BIO 116 Exam 2 Questions with
Complete Answers
LD Step 2: Electron acceptor - ANSWER-Within PS II and I, P680 is activated by
energy from photons and electron is accepted, causing a redox reaction.
LD Step 3: Splitting/Oxidation of Water - ANSWER-As photons hit PS II, enzymes
split water to H+ ions into thylakoid space and O2 as a biproduct.
- 2 H2O + 4 photons --> 4e- + 4H+ + O2
-Thylakoid space becomes more acidic
In PS I, electrons are transferred to ferredoxin and NADP+ accepts H+ ions from
stroma and brings them to Calvin Cycle.
LD Step 4: Electron Transport Chain - ANSWER-Primary electron acceptor donates
electrons to the transport chain which drives the H+ gradient.
LD Step 5: Chemiosmosis - ANSWER-H+ gradient causes activation of ATP
Synthase and chemiosmosis and diffuse down the gradient. ATP is produced from
this enzyme from H+ ions causing enzyme to dial.
electron donor in photosynthesis - ANSWER-water
electron acceptor in photosynthesis - ANSWER-NADP+
Light Independent Reactions (Calvin Cycle) - ANSWER-set of reactions in
photosynthesis that do not require light; energy from ATP and NADPH is used to
build high-energy compounds such as sugar; also called the Calvin cycle
-occurs in thylakoid space (lumen)
Simplified Calvin Cycle - ANSWER-3CO2 + 9ATP + 6NADPH --> G3P + 9ADP +
6NADP+
LI Step 1: Carbon Fixation - ANSWER-Rubisco enzyme incoporates CO2 to make
RuBP, an unstable 6-carbon protein which breaks to 2 3-Phosphoglycerate.
LI Step 2: Reduction - ANSWER-6 ATP and 6 NADPH donate electrons (reduce) to
create 6 G3P molecules.
LI Step 3: Regeneration of CO2 acceptor - ANSWER-Since Calvin Cycle needs to 2
cycles to produce 1 glucose molecule since G3P only has 3 carbons. The other 5
G3P molecules regenerate to RuBP so it can remain cyclical, which uses 3 more
ATP to do so.
, Stomata - ANSWER-Small openings on the underside of a leaf through which
oxygen and carbon dioxide can move.
-When open, water is lost but high gas exchange.
-Closed in hot and dry conditions to prevent water loss.
Rubisco - ANSWER-Most abundant protein on earth. Used in Calvin Cycle.
-Can take up O2 as the acceptor and perform photorespiration when CO2 levels are
low. Very wasteful process since it uses a lot of ATP.
C3 plants - ANSWER-Rely heavily on basic photosynthetic process.
C4 plants - ANSWER-Plants that are capable of converting any CO2 molecule using
a different enzyme and breaks it down again to increase CO2 concentration in both
low and high availability.
-Mesophyll contains PEP enzyme to increase CO@ concentration
-Bundle sheath cells have Calvin Cycle to produce sugar and transport to vascular
tissue.
i.e. sugar cane and corn
CAM plants - ANSWER-CAM plants open stomata at night and fix CO2 to organic
acid and during the day, they release it to be broken down to sugars using Calvin
Cycle.
Cellular Respiration - ANSWER-Process that releases energy by breaking down
glucose and other food molecules in the presence of oxygen
Cellular Respiration Equation - ANSWER-C6H12O6+6O2---> 6CO2+6H2O+ATP
-Glucose is oxidized (NAD+ is reducing agent)
-O2 is reduced (also the oxidizing agent)
CR Step 1: Glycolysis - ANSWER-Occurs outside of mitochondria and breaks down
glucose to pyruvate
-Uses substrate-level phosphorylation which is enzyme-catalyzed transfer of a
phosphate from intermediate substrate to make ATP.
-Energy Investment phase: breaks glucose to G3P (uses 2 ATP)
-Energy payoff phase: G3P is alter to pyruvate (makes 4 ATP)
Fermentation occurs here if O2 is low
Products: 2 ATP, 2 NADH, and 2 pyruvate
Outcome: cell needs more NAD+ to oxidize more glucose
CR Step 2: Citric Acid Cycle - ANSWER--Prep Step: Pyruvate is oxidized and
releases CO2, creating 2 NADH (reduced NAD+) and Acetyl CoA which is needed in
CA cycle. Occurs twice since there are 2 pyruvates.
-The Cycle: an eight-step process that breaks down Acetyl CoA to CO2. To produce
ATP, GDP takes up a Pi group and ADP then receives it causing substrate-level
phosphorylation.
Products: 2 CO2, 1 ATP, 3 NADH, 1 FADH2 (2x for one glucose molecule!)
Outcome: NADH and FADH2 electron carriers are brought e- transport chain and 6
CO2 (including prep step) and 2 ATP are created.
Complete Answers
LD Step 2: Electron acceptor - ANSWER-Within PS II and I, P680 is activated by
energy from photons and electron is accepted, causing a redox reaction.
LD Step 3: Splitting/Oxidation of Water - ANSWER-As photons hit PS II, enzymes
split water to H+ ions into thylakoid space and O2 as a biproduct.
- 2 H2O + 4 photons --> 4e- + 4H+ + O2
-Thylakoid space becomes more acidic
In PS I, electrons are transferred to ferredoxin and NADP+ accepts H+ ions from
stroma and brings them to Calvin Cycle.
LD Step 4: Electron Transport Chain - ANSWER-Primary electron acceptor donates
electrons to the transport chain which drives the H+ gradient.
LD Step 5: Chemiosmosis - ANSWER-H+ gradient causes activation of ATP
Synthase and chemiosmosis and diffuse down the gradient. ATP is produced from
this enzyme from H+ ions causing enzyme to dial.
electron donor in photosynthesis - ANSWER-water
electron acceptor in photosynthesis - ANSWER-NADP+
Light Independent Reactions (Calvin Cycle) - ANSWER-set of reactions in
photosynthesis that do not require light; energy from ATP and NADPH is used to
build high-energy compounds such as sugar; also called the Calvin cycle
-occurs in thylakoid space (lumen)
Simplified Calvin Cycle - ANSWER-3CO2 + 9ATP + 6NADPH --> G3P + 9ADP +
6NADP+
LI Step 1: Carbon Fixation - ANSWER-Rubisco enzyme incoporates CO2 to make
RuBP, an unstable 6-carbon protein which breaks to 2 3-Phosphoglycerate.
LI Step 2: Reduction - ANSWER-6 ATP and 6 NADPH donate electrons (reduce) to
create 6 G3P molecules.
LI Step 3: Regeneration of CO2 acceptor - ANSWER-Since Calvin Cycle needs to 2
cycles to produce 1 glucose molecule since G3P only has 3 carbons. The other 5
G3P molecules regenerate to RuBP so it can remain cyclical, which uses 3 more
ATP to do so.
, Stomata - ANSWER-Small openings on the underside of a leaf through which
oxygen and carbon dioxide can move.
-When open, water is lost but high gas exchange.
-Closed in hot and dry conditions to prevent water loss.
Rubisco - ANSWER-Most abundant protein on earth. Used in Calvin Cycle.
-Can take up O2 as the acceptor and perform photorespiration when CO2 levels are
low. Very wasteful process since it uses a lot of ATP.
C3 plants - ANSWER-Rely heavily on basic photosynthetic process.
C4 plants - ANSWER-Plants that are capable of converting any CO2 molecule using
a different enzyme and breaks it down again to increase CO2 concentration in both
low and high availability.
-Mesophyll contains PEP enzyme to increase CO@ concentration
-Bundle sheath cells have Calvin Cycle to produce sugar and transport to vascular
tissue.
i.e. sugar cane and corn
CAM plants - ANSWER-CAM plants open stomata at night and fix CO2 to organic
acid and during the day, they release it to be broken down to sugars using Calvin
Cycle.
Cellular Respiration - ANSWER-Process that releases energy by breaking down
glucose and other food molecules in the presence of oxygen
Cellular Respiration Equation - ANSWER-C6H12O6+6O2---> 6CO2+6H2O+ATP
-Glucose is oxidized (NAD+ is reducing agent)
-O2 is reduced (also the oxidizing agent)
CR Step 1: Glycolysis - ANSWER-Occurs outside of mitochondria and breaks down
glucose to pyruvate
-Uses substrate-level phosphorylation which is enzyme-catalyzed transfer of a
phosphate from intermediate substrate to make ATP.
-Energy Investment phase: breaks glucose to G3P (uses 2 ATP)
-Energy payoff phase: G3P is alter to pyruvate (makes 4 ATP)
Fermentation occurs here if O2 is low
Products: 2 ATP, 2 NADH, and 2 pyruvate
Outcome: cell needs more NAD+ to oxidize more glucose
CR Step 2: Citric Acid Cycle - ANSWER--Prep Step: Pyruvate is oxidized and
releases CO2, creating 2 NADH (reduced NAD+) and Acetyl CoA which is needed in
CA cycle. Occurs twice since there are 2 pyruvates.
-The Cycle: an eight-step process that breaks down Acetyl CoA to CO2. To produce
ATP, GDP takes up a Pi group and ADP then receives it causing substrate-level
phosphorylation.
Products: 2 CO2, 1 ATP, 3 NADH, 1 FADH2 (2x for one glucose molecule!)
Outcome: NADH and FADH2 electron carriers are brought e- transport chain and 6
CO2 (including prep step) and 2 ATP are created.
