Unit 3 AOS 2 Flashcards
(186 cards)
1
Q
Who has the most important anabolic reactions?
A
The most important anabolic reactions of living organisms are those of autotrophic organisms
2
Q
What are reactions to autotrophic organisms undergo?
A
trap radiant energy of the sun & use it to build organic molecules in the process of photosynthesis
3
Q
Can heterotrophs undergo photosynthesis?
A
Heterotrophs cannot trap energy from the environment and they are entirely dependent on autotrophs for this.
4
Q
What similarity do both autotroph and heterotrophs have?
A
In contrast, both autotrophs and heterotrophs use similar catabolic reactions to release the chemical energy from organic molecules to fuel their cellular activities in the process of cellular respiration.
5
Q
What is photosynthesis?
A
Photosynthesis is the process of capturing light energy to power the production of glucose and oxygen from carbon dioxide and water. It is carried out by plants, algae & some bacteria.
6
Q
What is a photoautotroph?
A
A photoautotroph is an organism capable of undertaking photosynthesis.
7
Q
What is the word equation for photosynthesis?
A
6 carbon dioxide + 12 water —sunlight–> 1 glucose + 6 oxygen + 6 water
8
Q
What is important about leaves on a plant?
A
Leaves, which house the cells capable of carrying out photosynthesis, have the shape and structure that promotes this process.
9
Q
Features of leaves that help with photosynthesis?
A
- Flat shape with S.A. exposed to light
- Many stomata present provides access to CO2
- Thinness & presence of air spaces increases the diffusion rate
- Network of xylem vessels transports H2O
- Possess many chloroplasts to trap light energy
10
Q
What are the main cells in leaves that photosynthesis?
A
The main cells in leaves that photosynthesise are called mesophyll cells.
11
Q
What is inside mesophyll cells?
A
Inside mesophyll cells are large populations of chloroplasts (membrane bound organelle).
12
Q
What does chloroplast contain?
A
Chloroplasts contain the photosynthetic pigment known as chlorophyll, which is directly responsible for initiating photosynthesis by capturing light energy.
13
Q
Chloroplast structure
A
Chloroplasts are oval-shaped and have two membranes: an outer membrane and an inner membrane.
14
Q
Define thylakoid
A
Thylakoids are membrane-bound compartments inside chloroplasts which contain chlorophyll.
15
Q
Define Grana
A
Grana is a stack of thylakoids
16
Q
Define stroma
A
The stroma is the fluid-filled space outside the thylakoids.
17
Q
What is a cofactor?
A
Some enzymes require assistance from a cofactor to catalyse their reactions. A cofactor is a molecule that assists enzyme functioning.
18
Q
What are coenzymes?
A
Coenzymes are a subset of cofactors that are organic, non-protein molecules, with their role being to assist enzymes in catalyzing reactions.
19
Q
Do coenzymes change in reactions?
A
While the enzyme remains unchanged, the structure of the coenzyme is changed.
20
Q
Process of coenzymes
A
- the coenzyme binds to the active site, donates energy or molecules
- after the reaction, the coenzyme leaves the enzyme and is recycled by accepting more energy
- This is referred to as the cycling of coenzymes and is integral to certain biochemical processes.
21
Q
what are some common coenzymes?
A
- Adenine triphosphate
- Nicotine adenine dinucleotide (based on the vitamin niacin)
- Nicotine adenine dinucleotide phosphate (based on the vitamin niacin)
- Flavine adenine dinucleotide (based on the vitamin B12)
22
Q
loaded form of Adenine triphosphate?
A
ATP
23
Q
loaded form of Nicotine adenine dinucleotide?
A
NADH
24
Q
loaded form of Nicotine adenine dinucleotide
phosphate?
A
NADPH
25
loaded form of Flavine adenine dinucleotide?
FADH2
26
unloaded form of Adenine triphosphate?
ADP
27
unloaded form of Nicotine adenine dinucleotide?
NAD+
28
unloaded form of Nicotine adenine dinucleotide
phosphate?
NADP
29
unloaded form of Flavine adenine dinucleotide?
FAD
30
function of Adenine triphosphate?
Energy transfer
31
function of Nicotine adenine dinucleotide?
Transfer of electrons and protons (only cellular respiration)
32
function of Nicotine adenine dinucleotide
phosphate?
Transfer of electrons and protons (only photosynthesis)
33
function of Flavine adenine dinucleotide?
Transfer of electrons and protons
34
what does photosynthesis need to occur?
For Photosynthesis to occur plants need to be able to absorb sunlight.
35
How do plants absorb light?
Plants use pigments to absorb the light required.
36
Photosynthetic pigments include:
- Chlorophylls
- Carotenoids
37
What do chlorophylls do?
- absorb red & blue-violet light
- appear green (reflect green light).
- main photosynthetic pigment
38
What do carotenoids do?
- absorb blue-violet light
- appear orange, yellow or red.
39
What are the stages of photosynthesis?
- The light dependent reaction (D) which occurs in the thylakoid membranes of a chloroplast
- The light independent reaction (I) or Calvin Cycle which occurs in the stroma of a chloroplast
40
Where does the light dependent reaction occur?
Thylakoid (Grana) of chloroplasts
41
Input of the light dependent reaction?
- 12 Water (H2O) molecules
- 12 NADP+
- 12 ADP + Pi
42
Outputs of the light dependent reaction?
- 6 Oxygen (O2) molecules
- 12 NADPH
- 12 ATP
43
Energy transformation in the light dependent reaction?
The light-dependent reactions convert light energy into chemical energy.
44
What is the goal of the light dependent reaction?
The goal of the light-dependent reactions of photosynthesis is to collect energy from the sun and break down water molecules to produce ATP and NADPH.
45
Where is ATP and NADPH used in photosynthesis?
These two energy-storing molecules are then used in the light-independent reactions.
46
Summary steps of light dependent reaction?
- Sunlight excites an electron within chlorophyll.
- Water absorbed by a plant’s root hairs is split into O2 and H+ as it donates one electron to the chlorophyll.
- The excited electron and H+ ion from water lead to the production of the coenzymes NADPH and ATP.
- The oxygen is released out of the chloroplast, and the coenzymes are ready for the second stage of photosynthesis.
47
What do NADPH and ATP transfer?
NADPH transfers hydrogen ions while ATP transfers energy.
48
Where does the light independent stage occur?
Stroma of chloroplasts
49
Inputs of light independent stage?
- 6 Carbon dioxide (CO2) molecules
- 12 NADPH
- 12 ATP
50
Outputs of light independent stage?
- 1 Glucose (C6H12O6)
- 6 Water (H2O) molecules
- 12 NADP+
- 12 ADP + Pi
51
Basics of light independent stage?
- CO2 enters the Calvin Cycle & undergoes reactions powered by ATP and NADPH
- This leads to the formation of glucose, with water also being produced in this stage.
52
Summary of light independent stage
- CO2 collected from the stomata in leaves enters a cyclic reaction.
- The carbon, from CO2, undergoes reactions powered by ATP and NADPH to produce a series of carbon-based molecules.
- Eventually, a specific carbon molecule is reached that goes on to contribute to the formation of glucose, with water also being produced in this stage.
53
Overview of light-dependent stage
where light energy splits water molecules to produce ATP, NADPH, and oxygen. This stage occurs in the thylakoid membranes of the grana.
54
Overview of light-independent stage
where carbon dioxide is converted into organic molecules (glucose) using ATP and NADPH, and more water is produced. This stage occurs in the stroma, and is also known as the Calvin cycle.
55
What are the steps of the photosynthetic reaction under the control of?
All steps of the photosynthetic reaction are under the control of enzymes.
56
What is the main enzyme in photosynthesis?
crucial enzyme that is involved in the light-independent stage: ribulose bisphosphate carboxylase-oxygenase, also known as Rubisco
57
What is rubisco?
Rubisco is a very large enzyme made up of 16 polypeptide chains. It has many active sites requiring Mg2+ as a cofactor. It is the most abundant protein in leaves (and perhaps the planet).
58
Why is rubisco needed?
Plants cannot convert CO2 directly into glucose as it would waste too much energy, so the Calvin Cycle and the enzymes within it (e.g. Rubisco) are the most effective way to use CO2 to produce glucose.
59
What is the role of Rubisco?
the role of Rubisco can be summarised as binding CO, and fixing the carbon into the organic 3-PGA, thus initiating the Calvin cycle.
60
What does rubisco control?
Rubisco controls the first reaction in the light-independent stage of photosynthesis.
61
What is Rubiso responsible for?
Rubisco is responsible for the initial changes to carbon dioxide at the beginning of the Calvin cycle.
62
What does Rubisco do in the calvin cycle?
Rubisco catalyses carbon fixation during photosynthesis.
Facilitates the fixing of CO2 into 3-phosphoglycerate (3-PGA), thus initiating the Calvin cycle.
63
What is the problem with rubisco?
While effective most of the time, Rubisco can be flawed.
Sometimes, rather than using CO2 as a substrate, it uses O2 instead.
Without Rubisco-CO2 pairing, photosynthesis cannot proceed.
64
What happens when Rubisco binds to O2 instead?
When Rubisco binds to O2 instead, a different reaction called photorespiration occurs.
65
What does photorespiration cause?
- produces no glucose and also wastes more energy
- this negatively impacts a plant’s ability to grow, survive, and reproduce
66
What are the two key factors that influence with Rubisco can bind to CO2?
The two key factors that influence whether Rubisco binds CO2 or O2 are: temperature and substrate concentration.
67
What are the different substrates rubisco’s pathways?
- CO2 is the substrate of the Calvin cycle pathway
- O2 is the substrate of the photorespiration pathway.
68
How to substrate concentration influence rubisco?
- Plants aim to expose Rubisco to a high CO2 conc. & a low O2 conc. (to maximise photosynthesis).
- High substrate conc. increases the chance of it binding to an enzyme and undergoing a reaction.
- A greater concentration of oxygen in the cells leads to increased photorespiration.
69
How do plants maximise CO2 binding?
To maximise CO2 binding, plants leave their stomata open to allow CO2 to enter the plant, while O2 and water vapour simultaneously diffuse out of the plant.
70
What is the problem with leaving stomata open to allow CO2 to enter?
However, when a plant needs to conserve water, stomata close, causing the O2 produced during the light-dependent stage of photosynthesis to build up inside its cells.
71
How does temperature affect rubisco?
- At regular temperatures, Rubisco’s affinity for CO2 is far greater than that for O2.
- At higher temperatures, the affinity for O2 is higher, leading to Rubisco binding oxygen more often.
72
In what weather does photorespiration occur?
Photorespiration occurs more in hot and dry weather when Rubisco has a greater affinity for O2 and the conditions have caused stomata to close.
73
How do plants counter photorespiration?
To counter photorespiration, certain plants have evolved adaptations to increase the likelihood of Rubisco binding to CO2, thus increasing photosynthesis rates and improving plant health.
74
What are the different plant types?
The plant types with different strategies to counter photorespiration are C3, C4, and CAM plants.
75
How common are C3 plants?
Make up approximately 85% of plants on Earth.
76
How do C3 plants undergo photosynthesis?
Undertake the ‘normal’ photosynthesis that we already explored & possess no adaptations to reduce photorespiration.
77
What is Rubisco's role in C3 plants?
Rubisco is responsible for fixing carbon dioxide (into a 3-carbon molecule) during the Calvin Cycle and this all occurs within a single mesophyll cell (leaf cells).
78
Examples of C3 plants
Examples: all trees, cereals such as wheat and rice, and the majority of nuts, fruits, and vegetables.
79
When do C4 plants avoid photorespiration?
C4 plants avoid photorespiration during the first step of carbon fixation.
80
What stages are different in C4 and C3 plants?
The light-dependent stage is the same in C4 plants, while the light-independent stage is different.
81
Process of photosynthesis in C4 plants?
- In C4 plants CO2 is fixed (into a 4-carbon molecule) in an additional step in the biochemical pathway, by an enzyme that has a high affinity for CO2 and does not bind with O2. This occurs in a mesophyll cell.
- The fixed CO2 is then transferred to uniquely specialised cells (bundle-sheath cells) that later release the fixed CO2 to enter the Calvin Cycle with very little competition from O2.
82
How does the change in area reduce photorespiration in C4 plants?
Mesophyll cells are constantly pumping a source of CO2 into the bundle-sheath cells, so there is always a higher concentration of CO2 present for Rubisco rather than O2.
Therefore, photorespiration is minimised and photosynthesis is maximised.
83
What are the costs of C4 photosynthesis over C3 photosynthesis?
- ATP is required to for the initial step of carbon fixation.
- Therefore C4 plants use more energy than C3 plants.
84
Where is C4 photosynthesis advantage advantageous?
C4 photosynthesis is still advantageous in hot environments where C3 plants suffer from increased photorespiration.
85
Examples of C4 plants?
Examples: corn, sugarcane and several weed species.
86
How have CAM plants adapted?
- CAM plants (e.g. cactus & pineapple) have also adapted to decrease photorespiration compared to C3 plants.
- CAM plants have adapted to arid conditions, which allows a plant to photosynthesize during the day, but only exchange gases at night.
87
What stages differ in CAM plants C3 and C4 plants?
The light-dependent stage of photosynthesis in CAM plants is still identical to that of C3 and C4 plants, but the light-independent stage differs.
88
Process of photosynthesis in CAM plants?
- CAM plants have their stomata closed during the day (to prevent water loss). However this means that CO2 cannot enter.
- During the night the stomata are open, allowing CO2 to enter and be fixed in other compounds.
- This is then is stored inside vacuoles within the mesophyll cell until the daytime.
- CO2 is then released during the daytime and is free to enter the Calvin cycle in the same fashion as in C3 and C4 plants, leading to glucose production.
89
define Enzyme
an organic molecule, typically a protein, that catalyses (speeds up) specific reactions
90
Define saturation point
the point at which a substance (e.g. an enzyme) cannot receive more of another substance (e.g. a substrate)
91
Define limiting factor
a factor that prevents the rate of reaction from increasing
92
Define C3 plants
plants with no evolved adaptation to minimize photorespiration
93
Define C4 plants
plants that minimize photorespiration by separating the initial carbon fixation step and the remainder of the Calvin cycle over space
94
Define CAM plants
plants that minimize photorespiration by separating initial carbon fixation and the remainder of the Calvin cycle over time
95
Where is light required in photosynthesis?
Light is required for the light-dependent stage of photosynthesis.
96
What happens in photosynthesis light increases?
As light increases, the rate of photosynthesis increases - until a certain point. Increased rate of photosynthesis towards point X (Figure 1) is because the plant is exposed to greater light energy, which is required for photosynthesis to occur.
97
What happens to photosynthesis after light reaches a saturation point?
Increased rate of photosynthesis towards point X (Figure 1) is because the plant is exposed to greater light energy, which is required for photosynthesis to occur.
98
Why can't the rate of photosynthesis increase past the saturation point of light?
This maximum possible rate cannot increase any further as the enzymes within chloroplasts are operating at their full capacity.
99
Before the saturation point what is the limiting factor in light?
Before point X, light is the limiting factor as increasing light while keeping all other factors constant increases the reaction rate.
100
How does light influence the different types of plants?
Light influences C3, C4 & CAM plant types in the same manner. This is because the plant types have the same light-dependent reactions.
101
When does photosynthesis work the best for temperature and pH?
Photosynthesis requires many enzymes which function best at their optimal temperature and pH.
The rate of photosynthesis is greatest when the temperature matches the enzyme’s optimal temperature.
102
What is the rate of photosynthesis increase while working towards the optimum temperature?
The rate of photosynthesis increases toward the enzyme’s optimal temperature due to more frequent enzyme-substrate collisions.
103
After the optimum temperature what happens to photosynthesis rate?
However, above the optimal temperature, the enzymes begin to denature and are unable to function, causing a steep drop-off in photosynthesis rate.
104
When do photosynthesis occur the fastest in pH?
Enzymes function best at their optimal pH and photosynthesis occurs fastest under these conditions.
105
What happens to write photosynthesis above and below the optimum pH?
Above and below the optimal pH, enzymes denature. This means that a graph of pH against the rate of photosynthesis is more symmetrical than the graph of temperature.
106
How does temperature and pH affect the different types of plants?
C3, C4, and CAM plants are all impacted by temperature and pH as each pathway is heavily reliant on enzymes. Each plant type has evolved to be suited to their respective environments, meaning that while the general shape of the graph remains the same, the optimal temperature and pH values and ranges may differ between them.
107
What temperatures are the different plants optimal at?
In general, C4 and CAM plants are better adapted to hot and dry environments, whereas C3 plants are better suited to cooler temperatures.
108
How does carbon dioxide concentration impact photosynthesis right?
The rate of photosynthesis increases as CO2 concentration increases, but only up until point X where it starts to plateau.
109
What is the initial increase in photosynthesis due to increase carbon dioxide concentration due to?
The initial increase is due to chloroplasts having a higher concentration of CO2 molecules for the light-independent stage.
110
What is the plateau in photosynthesis rate after a certain carbon dioxide concentration increase?
Plateau is due to the enzyme-catalysed systems in the chloroplast being fully saturated & operating as fast as possible (or other limiting factors are involved).
111
What happens to plants when CO2 concentration is low?
When CO2 concentrations within plant cells are low, plants are susceptible to undertaking the wasteful process of photorespiration.
112
How have C4 and CAM plant adapted for carbon dioxide concentration?
C4 and CAM plants have evolved adaptations to counter photorespiration and expose Rubisco to greater levels of CO2.
113
How do C4 and CAM plants combat low carbon dioxide concentration over C3 plants?
Because of this, C4 and CAM plants are less susceptible to the impacts of low CO2 concentration on the rate of photosynthesis compared to C3 plants, which have no strategy to combat photorespiration.
114
How does water impact photosynthesis?
Water can also influence the rate of photosynthesis given it is an input in the light-dependent stage of photosynthesis and influences the opening and closing of stomata.
115
Comparison of C4, CAM and C3 plants in water availability?
Due to their evolved adaptations C4 and CAM plants are not affected by water availability unless it is extreme.
C3 plants are more susceptible to water loss and therefore reduced rate of photosynthesis.
116
What do inhibitors do to photosynthesis rate?
Competitive and non-competitive inhibitors can act on enzymes to reduce the rate of photosynthesis.
117
Can the effect of competitive inhibitor be overcome for photosynthesis?
The effect of competitive inhibitors can be gradually overcome if the substrate concentration is continually increased.
118
Can the effect of non-competitive inhibitor be overcome for photosynthesis?
Increasing substrate concentration does not reduce the effect of non-competitive inhibitors.
119
How do non-competitive inhibitor impact photosynthesis rate?
Non-competitive inhibitors reduce the rate of photosynthesis by binding to an enzyme at a site other than the active site, causing a change to the shape of the enzyme
120
How do inhibitor impact the C3, C4 and CAM plants?
As C3, C4 & CAM plants all use enzymes, they are all susceptible to the negative impact of inhibitors.
121
What happens to photosynthesis if you increase light?
Increases photosynthesis rate until a plateau is reached
122
What happens to photosynthesis if you increase temperature?
Increases rate when below the optimal, decreases rate when above optimal
123
What happens to photosynthesis if you increase pH?
Increases rate when below the optimal, decreases rate when above optimal
124
What happens to photosynthesis if you increase carbon dioxide concentration?
Increases photosynthesis rate until a plateau is reached
125
What happens to photosynthesis if you increase water?
Typically in excess in a plant. Still, as an input, we can say that increasing it will increase photosynthesis by avoiding the closing of stomata
126
What happens to photosynthesis if you increase enzyme inhibition?
Greater inhibitors decrease photosynthesis rate
127
What happens to photosynthesis if you decrease the Light?
Decreases photosynthesis rate
128
What happens to photosynthesis if you decrease the Temperature?
Decreases rate due to fewer enzyme-substrate collisions
129
What happens to photosynthesis if you decrease the pH?
Increases rate when above the optimal, decreases rate when below optimal
130
What happens to photosynthesis if you decrease the Carbon dioxide concentration?
Decreases photosynthesis rate
131
What happens to photosynthesis if you decrease the Water?
Can result in closed stomata and a lower CO, concentration, decreasing photosynthesis rate
132
What happens to photosynthesis if you decrease the Enzyme inhibition?
Fewer inhibitors increases photosynthesis rate
133
Differences in C3, C4, and CAM plants of light?
Same among all plants
134
Differences in C3, C4, and CAM plants of Temperature?
Affected in a similar pattern, with C4 and CAM plants better suited to hotter environments and C3 plants better suited to cooler environments
135
Differences in C3, C4, and CAM plants of pH?
All can be affected
136
Differences in C3, C4, and CAM plants of Carbon dioxide concentration?
C4 and CAM plants are less impacted by changes than C3 plants, due to their respective abilities to consistently expose Rubisco to COz
137
Differences in C3, C4, and CAM plants of Water?
C4 and CAM plants are less impacted by changes than C3 plants, due to their respective abilities to consistently expose Rubisco to COz
138
Differences in C3, C4, and CAM plants of Enzyme inhibition?
All can be affected
139
What is CRISPR?
CRISPR are detectable sequences of DNA that act as an adaptive immune system within prokaryotes such as bacteria.
140
What is Cas9?
Cas9 is an endonuclease that can cut DNA.
141
what can the CRISPR Cas9 undergo?
Therefore, Cas9 can be instructed by CRISPR to target specific DNA recognition sites, altering the DNA.ns
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how can CRISPR-Cas9 technology be used in plants?
CRISPR-Cas9 technology can therefore be utilised to genetically modify an organism’s genome.
143
How does modifying an organisms genome improve the plant?
This can result in an improved or desired phenotype.
The new and improved genetically modified organism (GMO) can then adapt to and survive in its environment more effectively.
144
Why improve photosynthetic efficiencies and crop yields?
- Most agricultural crops are C3 plants that have no adaptations to limit photorespiration.
- By 2050, it is predicted that agricultural productivity will need to almost double to cope with the demands of the rising global population.
- Climate change, however, has the potential to significantly reduce crop yields globally.
- Arable land (land capable of being ploughed and used to grow crops) is already largely exhausted and emissions from land use (e.g. clearing more land for agriculture) releases greenhouse gases into the atmosphere.
- Agricultural yields need to increase while using the same amount of land. This is where gene editing comes in.
- Editing crop genomes could enable farmers to maximise crop productivity without clearing any additional land.
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CRISPR-Cas9 potential changes to crops?
- Disease resistance
- Chemical resistance
- Plant oganelles
- Production enhancement
- Calvin cycle
- Physical tolerance
146
what can CRISPR-Cas9 potential changes to Production enhancement do?
- Longer shelf life
- Improve nutritional value
- Bioactive compounds
147
what can CRISPR-Cas9 potential changes to Calvin cycle do?
- Modify activity of other Calvin cycle enzymes
- Modify Rubisco's activity
- Change C3 plants to C4 or CAM
- Introduce alternative routes to photorespiration
148
what can CRISPR-Cas9 potential changes to Physical tolerance do?
- Drought tolerance
- Heat stress tolerance
- Frost tolerance
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what can CRISPR-Cas9 potential changes to Disease resistance do?
- Immunity against viruses
- Immunity against bacteria
150
what can CRISPR-Cas9 potential changes to Chemical resistance do?
- Greater herbicide resistance
- Greater pesticide resistance
151
what can CRISPR-Cas9 potential changes to Plant oganelles do?
- Increase chloroplast efficiency
- Adjust stomata to improve CO, uptake
- Improve light capture in chloroplasts
152
what does CRISPR-Cas9 aim to do engineer in plants?
Aim is to use CRISPR-Cas9 technology to engineer more productive crop species.
Engineer crops that bypass photorespiration, somewhat mimicking the function of C4 and CAM plants.
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how does CRISPR-Cas9 maximise photosynthesis?
- Targeting Rubisco’s function directly
- Editing the function of chloroplasts to make them more efficient
- Targeting stomata to reduce the impacts of water stress
- Increasing crop tolerance for harsh physical conditions such as drought, frost, disease, or the chemicals used in farming.
154
What is the potential for CRISPR-Cas9 maximising photosynthesis?
The potential of CRISPR-Cas9 technologies to improve the agricultural industry is huge, given that virtually any plant DNA can be altered.
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What is the current reality for CRISPR-Cas9 maximising photosynthesis?
Currently, CRISPR-Cas9 applications mostly apply to research and development. These applications must undergo rigorous checks to determine whether they adhere to Australian GMO standards and regulations before being made available for public consumption.
156
is cellular respiration necessary?
Vital for the survival of all organisms
157
what does cellular respiration do?
Allows cells to break down large molecules (e.g. glucose) to produce the high-energy molecule ATP
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what are the two pathways of cellular respiration?
Two biochemical pathways exist (Aerobic respiration and Anaerobic fermentation)
159
what are the difference between the pathways of cellular respiration?
The main difference between the pathways is the presence or absence of oxygen. Aerobic cellular respiration requires oxygen, whereas anaerobic fermentation does not.
160
goal of cellular respiration?
GOAL: produce ATP (usable, free energy for the cell)
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define Aerobic Cellular Respiration
Aerobic Cellular Respiration is respiration in the presence of oxygen where glucose is broken down to carbon dioxide and water and transfers part of its energy to ATP.
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word equation of Aerobic Cellular Respiration
1 glucose + 6 oxygen ---> 6 carbon dioxide + 6 water + 30 or 32 ATP energy
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define mitochondria
an oval shaped organelle made up of double membranes (outer and inner membrane) and the site of the second and third stages of aerobic respiration.
164
define Cristae
the folds of the inner membrane and the site of the electron transport chain
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define matrix
protein rich fluid inside the cristae and the site of the Krebs cycle
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three stages of aerobic respiration?
1. Glycolysis
2. The Krebs Cycle
3. The Electron Transport Chain.
167
can biochemical pathways occur without enzymes and coenzymes?
Without enzymes and coenzymes the biochemical pathways leading to the production of ATP in respiration would not be possible.
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what do coenzymes cycle between?
Coenzymes help to cycle between and loaded and unloaded states.
Coenzymes are unloaded in reactions that need extra energy and become loaded in reactions that produce energy. This ensures that coenzymes can always be efficiently recycled.
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key coenzymes in cellular respiration
Three key coenzymes in cellular respiration are ADP, NAD+ and FAD.
170
unloaded enzymes in cellular respiration
Unloaded coenzymes included (ADP, NAD+, FAD, CoA)
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loaded enzymes in cellular respiration
loaded coenzymes include (ATP, NADH, FADH2, acetyl-CoA).
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key enzymes in cellular respiration
- Pyruate kinase
- Citrate synthase
- Cytochrome c oxidase
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Pyruate kinase role in cellular respiration
Catalyses the final step in glycolysis to produce pyruvate and ATP
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Citrate synthase role in cellular respiration
First enzyme in the Krebs cycle that allows recycling of acety-COA
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Cytochrome c oxidase role in cellular respiration
Key enzyme complex of the electron transport chain that attaches H+ and e- to and ATP oxygen to produce water
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features of glycolysis?
- Occurs in the cytosol where enzymes catalyse each step
- Proceeds whether O2 is present or not
- Glucose gets broken down to two pyruvate molecules (3 carbon)
- 2 ATP and 2 NADH are also created
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location of glycolysis?
cytosol
178
inputs of glycolysis?
- 1 glucose (C6H1206)
- 2 ADP + 2 Pi
- 2 NAD+ + 2 H+
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outputs of glycolysis?
- 2 pyruvate
- 2 ATP
- 2 NADH
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what is the step between glycolysis and Krebs cycle?
Link reaction
1. This reaction transports the Pyruvate made in the cytoplasm into the mitochondria, forming Acetyl-CoA.
2. The Acetyl-CoA will then go into the Krebs cycle, which takes place in the mitochondria.
3. Since there were 2 pyruvates formed in glycolysis, 2 Acetyl CoA's are formed in total unlikely particularly
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what is the Krebs cycle also known as?
CITRIC ACID CYCLE
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features of the Krebs cycle?
- Occurs in the inner matrix of mitochondria
- This stage generates lots of high energy coenzymes which are electron and proton carriers (NADH and FADH2)
- For every one acetyl-CoA molecule 2 CO2 and 1 ATP are produced
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location of Krebs cycle?
the mitochondrial matrix
184
inputs of Krebs cycle?
- 2 acetyl-CoA
(derived from 2 pyruvate)
- 2 ADP + 2Pi
- 6 NAD+ + 6H+
- 2 FAD + 4 H+
185
outputs of Krebs cycle?
- 4 carbon dioxide (CO2)
- 2 ATP
- 6 NADH
- 2 FADH
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