Pd Bio 120: Photosynthesis
Which best represents the overall equation for photosynthesis?
6 CO2 + 12 H2O + Light energy → C6H12O6 + 6 O2 + 6 H2O
Why is light considered a form of electromagnetic radiation?
Because it consists of both electric and magnetic energy
A(n) --- can synthesize organic molecules from inorganic molecules, while a(n) --- must consume food to obtain organic molecules.
Blank 1: autotroph or photoautotroph Blank 2: heterotroph
Living organisms that are not plants depend on photosynthesis because photosynthesis produces: (1) organic molecules such as --- that can be used for nourishment; and (2) the --- gas that makes up a large portion of the Earth's atmosphere.
Blank 1: glucose Blank 2: oxygen
The Calvin cycle is affected by certain environmental conditions, including light intensity, --- availability, and ---.
Blank 1: water Blank 2: temperature
Atrazine is a chemical that blocks the electron from being transferred from photosystem II to photosystem I even though water can still be broken down into oxygen. What would be the effect on the plant?
Blocks ATP synthesis
How do CAM plants avoid water loss?
CAM plants close their stomata during the day and open them at night when it is generally cooler and more humid.
Heterotroph
Must consume food to obtain organic molecules
What are the products of the light reactions that are used by the Calvin cycle to make carbohydrates?
NADPH and ATP
Autotroph
Produces organic molecules from inorganic molecules
Photoautotroph
Uses light energy to drive the synthesis of organic molecules from inorganic molecules
Enhancement Effect: Leaves exposed to light of wavelength 680 nm alone or 700nm alone will undergo a similar amount of photosynthesis. However, when both wavelengths are shined at the same time more than double the amount of photosynthesis occurred. Which of the following best explains this observation?
When both wavelengths are used, electrons can pass from photosystem II to photosystem I generating more ATP.
Which of the following are products of the light reactions? a) ATP, b) O2, c) Carbohydrates, d) NADPH, e) NADP+, f) CO2
a) ATP, b) O2, and d) NADPH
What happens during photorespiration? a) Rubisco attaches O2 to RuBP, and CO2 is produced. b) Light stimulates mitochondria to consume O2 and produce CO2. c) Light energy is used to oxidize glucose, resulting in the production of CO2.
a) Rubisco attaches O2 to RuBP, and CO2 is produced.
A pigment is a molecule that can:
absorb light
What is the role of rubisco in the Calvin cycle?
as a catalyst to add CO2 onto RuBP
Which of the following are components of both PSI and PSII? a) An ATP synthase b) A light harvesting complex c) NADP+ reductase d) A reaction center
b) A light harvesting complex d) A reaction center
In C4 plants, the first product of carbon fixation is: a) four molecules of glucose b) a four-carbon molecule c) our molecules of 3GP d) four molecules of CO2
b) a four-carbon molecule
The reactions of the Calvin cycle occur in the: a) cytoplasm, b) stroma, c)plasma membrane, d) thylakoid membrane, or e) thylakoid lumen.
b) stroma
In photosynthesis, light energy is converted to --- energy, which in turn is converted to --- energy in a sugar molecule.
blank one: electrochemical blank two: chemical
All of the following are true about chlorophyll except: a) Chlorophyll a and b are pigments that absorb light at differing wavelengths. b) Color change in leaves is partially due to the death of chlorophyll. c) Chlorophyll absorbs light strongest in the blue portion of the visible light spectrum. d) Chlorophyll is a good absorber of green light.
d) Chlorophyll is a good absorber of green light.
Which of the following is the primary output of the Calvin cycle? a) Glucose b) Starch c) Ribulose biphosphate d) Glyceraldehyde-3-phosphate
d) Glyceraldehyde-3-phosphate
Sunlight provides the --- that is necessary for the synthesis of glucose from carbon dioxide.
energy
The rate of photosynthesis is influenced by a variety of factors. What shape of graph would most accurately represent the rate of photosynthesis as light intensity increases?
exponentially increasing and then leveling out
The light reactions of photosynthesis take place in the --- membrane, while the Calvin cycle occurs in the --- of the chloroplast.
light reaction: thylakoid calvin cycle: stroma
When a compound is oxidized, it generally ________.
loses potential energy
The light reactions synthesize ATP, NADPH, and O2 using the following process(es):
oxidation and reduction
The energy required for the synthesis of glucose from carbon dioxide ultimately comes from ---.
sunlight
The --- membrane of the chloroplast contains two independent, light capturing complexes of proteins and pigments called photosystems I and II.
thylakoid
What is the function of chlorophyll during photosynthesis?
It absorbs light energy.
What energy conversion occurs during photosynthesis?
Light energy is converted to electrochemical energy, which is converted to chemical energy
T/F: The ATP used during the Calvin Cycle in photosynthesis comes from cellular respiration.
False Recall that the ATP used in the Calvin Cycle gets turned into ADP and the light reaction in the thylakoids turns it back into ATP. *Be familiar with the intake and output of the Calvin Cycle and light reaction.
True or false: Glucose is the primary output of the Calvin cycle.
False. Reason: the primary output of the Calvin cycle is glyceraldehyde-3-phosphate, which can be used for glucose synthesis in another set of reactions.
How does photosynthesis benefit organisms that are not plants? a) It produces CO2 that is necessary to sustain the life of other organisms. b) It produces enzymes used for metabolic purposes by other organisms. c) It produces organic molecules that other organisms use as food. d) It produces oxygen that can be used for cellular respiration.
c) It produces organic molecules that other organisms use as food. d) It produces oxygen that can be used for cellular respiration.
Homologous genes are similar to one another because: a) they are expressed at the same time b) they are derived from a similar organism c) they are derived from the same ancestral gene d) they are found in similar tissues
c) they are derived from the same ancestral gene
Green plants utilize --- a and b to absorb light energy in photosynthesis.
chlorophyll
