Exam 3 Review
which of the following statements about the Calvin cycle is true?
-Calvin and Benson used 14C radioisotope to determine the sequence of reactions in CO2 fixation -the three processes of the calvin cycle are fixation, reduction, and regeneration -during the reduction proceses, 3PG is converted to G3P which is the product of the calvin cycle
which of the following is true
-G3P can enter glycolysis or gluconeogenesis -protons pumped from the stroma into the thylakoids increase the pH, which activates rubisco -electron transport from photosystem 1 reduces disulfide bonds in Calvin cycle enzymes and activates them -C3 plants are more ancient than C4 plants
For every 6 CO2 fixed, the calvin cycle uses _____ molecules of NADPH, and _____ molecules of ATP.
12.....18
the first stable product synthesized during CO2 fixation is the sugar phosphate called
3-phosphoglycerate (3PG)
which is false?
NADPH is synthesized in the thylakoid lumen
In C4 and CAM plants, the primary CO2 fixing enzyme is
PEP carboxylase
which is false
PEP carboxylase fixes CO2 only when levels of CO2 are very high
Identify the correct statement
a photosystem is composed of pigments arranged in light-harvesting complexes around a reaction center
in noncyclic electron transport, oxidized chlorophyll in photosystem I returns to its reduced state by
accepting electrons from photosystem II through the electron transport chain
Which of the following is false?
accessory pigments always reflect light and do not contribute to photosynthesis
During chemiosmotic photophosphorlation by ATP synthase in the chloroplast, protons are moving
across the thylakoid membrane from the thylakoid lumen to the stroma
What was the conclusion from the above experiment
all the oxygen gas produced during photosynthesis comes from water
In CAM plants such as cacti, CO2 is fixed ____ to form a four-carbon molecule called _____ which is converted to malatew and stored in the the vacuoles of mesophyll cells for use in the calvin cycle_____
at night;oxaloacetate;during the day
Plants look green because
chlorophyll absorbs red and blue light and reflects or transmits green light
the electron transport chain that chain that exists between photosystem II and photosystem I
generates ATP
Which of the following statments is FALSE about cyclic electron transport?
it uses P680 reaction center only
which sequence gives a correct order of steps taking place during the light reactions?
light energy->excited electron->electron transport->ATP synthesis
the calvin cycle occurs in the
stroma of the chloroplast
the precise moment when light energy is transformed into chemical energy is the point at which
the P680 chlorophylls are oxidized
if 2 plants have different have different-colored leaves
their action spectra may match, but their absorption spectra will differ