UA BSC 108 EXAM 2 NEWEST 2024-2025 ACTUAL EXAM COMPLETE 90 QUESTIONS AND CORRECT
DETAILED ANSWERS
What is a photosynthetic autotroph? - (answer) An organism that makes its own food from inorganic
ingredients.
What is the fluid inside chloroplasts called? - (answer) Stroma
What are the membranes inside chloroplasts called? - (answer) inner and outer membranes
Write the overall equation for photosynthesis. - (answer) 6CO2+6H2O→C6H12O6+6O2
What is the primary function of pigments in photosynthesis? Name the primary pigment used in
photosynthesis. - (answer) Pigments absorb certain wavelengths. They are the means by which the
energy of sunlight is captured for photosynthesis. The primary pigment used in photosynthesis is
Chlorophylla-a.
Why are leaves green? - (answer) Their green color is from chlorophyll, a pigment (light- absorbing
molecule) in the chloroplasts that plays a central role in converting solar energy to chemical energy.
How and where does water enter a plant? - (answer) Water enters root hair cells by osmosis.
How and where does carbon dioxide enter a plant? - (answer) Carbon Dioxide diffuses through small
holes in the underside of leaves, called the stomata.
The light reactions take place in three stages. Name the stages and summarize the events of each stage.
1. Photons excite electrons in the chlorophyll of the first photosystem. These photons are then trapped
by the primary electron acceptor. This photosystem then replaces the lost electrons by extracting new
ones from water. This is the step that releases O2 during photosynthesis. 2. Energized electrons from the
first photosystem pass down an electron transport chain to the second photosystem. The chloroplast
uses the energy released by this electron "fall" to make ATP. 3. The second photosystem transfers its
light-excited electrons to NADP+, reducing it to NADPH.
List all products of the light reactions. carbon dioxide, water. Glucose, oxygen
The Calvin cycle has three main stages. Name the stages and summarize the events of each stage. -
(answer) "1) Carbon Fixation- The enzyme rubisco combines CO2 with 5-carbon sugar rubulose
, UA BSC 108 EXAM 2 NEWEST 2024-2025 ACTUAL EXAM COMPLETE 90 QUESTIONS AND CORRECT
DETAILED ANSWERS
biphosphate (RuBP). The unstable product formed splits into 2 molecules of 3-carbon 3-phosphoglyceric
acid (3-PGA).
2) Reduction- Energy from 6 molecules of ATP is used to oxidize NADPH to NADP+. Six molecules of 3-
PGA are reduced, producing six molecules of energy-rich 3-carbon sugar G3P.
3) Release of one molecule of G3P- Five of the previously created G3Ps remain in the cycle, but one
molecule is released.
4) Regeneration of RuBP - series of chemical reactions uses energy from ATP to rearrange the atoms of
the 5 G3P molecules, (15 total carbons), which forms 3 RuBP molecules (15 total carbons).
These will start another turn of the cycle.
"
List all products in the Calvin cycle. - (answer) "6 Turns of the Calvin Cycle→ 1 C₆H₁₂O₆
6CO₂ → 1 C₆H₁₂O₆
18 ATP + 12 NADPH → 1 C₆H₁₂O₆
Left over ATP is used elsewhere by the cell. "
Give two examples of plants that use C4 photosynthesis. - (answer) "1) Corn
2) Sugarcane"
What environmental factor is C4 photosynthesis an adaptation for? - (answer) High levels of CO2 and
drought environments
Contrast carbon fixation in C4 and CAM plants. C4 plants initially attach CO2toPEP to form the four-
carbon compound OAA using the enzyme PEP carboxylase. This takes place in the loosely packed cells
called mesophyll cells. OAA is then pumped to another set of cells, the bundle sheath cells, which
surround the leaf vein. There, it releases the CO2for use by Rubisco. By concentrating CO2in the bundle
sheath cells, C4plants promote the efficient operation of the Calvin-Benson cycle and minimize
photorespiration. CAM plants also initially attach CO2to PEP and form OAA. However, instead of fixing
carbon during the day and pumping the OAA to other cells, CAM plants fix carbon at night and store the
OAA in large vacuoles within the cell. This allows them to have their stomates open in the cool of the
evening, avoiding water loss, and to use the CO2 for the Calvin-Benson cycle during the day, when it can
be driven by the sun's energy.
DETAILED ANSWERS
What is a photosynthetic autotroph? - (answer) An organism that makes its own food from inorganic
ingredients.
What is the fluid inside chloroplasts called? - (answer) Stroma
What are the membranes inside chloroplasts called? - (answer) inner and outer membranes
Write the overall equation for photosynthesis. - (answer) 6CO2+6H2O→C6H12O6+6O2
What is the primary function of pigments in photosynthesis? Name the primary pigment used in
photosynthesis. - (answer) Pigments absorb certain wavelengths. They are the means by which the
energy of sunlight is captured for photosynthesis. The primary pigment used in photosynthesis is
Chlorophylla-a.
Why are leaves green? - (answer) Their green color is from chlorophyll, a pigment (light- absorbing
molecule) in the chloroplasts that plays a central role in converting solar energy to chemical energy.
How and where does water enter a plant? - (answer) Water enters root hair cells by osmosis.
How and where does carbon dioxide enter a plant? - (answer) Carbon Dioxide diffuses through small
holes in the underside of leaves, called the stomata.
The light reactions take place in three stages. Name the stages and summarize the events of each stage.
1. Photons excite electrons in the chlorophyll of the first photosystem. These photons are then trapped
by the primary electron acceptor. This photosystem then replaces the lost electrons by extracting new
ones from water. This is the step that releases O2 during photosynthesis. 2. Energized electrons from the
first photosystem pass down an electron transport chain to the second photosystem. The chloroplast
uses the energy released by this electron "fall" to make ATP. 3. The second photosystem transfers its
light-excited electrons to NADP+, reducing it to NADPH.
List all products of the light reactions. carbon dioxide, water. Glucose, oxygen
The Calvin cycle has three main stages. Name the stages and summarize the events of each stage. -
(answer) "1) Carbon Fixation- The enzyme rubisco combines CO2 with 5-carbon sugar rubulose
, UA BSC 108 EXAM 2 NEWEST 2024-2025 ACTUAL EXAM COMPLETE 90 QUESTIONS AND CORRECT
DETAILED ANSWERS
biphosphate (RuBP). The unstable product formed splits into 2 molecules of 3-carbon 3-phosphoglyceric
acid (3-PGA).
2) Reduction- Energy from 6 molecules of ATP is used to oxidize NADPH to NADP+. Six molecules of 3-
PGA are reduced, producing six molecules of energy-rich 3-carbon sugar G3P.
3) Release of one molecule of G3P- Five of the previously created G3Ps remain in the cycle, but one
molecule is released.
4) Regeneration of RuBP - series of chemical reactions uses energy from ATP to rearrange the atoms of
the 5 G3P molecules, (15 total carbons), which forms 3 RuBP molecules (15 total carbons).
These will start another turn of the cycle.
"
List all products in the Calvin cycle. - (answer) "6 Turns of the Calvin Cycle→ 1 C₆H₁₂O₆
6CO₂ → 1 C₆H₁₂O₆
18 ATP + 12 NADPH → 1 C₆H₁₂O₆
Left over ATP is used elsewhere by the cell. "
Give two examples of plants that use C4 photosynthesis. - (answer) "1) Corn
2) Sugarcane"
What environmental factor is C4 photosynthesis an adaptation for? - (answer) High levels of CO2 and
drought environments
Contrast carbon fixation in C4 and CAM plants. C4 plants initially attach CO2toPEP to form the four-
carbon compound OAA using the enzyme PEP carboxylase. This takes place in the loosely packed cells
called mesophyll cells. OAA is then pumped to another set of cells, the bundle sheath cells, which
surround the leaf vein. There, it releases the CO2for use by Rubisco. By concentrating CO2in the bundle
sheath cells, C4plants promote the efficient operation of the Calvin-Benson cycle and minimize
photorespiration. CAM plants also initially attach CO2to PEP and form OAA. However, instead of fixing
carbon during the day and pumping the OAA to other cells, CAM plants fix carbon at night and store the
OAA in large vacuoles within the cell. This allows them to have their stomates open in the cool of the
evening, avoiding water loss, and to use the CO2 for the Calvin-Benson cycle during the day, when it can
be driven by the sun's energy.
