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Biology > Energy transfers in and between organisms (3.5) > Flashcards

Energy transfers in and between organisms (3.5) Flashcards

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1
Q

What are the 2 parts of photosynthesis?

A

Light dependent reaction (LDR)
Light independent reaction (LIR)

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2
Q

How big a chloroplast?

A

5-10 micrometers

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3
Q

Outline the structure of a chloroplast.

A
  • double membrane
  • grana - stack of thylakoids (some thylakoids have tubular extensions called stomal lamellae)
  • stroma - fluid filled matrix where LIR takes place, contains starch grains
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4
Q

Where does the light dependent reaction taken place?

A

Thylakoid membrane

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5
Q

What are the products of the LDR?

A

ATP and reduced NADP

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6
Q

What is oxidation?

A

Loss of electrons
Gains oxygen

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7
Q

What is reduction?

A

Gain of electrons
Loss of oxygen

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8
Q

Outline the process of photophosphorylation.

A
  • light energy is absorbed by photo system 2 and a pair of electrons are excited.
  • the pair of electrons pass through an electron transport chain via a series of oxidation and reduction reactions
  • at the end of the electron transport chain the electrons are passed to photosystem 1
  • light energy is absorbed by PS1 and a pair of electrons are excited again
  • as the electron pair moves through the electron transport chain, the energy of the electorns is used to produce ATP by chemiosmosis.
  • at the end, the electron pair is added to NADP in the stoma to form reduced NADPH
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9
Q

Which stage of photosynthesis does photophosphorylation take place in?

A

Light dependent reaction

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10
Q

What happens in the LDR when light energy is absorbed by ps2?

A

A pair of electrons are excited and pass through an electron transport chain

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11
Q

How is ATP produced in photophosphorylation?

A

As electron pairs move through the electron transport chain, the energy of the electrons is used to produce ATP by chemiosmosis

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12
Q

What is non-cyclic photophosphorylation?

A

The pair of electrons that left photosystem 2 have not returned to PS2

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13
Q

Why is photolysis required?

A

PS2 has lost a pair of electrons
To replace the electron pair an enzyme in PS2 splits a module of water

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14
Q

What does photolysis produce?

A

2 electrons which replace the pair lost from PS2 (and oxygen which is the source of oxygen in photosynthesis)

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15
Q

Describe the process of photophosphorylation.

A

An enzyme in PS2 splits a molecule of water
The energy for this process ultimately came from the light that was absorbed at the start
This produces 2 electrons which replace the lost pair from PS2
Photolysis also produces oxygen which is the source of oxygen in photosynthesis

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16
Q

What is cyclic photophosphorylation?

A

Light energy is absorbed by PS1
A pair of electrons on PS1 are excited
The electron pair pass through an electron transfer chain, generating ATP

At the end the electron pair return to PS1

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17
Q

When does cyclic photophosphorylation take place?

A

When the chloroplast requires an increased amount of ATP

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18
Q

How is a proton gradient created in the thylakoid membrane?

A

As electrons pass through the electron transport chain the energy of the electrons is used to pump protons (H+ ions) from the stroma to the thylakoid interior.

The thylakoid membrane is impermeable to protons so they cannot diffuse back.

The concentration of protons is grater in the thylakoid interior than the stroma, so a portion gradient is created.

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19
Q

Explain the 2 processes that enhance the proton gradient.

A
  1. During non-cyclic photophosphorylation a portion is removed from the stroma and added to NADP to make reduced NADP. This lowers concentration of protons in the stroma
  2. During photolysis, protons are produced from water in the thylakoid interior, this increases the concentration of protons in the thylakoid interior, enhancing the proton gradient
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20
Q

How is ATP generated in photosynthesis?

A

Chemiosmosis

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21
Q

Describe the process of chemiosmosis.

A

The enzyme ATP synthase is found on the thylakoid membrane

ATP synthase contains an ion channel through the centre

Protons can diffuse down the gradient through the ion channel into the stroma

This movement of protons is used by ATP synthase to generate ATP (ADP + Pi ——->ATP)

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22
Q

How are chloroplasts adapted to function?

A
  1. Thylakoids have a large surface area for the attachment of the chlorophyll, electron carriers ands enzymes that carry out the LDR
  2. They have a network of proteins in grana that hold chlorophyll in a very precise manor that allows maximum absorption of light
  3. Granal membranes have ATP synthase channels which catalyse ATP production - they are selectively permeable, allowing a proton gradient
  4. Chloroplasts have DNA and ribosomes so they can quickly and easily manufacture proteins
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23
Q

Energy cannot be ______ or destroyed. It can only be converted.

A

Created

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24
Q

Define what an ecosystem is.

A

Any group of living organisms and non-living things occurring together, and the relationships between them

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25
Q

What components make up an ecosystem?

A

Habitat
Population
Community

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26
Q

what is a habitat?

A

Where an organism lives

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27
Q

What is a population?

A

All the organisms of one species who live in the same place at the same time and can breed together

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28
Q

What is a community?

A

All the populations of different species who live in the same place at the same time and can interact together

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29
Q

What is a niche?

A

The role something plays in an ecosystem

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30
Q

What are biotic factors?

A

Living factors

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31
Q

What are biotic factors?

A

Living factors

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32
Q

What are abiotic factors?

A

Non living factors

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33
Q

Name some biotic factors

A

Disease agents
Competition
Animals
Plants
Symbiosis

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34
Q

Name some Abiotic factors

A

Wind
Air
Conc of carbon dioxide, oxygen, nitrogen
Salinity
Humidity

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35
Q

What are the two sectors of symbiosis?

A

Parasitism
Mutualism

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36
Q

What is an example of parasitism?

A

Rabies
Tics
Leeches

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37
Q

What is mutualism?

A

When 2 biotic factors benefit each other

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38
Q

Name the elements in the food chain

A

Producer
Primary consumer
Secondary consumer
Tertiary consumer
Quaternary consumer

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39
Q

A producer is always _________________.

A

Photosynthetic

40
Q

What is a saprobiont in the food chain?

A

Decomposing bacteria and fungi

41
Q

How much energy is transferred at each trophic level?

A

10%

42
Q

How is energy lost at each trophic level?

A

Waste products
Metabolism
Respiration (thermal + kinetic energy)

43
Q

What does GPP stand for?

A

Gross primary productivity

44
Q

What is GPP?

A

The rate at which plants convert light energy to chemical energy

45
Q

What does NPP stand for?

A

Net primary production

46
Q

What does NPP measure?

A

Energy remaining

47
Q

Chemical energy is stored in _______.

A

Biomass

48
Q

In respiration biomass is broken down to release ________.

A

Energy

49
Q

What experiment can be conducted to calculate the amount of energy in something?

A

Calorimetry

50
Q

A calorimetry experiment is done in a closed system to reduce ________ loss.

A

Energy

51
Q

Where does the light independent reaction take place?

A

The stroma

52
Q

In the light independent reaction, _______ __________ is used to make glucose.

A

Carbon dioxide

53
Q

The light independent reaction does not require ______.

A

Light

54
Q

What are the 3 stages of the light independent reaction?

A

1) fixation
2) reduction
3) regeneration

55
Q

Describe the fixation stage of the light independent reaction.

A
  • the 5 carbon molecule ribulose biphosphate (RuBP) reacts with carbon dioxide.
  • this reaction is catalysed by the enzyme ribulose bisphosphate carboxylase (RuBisCo).
  • from this reaction we make 2 molecules of glycerate 3-phosphate (each molecule has 3 carbons)
56
Q

Describe the reduction stage of the light independent reaction.

A
  • each molecule of glycerate 3-phosphate is reduced forming the 3 carbon sugar triose phosphate (TP)
  • this reaction uses reduced NADP and ATP from the light dependent reactions (the reduced NADP provides hydrogen needed for the reduction and the ATP provides energy)
  • some of the triose phosphate is removed from the cycle and used by the plant cell to make glucose and other molecules such as lipids and amino acids
57
Q

Describe the regeneration stage of the light independent sage of photosynthesis

A
  • the ribulose bisphosphate is regenerated using ATP. This stage allows the cycle to continue
58
Q

Each turn of the Calvin cycle takes in ___ carbon atom from carbon dioxide.

A

One

59
Q

how many times does the Calvin cycle have to turn to make 1 molecule of glucose and why?

A

6 times as glucose has 6 carbon atoms

60
Q

NPP=?

A

NPP=GPP-R

61
Q

NPP=?

A

NPP=GPP-R

62
Q

N=?

A

N=I-(F+R)

63
Q

What chemical molecules contain phosphate?

A

DNA
ATP
RNA
Phospholipids

64
Q

Where is phosphate mainly found? And in what form?

A

As a phosphate ion in mineral form in sedimentary rock

65
Q

What are mycorrhizae?

A

Fungal associations between plant roots and beneficial fungi

66
Q

How do mycorrhizae improve the uptake of scarce ions such as phosphate ions?

A

1) the fungi increase the surface area for water and mineral absorption
2) it acts like a sponge so hold water and minerals around the roots

This makes the plant more draught resistant and able to take up inorganic ions

67
Q

Mycorrhizae and plants have a _____________ relationship

A

Mutualistic

68
Q

What are the stages of the phosphorus cycle?

A

Absorption
Consumption
Excretion
Excretion and decomposition
Erosion
Decomposition
Erosion and fertilisers
Sedimentation

69
Q

Describe the stage of absorption in the phosphorous cycle.

A
  • phosphate ions are dissolved in water e.g oceans
  • plants absorb the phosphate ions by active transport
70
Q

Describe the stage of consumption in the phosphorous cycle.

A
  • an animal consumes the plant containing phosphate ions. They digest, absorb the ions and incorporate them into their biomass
71
Q

Describe the stage of excretion in the phosphorus cycle.

A

Some excretion will contain phosphate ions and some could go directly into the oceans again

72
Q

Describe the stage of excretion and decomposition in the phosphorus cycle.

A
  • after an animal dies there is the break down of material
  • phosphate ions from waste and remains are released (guano, bones and shells)
  • guano - produced by birds in excretion and is rich in phosphate ions
73
Q

What is guano?

A
  • guano - produced by birds in excretion and is rich in phosphate ions
74
Q

Describe the stage of erosion in the phosphorous cycle.

A
  • dead animal will erode, break down and release phosphate ions back into the ocean/ bodies of water
75
Q

Describe the stage of decomposition in the phosphorous cycle.

A
  • some material will go towards creating phosphate ions in rocks e.g guano disposition
76
Q

Describe the stage of erosion and fertilisers in the phosphorous cycle.

A
  • rocks can be eroded and return phosphate ions to the ocean/ bodies of water
  • runoff into the oceans can act as fertilisers
77
Q

Describe the stage of sedimentation in the phosphorous cycle.

A
  • sediment builds up and crated rocks containing phosphate ions
78
Q

Describe the stage of sedimentation in the phosphorous cycle.

A
  • sediment builds up and creates rocks containing phosphate ions
79
Q

How much of the atmosphere is composed of nitrogen gas?

A

78%

80
Q

What is the purpose of the nitrogen cycle?

A

To convert nitrogen gas into a form that can be taken up by plants

81
Q

What are the stages in the nitrogen cycle?

A

Nitrogen fixation
Ammonification
Nitrification
Denitrification

82
Q

Describe the process of nitrogen fixation in the nitrogen cycle.

A

Atmospheric nitrogen gas is converted into nitrogen-containing compounds

This biological nitrogen fixation is carried out by nitrogen-fixing bacteria

The bacteria convert nitrogen into ammonia, which forms ammonium ions (in solution) that can then be used by plants

These nitrogen-fixing bacteria are found inside the root nodules (small growths on the roots) of leguminous plants such as peas, beans and clover

The bacteria have a symbiotic (mutually beneficial) relationship with these plants - the bacteria provide the plants with nitrogen-containing compounds and the plants provide the bacteria with organic compounds such as carbohydrates

83
Q

What bacteria is involved in nitrogen fixation in the nitrogen cycle?

A

Nitrogen-fixing bacteria

84
Q

Where is nitrogen-fixing bacteria found (nitrogen fixation stage of the nitrogen cycle)?

A

Root nodules

85
Q

Why does nitrogen-fixing bacteria have a symbiotic relationship with the plant in the nitrogen fixation stage of the nitrogen cycle?

A

The bacteria have a symbiotic (mutually beneficial) relationship with these plants - the bacteria provide the plants with nitrogen-containing compounds and the plants provide the bacteria with organic compounds such as carbohydrates

86
Q

Describe the process of ammonification in the nitrogen cycle.

A

Nitrogen compounds in waste products (e.g. urine and faeces) and dead organisms are converted into ammonia by saprobionts (a type of decomposer including some fungi and bacteria)

This ammonia forms ammonium ions in the soil

87
Q

Describe the process of nitrification in the nitrogen cycle.

A

The ammonium ions in the soil are converted by nitrifying bacteria into nitrogen compounds that can be used by plants, known as nitrates

Initially, nitrifying bacteria convert ammonium ions into nitrites

Different nitrifying bacteria then convert these nitrites into nitrates

88
Q

How many different types of bacteria are involved in nitrification in the nitrogen cycle?

A

2 types of nitrifying bacteria

89
Q

Describe the process of denitrification in the nitrogen cycle.

A

Denitrifying bacteria use nitrates in the soil during respiration
This process produces nitrogen gas, which returns to the atmosphere
This process occurs in anaerobic conditions (when there is little or no oxygen available, such as in waterlogged soil)

90
Q

What conditions does denitrification happen in?

A

Anaerobic - such as in waterlogged soil

91
Q

What conditions does denitrification happen in?

A

Anaerobic - such as in waterlogged soil

92
Q

What do fertilisers do?

A

boost crop yields by providing essential nutrients.

93
Q

What are the 2 types of fertiliser?

A

Organic
Artificial

94
Q

What is the harber process?

A

Taking nitrogen from the atmosphere and industrially producing ammonia

95
Q

How can fertilisers effect biodiversity?

A

• Excessive fertilizer use promotes fast-growing species, reducing biodiversity.
Outcompeting slower-growing species disrupts ecosystems and food chains.

96
Q

What is leaching?

A

• Soluble nitrates from fertilizers can leach into groundwater and surface water.
• Nitrate contamination affects drinking water quality and aquatic ecosystems.
•

97
Q

Describe the process of eutrophication.

A
  1. Chemical fertilisers leach into water sources. Nitrates are soluble and are readily leached into ponds and lakes.
  2. The fertiliser accumulates, and is absorbed and utilised by algae. The excess of nitrates will lead to an algae bloom (a rapidly increasing population of algae).
  3. Light is unable to penetrate past the algae. Algae grows rapidly on the surface of the water, blocking any light.
  4. Plants cannot photosynthesise and will die.
  5. Animal species diversity will decrease. Many organisms rely on the plants for food and shelter, so when these die it disrupts the food chain.
  6. Respiration of decomposers uses up oxygen in the water. Dead organic matter provides more nutrients to the saprobionic bacteria. The bacteria respire aerobically, so use up the oxygen.
    This causes fish and other aquatic organisms to die.

Biology (8 decks)

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