bio unit 2: chapter 8
Visible light has a wavelength range of
400-700 nanometers
How many revolutions of the Calvin cycle are required to produce the sugar glucose?
6
What products of light reactions of photosynthesis are used in the Calvin cycle?
ATP and NADPH
Under what circumstances would increasing light intensity not result in an increase in the rate of photosynthesis?
At any given time, the rate of photosynthesis is limited by the factor which is in the shortest supply. Therefore, if a factor other than light is limited, increasing the light intensity would not result in an increase in the rate of photosynthesis.
The ______ plants utilize a specialized carbon fixation enzyme and a unique cell structure to reduce the problems of photorespiration
C4
_______ adapted plants such as cacti, pineapples, etc. show a pattern of stomatal opening and closing that is the reverse of C3 plants
CAM
Jean Baptista van Helmont performed an experiment in which he planted a small willow tree in a pot of soil, after weighing both the plant and the soil. He watered the plant regularly. At the conclusion of the experiment five years later, the weight of the tree increased by 74.4 kg, while weight of the soil decreased by 57 kg. The primary source of the increased weight (mass) of the plant is from
CO2 in the air
The cyclic carbon fixation reactions are also known as the
Calvin cycle
Which of the following is not part of the light-dependent reactions
Calvin cycle
Most plants incorporate carbon dioxide into sugars by means of a cycle of reactions called the
Calvin cycle.
If chlorophyll a is blocked from absorbing, what will happen to chlorophyll b since it is an accessory pigment?
Chlorophyll b will still absorb near the green wavelengths of light, but photosynthesis will be greatly reduced.
Describe the conflict between a plant's need to undergo photosynthesis and its need to conserve water when it is in short supply. Briefly state how plants overcome this problem.
For photosynthesis to occur, plants need to take in CO2 and release O2. Plants accomplish this task by opening and closing the stomata on their leaves. Each time the stomata are open, however, plants also lose water vapor. If water is in short supply, this loss can decrease the rate of photosynthesis. To overcome this problem, plants undergo photorespiration.
Which of the following statements best describes the relative concentrations of G3P and RuBP in a chloroplast as a result of a transition from daytime (light) to nighttime (dark)?
G3P would increase and RuBP would decrease
Your research project involves a mutational analysis of the light harvesting complex Lhca1. Your labmate asks if you are working on a cytochrome found in the outer membrane of the chloroplast. You explain that
I am working on a protein found in the antenna complex and it is located in the thylakoid membrane
Which of the following scientists is not associated with studies on photosynthesis?
Krebs
Photosystem II differs from photosystem I in that _____________ is not made directly from the process
NADPH
The Calvin cycle is driven by ATP and _____ produced in the light reactions
NADPH
Photosystem II absorbs protons that are slightly more energetic than photosystem I, but similarly pass this energy to a pigment called
P680
In the photosystem I photocenter, light energy captured by pigment molecules is passed on to a special molecule called
P700.
__________ is the process by which certain organisms capture energy from sunlight and use it to build energy-rich food molecules.
Photosynthesis
In the dark reactions of photosynthesis, CO2 is added to a five-carbon sugar-phosphate known as
RuBP
Which of the following statements supports the fact that chlorophyll a is not the only pigment involved in photosynthesis?
The rate of photosynthesis is high at wavelengths when the absorption by chlorophyll a is low.
In the plants that utilize the CAM pathway, what happens to the stomata?
The stomata open in the evening but close in the morning.
Carotenoids are important to many plants because these pigments are able to
absorb wavelengths of light that neither chlorophyll a nor b can absorb
Each pigment molecule has a characteristic ________ spectrum.
absorption
Which of the following would not be considered to be a function of the antennae complex in photosynthesis?
acts as reaction center
Engelmann (1883) determined the wavelengths of light that plants could use most effectively. He used a green algae and __________ to obtain his results.
aerobic bacteria
Chlorophyll b absorbs in green wavelengths of light that chlorophyll a cannot absorb. In this respect, chlorophyll b acts as
an accessory pigment
What did the radioactive molecules represent
carbon compounds produced in the Calvin cycle
Carbon atoms of CO2 are incorporated into organic molecules in a series of dark reactions called
carbon fixation.
Fall leaf color on deciduous trees is a result of
cessation of chlorophyll production, which allows the accessory pigments to be revealed.
The general process whereby protons accumulate on one side of a membrane and can flow back across the membrane through ATP synthase resulting in ATP production is called _________________
chemiosmosis
In eukaryotes, photosynthesis takes place inside the _________
chloroplasts
The dark reactions of photosynthesis are those that
convert CO2 into reduced molecules (sugars)
Even though the Calvin cycle reactions require the products of the light reactions, its reactions can occur in the ________
dark
The wavelengths absorbed by a particular pigment depend on the available ______ levels to which the light-excited electrons can be absorbed
energy
Which of the following experimental modifications would help to determine the sequence of reactions and the reaction intermediates in the Calvin cycle?
exposing the cells to 14 CO2 for various time intervals
Your class project involves a presentation of the photoelectric effect. Which of the following materials would be the most helpful for a clear demonstration?
glow in the dark stickers and a UV light
Apparent color of chlorophylls.
green
Visible light not strongly absorbed by chlorophyls
green
The loss of carbon fixing activity of the enzyme RuBP carboxylase is directly proportional to
high temperatures and high light intensities
A scientist is hoping to synthesize a new herbicide that will kill certain weeds. She has found that one weed species in particular has thylakoids that have rather large pores. The herbicide will open the pores of these thylakoids, causing them to leak
hlorophyll
Engelmann (1883) discovered that the wavelengths of light that chlorophyll most strongly absorbed were
in the red-violet wavelengths of the visible light spectrum
The photosynthetic electron transport causes the accumulation of protons in which part of the chloroplast
internal thylakoid space
In the _____ reactions of photosynthesis, electron carrier molecules are reduced and ATP is synthesized.
light
One of the disadvantages of the C4 pathway is that it requires
more ATP
During electron transport, the thylakoid space becomes
more acidic than the stroma
If you exposed a C4 plant to 14CO2 in the light, which of the following would be the first organic molecule labeled with 14C?
oxaloacetate
The Calvin cycle requires all of the following except
oxygen
In dark reactions, when CO2 is added to a molecule of RUBP the product is
phosphoglycerate
Light consists of units of energy called
photons
CO2 is released without the production of ATP or NADPH. This process is called
photorespiration
merson and colleagues discovered the enhancement effect while studying photosynthesis in green algae. The algae were illuminated with light of either 680 nm or 700 nm, and the rate of photosynthesis was measured. The researchers found that the rate of photosynthesis when the lights were applied simultaneously was greater than the sum of the rates when the lights were applied individually. These results provided evidence that
photosynthesis is carried out by two photosystems that act in series.
Plants and algae use a two-stage _________ in the light dependent reactions
photosystem
Clusters of chlorophyll and accessory pigments are called _________
photosystems
You are working to isolate pigments from a cyanobacteria species recovered from the ocean floor. Which of the following would you most likely expect to find?
phycobiloproteins
Molecules that absorb light are called
pigments
Embedded in the thylakoid membrane and protruding as knobs from the outer surface into the stroma, there are
proton channels that synthesize ATP
Visible light with longest wavelength and lowest-energy photons; one of the regions where chlorophylls absorb
red
The connection between carrots and vision is that the β-carotene of carrots can produce two molecules of vitamin A and oxidation of vitamin A produces a pigment used in vertebrate vision. This pigment's name is
retinal
In which part of the chloroplasts are the Calvin cycle enzymes located?
stroma
A method devised by succulent desert plants to reduce the problem of photorespiration is
the CAM metabolism
Carbon fixation occurs during the dark reactions, or _____________, in photosynthesis
the Calvin cycle
Which of the following is common to both cellular respiration and the light reactions of photosynthesis?
the chemiosmotic formation of ATP
The plant hormone abscisic acid (ABA) is involved in the regulation of photorespiration. Based on this information, ABA likely plays a role in
the opening and closing of stomata.
The photosystem channels the excitation energy gathered by absorption of light by any one of the pigment molecules to a specific "reaction center chlorophyll," which in turn passes the energy to
the primary electron acceptor
Flattened sacs of internal membranes associated with photosynthesis are called
thylakoids
Sunburn is caused by which component of sunlight?
ultra violet rays
High energy component of the electromagnetic spectrum; associated with sunburn.
ultraviolet
Shortest wavelength and highest-energy photons within the visible spectrum; one of the regions where chlorophylls absorb
violet-blue
C. B. van Niel used sulfur bacteria in his research on photosynthesis. His equation involved carbon dioxide and hydrogen sulfide. The bacteria produce sulfur. In green plants which molecule is split to form the oxygen?
water
Most of the atmospheric oxygen occurs as a result of photosynthesis. From which of the following molecules is the oxygen derived?
water
In green plant photosynthesis, the electron donor for the light dependent reaction is
water.