same shape as the substrate and can bind to the active site
110
what do competitive inhibitors do?
prevents the substrate from binding and the reaction occurring
if you add more substrate this will out-compete the inhibitor, knocking them out of the active site
111
where do non - competitive inhibitors bind to?
bind to the enzyme away from the active site (the allosteric site)
112
what do non - competitive inhibitors cause the active site to do?
causes the active site to permanently change shape, and therefore the substrate can no longer bind, regardless of how much substrate is added
113
what happens to competitive inhibitors at a high enough substrate concentration?
competitive inhibitors are knocked out of the active site and the rate of reaction will therefore return to the same as with no
inhibitor
114
what is the rate of reaction with a non competitive inhibitor like?
will be lower at all substrate concentrations
115
what structure of the proteins is an enzyme?
tertiary structure proteins
116
what are the two types of lipids?
triglycerides and phospholipids
117
how are triglycerides formed?
via condensation reactions
118
what are triglycerides made up of?
one molecule of glycerol and three molecules of fatty acid
119
what bonds are formed in triglycerides?
ester bonds are formed
120
what does it mean by a saturated fatty acid?
the hydrocarbon chain has only single bonds between carbons
121
what does it mean by an un-saturated fatty acid?
the hydrocarbon chain consists of at least one double bond between carbons
122
what does an R-group on a triglyceride consist of?
R-groups are fatty acids which can be saturated or unsaturated
123
why is a lot of energy stored in the triglyceride molecule due to its structure?
due to the large ratio of energy-storing carbon-hydrogen bonds compared to the number of carbon atoms
124
why can triglycerides release water if they are oxidised due to their function?
due to the high ratio of hydrogen to oxygen atoms they act as a metabolic water source
125
why do triglycerides not affect water potentials and osmosis due to their structure?
they are large and hydrophobic, making them insoluble in water
126
why can a lot of triglycerides be stored without increasing the mass
and preventing movement due to their structure?
lipids have a relatively low mass
127
why do phospholipids contain?
made of a glycerol molecule
two fatty acid chains
a phosphate group (attached to the glycerol)
128
how do the two fatty acids also bond to the glycerol in a phospholipid?
via two condensation reactions
129
what bonds are in a phospholipid?
two ester bonds.
130
why does the hydrophilic ‘head’ of a phospholipid attract water?
it is charged
due to the phosphate being charged (polar), it repels other
fats
131
is the fatty acid chain on a phospholipid non-polar or polar?
non-polar
it is known as the hydrophobic ‘tail’ and it repels water but will mix with fats
132
why are phospholipids polar?
phospholipids have two charged regions
133
what does a phospholipid bilayer make up?
the plasma membrane around cells
134
how is the structure of a phospholipid bilayer positioned?
they are positioned so that the heads are exposed to water and
the tails are not
135
What reagent confirms the presence of starch?
Iodine
## Footnote
Iodine turns blue/black in the presence of starch and is orange/brown when starch is absent.
136
What color does biuret reagent turn when protein is present?
Purple
## Footnote
Biuret reagent is originally blue and changes to purple when it reacts with proteins.
137
How do you test for lipids?
Dissolve sample in ethanol, then add distilled water
## Footnote
A white emulsion indicates the presence of lipids.
138
What must be done to Benedict's reagent for the reaction to occur?
Heated
## Footnote
Heating is necessary for the test to show a positive result for reducing sugars.
139
What is the appearance of a positive test for starch?
Blue/black color
## Footnote
This indicates the presence of starch when iodine is added.
140
What is the initial color of biuret reagent before adding protein?
Blue
## Footnote
The color changes to purple only when protein is present.
141
Fill in the blank: To test for lipids, first dissolve the sample in _______.
Ethanol
142
What happens after adding distilled water to the lipid solution?
Shake again to observe a white emulsion
## Footnote
This indicates the presence of lipids in the sample.
143
True or False: Acid must be boiled for the hydrolysis of non-reducing sugars.
True
144
What is a characteristic observation for proteins when using biuret reagent?
Purple color change
145
What color indicates no starch is present when using iodine?
Orange/brown
## Footnote
This is the color of iodine when starch is absent.
146
What type of sugar is sucrose classified as?
Non-reducing sugar
## Footnote
Sucrose cannot reduce Cu²⁺ due to its glycosidic bonds.
147
Why is sucrose considered a non-reducing sugar?
It cannot reduce Cu²⁺ because the chemical group needed for reduction is involved in glycosidic bonds.
## Footnote
Hydrolysis of glycosidic bonds is necessary to expose the reducing group.
148
What is the first step to test for a non-reducing sugar?
Mix sucrose with HCl and boil.
## Footnote
This is acid hydrolysis, which breaks the glycosidic bond.
149
What temperature is required for acid hydrolysis of sucrose?
Above 100 °C
## Footnote
Boiling is essential to provide enough energy to break the glycosidic bond.
150
What is done after boiling the sucrose and HCl mixture?
Cool the solution and add sodium hydroxide.
## Footnote
This makes the solution alkaline, which is necessary for Benedict's reagent to function.
151
Why must the solution be cooled before adding sodium hydroxide?
To prevent excessive, dangerous fizzing.
## Footnote
This is important for safety during the test.
152
What reagent is added after making the solution alkaline?
Benedict's reagent
## Footnote
This reagent tests for the presence of reducing sugars.
153
What indicates the presence of a non-reducing sugar in the test?
A color change from blue to yellow/green/red.
## Footnote
This indicates that reducing sugars are present after hydrolysis.
154
What does a rustier red precipitate in the sugar test indicate?
A higher concentration of sugar present.
## Footnote
More Cu²⁺ has been reduced to Cu⁺, forming copper oxide.
155
Fill in the blank: Sucrose is hydrolyzed back into _______ and _______ during the non-reducing sugar test.
glucose and fructose
156
What is a reducing sugar?
Sugars that can reduce Cu²⁺ ions in Benedict's reagent to Cu⁺ ions, forming a brick-red precipitate
## Footnote
Reducing sugars include monosaccharides like glucose and some disaccharides like maltose.
157
What reagent is used to test for reducing sugars?
Benedict's reagent
## Footnote
Benedict's reagent is a bright blue liquid containing copper sulfate.
158
What color change indicates the presence of reducing sugars in a test?
Blue to yellow/green/red
## Footnote
A positive test result shows a gradual color change from blue to these colors depending on the concentration of reducing sugar.
159
What does it mean if the solution remains blue after testing for reducing sugars?
No reducing sugar is present
## Footnote
The absence of color change indicates a negative result.
160
List the biological molecules that require testing in biochemical tests.
* Reducing sugars
* Non-reducing sugars
* Starch
* Proteins
* Lipids
## Footnote
These tests help identify the presence of various essential biological macromolecules.
161
What is the first step in the procedure for testing reducing sugars?
Add Benedict's reagent to the sample
## Footnote
This initiates the chemical reaction necessary for detecting reducing sugars.
162
What is the second step in the procedure for testing reducing sugars?
Heat the mixture
## Footnote
Heating is essential to facilitate the reaction between the reducing sugar and Benedict's reagent.
163
True or False: Benedict's reagent changes from blue to brick-red in the presence of reducing sugars.
True
## Footnote
This color change confirms the presence of reducing sugars.
164
What are the two charged regions of phospholipids?
Hydrophilic head and hydrophobic tail
165
What structure forms the plasma membrane around cells?
Phospholipid bilayer
166
What type of reaction forms triglycerides and phospholipids?
Condensation reaction
167
What type of bond is formed in triglycerides and phospholipids?
Ester bonds
168
What are the two types of fatty acids based on carbon bonds?
Saturated and unsaturated
169
What is the role of lipids in the nervous system?
Form the insulating myelin sheath on neurones to enable saltatory conduction
170
Where do lipids form the membrane within organelles?
Mitochondria and chloroplasts
171
Fill in the blank: Phospholipids have a _______ head and a hydrophobic tail.
Hydrophilic
172
Fill in the blank: The _______ tail of phospholipids is not exposed to water.
Hydrophobic
173
True or False: Phospholipids are non-polar molecules.
False
174
What is the composition of the phospholipid bilayer in relation to water?
Heads are exposed to water, tails are not
175
What type of vesicle is formed by lipids?
Phagosome
176
How do lipids contribute to viral structure?
Form an envelope around viruses such as HIV
177
What is the primary source of metabolic water?
Triglycerides can act as a metabolic water source
## Footnote
They can release water when oxidized, which is essential for animals in arid environments.
178
What property of triglycerides allows them to store a lot of energy?
Large ratio of energy-storing carbon-hydrogen bonds
## Footnote
This high ratio compared to the number of carbon atoms contributes to their energy storage capacity.
179
Do triglycerides affect water potentials and osmosis?
No, triglycerides do not affect water potentials and osmosis
## Footnote
They are large and hydrophobic, making them insoluble in water.
180
What is the advantage of lipids having a relatively low mass?
A lot can be stored without increasing mass and preventing movement
## Footnote
This property is beneficial for organisms needing mobility.
181
What are the components of phospholipids?
Glycerol, two fatty acid chains, and a phosphate group
## Footnote
These components create the structural basis of phospholipids.
182
What is the hydrophilic part of a phospholipid called?
Hydrophilic head
## Footnote
The hydrophilic head can attract water due to its charged nature.
183
What is the non-polar part of a phospholipid known as?
Hydrophobic tail
## Footnote
The hydrophobic tail repels water but will mix with fats.
184
What type of bonds are formed between fatty acids and glycerol in phospholipids?
Ester bonds
## Footnote
Two condensation reactions result in the formation of these bonds.
185
Fill in the blank: Phospholipids have a hydrophilic ______ and a hydrophobic ______.
head; tail
## Footnote
The head is charged and attracts water, while the tail is non-polar and repels water.
186
True or False: Phospholipids are soluble in water.
False
## Footnote
The hydrophobic tails make phospholipids insoluble in water.
187
What is the significance of the high ratio of hydrogen to oxygen in triglycerides?
It allows triglycerides to act as a metabolic water source
## Footnote
This is particularly important for animals in dry environments.
188
What are the two main types of lipids discussed?
Triglycerides and phospholipids
189
What is the structure of a triglyceride?
One molecule of glycerol and three molecules of fatty acid
190
What type of reaction forms triglycerides?
Condensation reaction
191
What type of bond is formed between glycerol and fatty acids in triglycerides?
Ester bond
192
What are the components of glycerol?
Three carbon atoms and hydroxyl groups
193
What are the two types of fatty acids?
Saturated and unsaturated
194
Fill in the blank: Saturated fatty acids have ________ bonds between carbons.
only single
195
Fill in the blank: Unsaturated fatty acids consist of at least one ________ bond between carbons.
double
196
What is the general formula of a triglyceride?
Glycerol + 3 Fatty Acids
197
Define saturated fatty acids.
Fatty acids with only single bonds between carbon atoms
198
Define unsaturated fatty acids.
Fatty acids that contain at least one double bond between carbon atoms
199
What is a competitive inhibitor?
A substance that competes with the substrate for the active site of an enzyme.
200
What happens to the rate of reaction when substrate concentration is high enough in the presence of a competitive inhibitor?
The rate of reaction returns to the same as with no inhibitor.
201
What is a non-competitive inhibitor?
A substance that decreases the rate of reaction regardless of substrate concentration.
202
How do enzymes lower activation energy?
Through the induced fit model.
203
What type of structure do enzymes have?
Tertiary structure proteins.
204
List three factors that affect the rate of reaction in enzymatic processes.
* Inhibitors
* Substrate concentration
* Enzyme concentration
205
True or False: Enzymes are not sensitive to temperature and pH.
False
206
Fill in the blank: Enzymes catalyse specific reactions due to their uniquely shaped _______.
[active site]
207
What is the effect of non-competitive inhibitors on the rate of reaction?
The rate of reaction is lower at all substrate concentrations.
208
Cyanide is an example of a _______ inhibitor for an enzyme in respiration.
[competitive]
209
How is enzyme sensitivity to pH and temperature linked to homeostasis?
It relates to thermoregulation and regulation of pH of the blood.
210
What is lysozyme?
A hydrolytic enzyme involved in phagocytosis.
211
What does the induced fit model demonstrate?
How enzymes lower activation energy.
212
How can enzyme function and sensitivity to temperature be linked to photosynthesis?
Through Rubisco.
213
What are competitive inhibitors?
Competitive inhibitors are the same shape as the substrate and can bind to the active site
## Footnote
They prevent the substrate from binding and the reaction occurring.
214
What happens when more substrate is added in the presence of a competitive inhibitor?
More substrate can out-compete the inhibitor, knocking them out of the active site
## Footnote
This allows the substrate to bind and the reaction to occur.
215
What is the function of non-competitive inhibitors?
Non-competitive inhibitors bind to the enzyme away from the active site, causing a permanent change in shape
## Footnote
This prevents the substrate from binding regardless of substrate concentration.
216
Where do non-competitive inhibitors bind?
Non-competitive inhibitors bind to the allosteric site
## Footnote
This is away from the active site.
217
What effect do non-competitive inhibitors have on the active site?
They cause the active site to permanently change shape
## Footnote
As a result, the substrate can no longer bind.
218
Fill in the blank: Competitive inhibitors prevent the substrate from binding to the _______.
active site
219
True or False: Non-competitive inhibitors can be out-competed by adding more substrate.
False
## Footnote
Non-competitive inhibitors permanently change the active site.
220
What happens to an enzyme when the pH is too high or too low?
The enzyme denatures and its active site changes shape
## Footnote
This occurs because the charges in the amino acids in the active site are interfered with, breaking ionic and hydrogen bonds.
221
What is the term for the complex formed when an enzyme binds with its substrate?
Enzyme-substrate complex
222
What is denaturation in the context of enzymes?
The process where an enzyme loses its tertiary structure and functionality
223
Fill in the blank: Different enzymes have a different optimal _______.
pH
224
How does insufficient substrate concentration affect the rate of reaction?
The reaction will be slower due to fewer collisions between the enzyme and substrate
225
What occurs if there are insufficient enzymes in a reaction?
The enzyme active sites become saturated with substrate and cannot work faster
226
What is meant by enzyme active site saturation?
All active sites of the enzymes are occupied by substrate, preventing further reaction increase
227
What are the key factors that affect the rate of enzyme reactions?
pH, substrate concentration, enzyme concentration
## Footnote
Each of these factors can influence how effectively enzymes catalyze reactions.
228
True or False: A higher concentration of substrate always increases the rate of reaction.
False
## Footnote
The rate of reaction can plateau if the enzyme active sites become saturated.
229
What are enzymes?
Proteins that act as catalysts in biochemical reactions
## Footnote
Enzymes lower the activation energy required for reactions.
230
What is meant by 'successful collisions' in the context of enzymes?
Collisions between enzyme and substrate that result in a reaction
## Footnote
Successful collisions are necessary for enzyme-substrate complexes to form.
231
What does it mean for an enzyme to be denatured?
The enzyme's active site changes shape, preventing enzyme-substrate complexes from forming
## Footnote
Denaturation can be caused by extreme temperatures or pH levels.
232
List the factors affecting the rate of enzyme-controlled reactions.
* Temperature
* pH
* Substrate concentration
* Enzyme concentration
* Inhibitors
## Footnote
Each factor influences the efficiency and speed of enzyme activity.
233
What happens to enzyme activity when the temperature is too low?
There is not enough kinetic energy for successful collisions
## Footnote
Low temperatures can slow down reaction rates significantly.
234
What happens to enzymes when the temperature is too high?
Enzymes denature and the active site changes shape
## Footnote
Denaturation results in the inability to form enzyme-substrate complexes.
235
At what point does temperature increase enzyme activity?
Up to the optimal temperature
## Footnote
Beyond this point, denaturation occurs and activity decreases.
236
Fill in the blank: The rate of reaction increases with temperature until the _______ is reached.
[optimal temperature]
237
True or False: Enzyme concentration affects the rate of enzyme-controlled reactions.
True
## Footnote
Higher enzyme concentrations can increase the rate of reaction, provided there is enough substrate.
238
What are the two models to explain enzyme action?
Lock and Key Model, Induced Fit Model
239
In the Lock and Key Model, what does the enzyme represent?
A lock
240
In the Lock and Key Model, what does the substrate represent?
A key
241
What is the shape of the enzyme active site in the Lock and Key Model?
Fixed shape
242
What forms when the substrate attaches to the enzyme in the Lock and Key Model?
Enzyme-substrate complex
243
What happens to the substrate when the enzyme-substrate complex is formed?
Charged groups distort the substrate, lowering activation energy
244
What occurs after the products are released from an enzyme?
The enzyme active site is empty and ready to be reused
245
In the Induced Fit Model, what does the enzyme represent?
A glove
246
In the Induced Fit Model, what does the substrate represent?
Your hand
247
How does the enzyme active site change in the Induced Fit Model?
It slightly changes shape to mould around the substrate
248
What effect does the enzyme moulding around the substrate have?
It puts a strain on the bonds and lowers the activation energy
249
What is the accepted model for how enzymes function?
Induced Fit Model
250
Fill in the blank: The _______ model suggests that the enzyme is like a lock and the substrate like a key.
Lock and Key
251
True or False: The Lock and Key Model suggests that the enzyme active site is flexible in shape.
False
252
What happens to the active site of the enzyme after the products are released in the Induced Fit Model?
Returns to its original shape
253
What is the site on an enzyme where a substrate attaches to catalyze a reaction?
Active site
## Footnote
The active site is specific and unique in shape due to the specific folding and bonding in the tertiary structure of the protein.
254
What determines the specificity of an enzyme for its substrate?
Complementary shape
## Footnote
Enzymes can only attach to substrates that are complementary in shape.
255
What is the term for the energy required for a reaction to occur?
Activation energy
## Footnote
All reactions require a certain amount of energy before they occur.
256
How do enzymes affect the activation energy of a reaction?
Lower the activation energy
## Footnote
When enzymes attach to the substrate, they can lower the activation energy needed for the reaction to occur.
257
Where are protein polymer chains, or polypeptides, created in cells?
Ribosomes
## Footnote
Polypeptides are then further folded and modified in the Golgi apparatus.
258
What type of structure is important for the function of enzymes?
Tertiary structure
## Footnote
The specific folding and bonding in the tertiary structure of the protein create the active site.
259
Fill in the blank: Enzymes speed up reactions by lowering the _______.
Activation energy
260
True or False: Enzymes can attach to any substrate regardless of shape.
False
## Footnote
Enzymes are specific and can only attach to substrates that fit their active site.
261
What happens to the activation energy requirement when an enzyme is present?
It decreases
## Footnote
This allows the reaction to occur more quickly.
262
What type of molecules are enzymes?
Relatively large molecules
## Footnote
Enzymes are large due to their polypeptide chains.
263
What is the tertiary structure of a protein?
The further folding of the secondary structure to create a unique 3D structure held in place by hydrogen, ionic, and disulfide bonds.
## Footnote
The tertiary structure is a critical aspect of protein functionality.
264
How are tertiary structures of proteins held in place?
By hydrogen bonds, ionic bonds, and sometimes disulfide bonds.
## Footnote
Disulfide bonds form between the R-groups of two amino acids containing sulfur.
265
What distinguishes the quaternary structure of a protein?
A protein made up of more than one polypeptide chain, still folded into a 3D shape and held by hydrogen, ionic, and disulfide bonds.
## Footnote
Haemoglobin is an example of a protein with quaternary structure, consisting of 4 polypeptide chains.
266
What is a prosthetic group in proteins?
Any group attached to a protein that is not made up of amino acids.
## Footnote
In haemoglobin, the heme group containing iron acts as the prosthetic group.
267
What is a conjugated protein?
A protein that has a prosthetic group added onto it.
## Footnote
Conjugated proteins play important roles in various biological processes.
268
List the types of bonds involved in maintaining protein structures.
* Hydrogen bonds
* Ionic bonds
* Disulfide bonds
## Footnote
These bonds are crucial for maintaining the unique shapes of proteins.
269
True or False: The secondary structure of proteins cannot be further folded.
False.
## Footnote
The secondary structure can be further folded to form the tertiary structure.
270
Fill in the blank: The _______ structure of a protein refers to its overall 3D shape formed by the folding of its secondary structure.
[tertiary]
271
What are the two main forms of secondary structure in proteins?
* Pleated sheet
* Alpha helix
## Footnote
These structures are key components of protein folding.
272
What is the primary structure of a protein?
The sequence of amino acids in a polypeptide chain
## Footnote
It is essential to state the word 'sequence' for clarity.
273
How is the order of amino acids in a protein determined?
By DNA
## Footnote
The specific order of amino acids influences bonding and protein folding.
274
What determines the final 3D shape and function of a protein?
The primary structure
## Footnote
The specific sequence of amino acids alters where bonds occur.
275
How many different amino acids can form the primary structure of proteins?
20
## Footnote
These amino acids combine to create polypeptide chains.
276
What type of reactions create the polypeptide chain?
Condensation reactions
## Footnote
These occur between amino acids to form peptide bonds.
277
What holds the amino acids in the polypeptide chain together?
Peptide bonds
## Footnote
These bonds are formed during the condensation reactions.
278
What structures can the secondary structure of a protein form into?
a helix and B pleated sheets
## Footnote
These structures are influenced by the sequence of amino acids.
279
What type of bonds hold the secondary structure in place?
Hydrogen bonds
## Footnote
These form between the carboxyl groups of one amino acid and the amine group of another.
280
Fill in the blank: The first structure that forms in the creation of a protein is the _______.
polypeptide chain
281
True or False: The primary structure of a protein is vital for determining its 3D shape.
True
## Footnote
The primary structure directly influences folding and function.
282
What are proteins made up of?
Proteins are large polymers made up of monomers called amino acids.
283
What are the four levels of structural arrangements in a protein?
Primary, secondary, tertiary, quaternary.
284
Where are protein polymer chains created?
On ribosomes in cells.
285
What is the role of the Golgi apparatus in protein processing?
Proteins are further folded and modified.
286
What is the monomer in proteins?
Amino acid.
287
How many different amino acids are there?
20.
288
What is the general structure of an amino acid?
A central carbon, an amine group (NH2), a hydrogen atom, a carboxyl group (COOH), and a variable group (R group).
289
What connects amino acids to form polypeptides?
Peptide bonds.
290
How do amino acids join together to form polypeptides?
Via condensation reactions.
291
What does the 'R' in the general structure of amino acids represent?
The variable group.
292
True or False: Proteins can only have one level of structural arrangement.
False.
293
What is the primary function of cellulose in plants?
To provide structural strength
## Footnote
Cellulose is located in the cell wall of plants and prevents cells from bursting if they take in excess water.
294
What type of monomers make up cellulose?
B-glucose monomers
## Footnote
Cellulose is the only polysaccharide made up of B-glucose monomers.
295
What type of bonds join the monomers in cellulose?
1,4 - glycosidic bonds
## Footnote
These bonds create straight chains, unlike 1-6 bonds which create branches.
296
What is the structure formed by parallel chains of B-glucose in cellulose?
Fibril
## Footnote
Fibrils align in parallel and are held together by hydrogen bonds.
297
What are the three key disaccharides?
* Maltose
* Lactose
* Sucrose
## Footnote
These are important for understanding carbohydrate structures.
298
What are the three key polysaccharides?
* Starch
* Glycogen
* Cellulose
## Footnote
Each serves a distinct purpose in storage and structure.
299
What is the function of glycogen in animals?
Glucose storage
## Footnote
Glycogen serves as a storage form of glucose in animals.
300
What is the function of starch in plants?
Glucose storage
## Footnote
Starch acts as the storage form of glucose in plants.
301
What property of cellulose makes it insoluble?
Large molecule size
## Footnote
This property prevents it from changing the water potential of a cell.
302
Why is cellulose considered a strong polysaccharide?
Due to the large number of hydrogen bonds
## Footnote
Hydrogen bonds in and between the fibrils contribute to its strength.
303
Fill in the blank: Monomers join together by _______ reactions to make polymers.
condensation
## Footnote
These reactions are crucial in the formation of larger carbohydrate structures.
304
True or False: Cellulose is soluble in water.
False
## Footnote
Cellulose's large size makes it insoluble, which is advantageous for cell water potential.
305
What is the structural arrangement of cellulose fibers?
Parallel chains held by hydrogen bonds
## Footnote
This arrangement provides structural integrity to plant cell walls.
306
What are the two isomers of glucose that exist?
* a-glucose
* B-glucose
## Footnote
These isomers have different structures and functions in carbohydrates.
307
What is glycogen?
The major carbohydrate storage molecule found in animal cells
## Footnote
Glycogen is primarily stored in liver and muscle cells.
308
Where is glycogen mainly stored in the body?
Liver and muscle cells
## Footnote
These cells ensure access to glucose for respiration and energy release.
309
How is glycogen formed?
From excess glucose that has been eaten and absorbed into the bloodstream
## Footnote
If more glucose is consumed than needed for respiration, it is converted into glycogen.
310
What is the primary function of glycogen in liver and muscle cells?
To ensure these cells have access to glucose to respire and release energy
## Footnote
Liver cells help remove toxins while muscle cells are responsible for movement.
311
What type of monomer makes up glycogen?
α-glucose
## Footnote
Glycogen is a polymer made from α-glucose monomers.
312
How are the monomers in glycogen joined together?
Via condensation reactions using 1,4 and 1,6-glycosidic bonds
## Footnote
This structure is similar to amylopectin in starch.
313
What is the key structural difference between glycogen and starch?
Glycogen contains more 1,6-glycosidic bonds and is more branched
## Footnote
This branching allows for more efficient glucose release.
314
Why is glycogen insoluble?
Because it is a large molecule
## Footnote
This property allows glycogen to be stored within cells without affecting water potential.
315
What advantage does the branched structure of glycogen provide?
A larger surface area for enzymes to attach
## Footnote
This allows glycogen to be hydrolysed into glucose more readily.
316
True or False: Glycogen is hydrolysed back into glucose more rapidly than starch.
True
## Footnote
This is essential for animals with higher metabolic rates.
317
Fill in the blank: Glycogen is even more branched than ______.
starch
## Footnote
This increased branching allows for faster glucose availability.
318
What is a primary reason animals need rapid access to glucose from glycogen?
To provide energy to run from a predator
## Footnote
Animals have a higher metabolic rate compared to other organisms.
319
What are the two polymers that make up starch?
Amylose and amylopectin
## Footnote
Starch consists of these two distinct structures which contribute to its overall function.
320
What type of bonds join the glucose monomers in amylose?
1,4 - glycosidic bonds
## Footnote
These bonds result in a spiral-shaped polymer structure.
321
What characteristic shape does amylose have?
Spiral-shaped
## Footnote
This spiral structure allows for compact storage of glucose.
322
What type of bonds join the glucose monomers in amylopectin?
1,4 and 1,6 - glycosidic bonds
## Footnote
The 1,6 bonds create branches in the structure.
323
What is the significance of the branched structure of amylopectin?
Provides a larger surface area for enzyme attachment
## Footnote
This enables more efficient hydrolysis back into glucose.
324
Why is starch insoluble in water?
It is a large molecule
## Footnote
This property allows starch to be stored within cells without affecting water potential.
325
What is the advantage of starch being insoluble?
It does not change the water potential of a cell
## Footnote
This prevents osmosis from occurring.
326
How does the structure of amylose contribute to its function?
It can be readily compacted
## Footnote
This compact nature is beneficial for storage.
327
Fill in the blank: Starch is readily hydrolysed back into glucose when plant cells are running low on _______.
glucose
## Footnote
This process is crucial for respiration in plant cells.
328
What is the chemical formula for glucose?
C6H12O6
## Footnote
Glucose is a vital monosaccharide involved in energy production and storage.
329
What are the two structural isomers of glucose?
* α-glucose
* β-glucose
## Footnote
Isomers have the same molecular formula but different structural arrangements.
330
What is the main function of glucose in biological systems?
Provides energy or forms structural support (cellulose) and energy storage molecules (glycogen and starch).
## Footnote
Glucose is a key energy source for cells.
331
What is the difference between α-glucose and β-glucose?
The hydrogen (H) and hydroxyl group (OH) on carbon 1 are in swapped positions.
## Footnote
This small change can significantly affect the polymers formed.
332
True or False: Isomers have the same structural arrangement.
False
## Footnote
Isomers differ in their structural arrangement despite having the same molecular formula.
333
Fill in the blank: Glucose can be polymerised to form _______.
cellulose, glycogen, starch
## Footnote
These polymers serve various functions including structural support and energy storage.
334
What type of biological molecules are monosaccharides?
Simple sugars
## Footnote
They are the building blocks of more complex carbohydrates.
335
What are polysaccharides?
Polymers made up of many monosaccharides
## Footnote
Polysaccharides are formed through condensation reactions.
336
What is the process by which polysaccharides are created?
Condensation reactions
## Footnote
This process is similar to the formation of disaccharides.
337
Name three key polysaccharides you need to learn.
* Starch
* Glycogen
* Cellulose
## Footnote
Understanding their structure and function is important.
338
What is the primary function of starch and glycogen?
Energy storage
## Footnote
Both serve as energy reserves for organisms.
339
What is the main function of cellulose?
Provides structural support
## Footnote
Cellulose is important for the integrity of plant cell walls.
340
Where is starch found?
In plants, not in animal cells
## Footnote
It is the major carbohydrate store in plants.
341
What is starch made from?
Excess glucose created during photosynthesis
## Footnote
When more glucose is produced than needed for respiration, it is converted to starch.
342
What type of glucose monomers make up starch?
a-glucose
## Footnote
Starch is a polymer specifically composed of a-glucose units.
343
How are the a-glucose monomers in starch joined together?
Via condensation reactions
## Footnote
These reactions form glycosidic bonds between the monomers.
344
What types of glycosidic bonds are present in starch?
* 1,4 - glycosidic bonds
* 1,6 - glycosidic bonds
## Footnote
These bonds refer to the carbon atoms they connect.
345
Fill in the blank: Starch is converted from glucose during _______.
[photosynthesis]
346
What are polysaccharides?
Polymers made up of many monosaccharides
## Footnote
Polysaccharides are formed through condensation reactions.
347
What is the process by which polysaccharides are created?
Condensation reactions
## Footnote
This process is similar to the formation of disaccharides.
348
Name three key polysaccharides you need to learn.
* Starch
* Glycogen
* Cellulose
## Footnote
Understanding their structure and function is important.
349
What is the primary function of starch and glycogen?
Energy storage
## Footnote
Both serve as energy reserves for organisms.
350
What is the main function of cellulose?
Provides structural support
## Footnote
Cellulose is important for the integrity of plant cell walls.
351
Where is starch found?
In plants, not in animal cells
## Footnote
It is the major carbohydrate store in plants.
352
What is starch made from?
Excess glucose created during photosynthesis
## Footnote
When more glucose is produced than needed for respiration, it is converted to starch.
353
What type of glucose monomers make up starch?
a-glucose
## Footnote
Starch is a polymer specifically composed of a-glucose units.
354
How are the a-glucose monomers in starch joined together?
Via condensation reactions
## Footnote
These reactions form glycosidic bonds between the monomers.
355
What types of glycosidic bonds are present in starch?
* 1,4 - glycosidic bonds
* 1,6 - glycosidic bonds
## Footnote
These bonds refer to the carbon atoms they connect.
356
Fill in the blank: Starch is converted from glucose during _______.
[photosynthesis]
357
What are disaccharides?
Two monosaccharides bonded together by a glycosidic bond formed by a condensation reaction.
358
What is a glycosidic bond?
A bond formed between two monosaccharides during a condensation reaction.
359
What is the result of the condensation reaction between glucose and glucose?
Maltose
360
What is the result of the condensation reaction between glucose and galactose?
Lactose
361
What is the result of the condensation reaction between glucose and fructose?
Sucrose
362
Fill in the blank: Disaccharides are formed by the _______ of two monosaccharides.
[bonding]
363
What reaction breaks down disaccharides back into monosaccharides?
Hydrolysis reaction
364
True or False: Hydrolysis involves adding a water molecule to break a bond.
True
365
In a glycosidic bond, which carbons are involved in a 1-4 glycosidic bond?
Carbon 1 and Carbon 4
366
What happens during a condensation reaction in the formation of disaccharides?
A water molecule is removed from the hydroxyl groups.
367
What are the three key disaccharides to remember?
* Maltose
* Lactose
* Sucrose
368
What is the main function of a glycosidic bond in carbohydrates?
To link monosaccharides together to form disaccharides.
369
What are the three main types of carbohydrates?
Monosaccharides, Disaccharides, Polysaccharides
## Footnote
These classifications are based on the number of sugar units.
370
Define monosaccharides.
Monomers of carbohydrates, soluble in water
## Footnote
Examples include glucose, galactose, and fructose.
371
What is the general formula for a monosaccharide?
CH₂nOn
## Footnote
Where n = the number of carbon atoms.
372
What are three common examples of monosaccharides?
Glucose, Galactose, Fructose
373
What are disaccharides?
Dimers of carbohydrates formed from two monosaccharides
## Footnote
Examples include maltose, sucrose, and lactose.
374
What are polysaccharides?
Polymers of carbohydrates made from many monosaccharides
## Footnote
Examples include starch, glycogen, and cellulose.
375
What is the function of monosaccharides?
To provide energy or serve as building blocks for larger molecules
376
What elements do all carbohydrates contain?
Carbon, Hydrogen, Oxygen (CHO)
377
True or False: Carbohydrates can provide structural support to plant cells.
True
378
Fill in the blank: Carbohydrates are key biological molecules that store _______.
energy
379
Name a larger carbohydrate that is a disaccharide.
Sucrose
## Footnote
Other examples include maltose and lactose.
380
What type of carbohydrates are starch and glycogen classified as?
Polysaccharides
381
What are the three main types of carbohydrates?
Monosaccharides, Disaccharides, Polysaccharides
## Footnote
These classifications are based on the number of sugar units.
382
Define monosaccharides.
Monomers of carbohydrates, soluble in water
## Footnote
Examples include glucose, galactose, and fructose.
383
What is the general formula for a monosaccharide?
CH₂nOn
## Footnote
Where n = the number of carbon atoms.
384
What are three common examples of monosaccharides?
Glucose, Galactose, Fructose
385
What are disaccharides?
Dimers of carbohydrates formed from two monosaccharides
## Footnote
Examples include maltose, sucrose, and lactose.
386
What are polysaccharides?
Polymers of carbohydrates made from many monosaccharides
## Footnote
Examples include starch, glycogen, and cellulose.
387
What is the function of monosaccharides?
To provide energy or serve as building blocks for larger molecules
388
What elements do all carbohydrates contain?
Carbon, Hydrogen, Oxygen (CHO)
389
True or False: Carbohydrates can provide structural support to plant cells.
True
390
Fill in the blank: Carbohydrates are key biological molecules that store _______.
energy
391
Name a larger carbohydrate that is a disaccharide.
Sucrose
## Footnote
Other examples include maltose and lactose.
392
What type of carbohydrates are starch and glycogen classified as?
Polysaccharides
