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Flashcards in Photosynthesis and Respiration Deck (64):

What are the two types of respiration?

1. Aerobic: requires oxygen, produces water and ATP
2. Anaerobic: Absence of oxygen, produces lactate (in animals) and ethanol + CO2 (in plants), small amount of ATP produced


What are the four stages of aerobic respiration and where do they take place?

1. Glycolysis - cytoplasm
2. Link reaction - matrix (mitochondria)
3. Krebs Cycle - matrix (mitochondria)
4. Oxidative Phosphorylation/ETC - cristae (mitochondria)


Explain briefly the process of glycolysis

1. Phosphorylation of glucose (6C)
2. So 1 molecule of Glucose Phosphate is produced (6C)
3. This splits into two Triose Phosphate molecules (3C each)
3. For formation of pyruvate (3C) and formation of reduced NAD (by NAD collecting H+ ions)
4. Total production 4 ATP / net production 2 ATP


What is the net production of ATP in glycolysis?

2 ATP molecules released


Explain the Link Reaction

1. Pyruvate molecules produced in glycolysis are actively transported from cytoplasm to matrix
2. The pyruvate (3C) is oxidised by removing hydrogen
3. This hydrogen is accepted by NAD to from reduced NAD
4.Acetyl group (2C) formed from pyruvate combines with co enzyme A to produce acetylcoenzyme A
5. A CO2 molecule is formed


What is the equation for the Link Reaction?

Pyruvate + NAD + CoA > acetyl CoA + reduced NAD + CO2


Summarise the Krebs Cycle

1. Acetylcoenzyme A combines with a 4-carbon molecule to form a 6 carbon-molecule
2. NAD is reduced to NAD and CO2 is released causes a %-carbon molecule to form
3. x2 NAD & x1 FAD is reduced again to form reduced x2 NAD & x1 FAD and a single molecule of ATP is produced


Apart from respiration, give three uses of ATP in a liver cell

- Active Transport
- Mitosis


Explain what happens to pyruvate in anaerobic conditions

In animals: forms lactate
In plants; forms ethanol and CO2
Both: use reduced NAD regenerated to produce NAD so glycolysis can be continued and small amounts of ATP can be produced


Name the four products of the Krebs Cycle

1. ATP
2. CO2
3. Reduced NAD
4. Reduced FAD


Describe the part played by the inner membrane of the mitochondrion in producing ATP

- Electrons are transferred down ETC which provides energy top take protons into space between membranes.
- Protons then pass back through membrane (through ATP Synthase)into matrix and energy is used to combine ADP and phosphate (Pi) to produce ATP


Give two advantages of ATP as an energy-storage molecule in a cell

1. Cannot pass out of cell
2. Quick, single reaction to release energy
3. Releases small, manageable amounts of energy at any one time


Name the two stages in Aerobic Respiration where CO2 is produced

1. Links Reaction
2. Krebs Cycle


What is the equation for Photosynthesis?

6CO2 + 6H20 + Energy > C6H12O6 +6o2


What is the process of photosynthesis an example of?

A metabolic pathway- a series of small reactions controlled by enzymes


How do animals obtain glucose?

By eating plants or eating other animals, then respire the glucose to release energy


Why do plants and animal cells need energy?

For biological processes to occur


What is any organism that carries out photosynthesis known as?

As a 'photoautotroph' (can make its own food using light energy)


What is the equation for Respiration?

C6H12O6 + 602 > 6CO2 + 6H2O + Energy


What does ATP stand for?

Adenosine triphosphate


How is ATP synthesised?

Ina condensation reaction between ADP and inorganic phosphate (Pi) using energy from an energy-releasing reaction (e.g the breakdown of glucose)


Which enzyme catalyses the synthesis of ATP?

ATP synthase


Give three properties of ATP?

1. It's a small, soluble molecule so it can be easily transported around the cell
2. Releases small, manageable amount of energy at a time
3. It's easily broken down, takes a single reaction


What is the 'Condensation point' for light intensity?

There's a particular level of light intensity at which the rate of photosynthesis exactly matches the rate of respiration


What is the unit that can be used when measuring light intensity?

m-2 s-1 (u moles)


ATP isn't energy it is a ...

store of energy


Which structure in chloroplast absorbs the light energy needed for photosynthesis?

Photosynthetic pigments



Oxidation is Loss (of electrons)
Reduction is Gain (of electrons)


Where does the light-dependent reaction take place?

Thylakoid Membrane


What is a co-enzyme?

A molecule that aids the function of an enzyme


What co-enzyme is used in photosynthesis?



What does the co-enzyme NADP do?

Transfers hydrogen from one molecule to another - reduce or oxidise


What is photoionisation?

1. Light energy is absorbed by chlorophyll
2. The light energy excites the electrons in the chlorophyll, giving them more energy, causing them to be released


What is phosphorylation?

Making ATP from ADP and inorganic phosphate (Pi) - adding phosphate to a molecule using light


What is the energy from photoionisation used for?

1. Phosphorylation
2. Making reduced NADP from NADP
3. Photolysis = splitting water into protons, electrons and oxygen


After photoionisation, what happens to the released, excited electrons?


-These high-energy electrons move down the ETC through a series of REDOX reactions.
-They lose energy as they move down the ETC and this energy is sued to transport protons (H+ ions) into the thylakoid membrane.
-Protons then move down a concentraionn gradient into the Stroma via the enzyme ATP synthase, which is embedded in the thylakoid membrane.
-The energy from this movement combines ADP and inorganic phosphate to form ATP


The process of electron flowing down the ETC and creating a proton gradient across the membrane to drive ATP synthesis is called..,



What is the light-independent reaction also known as?

The Calvin Cycle


Give the order of events in the Calvin Cycle

1. Rubulose biphosphate (RuBP) combines with CO2 to form 2 x Glycerate 3-phosphate (3C) using the enzyme rubisco
2. 2x Glycerate 3-phosphate is then reduced to form 2x triose phosphate (3C). Some of this triose phosphate is converted into useful organic compounds
3. ATP is converted into ADP + Pi
4. Reduced NADP is recycled to NADP
5. Triose phosphate, not used to make organic compounds, is regenerated to RuBP


How many turns of the Calvin cycle would produce 2 GP?

One turn


How many turns of the Calvin cycle would produce 12 GP?

6 x 2 GP = 12 GP six turns


What are the inputs of the Calvin cycle?

Reduced NADP


What are the outputs of the Calvin cycle?

Organic substances (TP)
RuBP (ribulose bisphosphate)


Can the light-independent reaction take place in the dark?

YES, however it needs products from the LDR (ATP and reduced NADP) in order for it to continue


What is different about cyclic photophosphorylation compared to non-cyclic (the normal way)?

Electrons from the chlorophyll molecule aren't passed onto NADP, but are passed back to photo-systems via electron carriers. The produce does not produce any reduced NADP or oxygen - only small amounts of ATP


Where does the oxygen in photosynthesis come from?

From water and is made in the LDR. It diffuses out of the chloroplast and eventually into the atmosphere


Why do plants look green?

As green light is reflected


What happens when an enzyme becomes denatured which may affect photoysnthesis?

1. The tertiary structure changes shape
2. so hydrogen, disulphide and ionic bonds form in different places
3. meaning the active site will change shape and therefore substrates will no longer fit into it
4. which stops ES complexes from occurring


What factors provide optimum conditions for photosynthesis?

-Temperature around 25 degrees
-Carbon dioxide at 0.4% (any higher stomata closes)
-High light intensity


What are stomata?

Pores in the epidermis of a plant that allow gas exchange


There is less oxygen in waterlogged soil, how does this affect transport of minerals into roots?

* Less oxygen so roots are unable to respire aerobically
* This means less ATP available for the active transport of minerals into the roots


What is the 'saturation point'?

The point where a factor is no longer limiting the reaction - something else is now the limiting factor


How does management of glasshouses provide ideal conditions for plant growth?

- Carbon dioxide is added to the air
- Light can get through glasshouse and lamps are provided at night
- Glasshouses trap heat energy from sunlight and hearers/cooling systems can be used to keep a constant optimum tempertaure


Why would a control such as growing plants in a greenhouse where CO2 wasn't added be needed?

To make sure that no other factors, apart from CO2, were affecting the results


What is a popular photosynthesis experiment to do?



What is a centrifuge?

A machine that spins samples really quickly and results in the separation of the components. The same weight is required for all components


How can you measure the rate of dehydrogenase activity?

By measuring the rate at which DCPIP loses its blue colour and turns colourless. A colorimeter is needed to do this.


Overall how many molecules of ATP are produced using aerobic respiration?

32 ATP molecules


Give one way ATP production can be affected

By Mitochondrial Diseases - they can affect proteins and may cause anaerobic respiration to increase so lactate is produced, causing muscle fatigue and weakness.


What is Oxygen's role in respiration?



For each molecule of glucose, how many ATP molecules are produced?



How many molecules of CO2 are released during the Krebs Cycle?

Two CO2 molecules


What is the purpose of a buffer solution?

It is able to resist changes in pH when small amounts of acid or alkali are added - maintains pH value


How do you calculate the rate of CO2 production?

The total volume of CO2 produced at a certain temp
the number of minutes the apparatus was left for