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Photosynthesis Study Questions OLD

STUDY
PLAY
What is a biochemical pathway of photosynthesis in which CO2 is converted into carbohydrate using the energy stored in ATP and NADPH during the light reactions?
The Calvin Cycle
In the Calvin Cycle, CO2 is converted into carbohydrate using the energy stored in what two molecules?
ATP & NADPH
What is the incorporation of carbon dioxide into organic compounds?
Carbon fixation
Carbon fixation involves the incorporation of carbon dioxide into what?
Organic compounds
In what part of the chloroplast does carbon fixation occur?
In the stroma
Initially, in the Calvin cycle, carbon dioxide diffuses into the stroma from where?
The cytosol
In the first step of the Calvin cycle, what diffuses into the stroma from the cytosol?
Carbon dioxide
At the beginning of the Calvin cycle, what does carbon dioxide diffuse into?
The stroma
In the first part of the Calvin cycle, when carbon dioxide diffuses into the stroma, what molecule does the carbon dioxide bind to?
Ribulose Bisphosphate (RuBP)
How many carbon molecules are found in Ribulose Bisphosphate (RuBP)?
5
What type of macromolecule is Ribulose Bisphosphate?
A carbohydrate
What happens to the 6-carbon molecule that is formed during the Calvin cycle from carbon dioxide binding to Ribulose Bisphosphate?
It splits into two molecules of phosphoglycerate (PGA)
How many carbon molecules are found in Phosphoglycerate (PGA)?
3
In the Calvin cycle, when PGA is converted into G3P, where does the phosphate come from that is required to make that happen?
From ATP
In the Calvin cycle, when PGA is converted into G3P, where does the proton come from that is required to make that happen?
From NADPH
When ATP loses a phosphate, what is the ATP converted into?
ADP
What is the chemical symbol of a proton?
H+
What does ATP stand for?
Adenosine Triphosphate
What does ADP stand for?
Adenosine Diphosphate
In the Calvin cycle, when NADPH loses a proton, what is the NADPH converted into?
NADP+
How many carbons are in a molecule of G3P?
3
What is the actual name of G3P?
Phosphoglyceraldehyde
What is the balanced chemical equation for photosynthesis?
6CO2 + 6H2O + light energy yields C6H12O6 + 6O2
What are three examples of C4 plants?
Corn, Crabgrass, & Sugar cane
What are two examples of CAM plants?
Pineapple & Cactus
What type of plants lose the least amount of water: C3, C4, or CAM?
CAM
What does CAM stand for?
Crassulacean Acid Metabolism
When are the stomata opened in C3 plants?
Opened all day
When are the stomata closed in C3 plants?
Closed all night
When are the stomata opened in C4 plants?
Opened all day, except during the hottest part of the day
When are the stomata closed in C4 plants?
At night and during the hottest part of the day
When are the stomata opened in CAM plants?
Opened all night
When are the stomata closed in CAM plants?
Closed all day
During which pathway is carbon dioxide incorporated into organic acids at night?
The CAM pathway
What are the small pores found on leaves?
Stomata
On which side of a leaf are stomata usually found?
On the underside
What type of plants have stomata on the top surface of their leaves?
Aquatic plants whose leaves float on the surface of the water
How many ATP molecules get used in three turns of the Calvin cycle?
9
How many NADPH molecules get used in three turns of the Calvin cycle?
6
When water is split during the light reactions of photosynthesis, what is produced?
Protons, electrons, and oxygen
Where does the oxygen come from that is produced during the light reactions?
From the splitting of water
What is most of the G3P from the Calvin cycle used for?
To regenerate RuBP
What is a small portion of the G3P from the Calvin cycle used for?
To make organic compounds like amino acids, lipids, and carbohydrates
How many molecules of carbon dioxide are fixed during one full turn of the Calvin cycle?
1
How many molecules of RuBP are regenerated during one full turn of the Calvin cycle?
1
How many turns of the Calvin cycle does it take to produce one molecule of G3P?
3
Try to draw the diagram of the Calvin cycle without looking at your notes or textbook.
Check your drawing
How many molecules of ATP get used in one turn of the Calvin cycle?
3
How many molecules of NADPH get used in one turn of the Calvin cycle?
2
Why are C3 plants so named?
Because they incorporate carbon dioxide into 3-carbon compounds in the Calvin cycle
Why are C4 plants so named?
Because they incorporate carbon dioxide into 4-carbon compounds in the Calvin cycle
What enters a plant through stomata?
Carbon dioxide
What leaves a plant through stomata?
Oxygen and water
Why do C4 plants require less water than C3 plants?
Because C4 plants close their stomata during the hottest part of the day to reduce water loss, but C3 plants cannot
What happens to the level of carbon dioxide when the stomata are closed?
The level of carbon dioxide falls
What happens to the level of carbon dioxide when the stomata are closed?
The level of carbon dioxide decreases
Describe the levels of carbon dioxide and oxygen when carbon fixation by the Calvin cycle is inhibited.
The level of carbon dioxide is low and the level of oxygen is high
What do C4 plants have that allow them to fix carbon 4 times faster than C3 plants during periods of low carbon dioxide and high oxygen?
Enzymes
What is the function of the enzymes found in C4 plants?
They allow C4 plants to fix carbon dioxide 4 times faster than C3 plants is low carbon dioxide and high oxygen
How do C4 plants compensate for requiring more energy than C3 plants?
They grow in areas where more abundant sunlight (energy) is available
When does the Calvin cycle run in CAM plants?
During the day
Describe how light intensity affects the rate of photosynthesis.
As light intensity increases, the rate of photosynthesis initially increases then levels off
Describe how the level of carbon dioxide affects the rate of photosynthesis.
As the level of carbon dioxide increases, the rate of photosynthesis initially increases then levels off
Describe how temperature affects the rate of photosynthesis.
As temperature increases, photosynthesis accelerates then reaches a peak; Some of the enzymes that catalyze photosynthesis become unstable and ineffective; Stomata close which limits water loss and carbon dioxide entry into the leaves; Photosynthesis decreases
Write the balanced chemical equation showing how water is split into protons, electrons, and oxygen at the beginning of electron transport.
2H2O yields 4H + 4e- + O2
Where, in the chloroplast, is the electron transport chain located?
In the thylakoid membrane
Where do the electrons in photosystem II come from?
From the splitting of water molecules
How many electrons are made available by the splitting of two water molecules before electron transport?
Four electrons
What is the balanced chemical equation for photosynthesis?
6CO2 + 6H2O + light energy yields C6H12O6 + 6O2
What is the equation for photosynthesis in words?
Carbon dioxide + water + energy from the Sun yields carbohydrate (glucose) + oxygen
What are organisms that use photosynthesis to convert light energy into chemical energy called?
Autotrophs
What are some examples of autotrophs?
Plants, algae, and some bacteria
The products of photosynthesis are reactants used in what process?
Cellular respiration
What are the products of photosynthesis?
Carbohydrates & oxygen
What are the reactants of photosynthesis?
Carbon dioxide, water, & light energy
What are the waste products of cellular respiration?
Carbon dioxide & water
What are the reactants of cellular respiration
Oxygen & carbohydrates
How can you separate white light into its component colors?
By passing it through a prism
Put the colors of the visible spectrum in order from longest to shortest wavelength
red, orange, yellow, green, blue, indigo, violet
How are light waves measured?
by measuring their wavelength
Why are there different colors in the visible spectrum?
all the colors have different wavelengths
What can happen to white light when it strikes an object?
it can be reflected, transmitted, or absorbed
What happens to colors if they are absorbed by a pigment?
they are subtracted from the visible spectrum
Where in the chloroplast is chlorophyll found?
in the membrane of the thylakoids
What is the most important pigment used in photosynthesis?
chlorophyll
What are the two most common types of chlorophyll?
chlorophyll a & chlorophyll b
Does chlorophyll a or chlorophyll b absorb less blue light?
chlorophyll a
Does chlorophyll a or chlorophyll b absorb more red light?
chlorophyll a
Does chlorophyll a or chlorophyll b absorb more blue light?
chlorophyll b
Does chlorophyll a or chlorophyll b absorb less red light?
chlorophyll b
What is the function of accessory pigments?
They capture more of the energy in light
What are two types of accessory pigments?
Chlorophyll b & Carotenoids
What is the function of carotenoids?
They absorb colors that chlorophylls a and b do not
What parts of plants show the colors of the carotenoids?
The non-photosynthetic parts like fruits and flowers
Where in the chloroplast do the light reactions take place?
In the thylakoid membrane
What are the two types of Photosystems?
Photosystem I and II
Describe what happens in step one of electron transport?
Light excites electrons in chlorophyll a molecules of photosystem II
Which photosystem is the first chlorophyll a molecule of the electron transport chain?
Photosystem II
Describe what happens in step two of electron transport.
The electrons move to a primary electron acceptor
Describe what happens in step three of electron transport.
The electrons are transferred along a series of molecules called an electron transport chain
Where do the electrons come from that move into photosystem I?
From photosystem II
Describe what happens in step 4 of electron transport?
Light excites electrons in chlorophyll a molecules of photosystem I and the electrons move to another primary electron acceptor
In step 5 of electron transport, after electrons are transferred along a second electron transport chain, what happens to them?
The combine with NADP+ and H+ to produce NADPH
How is water used in electron transport?
An enzyme at the beginning of electron transport splits water into protons, electrons, and oxygen
When water is split before electron transport, what is produced that is considered to be a waste product that the plant does not need for photosynthesis?
Oxygen
Where does the oxygen that we breathe come from?
From the splitting of water before electron transport in photosynthetic organisms
What two molecules provide energy for the Calvin Cycle?
NADPH & ATP
What does chemiosmosis rely on?
A concentration gradient of protons across the thylakoid membrane
Where do the protons come from that are needed for chemiosmosis?
Some come from the splitting of water molecules, others are pumped from the stroma of the interior of the thylakoid
Where does the energy come from that is needed to pump protons from the stroma?
From the excited electrons that pass along the electron transport chain of photosystem II
Describe the concentration gradient of protons inside the thylakoid and in the stroma.
The concentration of protons is higher inside the thylakoid than in the stroma
What is a series of chemical reactions in which the product of one reaction is consumed in the next reaction?
Biochemical pathway
Why are cellular respiration and photosynthesis referred to as biochemical pathways?
Because the products of cellular respiration are the reactants of photosynthesis, and the products of photosynthesis are the reactants of cellular respiration
An organism that produces its own nutrients from inorganic substances or from the environment instead of consuming other organisms
Autotroph
The process by which plants, algae, and some bacteria use the energy of sunlight, carbon dioxide, and water to produce ATP, carbohydrates, and oxygen
Photosynthesis
An organism that obtains organic food molecules by eating other organisms or their byproducts and that cannot synthesize organic compounds from inorganic materials
Heterotroph
The initial reactions in photosynthesis, which are triggered by the absorption of light by photosystems I & II and include the passage of electrons along the electron transport chains, the production of NADPH and oxygen gas, and the synthesis of ATP through chemiosmosis
Light reactions
An organelle found in plant and algae cells where photosynthesis occurs
Chloroplast
A membrane system found within chloroplasts that contains the components for photosynthesis
Thylakoid
A stack of thylakoids in a chloroplast
Granum
In plants, the solution that surrounds the thylakoids in a chloroplast
Stroma
A substance that gives another substance or a mixture its color
Pigment
A green pigment that is present in most plant cells, that gives plants their characteristic green color, and that reacts with sunlight, carbon dioxide, and water to form carbohydrates
Chlorophyll
A class of pigments that are present in the thylakoid membrane of plants and that aid in photosynthesis
Carotenoid
In the thylakoid membranes of chloroplasts, a cluster of chlorophyll and other pigment molecules that harvest light energy for the light reactions of photosynthesis
Photosystem
In chloroplasts, an acceptor of electrons lost from chlorophyll a, found in the thylakoid membrane
Primary electron acceptor
A series of molecules, found in the inner membranes of mitochondria and chloroplasts, through which electrons pass in a process that causes protons to build up on one side of the membrane
Electron transport chain
In chloroplasts and mitochondria, a process in which the movement of protons down their concentration gradient across a membrane is coupled to the synthesis of ATP
Chemiosmosis
A biochemical pathway of photosynthesis in which carbon dioxide is converted into glucose using ATP
Calvin cycle
The synthesis of organic compounds from carbon dioxide, such as in photosynthesis
Carbon fixation
One of many openings in a leaf or a stem of a plant that enable gas exchange to occur
Stomata
A carbon-fixing process in which carbon dioxide is bound to a compound to form a four-carbon intermediate
C4 pathway
A water-conserving, carbon fixing process; these plants take in carbon at night and fix it into various organic compounds and release it during the day
CAM pathway
Green pigment that absorbs light during photosynthesis
Chlorophyll
Organelle that is the site of photosynthesis
Chloroplast
Organelle containing chlorophyll and other pigments
Chloroplast
The process by which living things obtain energy fro the chemical bonds in food molecules
Cellular respiration
An organic molecule that acts as the main energy source for cell processes
ATP
The first phase of photosynthesis
Light dependent reaction