BIOL 251 Exam
Comprehensive
Questions and
Verified Answers
(Detailed &
Elaborated) Actual
Exam 2026
what are the light dependent reactions
of photosynthesis?
-convert light energy into chemical
energy (ATP to NADPH)
-cyclic photophosphorylation
-oncyclic photophosphorylation
what are the light independent
reactions of photosynthesis?
1
,-convert CO2 to organic molecules
-anabolic- requires energy to build
complex molecules
-calvin cycle- takes energy from light
dependent reactions to create sugar
which of the following is required for
both photosynthesis and respiration?
-electron transport chain
What is cyclic photophosphorylation?
-light dependent reaction
-light energy excites electrons
-electron transport chain generates a
proton gradient
-ATP is generated by chemiosmosis
-electrons return to chlorophyll
what is noncyclic
photophosphorylation?
-light energy excites electrons
-electron transport chain between PSII
and PSI generates a proton gradient
2
,-ATP generated by chemiosmosis
-electrons are excited again
-electrons reduce NADP+ to NADPH
-electrons are replaced by splitting
water
-release O2
A flask containing photosynthetic
green algae and a control flask
containing water with no algae are
both placed under a bank of lights,
which are set to cycle between 12
hours of light and 12 hours of dark.
The dissolved oxygen concentrations
in both flasks are monitored. Predict
what the relative dissolved oxygen
concentrations will be in the flask with
algae compared to the control flask.
-the concentration of dissolved oxygen
in the flask with algae will be higher in
the light, but lower in the dark.
What is the calvin-benson cycle?
3
, - carbon fixation: conversion of CO2 to
organic molecules
-G3P can be used to make other
sugars
-no light required
what are the inputs and ouputs of the
calvin cycle?
-input = 3 CO2, 9 ATP, and 6 NADPH
-output= 1 G3P, 9 ADP, and 6 NADP+
How many molecules of CO2 are
needed to make one molecule of
glucose using the calvin cycle?
-6
-3 CO2 = 1 G3P
-2 G3P = 1 glucose
-2x3=6
what are are phototrophs?
-energy source is light
what are chemotrophs?
4
Comprehensive
Questions and
Verified Answers
(Detailed &
Elaborated) Actual
Exam 2026
what are the light dependent reactions
of photosynthesis?
-convert light energy into chemical
energy (ATP to NADPH)
-cyclic photophosphorylation
-oncyclic photophosphorylation
what are the light independent
reactions of photosynthesis?
1
,-convert CO2 to organic molecules
-anabolic- requires energy to build
complex molecules
-calvin cycle- takes energy from light
dependent reactions to create sugar
which of the following is required for
both photosynthesis and respiration?
-electron transport chain
What is cyclic photophosphorylation?
-light dependent reaction
-light energy excites electrons
-electron transport chain generates a
proton gradient
-ATP is generated by chemiosmosis
-electrons return to chlorophyll
what is noncyclic
photophosphorylation?
-light energy excites electrons
-electron transport chain between PSII
and PSI generates a proton gradient
2
,-ATP generated by chemiosmosis
-electrons are excited again
-electrons reduce NADP+ to NADPH
-electrons are replaced by splitting
water
-release O2
A flask containing photosynthetic
green algae and a control flask
containing water with no algae are
both placed under a bank of lights,
which are set to cycle between 12
hours of light and 12 hours of dark.
The dissolved oxygen concentrations
in both flasks are monitored. Predict
what the relative dissolved oxygen
concentrations will be in the flask with
algae compared to the control flask.
-the concentration of dissolved oxygen
in the flask with algae will be higher in
the light, but lower in the dark.
What is the calvin-benson cycle?
3
, - carbon fixation: conversion of CO2 to
organic molecules
-G3P can be used to make other
sugars
-no light required
what are the inputs and ouputs of the
calvin cycle?
-input = 3 CO2, 9 ATP, and 6 NADPH
-output= 1 G3P, 9 ADP, and 6 NADP+
How many molecules of CO2 are
needed to make one molecule of
glucose using the calvin cycle?
-6
-3 CO2 = 1 G3P
-2 G3P = 1 glucose
-2x3=6
what are are phototrophs?
-energy source is light
what are chemotrophs?
4
