Chapter 8 Flashcards
Photosynthesis
1
Q
absorption spectrum
A
range of wavelengths of
electromagnetic radiation absorbed by a given substance
2
Q
antenna protein
A
pigment molecule that directly absorbs
light and transfers the energy absorbed to other pigment
molecules
3
Q
Calvin cycle
A
light-independent reactions of photosynthesis
that convert carbon dioxide from the atmosphere into
carbohydrates using the energy and reducing power of
ATP and NADPH
4
Q
carbon fixation
A
process of converting inorganic CO2 gas
into organic compounds
5
Q
carotenoid
A
photosynthetic pigment (yellow-orange-red)
that functions to dispose of excess energy
6
Q
chemoautotroph
A
organism that can build organic
molecules using energy derived from inorganic chemicals
instead of sunlight
7
Q
chlorophyll a
A
form of chlorophyll that absorbs violet-blue
and red light and consequently has a bluish-green color;
the only pigment molecule that performs the
photochemistry by getting excited and losing an electron
to the electron transport chain
8
Q
chlorophyll b
A
accessory pigment that absorbs blue and redorange
light and consequently has a yellowish-green tint
9
Q
chloroplast
A
organelle in which photosynthesis takes place
10
Q
cytochrome complex
A
group of reversibly oxidizable and
reducible proteins that forms part of the electron
transport chain between photosystem II and
photosystem I
11
Q
electromagnetic spectrum
A
range of all possible frequencies
of radiation
12
Q
electron transport chain
A
group of proteins between PSII
and PSI that pass energized electrons and use the energy
released by the electrons to move hydrogen ions against
their concentration gradient into the thylakoid lumen
13
Q
granum
A
stack of thylakoids located inside a chloroplast
14
Q
heterotroph
A
organism that consumes organic substances
or other organisms for food
15
Q
light harvesting complex
A
complex that passes energy from
sunlight to the reaction center in each photosystem; it consists of multiple antenna proteins that contain a
mixture of 300 to 400 chlorophyll a and b molecules as
well as other pigments like carotenoids
16
Q
light-dependent reaction
A
first stage of photosynthesis
where certain wavelengths of the visible light are
absorbed to form two energy-carrying molecules (ATP
and NADPH)
17
Q
light-independent reaction
A
second stage of
photosynthesis, through which carbon dioxide is used to
build carbohydrate molecules using energy from ATP and NADPH
18
Q
mesophyll
A
middle layer of chlorophyll-rich cells in a leaf
19
Q
P680
A
reaction center of photosystem II
20
Q
P700
A
reaction center of photosystem I
21
Q
photoact
A
ejection of an electron from a reaction center
using the energy of an absorbed photon
22
Q
photoautotroph
A
organism capable of producing its own
organic compounds from sunlight
23
Q
photon
A
distinct quantity or “packet” of light energy
24
Q
photosystem
A
group of proteins, chlorophyll, and other pigments that are used in the light-dependent reactions
of photosynthesis to absorb light energy and convert it into chemical energy
25
photosystem I
integral pigment and protein complex in
thylakoid membranes that uses light energy to transport
electrons from plastocyanin to NADP+ (which becomes reduced to NADPH in the process)
26
photosystem II
integral protein and pigment complex in
thylakoid membranes that transports electrons from
water to the electron transport chain; oxygen is a product
of PSII
27
pigment
molecule that is capable of absorbing certain
wavelengths of light and reflecting others (which
accounts for its color)
28
primary electron acceptor
pigment or other organic
molecule in the reaction center that accepts an energized
electron from the reaction center
29
reaction center
complex of chlorophyll molecules and other
organic molecules that is assembled around a special pair
of chlorophyll molecules and a primary electron acceptor;
capable of undergoing oxidation and reduction
30
reduction
gain of electron(s) by an atom or molecule
31
spectrophotometer
instrument that can measure
transmitted light and compute the absorption
32
stoma
opening that regulates gas exchange and water
evaporation between leaves and the environment,
typically situated on the underside of leaves
33
stroma
fluid-filled space surrounding the grana inside a
chloroplast where the light-independent reactions of
photosynthesis take place
34
thylakoid
disc-shaped, membrane-bound structure inside
a chloroplast where the light-dependent reactions of
photosynthesis take place; stacks of thylakoids are called
grana
35
thylakoid lumen
aqueous space bound by a thylakoid
membrane where protons accumulate during light-driven
electron transport
36
wavelength
distance between consecutive points of equal position (two crests or two troughs) of a wave in a graphic
representation; inversely proportional to the energy of
the radiation
37
On a hot, dry day, the guard cells of plants
close their stomata to conserve water. What impact will
this have on photosynthesis?
Because there isn't enough water in the cells during the hot dry season, the guard cells don't expand, keeping the stomata closed. As a result, photosynthesis is disrupted, resulting in the plant's hunger.
Explanation
To conserve water in hot, dry weather, the stomata limit their entrance. The temperature of the air around the leaves affects the humidity around the leaves. The water from the leaves will diffuse more into the air as the air temperature rises. However, the leaf's waxy cuticle prevents water loss, whereas photosynthesis necessitates carbon dioxide and oxygen exchange with the environment.
Guard cells are specialised epidermal cells that surround the stomata. When there is enough water in the cells, the guard cells swell up, allowing the stomata to open. However, if there is insufficient water, these guard cells do not enlarge, and the stomata remain closed, allowing the plant to survive.
38
What is the initial source of electrons for the chloroplast electron transport chain?
Water
39
Which of the following statements is true?
In photosynthesis, chlorophyll, water, and carbon
dioxide are reactants. G3P and oxygen are products.
From another text: Both H2O and CO2 are reactants in photosynthesis. Products are G3P and oxygen. When carbohydrates are generated in the presence of chlorophyll, the process is known as photosynthesis.
40
Which of the following components is not used by both
plants and cyanobacteria to carry out photosynthesis?
chloroplasts
41
What two main products result from photosynthesis?
Sugars/carbohydrates and oxygen
42
In which compartment of the plant cell do the lightindependent
reactions of photosynthesis take place?
Stroma is compartment of the plant cell do the light independent reactions of photosynthesis take placed.
43
Which statement about thylakoids in eukaryotes is not
correct?
Thylakoids exist as a maze of folded membranes.
44
Predict the end result if a chloroplast’s light-independent
enzymes developed a mutation that prevented them from activating in response to light.
ATP and NADPH accumulation
45
Which part of the light-independent reactions would be affected if a cell could not produce the enzyme RuBisCO?
None of the cycle could take place, because RuBisCO its essential in fixing carbon dioxide.
46
How are the NADPH and G3P molecules made during photosynthesis similar?
The NADPH and G3P molecules made during photosynthesis similar, **They both store energy in chemical bonds.**
47
Which of the following structures is not a component of
a photosystem?
ATP synthase
Both photoreceptors have just the same underlying basis, with a reaction Centre encircled by antenna proteins that bind chlorophyll, and a light harvesting component that takes light energy from the sun and passes it to the excited state. The electric cell doesn't feature ATP synthase. It is also expressed in cell thylakoid sheets and produces ATP after photosynthesis.
48
How many photons does it take to fully reduce one
molecule of NADP+ to NADPH?
2
49
Which complex is not involved in the establishment of
conditions for ATP synthesis?
photosystem II
50
From which component of the light-dependent
reactions does NADPH form most directly?
photosystem I
51
Three of the same species of plant are each grown under
a different colored light for the same amount of time.
Plant A is grown under blue light, Plant B is grown
under green light, and Plant C is grown under orange
light. Assuming the plants use only chlorophyll a and
chlorophyll b for photosynthesis, what would be the
predicted order of the plants from most growth to least
growth?
A, C, B
52
Plants containing only chlorophyll b are exposed to
radiation with the following wavelengths: 10nm (x-rays),
450nm (blue light), 670nm (red light), and 800nm
(infrared light). Which plants harness the most energy
for photosynthesis?
Blue light irradiated plants
53
Which molecule must enter the Calvin cycle continually
for the light-independent reactions to take place?
CO2
54
Which order of molecular conversions is correct for the
Calvin cycle?
RuBisCO -> CO2 -> RuBP -> G3P
55
Where in eukaryotic cells does the Calvin cycle take
place?
chloroplast stroma
56
Which statement correctly describes carbon fixation?
the conversion of CO2 into an organic compound
57
If four molecules of carbon dioxide enter the Calvin
cycle (four carboxylation reactions), how many G3P
molecules are produced and how many are exported?
8 G3P made, 1 G3P exported
58
What is the overall outcome of the light reactions in
photosynthesis?
ATP and NADPH molecules are the end products of the light process. The dark processes employ the energy stored in ATP and NADPH to fix carbon dioxide into a glucose molecule. One molecule of NADPH and one molecule of ATP are produced when one molecule of water is hydrolyzed.
59
Why are carnivores, such as lions, dependent on
photosynthesis to survive?
Carnivores eat on herbivores, which get their food from plants that use photosynthesis to prepare it. As a result, carnivores rely on photosynthesis indirectly to thrive.
60
Why are energy carriers thought of as either “full” or
“empty”?
As a result, energy carriers either carry energy or do not; there is no in-between state, which is why they are either empty (no energy) or filled (energy) (carrying energy).
61
Describe how the grey wolf population would be
impacted by a volcanic eruption that spewed a dense ash
cloud that blocked sunlight in a section of Yellowstone
National Park.
The population of grey wolves in the ash cloud area would drop owing to a decrease in herbivore population, which is attributable to the loss in vegetation.
62
How does the closing of the stomata limit
photosynthesis?
As a result, closing stomata prevents gas exchange, limiting the quantity of carbon dioxide available to the chloroplast. The amount of carbon dioxide inside the plant leaves will cause photosynthesis to slow down and eventually stop.
63
Describe the pathway of electron transfer from
photosystem II to photosystem I in light-dependent
reactions.
A sequence of electron carriers transport the electron from photosystem -II to photosystem -I in the following order: PSII -> plastoquinone -> cytochrome complex -> plastocyanin -> PSI
64
What are the roles of ATP and NADPH in photosynthesis?
The role of ATP and NADPH is to function as an energy carrier in photosynthesis.
NADPH is employed as a reducing agent while ATP is used to supply energy for numerous endogenic reactions in the Calvin cycle or dark reactions.
65
How and why would the end products of photosynthesis
be changed if a plant had a mutation that eliminated its
photosystem II complex?
As a result, oxygen would not evolve in the absence of photosystem II. Electrons would not be extracted from water, and the electron flow would be disrupted, resulting in a halt of ATP, NADPH, and oxygen production.
66
Why is the third stage of the Calvin cycle called the
regeneration stage?
The third step is known as regeneration stage because Ribulose - bis phosphate that begins the cycle is regenerated from G3P.
67
Which part of the light-independent reactions would be
affected if a cell could not produce the enzyme
RuBisCO?
No cycle could take place, if a cell could not produce the enzyme RuBisCo
Chapter 8: Q. 30 (page 225)
Which part of the light-independent reactions would be affected if a cell could not produce the enzyme RuBisCO?
Short Answer
Expert verified
No cycle could take place, if a cell could not produce the enzyme RuBisCo
Step by step solution
01
Introduction
RuBisCo is needed in the Calvin cycle's first stage, where it catalyzes the interaction of carbon dioxide with RuBP (ribulose-1, 5-biphosphate) to produce 3-phosphoglycerate. In the absence of Rubisco, the process will take a long time to complete and the rate of photosynthesis will be significantly reduced.
Explanation
RuBisCo, also known as ribulose bisphosphate carboxylase / oxygenase, is a plant cell enzyme. It serves as a carbon dioxide acceptor for the photosynthesis process.
It plays a role in the Calvin cycle, which aids in the production of glucose molecules.
This process would not have a catalyst, if RuBisCo was not formed in the plant cells.
By decreasing the activation energy required, a catalyst speeds up the process.
As a result, glucose would be generated at a very sluggish rate or, more likely, would not be created at all.
68
Why does it take three carboxylation reactions to
produce one G3P, the initial product of photosynthesis?
As a three-carbon molecule, three turns of the Calvin cycle are required to produce one molecule of G3P, and only one carbon is fixed per turn of the cycle.
69
Imagine a sealed terrarium containing a plant and a
beetle. How does each organism provide resources for the other? Could each organism survive if it was the only
living thing in the terrarium? Why or why not?
As a result, while the beetle and therefore the plant can remain during a co-dependent relationship fora quick length of your time, delaying their death,they're going to eventually run out of resources and die.
70
Compare the flow of energy with the flow of nutrients in
a closed, sunny ecosystem consisting of a giraffe and a
tree.
sun's energy is employed by plants to organize their food through photosynthesis, which is then consumed by the giraffe when it eats the tree's leaves. The plants use the carbonic acid gas created by the giraffe during photosynthesis, and therefore the giraffe uses the oxygen released during the identical process for respiration.
