bio 101 reading questions exam 2
For every six carbon dioxide molecules that enter the Calvin cycle and are fixed, ___ 3-carbon compounds are released /removed from the cycle and the remaining___ 3-carbon molecules continue in the cycle to remake RuBP.
2,10
Which of the following best describes the action spectrum of green photoautotrophic organisms?
380-750 nm
How many carbon dioxide molecules are required to make one molecule of glucose?
6
Which of these statements describe some aspect of energy in living organisms?
-anabolic pathways involve the input of energy -carbohydrates store potential energy
Which of the following are examples of anabolic pathways? (choose all that are correct)
-synthesis of proteins -synthesis of amino acids
Which of the following are products of the light reactions that will be utilized in the Calvin Cycle (light-independent reactions)?
ATP and NADPH
Which of the following occur during the light-dependent reactions of photosynthesis??
ATP is made
The H+ concentration gradient that is formed during the light reaction is used by ______ to form________.
ATP synthase, ATP
A certain species of bacteria, Halobacterium, has a photosynthetic membrne that is colored purple. Its photosynthetic action spectrum is exactly opposite (complementary) to the action spectrum of green plants and photosynthetic organisms. What wavelengths of light do the Halobacterium photosynthetic pigments absorb?
blue and red
Which of the following is uncharacteristic of ATP?
It is a good long-term energy storage molecule
Why is ATP an important molecule in metabolism?
It provides energy coupling between exergonic and endergonic reactions.
If levels of ATP and NADPH dropped, what would happen to the overall rate of the Calvin cycle and why?
It would decrease, ATP/NADPH are needed for reactions in the reduction/regeneration phases of the cycle
The light-dependent reactions of photosynthesis produce which of the following?
Oxygen and ATP
Which of the following must be true for a reaction to occur spontaneously?
delta G must be negative
The oxygen that we are all taught is a product of photosynthesis comes from what?
Splitting of water to replace chlorophyll electrons
______________ permit CO2 to enter the leaf, and O2 to escape.
Stomata
How does a photoreactive pigment react with light energy (radiation)?
The pigment absorbs the light energy
In lab you are asked to place a protein in an acidic solution. What would you expect might happen to that protein?
The shape of the protein may change
Which of the following statement is true?
The shortest wavelength of light is the ultraviolet ray, which is the highest in energy.
What is the relationship between the wavelength of light and the quantity of energy per photon?
They are inversely related.
What is the primary purpose of the light reactions in photosynthesis?
To release electrons needed to convert solar energy to chemical energy.
Excess carbohydrates produced by the Calvin cycle during the day are stored as starch in the stroma of the chloroplast.
True
The purpose of chlorophyll in a plant cell is to:
absorb light
Which type of membrane transport process uses ATP as an energy source?
active transport
If an enzyme solution is saturated with substrate, what is the most effective way to obtain an even faster product yield?
add more enzyme
Imagine that you are a cell and you want to join two low energy molecules together. They resist joining. What two special types of molecules would you need to supply to overcome this obstacle?
an enzyme and ATP
Plants provide animals with which of the following?
food and oxygen
The energy available to do work in a system is called?
free energy
In the thylakoid membrane, what is the main role of the accessory pigment molecules associated with the photosystems?
harvest photons and transfer light energy to the reaction-center chlorophyll
You are an example of what type of energy system?
open system
The energy stored within an ATP molecule is?
potential energy
Energy that is stored is ___________ energy, while energy in motion is ________ energy.
potential, kinetic
The breaking apart of water during photosynthesis is critical to us as animals because this specific event also:
produces oxygen
When a molecule of NADP + gains a hydrogen atom, what does the molecule become?
reduced
During the process of photosynthesis, CO 2 is _______________ and H 2O is _______________.
reduced; oxidized
Which of the following captures the exited electron from the photosystem once it has received the energy from excited pigment molecules?
the primary electron acceptor
Triose phosphates are the true products of the Calvin cycle (not glucose or sucrose) because they are the molecules exported from the chloroplast.
true
Photosynthesis is driven by the ___________ light spectrum.
visible
What accumulates inside the thylakoid compartment during the light-dependent reactions?
Hydrogen Ions
The second energy law includes the fact that ________.
energy cannot be transferred without some energy loss
Whenever energy is transformed, there is always an increase in?
entropy in the universe
The stomata are located on the plants ________________ and the chloroplasts are located in the plant's _______________.
epidermis, mesophyll
In energy coupling the energy from an ________ reaction is used to power an _________ reaction.
exergonic, endergonic
Cells that contain chloroplasts do not contain mitochondria.
false
The Calvin cycle, or carbon fixation reactions, take place in the:
stroma of the chloroplast.
What is the primary function of the Calvin cycle?
synthesize high energy carbohydrates from CO 2
How does an enzyme serve as a catalyst for a reaction?
By lowering the activation energy of a reaction
There is more energy stored in a chemical bond than was used to form it.
False
During photosynthesis, visible light has enough energy to?
elevate electrons in chlorophyll to higher energy states
Where in a molecule of ATP is the stored energy that can be used by a cell?
in the covalent bonds between the phosphate groups
Where are the photosystems of the light reactions physically located?
in the intermembrane space of the chloroplast
Where would one find the protein complexes and electron carriers associated with the light reactions of photosynthesis?
in thylakoid membrane
Carbon fixation is taking place when plants:
incorporate CO2 into sugars
What are the possible fates of the light energy that is absorbed by the electrons in pigment molecules ?
it can be released as heat, as light of a lower wavelength, transferred to another pigment molecule, or used to transfer electrons to other molecules
When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
it is lost in the environment
Which of the following does not occur in the Calvin cycle?
release of oxygen
The oxygen gas that is produced as a result of photosynthesis is a direct by-product of:
splitting water molecules
Where do the enzymatic reactions of the Calvin cycle take place?
stroma of the chloroplast
Where do the electrons that replace the ones lost due to light excitation of Photosystem I come from?
the electron transport chain
The ultimate source of energy for all life on Earth is:
the sun
What holds the photosystems in the thylakoid membranes?
they are amphipathic and are held in place by hydrophobic and hydrophilic interactions
What is the source of ATP and NADPH used during the Calvin cycle?
they are produced by the light reactions of photosynthesis
How might thylakoid membranes be unique from the chloroplast membranes?
they might be composed of different phospholipids and proteins
Some "ancient" forms of photosynthesis use molecules like H 2S as electron donors rather than water, Why?
they only have one photosystem
Light-dependent reactions occur at the.....
thylakoid membrane
