AOS2 Flashcards
1
Q
what are biomechanical reactions
A
reactions occurring in cells that lead to the formation of a product from a reactant.
2
Q
what are reactants
A
substances (molecules/elements) that are changed from a chemical reaction
3
Q
what are products
A
a compound produced from the reactants reacting (from the chemical reaction)
4
Q
what are biomechanical pathways
A
a series of linked biomechanical reactions
5
Q
what is metabolism
A
The total activity of the reactions of all biochemical pathways in a living organism
6
Q
what are substrates
A
a compound on which an enzyme acts
7
Q
what are the types of biomechanical pathways
A
- anabolic pathways
- catabolic pathways
8
Q
what are anabolic pathways (anabolism)
A
These pathways turn simple molecules into more complex ones
9
Q
what happens to the energy levels in the anabolic pathways
A
anabolic pathways are energy-requiring or endergonic
10
Q
what are catabolic pathways (catabolism)
A
These pathways break down complex molecules into more simple ones
11
Q
what happens to the energy levels in catabolic pathways
A
Catabolic pathways are energy-releasing or exergonic
12
Q
example of anabolic pathway
A
Photosynthesis, where glucose molecules are synthesised from carbon dioxide and water using radiant energy from the Sun
13
Q
example of catabolic pathway
A
Aerobic cellular respiration, where glucose molecules are broken down into carbon dioxide and water molecules
14
Q
are enzymes proteins
A
yes most enzymes are proteins
15
Q
what are catalysts
A
factors that increase rate of reaction
16
Q
are all catalysts enzymes?
A
no, enzymes are all catalysts but not all catalysts are enzymes
17
Q
are enzymes specific to reaction?
A
yes, each different reaction will be catalysed by a specific enzyme
18
Q
what is activation energy
A
minimum amount of energy required to initiate a chemical reaction
19
Q
what is the active site
A
region of an enzyme that binds temporarily with the specific substrate of the enzyme
20
Q
what do enzymes do to speed up a reaction
A
lower activation levels
21
Q
how do enzymes lower activation levels (2)
A
- Influence the stability of bonds in the reactants
- Providing an alternative reaction pathway;
22
Q
how do enzymes bind to substrates (2 steps)
A
- the enzyme and substrate with join to form the E-S complex (when it binds to the active site)
- the substrate forms weak bonds with particular amino acid residues (in the protein) at the active site.
23
Q
what are the 3 types of enzyme activity (ways they can bind to substrates)
A
- substrate specificity
- bond specificity
- group specificity
24
Q
what is substrate specificity (enzyme activities)
A
they catalyse one particular substrate only
25
what is bond specificity (enzyme activities)
they act only on one kind of chemical bond (only peptide bonds)
26
what is group specificity (enzyme activities)
they act only on particular functional groups present as part of the substrate molecule (-COOH, or -OH)
27
what are coenzymes
an organic molecule that acts with an enzyme to alter the rate of a reaction
28
what are cofactors
a non-protein molecule or ion that is essential for the normal functioning of some enzymes
29
are cofactors and coenzymes the same
no, coenzymes are cofactors but not all cofactors and coenzymes
30
what are inorganic cofactors
cofactors that do not contain carbon and include metal ions such as magnesium or copper
31
what are organic cofactors
small non-protein organic molecules that are essential for the function of particular enzymes
32
what are the 2 types of organic cofactors
- prosthetic groups
- coenzymes
33
prosthetic groups are ......
cofactors that are tightly bound to an enzyme and are essential for it to function as a catalyst.
34
what is the difference between prosthetic groups and coenzymes
prosthetic groups are tightly bound to an enzyme, whereas, coenzymes are loosely bound
35
what are the 5 main coenzymes we focus on
- NAD
- NADP
- FAD
- ATP
- CoA (coenzyme A)
36
what are the 2 roles of coenzymes to assist enzymes
- transfers of atoms or groups of atoms, such as hydrogens, phosphate groups and acetyl groups
- energy transfers
37
what are the 2 forms coenzymes can be in (interconvertible forms)
- loaded and
- unloaded
38
loaded coenzymes main info
they are high in energy and have a group that can be transferred. In simple they are electron donors
39
unloaded coenzymes main info
they have low energy, and accept groups. In simple they are electron acceptors
40
what are the 3 factors that impact enzyme activity
- temperature
- pH
- substrate concentration
41
summary of what happens with varied temperatures for enzyme activity (rate of reaction)
when temperature first increases, the reaction rate also increases. This is because the reactants absorb heat energy and move faster, allowing them to collide and overcome the activation energy.
However, in enzyme-catalysed reactions, this increase only occurs up to the optimum temperature, after which the rate decreases, due to denaturation and the change in enzyme structure.
42
summary of what happen with varied pH for enzyme activity (rate of reaction)
As pH increases or decreases from optimum pH, the rate of reaction and the activity of an enzyme decreases.
43
do each enzyme have different optimum pH
yes, each with have different so different graphs with rate of reaction
44
summary of what happen with varied substrate concentration for enzyme activity (rate of reaction)
the rate of reaction increases with increasing substrate concentration ā but only up to a point. Beyond this, any further increase in substrate concentration produces no significant change in reaction rate (active sites are all occupied)
45
what are enzyme inhibitors
substances that prevent the normal action of an enzyme and therefore slow the rate of enzymes-controlled reactions
46
what are the 2 types of inhibition
reversible inhibition
irreversible inhibition
47
what are the 2 types of reversible inhibition
- competitive inhibition
- non-competitive inhibition
48
what is competitive inhibition
inhibition in which a molecule binds to the active site of a molecule instead of the usual substrate
49
why does competitive inhibition slow down reaction rate
inhibitor molecules prevent the formation of the EāS complexes (as active site is partially occupied)
50
what is non-competitive inhibition
inhibition in which a molecule binds to the allosteric site of an enzyme causing a conformation change in the active site
51
is the active site and an allosteric site the same?
no, allosteric site is somewhere on the enzyme but not the active site itself
52
why does non-competitive inhibition slow down reaction rate
as the binding of the inhibitor to the allosteric site changes the shape of the enzyme's active site the E-S complex cannot form
53
what is irreversible inhibition
occurs when a specific molecule can form a strong covalent bond with an enzyme at its active site, so that the normal substrate is permanently blocked from accessing the active site
54
what are common irreversible inhibitors?
Heavy metals
55
what are 3 things that the regulation of rates of reaction does
- prevent waste, such as would occur if pathway products were made in excess of cell requirements
- prevent the build-up in cells of products to potentially harmful levels
- prevent depletion of substrates
56
what are the 2 types of regulation
- allosteric regulation
- feedback regulation
57
what is allosteric regulation
control of the reaction rate of enzymes through conformational changes in enzymes. This occurs when a regulator molecule binds to the allosteric site
58
what can the regulator molecules be (allosteric regulation)
- allosteric inhibitors
- allosteric activators
59
what does allosteric inhibitors do
their binding produces a change of shape in the enzyme that stops enzyme activity; they act like an OFF switch
60
what does allosteric activators do
the shape change resulting from the binding produces an increase in enzyme activity; they act like an ON switch
61
what is feedback regulation
the end product of a metabolic pathway acts as an inhibitor of the key enzyme that catalyses the first step in a pathway.
62
what is photosynthesis
the process by which plants use the radiant energy of sunlight trapped by chlorophyll to build carbohydrates (glucose) from carbon dioxide and water.
63
what is the photosynthesis equation
6 carbon dioxide + 6 water = glucose + 6 oxygen (gas)
64
what are the 2 stages of photosynthesis
- light-dependent stage
- light-independent stage
65
what is the function of the light dependent stage
to transform sunlight energy that is captured by chlorophyll into the chemical energy of loaded coenzymes
66
what is the function of the light independent stage
to assemble simple inorganic carbon dioxide molecules into more complex organic glucose molecules
67
what is another name for the light independent stage
Calvin cycle
68
where does photosynthesis occur
chloroplasts, in the chlorophyll pigment inside (in the cytosol of plants)
69
what does chloroplasts enable a plant to do
capture the radiant energy of sunlight, bringing it into cells as the starting point of photosynthesis
70
what are the 3 main things inside the chloroplasts (not including chlorophyll)
thylakoids
grana
stroma
71
what are thylakoids
flattened membranous sacs in chloroplasts that contain chlorophyll
72
what is the grana
stacks of thylakoids are known as grana, where a singular stack is a granum
73
what is stroma
fluid inside the chloroplasts, containing the enzymes that are involved in calvin cycle
74
what does the light dependent stage involve
involved in the capture of sunlight and the transformation of its energy to the chemical energy of loaded coenzymes, NADPH and ATP.
75
where is the light dependent stage occur (c3)
thylakoid (within the grana)
76
what are the 3 inputs in the light dependent stage
- water
- ADP + Pi
- NADP+
77
what are the 3 outputs of the light dependent stage
- oxygen
- ATP
- NADPH
78
summary of what happens in light dependent stage
the energy caught by the chlorophylls make the electrons have high energy (excited) and the splitting of water molecules gives H+ ions (protons).
This then allows NADPH to form as well as ATP
79
what do the chloroplasts have after the light dependent stage
a supply of high-energy loaded ATP molecules
a supply of high-energy loaded NADPH coenzymes that can act as donors of hydrogen ions and electrons
80
light dependent equation
water + 18ADP + NADP into 6O2 + 18ATP + NADPH
81
what happens in the light independent stage
inorganic carbon dioxide molecules (CO2) are built into energy-rich reduced organic molecules, such as glucose (C6H12O6).
82
where does the light independent stage occur
the stroma
83
what is required for the light independent stage
Rubisco, and the NADPH (donate H and e-) and ATP (energy source) from the previous stage
84
what are the 3 inputs of the light independent stage
- ATP
- NADPH
- CO2
85
what are the 3 outputs of the light independent stage
- ADP + Pi
- NADP+
- Glucose
86
summary of what happens in light independent stage
inorganic carbon is converted in organic CO2 thru carbon fixation
NADPH donate hydrogens and electrons as molecules are reduced to higher energy levels
ATP supplies energy for anabolic steps
87
what are the 3 types of plants
C3
C4
CAM
88
why are there different types of plants
they are categorised into how they fix carbon into glucose
89
how do C3 plants carry out the Calvin Cycle
These plants carry out the original Calvin Cycle, using Rubisco, and are prone to photorespiration
90
what are optimal conditions for C3 plants
moist and cool conditions
91
how do C3 plants use RuBisco
use the Rubisco enzyme to fix inorganic carbon dioxide from the air and it enters the Calvin cycle joined to a carrier molecule (RuBP)
92
where does the Calvin Cycle take place in C3 plants
in the stroma of the leaf mesophyll cells
93
Photorespiration definition
a process in which plants take up oxygen rather than carbon dioxide in the light, resulting in photosynthesis being less efficient. (Rubisco takes up O2 instead of CO2)
94
what does rubisco normally do
the critical enzyme in C3 plants that brings carbon dioxide from the air into the Calvin cycle where the glucose is made
95
when does photorespiration occur
rubisco binds oxygen rather than carbon dioxide
96
does photorespiration make glucose
nooooo
97
why will Rubisco bind to oxygen instead of carbon dioxide
the active site can readily accommodate the oxygen molecules as well as the carbon dioxide molecules, so the two different molecules are in competition for the active site of Rubisco.
98
2 ways photorespiration arise in C3 plants (increase amount)
- temperature increases
- conditions dry out
99
why does photorespiration increase as temperature increases
the ability of the Rubisco enzyme to distinguish between carbon dioxide and oxygen decreases and, as a result, Rubisco will increasingly bind oxygen.
100
why does photorespiration increase as conditions dry out
C3 plants close their stomata to prevent water loss. This closure blocks the entry of carbon dioxide needed as input to the Calvin cycle and limits the exit of oxygen produced
creating a high oxygen low CO2 environment inside the mesophyll cells
101
how do C4 plants carry out the Calvin Cycle
carry out an adapted Calvin cycle, in which carbon fixation and glucose production occur in different cells
102
what are optimal conditions for C4 plants
These cells will thrive in warm and tropical regions
103
what anatomy changes are present in C4 plants (compared to C3 and CAM)
- bundle sheath cells have chloroplasts
- mesophyll cells that are arranged in a close association around the bundle sheath cells
104
where do the two processes occur in C4 plants
leaf mesophyll cells and bundle sheath cells
105
what happens in the first process in C4 plants (light dependent stage)
Carbon dioxide is converted into malic acid, in the mesophyll cells
PEP carboxylase catalyses the binding of carbon dioxide to an acceptor molecule (malic acid) (this is called carbon fixation)
106
what enzyme is used in the first step of C4 plants in photosynthesis
PEP carboxylase
107
why is PEP carboxylase used instead of RuBisco (C4)
It cannot bind to oxygen so photorespiration cannot happen
108
what happens in the second process of the C4 plants
Calvin cycle (glucose production) occurs in the bundle sheath cells
produce a steady supply of carbon dioxide from the breakdown of malic acid that raises the carbon dioxide concentration in their leaves. This allows the RuBisco in the bundle sheath cells to bind only to CO2
109
how do CAM plants carry out the Calvin Cycle
two stages of the Calvin cycle occurring at different times
110
what are optimal conditions for CAM plants
thrive in hot and arid environments, that are exposed to droughts
111
when does carbon fixation happen in CAM plants
at night (stomata are open)
112
when does the Calvin cycle happen in CAM plants
in the day (when the stomata are closed)
113
where do photosynthesis processes occur in the CAM plants
mesophyll cells
113
does CAM plants use PEP carboxylase or Rubisco initially
PEP carboxylase
114
what happens to the malic acid produced in CAM plants when it is night time
it is stored in vacuoles waiting for the stomata to close (day time)
115
what 3 things will make RuBisco work most efficiently
- carbon dioxide levels in leaves are high
- oxygen levels are low (as happens when water is freely available)
- when temperatures are moderate.
116
what are the 4 main factors that affect the rate of photosynthesis
- the amount of light reaching their leaves
- the temperature of the environment
- the availability of water
- the concentration of carbon dioxide
117
what is a limiting factor
any environmental condition that restricts the rate of biochemical reactions in an organism.
118
what happens to the rate of photosynthesis as light intensity increases
increases as light intensity increases, until it reaches a maximal point.
119
what is the light saturation point
the point where further increases in light intensity have no effect and the rate of photosynthesis stays constant
120
why does increased light intensity increase the rate of photosynthesis
more chlorophylls are energised
121
what does too little or too much water do to the rate of photosynthesis
rate of photosynthesis declines and then stops because closed stomata prevent the uptake of carbon dioxide needed for the Calvin cycle
122
what does waterlogging do to the rate of photosynthesis
the rate of photosynthesis will also decline and stop because the lack of oxygen for cellular respiration in root cells stops water uptake
123
what happens to the rate of photosynthesis as temperature increases
As the ambient temperature is increased, the rate of photosynthesis also increases due to an increase in collisions between the reactants and the enzymes involved in photosynthesis. Eventually, as the heat passes a certain threshold, the enzymes start to denature, in which the tertiary structure of an enzyme is lost. This causes the rate to again decrease.
124
what happens to the rate of photosynthesis as CO2 concentration increases
the rate of photosynthesis will increase until it levels off due to limiting factors
125
does CO2 concentration impact the light dependent stage and why
no, because CO2 is not apart of the reaction
126
what is cellular respiration
the process of converting chemical energy into a useable form by cells, typically ATP.
127
what are the 2 types of cellular respiration
aerobic and anaerobic
128
what is the equation for aerobic cellular respiration (without coenzymes)
glucose + oxygen arrow carbon dioxide + water + ATP
129
how many ATP does aerobic respiration make
30-32, 36-38 in optimal conditions
130
what are the 3 steps of aerobic cellular respiration
1. glycolysis
2. Krebs cycle
3. electron transport chain
131
what is the main (broad) thing that happens in glycolysis
glucose is broken down into pyruvate
132
what is the main (broad) thing that happens in Krebs cycle
makes a supply of energy-rich loaded coenzymes
133
what is the main (broad) thing that happens in the electron transport cycle
transfers energy from electrons supplied by loaded coenzymes to make ATP.
134
where does glycolysis occur
cytosol
135
how much ATP is produced from glycolysis
2
136
what are the 3 inputs in glycolysis
glucose, 2x (ADP + Pi) and 2x (NAD+)
137
what are the 4 outputs in glycolysis
2x (pyruvate), 2x ATP, 2x (NADH) and two hydrogen ions (protons)
138
where does the Krebs cycle and electron transport chain occur
mitochondria
139
where specifically does the Krebs cycle occur
the matrix
140
what is the matrix of the mitochondria
gel like solution within their inner membrane
141
where specifically does the electron transport chain happen
the cristae
142
what does cristae do
It folds in the inner membrane of the mitochondria, it hold enzyme
143
what happens in between glycolysis and Krebs cycle
pyruvate oxidation
143
what in summary happens in pyruvate oxidation
pyruvate loses a C and an H atom, forming a 2C acetyl group that is delivered to the Krebs cycle by coenzyme A.
144
what are the 2 coenzymes that are becoming high in energy in the Krebs cycle
FAD+ and NAD+
145
what are the 4 inputs in Krebs cycle and pyruvate oxidation
2 x (acetyl CoA (acetyl groups)), 6 x (NAD+), 2 x (FAD) and 2 x (ADP + Pi)
146
what are the 4 outputs in Krebs cycle and pyruvate oxidation
4 x (CO2), 6 x (NADH), 2 x (FADH2) and 2 x (ATP)
147
detailed electron transport chain info
Electrons are transferred along enzyme complexes
The first input of high-energy electrons to the ETC comes from loaded NADH coenzymes.
FADH2 also donates its high-energy electrons to an acceptor, but further down the chain.
Oxygen accepts electrons and hydrogen ions, forming water
148
how is so much ATP produced in the ETC
As electrons transfer from one enzyme complex to the next, the energy released is ultimately used to power the production of ATP from ADP and Pi.
149
what are the 4 inputs of ETC
6 (oxygen)
26-28 (ADP + Pi)
10 (NADH)
2 (FADH2)
150
what are the 4 outputs of ETC
6 (water)
26-28 (ATP)
10 (NAD+)
2 (FAD)
151
which process of aerobic cellular respiration needs oxygen
electron transport chain
152
what is anaerobic respiration/fermentation
processes that occur without the presence of oxygen, producing a net of 2 ATP molecules
153
when does anaerobic fermentation occur in humans
occurs in human skeletal muscle cells when the supply of oxygen to the cells by aerobic cellular respiration cannot keep up with their demand for ATP.
154
where does anaerobic fermentation take place
the cytosol
155
is the rate of ATP production in anaerobic fermentation higher lower or similar to aerobic respiration
much faster, this is why it is able to produce enough ATP
156
what are the 2 anaerobic fermentation pathways
- alcohol (ethanol) fermentation
- lactic acid fermentation
157
what are the 2 processes that occur in both anaerobic fermentation pathways
glycolysis
short add on stage
158
is glycolysis the same in aerobic and anaerobic cellular respiration
yes
159
what happens in the add on stage for lactic acid fermentation
pyruvate, ADP and NADH is turned into ATP, lactic acid and NAD+
160
what happens in the add on stage for alcohol fermentation
alcohol is created, NAH+ is regeneraed for glycolysis again
161
what are the inputs and outputs of the alcohol fermentation
pyruvate, NADH, ADP
ethanol, CO2, NAD+ 2ATP
162
what fermentation does yeast and animals use
animals use lactic acid
yeast uses alcohol
163
what 3 factors affect the rate of cellular respiration
temp
oxygen concentration
glucose concentration
164
glucose concentration affecting cellular respiration summary
an increase in glucose concentrations leads to an increase in the rate of cellular respiration. This rate eventually levels off from rate-limiting factors
165
oxygen concentration affecting cellular respiration summary
As oxygen concentration increases, so does the rate of cellular respiration. This eventually levels off due to other factors limiting the rate.
166
what is biomass
the organic material from plants and animals; it is a renewable source of energy.
167
what is biofuel
Biofuels are any fuel source derived from biomass.
168
what is food vs fuel (biofuel sustainability)
world's population expected to increase, there needs to be a balance between increased production of biofuels and food availability
169
what is land requirements (biofuel sustainability)
To meet the 2060 target for biofuel production it is estimated an additional 100 million hectares of land will be required
170
what is energy efficiency (biofuel sustainability)
Creating biofuels from feedstocks is currently an inefficient process. The energy required to produce and then collect the raw materials required is far greater than the fuel produced
