photosythesis Flashcards
1
Q
what is the word equation for photosynthesis
A
carbon dioxide + water -> oxygen and glucose
2
Q
what is the chemical equation of photosynthesis
A
3
Q
what is meant by the term limiting factor
A
something, that leads to a reduction in product yield
4
Q
name three limiting factors
A
- light
- temp
- carbon dioxide
5
Q
what is meant by an autotroph
A
self feeding
6
Q
why do plants support all life
A
- primary producers
- produce oxygen
7
Q
what type of sugar is transported around the plant
A
scurose
8
Q
what vessel is sucrose transported in
A
the phloem
9
Q
what is the role of the chloroplast
A
absorb light
10
Q
what is photophosphorylation
A
adding phosphate groups
11
Q
what is the outer membrane
A
permeable to many small ions
12
Q
what is the inner membrane
A
- less permeable to small ions
- has transport proteins, embedded to control entry/ exit of substances
13
Q
what is the stroma
A
- fluid filled space surrounding the thylakoids
- site of the light dependent stage of photosynthesis (Calvin cycle)
14
Q
what is the granum
A
- thylakoids, stacked on top of each other to form the inner membrane site of the light dependent stage of photosynthesis
15
Q
what is the intergranular lamellae
A
membrane channels, joining grana together
16
Q
what is the photosystem
A
funnel - shaped structures that contain photosynthetic pigments found in the thylakoid membrane.
17
Q
what is photosynthetic pigment
A
colour substances, that absorb energy from certain wavelengths (colours) of light, they are embed in the thylakoid membranes.
18
Q
describe the contents of the thylakoid membrane
A
- photosynthetic pigments in photosystems
- electron carriers
- ATPase enzymes
19
Q
why is it useful, to have a range of light pigments
A
absorb different wavelengths/ colour of light.
20
Q
what is meant by the term photosynthetic pigment
A
pigment that absorbs specific wavelengths of light, and traps the energy associated with the light, such pigments include chlorophyll a and b, carotene and xanthophyll.
21
Q
where can we find photosystems
A
in the thylakoid membrane, in the chloroplasts.
22
Q
where is the primary reaction centre, in these photosystems, and what can we find there.
A
at the bottom of the photosystem and we find chlorophyll A there.
23
Q
what do electron carriers do
A
carry electrons
24
Q
what enzyme did respiration use to make ATP
A
ATPsynthase
25
what is the function of the light dependent reaction
to convert solar energy into chemical energy
26
what are the two things that are formed in the light dependent reaction
- NADPH (reduced NaDP)
- ATP
27
what is the Calvin cycle
- metabolic pathway of the light - independent stage of photosynthesis, occurring in the stroma of chloroplast where carbon dioxide is fixed, with the products of the light depend stage, to make organic compounds.
28
what are biotic components
components of an ecosystem that are living
29
what are abiotic components
components of an ecosystem that are non - living
30
what is this light energy used to do?
used to excite electrons in the chlorophyll A
31
what does the term photolysis mean
PSII, contains enzymes that in the presence of light, can split water into H+, protons, electrons and oxygen
32
why is photolysis important
- electrons from water, will replace electrons, lost from chlorophyll A.
- H+ ions, will be used to set up a H+ conc gradient
- H+ ions will be used to reduce NADP.
33
what is the equation that summarises photolysis
34
what does the photolysis of water do
light energy, hits a water molecule with the aid of enzyme , and water is split into oxygen, hydrogen ions and electrons.
35
explain the function of the Ph gradient
to encourage hydrogen, to diffuse out, using ATP synthase, in order to make ATP.
36
describe the diagram
37
describe the light harvesting and excitation
when a photon of light strikes PSII, its energy is channelled to the primary pigment reaction centre
38
describe the movement down the ETC
- energised electrons escape, form chlorophyll A molecule and are captured by an electron carrier
- electrons then pass down the ETC releasing energy as they pass from one electron carrier to the next.
- this energy is used to pump H+ ions into the thylakoid space.
39
describe the reduction of NADP
as the protons, pass through the channel proteins they are accepted, along with electrons, by NADP, which becomes reduced. The reduction of NADP, is catalysed by the enzyme NADP reductase.
40
what photosystems, are involved in cyclic photophosphorylation
PSI
41
describe what happens in cyclic photophosphorylation
- as light strikes PSI, a pair of electrons in the chlorophyll A molecule at the reaction centre gain energy and become excited
- the excited electrons, leave the chlorophyll A molecule and pass to an electron acceptor and then back again to the original chlorophyll A molecule from which they were lost in PSI via an electron transport chain.
- during the passage of electrons, along the electron carriers, a small amount of ATP is generated. No photolysis of water occurs.
42
ATP may be used in guard cells (their chloroplasts only contain PSI) to bring in potassium ions. Explain how this would cause the guard cells to open the stomata.
potassium ions, lower the water potential in the stomata, thus causing water to move in by osmosis causing cells to become turgid and this in turn causes the stomata to open.
43
where do the light depend reactions take place
thylakoid membrane
44
what is produced in the light dependent reactions
ATP, NADPH, oxygen
45
what happens to the electrons, that leave psII
the enter the electron transport chain in order to be used to reduce NADP
46
what happens to electrons that leave PSI
they go back to PSI
47
the build up of what type of gradient, allows for the synthesis of ATP
proton (electrochemical gradient)
48
name the protein responsible for the phosphorylation of ADP in these reactions
ATP synthase
49
which photosystem can carry out cyclic-photophosphorylation
PSI
50
what is the fate of oxygen that is produced
used for aerobic respiration
51
outline the role of water in photosynthesis
in order to split water by photolysis to create, electrons, oxygen and hydrogen.
52
suggest why a lack of iron in soil may reduce growth in plants
key in order to except and release electrons
53
what is photolysis and where exactly does it take place
- it is the splitting of a water molecule in order to produce electrons, hydrogen and oxygen.
- it takes place near the PSII
54
what is the light independent reaction
(the Calvin cycle) used to make TP (triose phosphate)
55
where does the light independent reaction occur
in the stroma
56
why is the light independent reaction not strictly light independent
because it requires NADPH , from the light dependent reaction
57
58
what is rubisco
an enzyme that joins RuBP and carbon dioxide
59
what is RuBP
ribulose bis phosphate ( 5 carbon sugar)
60
how many carbons, does GP have in it
3
61
what three steps summarise the Calvin cycle
- fixation of carbon dioxide
- reduction of GP
- regeneration of RuBP
62
what can TP molecules be used to make?
TP can be used to make glycerol, fructose, sugars, lipids etc.
63
what can GP be used to make
GP can be used to make fatty acids and amino acids
64
describe the Calvin cycle (the light independent reaction)
Carbon dioxide combines with the 5 carbon RuBP (via the enzyme rubisco, in order to form a 6 carbon compound, that immediately splits into two GP molecules. The addition of ATP, and NADPH (which is formed in the light dependent reaction) means that TP is able to be formed. Some of the TP molecules then combine (in pairs) in order to form a hexose sugar, which can later be turned into starch, via condensation reaction. The rest of the TP, is then used to regenerate RuBP, using ATP as the source of energy.
65
what is the compensation point
when photosynthesis and respiration, produce at the same rate, meaning that there will no net gain or loss of carbohydrates in the plant.
66
what is the compensation period
in the morning, the time a plant takes to reach is compensation points and after it has been dark.
67
what is the electron transport chain
chain or iron containing proteins, that can undergo reduction and oxidation, accepting and donating electrons, thus passing the electrons along the chain. Electron transport chains are involved in the production of ATP.
68
what is an electron carrier
molecules that can accept one or more electrons and then donate those electrons to another carrier. in photosynthesis, proteins embedded in the thylakoid membrane of chloroplasts are electron carriers and from an electron transport chain or system. Ferrodozin and NADp, are also an electron carriers.
69
what is water stress
- unable to replace water lost by transpiration.
- cells undergo plasmolysis.
- flaccid cells and wilting.
- abscisic acid to close stomata.
70
what are the two major ways we can investigate rates of photosynthesis
- the volume of carbon dioxide being used up.
- the volume of oxygen that is being produced.
71
