Energy Supply Flashcards

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1
Q

What is the equation for photosynthesis?

A

6CO2 + 6H2O + light energy ———->
C6 H12 O6 (glucose) + 6O2

Carbon dioxide + water + light energy ——-> glucose + oxygen

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2
Q

What is respiration?

A

Respiration is when plants and animals release energy from glucose.

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3
Q

What are the 2 types of respiration?

A

Aerobic and anaerobic.

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4
Q

What is aerobic respiration?

A

Aerobic respiration is when you respire using oxygen.

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5
Q

What is anaerobic respiration?

A

Anaerobic reparation is when you respire without using oxygen.

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6
Q

What is the equation for aerobic respiration?

A

C6 H12 O6 (glucose) + 6O2 ———->
6CO2 + 6H2O + energy

Glucose + oxygen ————->
Carbon dioxide + water + energy

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7
Q

What is ATP made out of?

A

ATP is made out of adenine, a ribose sugar and 3 phosphate groups.

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8
Q

What happens when ADP and Pi form ATP?

A

ATP is made from ADP and Pi using energy. The energy is stored as chemical energy in the phosphate bond.

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9
Q

Where is energy stored on ATP?

A

In the phosphate bond.

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10
Q

How is energy released when ATP is broken down?

A

The ATP diffuses to the part of the cell which needs energy. Then the ATP is broken down into ADP and Pi. Energy is released from the phosphate bond. This reaction is catalysed by ATPase.

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11
Q

Why is ATP a good energy source?

A

ATP only releases small amount of energy at a time, so no energy is wasted.
ATP is a small soluble molecule so it is easily transported around a cell.
ATP is easily broken down so energy can be released.
ATP can transfer energy to another molecule by transferring one phosphate group.
ATP cannot leave a cell so a cell always has a supply of energy.

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12
Q

What is a metabolic pathway?

A

A metabolic pathway is a series of small reactions which are controlled by enzymes.

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13
Q

What is phosphorylation?

A

Phosphorylation is when phosphate is added to a molecule, e.g. Phosphate is added to ADP to form ATP.

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14
Q

What is photo phosphorylation?

A

Photo phosphorylation is when phosphate is added to a molecule using light.

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15
Q

What is photolysis?

A

Photolysis is the splitting of a molecule using light energy.

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16
Q

What is hydrolysis?

A

Hydrolysis is the splitting of a molecule using water.

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17
Q

What is decarboxylation?

A

Decarboxylation is the removal of CO2 from a molecule.

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18
Q

What is dehydrogenation?

A

Dehydrogenation is the removal of hydrogen from a molecule.

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19
Q

What is a reduction reaction?

A

A reaction where something has gained electrons.

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20
Q

What is an oxidation reaction?

A

A reaction where something loses electrons.

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21
Q

What is a coenzyme?

A

A coenzyme is a molecule which aids the function of an enzyme.

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22
Q

What does NADP do?

A

NADP is a co enzyme used in Photosynthesis. It transfers hydrogen from one molecule to another, so it can reduce or oxidise molecules.

23
Q

What do NAD and FAD do?

A

NAD and FAD are co enzymes used in respiration. They transfer hydrogen from one molecule to another, so they reduce or oxidise molecules.

24
Q

Describe the structure of a chloroplast.

A

Chloroplasts have a double membrane called the chloroplast envelope. They contain thylakoids which are stacked up to form grana. The grana are linked together by bits of thylakoids membrane called lamallae.

25
Q

What is a photosystem?

A

In a chloroplast there are photosynthetic pigments, e.g. Chlorophyll. The pigments are attached to proteins. The pigment and protein is called a photosystem.

26
Q

What is the stroma?

A

The stroma is the found on the inside of chloroplasts. It is a gel like substance which surrounds thylakoids. It contains enzymes, sugars and organic acids.

27
Q

What are the 2 stages of photosynthesis?

A

The light dependant reaction and the light independent reaction.

28
Q

What happens during the light dependant reaction?

A

Light energy is absorbed by the chlorophyll. This excites electrons in the chlorophyll, so the electrons move out of the chlorophyll and they move along a series of electron carriers. The excited electrons lose energy as the move along the electron transport chain. This energy is used to transport protons into the thylakoid. Therefore the thylakoid gets a higher proton concentration than the stroma, so protons move out of the thylakoid into the stroma via ATP synthase. The energy from this combines ADP and Pi to form ATP. Then the electrons are transferred to NADP along with a proton to form reduced NADP.

29
Q

What is photolysis in the light dependant reaction?

A

Photolysis is when water is split into protons (H+ ions), electrons and oxygen.

30
Q

What is the equation for photolysis?

A

H20 ——-> 2H+ + 0.5O2

Water ——> hydrogen + oxygen

31
Q

What is cyclic photo phosphorylation?

A

Cyclic photo phosphorylation is when electrons from chlorophyll are not passed onto NADP. Therefore the electrons are recycled and repeatedly move through the electron carriers. This only produces a small amount of ATP.

32
Q

How is reduced NADP generated?

A

The electrons are excited to a high energy level. Then the electrons are transferred to NADP which forms reduced NADP.

33
Q

What is the Calvin cycle?

A

The Calvin cycle is also known as the light independent reaction.

34
Q

What happens in the Calvin cycle?

A

CO2 enters the leaf through the stomata and diffuses into the stroma and combines with RuBP (a 5 carbon compound) to form a 2 molecules of GP (a 3 carbon molecule). This reaction is catalysed by the enzyme rubisco. Then the molecules of GP are reduced into 2 molecules of TP (another 3 carbon molecule). This requires ATP and H+ ions. TP is now converted into organic compounds, e.g. Glucose. Some is regenerated into RuBP.

35
Q

What are the 3 limiting factors of photosynthesis?

A

Light intensity, temperature and carbon dioxide concentration.

36
Q

How does light intensity affect photosynthesis?

A

Light is needed to provide energy for the light dependant reaction. The higher the light intensity the more energy it provides so the higher the rate of photosynthesis. Also only light of certain wavelengths cans be used for photosynthesis.

37
Q

How does temperature affect photosynthesis?

A

Photosynthesis involves using enzymes, so if the temperature falls below 10°C the enzymes become inactive and if the temperature goes above 45°C the enzymes denature. Therefore the optimum temperature is around 25°C. Also, at high temperatures stomata close to avoid losing too much water. This makes photosynthesis slow down because less CO2 enters the leaf.

38
Q

How does CO2 concentration affect photosynthesis?

A

If the CO2 concentration in the atmosphere is 0.4% the will be the highest rate of photosynthesis.

39
Q

What are the 4 stages in aerobic respiration?

A

Glycolysis, the link reaction, the krebs cycle and the electron transport chain.

40
Q

How do commercial growers increase the yield from their plants?

A

Commercial growers know the limiting factors of photosynthesis so they create an environment where plants get the right amount of everything they need. This increases the yield.

41
Q

How do commercial growers control the limiting factors of photosynthesis?

A

They control CO2 concentration by adding CO2 into the air. They control light intensity by having glass windows which light can get in through. At nighttime, they have lamps which provide light at night time. They control temperature by using greenhouses which trap heat from sunlight. There can also be heaters and coolers which control temperature at make it close to an optimum temperature.

42
Q

Why is the inner mitochondrial membrane folded?

A

The folds (cristae) in the inner mitochondria membrane provide a large area for respiration.

43
Q

What happens in glycolysis?

A

Glucose is phosphorylated by adding 2 phosphates from 2 molecules of ATP. This makes 2 molecules of TP and 2 molecules of ADP. Then the Triose phosphate is oxidised (so it loses hydrogen) which forms 2 molecules of pyruvate. NAD collects the hydrogen ions, forming 2 reduced NAD. 4 ATP are produced (but 2 are used in phosphorylation, so there is a net gain of 2).

44
Q

What happens in the link reaction?

A

In the link reaction pyruvate is decarboxylated, so one carbon atom is removed in the form of CO2. NAD collects hydrogen from pyruvate which forms reduced NAD. This changes pyruvate into acetate. Acetate gets combined with coenzyme A (CoA) to form acetyl coenzyme A (acetyl CoA). No ATP is produced in this reaction.

45
Q

Why does the link reaction happen twice for every glucose molecule?

A

Because 2 molecules of pyruvate are formed in glycolysis from one glucose molecule.

46
Q

What products are released from the Link reaction?

A

2 molecules of acetyl CoA which go into the Krebs cycle, 2 reduced NAD which go into the electron transport chain and 2 CO2 which are a waste product.

47
Q

What happens in anaerobic respiration?

A

In anaerobic respiration there is no oxygen. Pyruvate is converted into ethanol (In plants and yeast) or lactate (in animal cells and some bacteria). The production of lactate or ethanol regenerates NAD, so glycolysis can continue when there isn’t much oxygen. Therefore a small amount of ATP is still produced.

48
Q

Where does the Krebs cycle happen?

A

The Krebs cycle takes place in the matrix of the mitochondria.

49
Q

What happens in the Krebs cycle?

A

Acetyl CoA (a 2 carbon molecule) from the link reaction combines with a 4 carbon molecule to form a 6 carbon molecule. This is converted to a 5 carbon molecule as CO2 is removed. Then hydrogen is removed and is taken up by NAD to form reduced NAD. The 5 carbon molecule is converted to a 4 carbon molecule. More CO2 and hydrogen are removed which produces 1 reduced FAD and 2 reduced NAD. The 4 carbon molecule is reused for the next Krebs cycle.

50
Q

What happens in the electron transport chain?

A

Hydrogen atoms are release from reduced NAD and reduced FAD. The hydrogen atoms split into protons and electrons. The electrons move along the electron transport chain and they lose energy at each carrier. This energy is used to pump protons from the matrix to the intermembrane space. This makes the proton concentration higher in the intermembrane space than the matrix so protons move down the concentration gradient back into the matrix via ATPase. The makes ATP from ADP and Pi.

51
Q

Where does the link reaction happen?

A

In the matrix of the mitochondria.

52
Q

Where does glycolysis happen?

A

In the cytoplasm.

53
Q

Where does the electron transport chain happen?

A

In the Christae.

54
Q

What is photosynthesis?

A

Photosynthesis is the process where energy from light is used to make glucose from water and carbon dioxide.