AO1 - Unit 5 Flashcards
1
Q
Which part of the leaf cell absorbs light energy?
A
in chloroplast
2
Q
Where does the light dependent stage occur?
A
Grana/ Thylakoid membranes
3
Q
What is a granum?
A
Stack of Thylakoids
4
Q
Name the 2 products of the LDR that are used in the LIR?
A
ATP and NADPH
5
Q
What does photolysis of water produce?
A
electrons, protons, and oxygen
6
Q
What happens during photoionisation?
A
electrons in chlorophyll are excited and lost
7
Q
Name the enzyme that catalyses the reaction to synthesis ATP
A
ATP synthase
8
Q
What is formed in the LIR?
A
Glucose (plus glycerol, fatty acids, amino acids)
9
Q
Give another name for the light independent step?
A
Calvin cycle
10
Q
What provides the energy for the LIR?
A
ATP
11
Q
Where does the light independent reaction occur?
A
Stroma of the chloroplast
12
Q
What is the first step of the LIR?
A
Fixation of carbon dioxide to Ribulose bisphosphate by the enzyme RUBISCO
13
Q
How many carbon atoms are in Ribulose bisphosphate?
A
5
14
Q
How is glycerate 3 phosphate (GP) made?
A
splitting of an unstable 6C intermediate
15
Q
What is the role of rubisco?
A
Fixing carbon dioxide to RuBP
16
Q
How is TP made?
A
reduction of Glycerate phosphate using ATP and NADPH
17
Q
What is the role of red NADP from the LD reaction?
A
To provide the H to reduce Glycerate phosphate to Triose phosphate
18
Q
What is the role of ATP?
A
To provide the energy to reduce Glycerate phosphate to triose phosphate
19
Q
What 2 substances can be made from TP
A
Glucose and ribulose bisphosphate (recycled)
20
Q
What is a limiting factor?
A
The factor, which if it increases, will increase the rate of the reaction ? it’s in shortest supply.
21
Q
What environmental factors limit the rate of photosynthesis?
A
Light intensity, carbon dioxide concentration, temperature (enzymes ? mainly in LIR)
22
Q
What is chromatography?
A
Separation of a mixture according to their solubility in a mobile phase
23
Q
What is a dehydrogenase?
A
Enzyme catalysing the transfer of hydrogen in redox reactions
24
Q
What is oxidation?
A
loss of electrons, hydrogen or gain of oxygen
25
What is reduction?
gain of electrons, hydrogen or loss of oxygen
26
What is a coenzyme?
A molecule that aids the function of an enzyme ? often by transferring groups ? hydrogen or acetyl groups
27
What does respiration produce?
aerobic - carbon dioxide, water, ATP anaerobic (plants & fungi) ethanol, carbon dioxide, ATP anaerobic (animals & bacteria) lactic acid + ATP
28
What is the first stage of aerobic and anaerobic respiration?
Glycolysis
29
Where does glycolysis occur?
Cytoplasm
30
What is the first step in glycolysis?
Phosphorylation of glucose
31
What are the products of glycolysis?
2 pyruvate, 2ATP and 2NADH
32
What is formed initially from the phosphorylated glucose?
Fructose 1,6 diphosphate which then splits into triose phosphate
33
How many carbon atoms in pyruvate?
3
34
What type of reaction converts TP into pyruvate?
oxidation
35
What happens to pyruvate in anaerobic respiration?
reduced to lactate (animals & bacteria) Decarboxylated to ethanal which is then reduced to ethanol (plants and fungi)
36
In aerobic conditions what happens to the pyruvate?
actively transported into the mitochondrion
37
Where does the link reaction happen?
Mitochondrial matrix
38
what is lost during the oxidation of pyruvate to acetate?
carbon dioxide and Hydrogen
39
How many carbon atoms in acetate?
2
40
What is the purpose of Kreb's cycle?
to oxidise acetyl group to carbon dioxide, transferring H to the coenzymes NAD and FAD, to produce ATP by substrate level phosphorylation
41
What happens to acetyl coenzyme A?
acetyl group combine to 4 C sugar, Coenzyme A recycled back to the link reaction
42
What is key role of NAD?
coenzyme to transfer Hydrogen
43
What is lost during Kreb's cycle?
carbon dioxide with hydrogen transferred to the coenzymes NAD and FAD
44
Where do the reactions of the kreb's cycle occur?
Mitochondrial matrix
45
Where does the link reaction occur?
Mitochondrial matrix
46
What are the purposes of cristae?
- Increase the surface area of the inner mitochondrial membrane
- more electron carriers and ATP synthase complexes
47
What occurs during the electron transport chain? Where does oxidative phosphorylation occur?
- Electrons are transferred down a chain of electron carriers at progressively lower energy levels through redox reactions.
- The energy released by the redox reactions is used to transfer hydrogen ions across the inner mitochondrial membrane
48
What does oxidative phosphorylation involve?
- the addition of an inorganic phosphate group to Adenosine diphosphate (ADP)
- transferring energy from the electron transfer chain to produce ATP according to the chemiosmosis theory
49
What type of reaction is each electron transfer?
redox
50
Energy released from redox reactions is used for what?
To transport protons (Hydrogen ions, H+) across the inner mitochondrial membrane from the matrix to the intermembrane space.
51
Protons diffuse back into mitochondrial matrix through what?
ATP synthase complex (channel protein and ATP synthase)
52
What is the final electron acceptor?
oxygen
53
What is chemiosmosis?
the movement of protons, H+ from the intermembrane space through the ATP synthase complex, down an electrochemical gradient. This movement is coupled to the phosphorylation of ADP and transfers kinetic energy as chemical energy
54
How could respiration be measured?
using a respirometer to measure the uptake of oxygen (with KOH absorbing any carbon dioxide released)
55
Why is sodium hydroxide used in a respirometer?
to absorb carbon dioxide release
56
Suggest units for the rate of respiration.
ml hr-1 g-1
57
What is the major route by which energy enters the ecosystem?
photosynthesis
58
What is a producer?
able to transfer energy to produce organic molecules
59
What is biomass?
EITHER:
- the dry mass of a living organism OR
- the chemical energy stored in biological molecules.
60
Why is dry mass often quoted?
Because the water content of living organisms (particularly plants) is highly variable AND it measures the mass of organic molecules
61
How is the energy in dry mass estimated?
- Using a bomb calorimeter
- burn the dry material and use the energy released to heat up a known volume of water.
62
Define gross primary productivity (GPP)
The total amount of chemical energy converted by plants in a given area, in a given time (production ? is not time related), GPP = NPP + R
63
Define net primary production(NPP)
NPP = GPP - R
The energy available to the plant for growth and reproduction AND to next trophic level, after producer has respired.
64
Write an equation to link GPP and NPP
GPP = NPP + R
65
Suggest units for GP
gross primary production units kJ m-2
66
What is net primary production available for?
to the plant for growth and reproduction AND then to the next trophic level
67
What is a herbivore?
An organism that consumes plants
68
What is a decomposer?
Organisms that feed on dead, decaying or their waste materials (they include detritivores and saprobionts)
69
Write an equation to show how net production of consumers can be calculated?
N= I - (F+R)
70
How is productivty increased by farming practices?
- Using pesticides, herbicides, fertilisers
- greenhouses with artificial lights red and blue and burning hydrocarbons
- genetic engineering
71
Why is photosynthesis inefficient?
- light reflected off the atmosphere and leaf surface
- light misses the chlorophyll molecules
- light is the wrong wavelength
72
Why do mammals a smaller proportion of energy up food chain than insects?
They use more energy to maintain a constant internal body temperature
73
Why are carnivores more efficient at converting their food into biomass than herbivores?
their food (meat) contains less indigestible material - cellulose
74
What is a saprobiont?
An organism that feeds on dead or decaying material by releaseing extra-cellular enzymes
75
What are mycorrhizae?
- fungi - made of long thin strands called hyphae, that live in a symbiotic relationship with plant roots
- they increase the surface area for the absorption of water and ions by the roots and are a means of communicating between plants.
76
What is mutualism?
symbiotic relationship in which both organisms benefit
77
Name 3 biological molecules containing Nitrogen
DNA, amino acids, RNA
78
What is detritis/ humus?
Dead plant material
79
How do saprobionts feed?
by releasing extra-cellular enzymes and reabsorbing the soluble products
80
What do saprobionts excrete?
extra-cellular enzymes
81
What is nitrification?
- the oxidation of ammonium ions to nitrite and then nitrate ions
- by aerobic nitrifying bacteria
82
What are nitrates used for?
uptake by roots for the production of amino acids and other nitrogen containing enzymes
83
Where are denitrifying bacteria found?
in anaerobic soils
84
What do denitrifying bacteria do?
convert nitrates into nitrogen gas
85
What natural phenomena can fix nitrogen gas?
Lightening
86
Where are nitrogen fixing bacteria found?
free in soil
87
What is nitrogenase?
the enzyme from N-fixing bacteria which allows nitrogen gas to be fixed at low temperatures
88
Name 3 important biological molecules that contain phosphorus.
DNA, RNA, ATP
89
What is an autotroph?
An organism that makes its own food using an external energy source-often sunlight
90
What is the difference between a chemoautotroph & a photoautotroph?
- An organism that makes its own organic compounds using energy from chemical reactions (usually oxidation)
- whereas organism that makes organic compounds using light
91
What is eutrophication?
Water becomes over-fertile: Main stages- Algal bloom/bacterial bloom/oxygen shortage
92
What is leaching?
When mineral ions are washed out of soil - often by rain on farmland - leads to eutrophication
93
What is regenerated during anaerobic respiration which allows glycolysis to continue?
NAD
