Biology : Unit 5 : Photosynthesis And Respiration

Front 1

Why is do plants need energy?

Back 1

For photosynthesis, active transport, DNA replication, cell division and protein synthesis

synthesis

Front 2

Why do animals need energy?

Back 2

Muscle contraction, maintaining body temperature, active transport, DNA replication, cell division and protein synthesis

Front 3

Equation for photosynthesis

Back 3

6CO2 + 6H2O -> C6H12O6 + 6O2

Front 4

What is a metabolic pathway?

Back 4

Process occurs in a series of small reactions controlled by enzymes

Front 5

What is aerobic respiration?

Back 5

Respiration using oxygen

Front 6

What is anaerobic respiration?

Back 6

Respiration without oxygen

Front 7

Aerobic respiration equation

Back 7

C6H12O6 + 6O2 -> 6CO2 + 6H20 + energy

Front 8

What does anaerobic respiration in plants and yeast produce?

Back 8

Ethanol, carbon dioxide and energy

Front 9

What does anaerobic respiration in humans produce?

Back 9

Lactate and releases energy

Front 10

When is ATP made?

Back 10

Energy released from glucose in respiration - carries energy around the cell to where it's needed

Front 11

What is ATP made from?

Back 11

Adenine combined with a ribose sugar and three phosphate groups

Front 12

How is ATP synthesised?

Back 12

Condensation reaction between ADP and Pi using energy from an energy-releasing reaction, catalysed by ATP synthase

Front 13

How is the energy in ATP stored?

Back 13

As chemical energy in the phosphate bond

Front 14

How is the synthesis of ATP phosphorylation?

Back 14

Adding phosphate to a molecule. ADP is phosphorylated to ATP.

Front 15

How is energy released from ATP?

Back 15

ATP diffuses to the part of the cell that needs energy and is hydrolysed to ADP and Pi, chemical energy is released from the phosphate bond, catalysed by ATP hydrolase

Front 16

What are the properties of ATP?

Back 16

Releases little energy so no waste heat energy

Small + soluble so easily transported

Easily broken down so energy released easily

Quickly remade

Transfers phosphate groups to make other molecules more reactive

ATP can't pass out cell so always has immediate energy

Front 17

What is the compensation point?

Back 17

Point at which the rate of photosynthesis exactly matches the rate of respiration

Front 18

How can you work out compensation point?

Back 18

Measure the rate at which O2 is produced and used by a plant at different light intensities - 0 net oxygen generation

Front 19

Where does photosynthesis take place?

Back 19

Chloroplasts - small, flattened organelles surrounded by double membrane

Front 20

What is the structure inside a chloroplast?

Back 20

Thylakoids stacked up in grana, linked by bits of thylakoid membrane called lamellae, with photosynthetic pigments

Front 21

What are photosynthetic pigments?

Back 21

Coloured substances that absorb light energy for photosynthesis, found in thylakoid membrane, attached to proteins.

Front 22

What is the protein and pigment?

Back 22

Photosystem

Front 23

What are the 2 Photosystems used by plants to capture energy?

Back 23

PSI and PSII

Front 24

What wavelength does PSI absorb?

Back 24

700nm

Front 25

What wavelength does PSII absorb?

Back 25

680nm

Front 26

Where is the stroma?

Back 26

Within the inner membrane of the chloroplast, surrounding the thylakoids

Front 27

What does stroma contain?

Back 27

Enzymes, sugars, organic acids and unused carbohydrates as starch grains

Front 28

What is oxidation?

Back 28

Gain of oxygen

Loss of hydrogen

Loss of electrons

Front 29

What is reduction?

Back 29

Loss of oxygen

Gain of hydrogen

Gain of electrons

Front 30

What is a co-enzyme?

Back 30

Molecule that aids the function of an enzyme that transfer a chemical group from one molecule to another

Front 31

What coenzyme is used in photosynthesis?

Back 31

NADP - transfers hydrogen from one molecule to another so it can reduce or oxidize

Front 32

Where does the light dependent reaction take place?

Back 32

Thylakoid membrane

Front 33

What is photoionisation?

Back 33

Light energy absorbed by chlorophyll excites electrons, giving them more energy, causing them to be released so chlorophyll is positively charged

Front 34

What is the energy from the released electrons used for?

Back 34

Add phosphate group to ADP to form ATP which transfers energy, reduce NADP to form NADPH which transfers hydrogen to light-independent reaction, H2O oxidizes to O2

Front 35

Where does the light-independent reaction take place?

Back 35

Stroma of the chloroplast

Front 36

What happens during the light independent reaction?

Back 36

ATP and reduced NADP supply energy and hydrogen to make glucose from CO2

Front 37

What 3 things is the energy from the photoionisation of chlorophyll used for?

Back 37

Making ATP from ADP - phosphorylation

Making reduced NADP from NADP

Photolysis

Front 38

What is photolysis?

Back 38

Splitting water into protons (H+), electrons and oxygen

Front 39

What does non-cyclic phosphorylation produce?

Back 39

ATP, reduced NADP and oxygen

Front 40

What are the Photosystems linked by?

Back 40

Electron carriers - proteins that transfer electrons

Front 41

What do the Photosystems and electron carriers form?

Back 41

Electron transport chain - chain of proteins through which excited electrons flow

Front 42

What is the first stage of non-cyclic phosphorylation? 1/4

Back 42

Light energy absorbed by PSII which excites electrons in chlorophyll so move to higher energy level then released and move down electron transport chain to PSI

Front 43

What is the second stage of non-cyclic phosphorylation? 2/4

Back 43

Light energy splits water into protons (H+), electrons and oxygen - photolysis

Front 44

What is the third stage of non-cyclic phosphorylation? 3/4

Back 44

Exited electrons lose energy as move down electron transport chain. Protons move down conc. gradient,to stroma via synthase (embedded in thylakoid membrane). Energy from this combines ADP + Pi to form ATP.

Front 45

What is the function of the electron transport chain?

Back 45

Transports protons (H+) into thylakoid so thylakoid has higher proton conc. than stroma so proton gradient across thylakoid membrane.

Front 46

What is the fourth stage of non-cyclic phosphorylation? 4/4

Back 46

Light energy absorbed by PSI which excites electrons again to even higher energy level. Electrons transferred to NADP with proton from stroma to form reduced NADP.

Front 47

What is chemiosmosis?

Back 47

Process of electrons flowing down electron transport chain and creating proton gradient across membrane to drive ATP synthesis.

Front 48

Why is cyclic phosphorylation 'cyclic'?

Back 48

Electrons from chlorophyll molecules aren't passed onto NADP, but are passed back to PSI via electron carriers - recycled

Front 49

What does cyclic phosphorylation produce?

Back 49

Small amount of ATP using PSI, no reduced NADP or oxygen

Front 50

What is the light independent reaction also known as?

Back 50

Calvin cycle

Front 51

What does the Calvin cycle produce?

Back 51

Triode phosphate from CO2 and ribulose bisphosphate.

Front 52

What is the use of triose phosphate?

Back 52

Makes glucose and other organic substances

Front 53

What is the first stage of the Calvin cycle? (1/3)

Back 53

CO2 enters leaf through stomata, diffuses into stroma, combines w/ ribulose bisphosphate catalysed by rubisco, creates 6C which breaks down to 3C glycerate 3-phosphate (GP)

Front 54

What is the second stage of the Calvin cycle? (2/3)

Back 54

Hydrolysis of ATP provides energy to reduce GP to triose phosphate with H+ ions from reduced NADP

Front 55

What is some triose phosphate recycled to form?

Back 55

Glucose and Galactose, the rest continues in the Calvin cycle to regenerate RuBP

Front 56

What is the third stage of the Calvin cycle? (3/3)

Back 56

5/6 molecules of TP produced in cycle used to regenerate RuBP, using the rest of the ATP produced by light dependent reaction

Front 57

What are hexose sugars?

Back 57

Simple 6 carbon sugars made by joining 2 molecules of TP and can be used to make larger carbohydrates

Front 58

How many times must the calvin cycle turn to make one hexose sugar?

Back 58

6 as 3 turns produces 6 molecules of TP but 5/6 of these are used to regenerate RuBP. 3 turns makes only 1 TP. 2 TP needed for 1 hexose sugar so 6 turns for 2 TP.

Front 59

What do 6 turns of the cycle need from the light-dependent reaction?

Back 59

18 ATP and 12 reduced NADP

Front 60

How are carbohydrates made?

Back 60

Hexose sugars made from 2 TP molecules and larger carbohydrates made by joining hexose sugars differently

Front 61

How are lipids made?

Back 61

Using glycerol synthesised from TP and fatty acids synthesised from GP

Front 62

How are amino acids made?

Back 62

Some are made from GP

Front 63

How does light intensity affect photosynthesis?

Back 63

High light intensity of red and blue wavelength - energy for light-dependent reaction

Front 64

How does temperature affect photosynthesis?

Back 64

Below 10°, enzymes become inactive but higher than 45°, they begin to denature and stomata close to stop water loss but less CO2 therefore enters leaf

Front 65

How does carbon dioxide affect photosynthesis?

Back 65

Carbon dioxide makes up 0.04% of atmosphere. Increase to 0.4% but any higher closes stomata.

Front 66

How does water affect photosynthesis?

Back 66

Too little stops photosynthesis and soil becomes waterlogged so reduce uptake of minerals. Need a constant supply.

Front 67

What are 3 limiting factors of photosynthesis?

Back 67

Light

Temperature

Carbon Dioxide

Front 68

What is the saturation point?

Back 68

The point at which adding more (light) no longer makes a difference as something else has become the limiting factor - shown by levelling off

Front 69

How do farmers stop carbon dioxide concentration being the limiting factor?

Back 69

Caron dioxide is added to the air e.g. by burning propane in a CO2 generator

Front 70

How do farmers stop light being the limiting factor?

Back 70

Light can get in through the glass during the day, and during the night, artificial light is used

Front 71

How do farmers stop temperature being the limiting factor?

Back 71

Glasshouses trap best energy from sunlight to warm the air, plus heating/cooling systems, and air circulation systems

Front 72

Why is the plant growth with more CO2 faster?

Back 72

Plants use CO2 to produce glucose by photosynthesis. More CO2 means more glucose so more respiration so more ATP for DNA replication, cell division and protein synthesis.

Front 73

Why may a plant grown by a wood fire have higher growth rate than one grown by an electric heater?

Back 73

Wood fire gives out more heat and also increases concentration of CO2 in air

Front 74

What is the purpose of chromatography?

Back 74

To seperate a mixture to identify the components

Front 75

What are 2 types of chromatography?

Back 75

Paper chromatography

Thin-layer chromatography

Front 76

What is the mobile phase?

Back 76

Where the molecules can move - liquid solvent

Front 77

What is the stationary phase?

Back 77

Where the molecules can't move - chromatography paper/thin layer of solid on a plate

Front 78

What is the basic principle of chromatography?

Back 78

Mobile phase moves through stationary phase, components spend different time in mobile/ stationary phase. Components that spend longer in mobile phase travel faster or further.

Front 79

Why do leaves contain a range of pigments?

Back 79

Each pigment absorbs a different wavelength of light so having more than one type of pigment increase range of light a plant can absorb.

Front 80

What is the other role of pigment?

Back 80

Protecting leaves from excessive UV radiation

Front 81

What is an Rf value?

Back 81

Distance substance has moved through stationary phase in relation to the solvent. Each pigment has specific value that can be looked up in a database.

Front 82

Rf value =

Back 82

Distance travelled by spot ÷ distance travelled by solvent

Front 83

How are the chloroplasts of shade-tolerant plants adapted for photosynthesis?

Back 83

Produce dark red and purple pigments called anthocyanins which protect chloroplasts from brief exposure to higher light levels.

Front 84

How can the activity of the dehydrogenase enzyme in PSI be investigated?

Back 84

By adding a redox indicator dye to extracts of chloroplasts - acts as electron acceptor and is reduced by dehydrogenase, shown by colour change from blue to colourless - rate of change using colorimeter

Front 85

What does a colorimeter measure?

Back 85

How much light a solution absorbs when a light source is shone directly through it - coloured absorbs more light than colourless

Front 86

Why is the control tube of investigating the activity of dehydrogenase wrapped in tinfoil?

Back 86

So no light reaches the contents of the tube - no absorbance should be seen

Front 87

What will show that dehydrogenase activity is taking place?

Back 87

Absorbance decreases as DCPIP is reduced and loses blue colour. Faster absorbance decreases, faster the rate of dehydrogenase activity.

Front 88

Where does aerobic respiration take place?

Back 88

Mitochondria

Front 89

What is a coenzyme?

Back 89

Molecule that aids the function of an enzyme by transferring chemical group from one molecule to another

Front 90

What are the four stages of aerobic respiration?

Back 90

Glycolysis - cytoplasm

The Link Cycle

The Krebs Cycle

Oxidative phosphorylation

Front 91

What are the stages of anaerobic respiration?

Back 91

No link reaction, krebs cycle or oxidative phosphorylation. Products of glycolisis converted to ethanol or lactate instead.

Front 92

What can be used as a respiratory substrate in aerobic respiration?

Back 92

Glucose

Products from breakdown of molecules e.g. fatty acids - lipids and amino acids - proteins.

Front 93

What does glycolisis make?

Back 93

Pyruvate

Front 94

What does glycolisis involve?

Back 94

Splitting one molecule of glucose into two smaller molecules of pyruvate in the cytoplasm - anaerobic process

Front 95

What are the 2 stages of glycolisis?

Back 95

Phosphorylation

Oxidation

Front 96

What occurs during phosphorylation?

Back 96

Glucose phosphorylated using phosphate from ATP to create 1 molecule of glucose phosphate and ADP. ATP adds phosphate to form hexose bisphosphate, which is split into 2 molecules of TP.

Front 97

What occurs during oxidation?

Back 97

Triose phosphate oxidized to form 2 molecules of pyruvate. NAD collects hydrogen ions forming 2 reduced NAD. 4 ATP produced but 2 used up in stage 1 so net gain of 2 ATP.

Front 98

Where does the 2 reduced NAD go?

Back 98

To oxidative phosphorylation

Front 99

Where does the 2 pyruvate go?

Back 99

Actively transported into the mitochondrial matrix for use in the link reaction

Front 100

Where does the 2 ATP (net gain) go?

Back 100

Used for energy

Front 101

In anaerobic respiration, what is the pyruvate produced in glycolisis converted into?

Back 101

Ethanol (alcoholic fermentation) or lactate (lactate fermentation) using reduced NAD

Front 102

Where does alcoholic fermentation occur?

Back 102

Plants and yeast

Front 103

Where does lactate fermentation occur?

Back 103

Animal cells and some bacteria

Front 104

What does the production of lactate or ethanol regenerate?

Back 104

Oxidised NAD

Front 105

What is the benefit of the regeneration of oxidised NAD from the production of lactate or ethanol?

Back 105

Glycolysis can continue even when there isn't much oxygen around so a small amount of ATP can still be produced to keep some biological process going

Front 106

What does the link reaction do?

Back 106

Converts pyruvate produced in glycolisis to acetyl coenzyme A.

Front 107

How is pyruvate converted to acetyl coenzyme A?

Back 107

Pyruvate decarboxylated so 1 carbon removed as CO2, pyruvate oxidised to acetate, NAD reduced to reduced NAD. Acetate combines w/ coenzyme A to acetyl coenzyme A. No ATP.

Front 108

How many times does the link reaction occur per glucose molecule?

Back 108

2 pyruvate molecules made for every glucose molecule that enters glycolysis so link reaction and krebs cycle happen twice for every glucose molecule.

Front 109

Where does 2 acetyl coenzyme A go?

Back 109

To the krebs cycle

Front 110

Where does 2 carbon dioxide go?

Back 110

Released as a waste product

Front 111

Where does 2 reduced NAD go?

Back 111

To oxidative phosphorylation

Front 112

What does the Krebs cycle produce?

Back 112

Reduced coenzymes and ATP using a series of oxidation-reduction reactions in the matrix of the mitochondria

Front 113

How many kreb cycles take place to produce 1 pyruvate molecule?

Back 113

1

Front 114

What happens in the first stage of the krebs cycle? (1/3)

Back 114

Acetyl CoA from link reaction combines with 4-carbon molecule (oxaloacetate) to form a 6-carbon molecule (citrate). Coenzyme A goes back to link reaction to be used again.

Front 115

What happens in the second stage of the krebs cycle? (2/3)

Back 115

6-carbon citrate molecule converted to 5-carbon molecule. Decarboxylation occurs, CO2 removed and dehydrogenation occurs. Hydrogen used to produce reduced NAD from NAD.

Front 116

What happens in the third stage of the krebs cycle? (3/3)

Back 116

5-carbon molecule converted to 4-carbon molecule. Decarboxylation and dehydrogenation occurs to produce 1 reduced FAD and 2 reduced NAD. ATP produced by direct transfer of phosphate group from intermediate compound to ADP. Citrate now converted to oxaloacetate.

Front 117

What is substrate-level phosphorylation?

Back 117

When a phosphate group is directly transferred from one molecule to another.

Front 118

Where does 1 coenzyme A go?

Back 118

Reused in next link reaction

Front 119

Where does oxaloacetate go?

Back 119

Regernated for use in next Krebs cycle

Front 120

Where does 2 carbon dioxide go?

Back 120

Released as waste product

Front 121

Where does 1 ATP go?

Back 121

Used for energy

Front 122

Where does 3 reduced NAD go?

Back 122

To oxidative phosphorylation

Front 123

Where does 1 reduced FAD go?

Back 123

To oxidative phosphorylation

Front 124

Why does the rate of CO2 production give an indication of yeasts respiration rate?

Back 124

Yeast can respire aerobically and anaerobically which both produce CO2

Front 125

What does liquid paraffin do when measuring rate of yeast's respiration rate?

Back 125

Stop oxygen getting in by covering top of solution so yeast has to respire anaerobically

Front 126

What do respirometers do?

Back 126

Indicate rate of aerobic respiration by measuring amount of oxygen consumed by an organism over period of time

Front 127

What is oxidative phosphorylation?

Back 127

Process where energy carried by electrons from reduced coenzymes (reduced NAD and reduced FAD) is used to make ATP - involves electron transport chain and chemiosmosis

Front 128

What is the first step of oxidative phosphorylation? (1/7)

Back 128

H atoms released from reduced NAD and reduced FAD as they're oxidised to NAD and dad. H atoms split into protons and electrons.

Front 129

What is the second step of oxidative phosphorylation? (2/7)

Back 129

Electrons move down electron transport chain, losing energy at each electron carrier.

Front 130

What is the third step of oxidative phosphorylation? (3/7)

Back 130

Energy used by electron carriers to pump protons from mitochondrial matrix into the intermembrane space.

Front 131

What is the fourth step of oxidative phosphorylation? (4/7)

Back 131

Concentration of protons is now higher in intermembrane space than mitochondrial matrix which forms electrochemical gradient

Front 132

What is the fifth step of oxidative phosphorylation? (5/7)

Back 132

Protons move down electrochemical gradient back across inner mitochondrial membrane and into mitochondrial matrix via ATP synthase embedded in inner mitochondrial membrane. Movement drives synthesis of ATP from ADP and Pi.

Front 133

What is the sixth step of oxidative phosphorylation? (6/7)

Back 133

Process of ATP prediction driven by movement of H+ ions across a membrane due to electrons moving down electron transport chain is chemiosmosis

Front 134

What is the seventh step of oxidative phosphorylation? (7/7)

Back 134

Protons, electrons and oxygens in the mitochondrial matrix at the end of the transport chain combine to form water. Oxygen is the final electron acceptor.

Front 135

How many ATP are made from each reduced NAD?

Back 135

2.5 ATP

Front 136

How many ATP are made from each reduced FAD?

Back 136

1.5 ATP

Front 137

What can ATP production be affected by?

Back 137

Mitochondrial diseases which affect the functioning of mitochondria and proteins involved in oxidative phosphorylation or the krebs cycle.

Front 138

What do mitochondrial diseases and shortage of ATP lead to?

Back 138

Increase in anaerobic respiration so lots of lactate which causes muscle fatigue and weakness, plus high lactate concentration in the blood.

Front 139

What is substrate level phosphorylation?

Back 139

When the P from a substrate (TP) is transferred from ADP to ATP.

Front 140

What is released and used up in alcoholic fermentation?

Back 140

Carbon dioxide released

Reduced NAD makes NAD

Front 141

Alcoholic fermentation

Back 141

Pyruvate (3C) -> Ethanal (2C) -> Ethanol (2C)

Front 142

Lactate formation

Back 142

Pyruvate (3C) -> Lactate

Front 143

What can pyruvate do that glucose can't?

Back 143

Be actively transported into the the membrane

Front 144

Where does the link reaction take place?

Back 144

Matrix in mitochondria

Front 145

What happens to oxidized NAD after fermentation?

Back 145

Returns to glycolisis so it can pick up more hydrogen

Front 146

Krebs cycle

Back 146

(4c) oxaloacetate -> (6c) citrate -> (5c)

NAD Co NAD Co A FAD NAD

Front 147

What is oxidative phosphorylation?

Back 147

Energy carried by electrons, from reduced coenzymes (reduced NAD and reduced FAD) is used to make ATP