Chapter Seven: Photosynthesis Flashcards
Photosynthesis is the conversion of light energy to what kind of energy?
Chemical Energy
Organisms which can not manufacture their own food from simple Carbon compounds
Heterotrophs
Organisms which can manufacture their own food from simple Carbon compounds
Autotrophs
What are the three reactants in Photosynthesis?
- Carbon Dioxide
- Water
- Light (energy)
What are the two products of Photosynthesis?
- Food (carbohydrates)
- Oxygen
What is the Photosynthesis equation?
H2O + CO2 -> C6H12O6 + o2
Light comes in particles called…
Photons
Light travels in…
waves
Wavelength is the distance from one _______ ________ to the next
wave peak
All forms of Radiant Energy, including the visible spectrum
Electromagnetic Radiation
What kind of relationship is there between wavelength and energy?
Inverse relationship - the longer the wavelength, the less the energy
What is the range of wavelengths for the visible spectrum?
400-700 nm
Molecules capable of absorbing some wavelengths (colors) of light but not others
Pigments
What is the composition of white light?
All wavelengths (colors) of light
Only the wavelengths not ____________ by a pigment are reflected or transmitted to be seen
absorbed
A graph for a pigment, plotting the amount of light absorbed vs wavelength
Absorption Spectrum
A graph for a plant, plotting the photosynthetic activity (action) vs wavelength
Action Spectrum
Hydrophobic, Hydrocarbon _______ of Chlorophyll inserts Chlorophyll into the Thylakoid membrane
tail
The ______ of Chlorophyll has alternating double and single bonds that are useful for picking up and giving off extra electrons
head
These two things are groups of many copies of Chlorophyll-a and b, Carotene and Xanthophyll as accessory pigments
Photosystems 1 and 2
What has pigments arranged to pass light energy absorbed from pigments that absorb shorter wavelengths to those that absorb longer wavelengths?
Photosystems
A pair of Chlorophyll-a molecules occur in each Photosystem and ultimately ____________ the energy from other pigments
receive
What Photosystem is P700?
Photosystem 1
What Photosystem is P680?
Photosystem 2
P680 and P700 have special associations with the Photosystem’s…
proteins
Photosystems pass the high energy from electrons into the Photosystem, absorbing light, to a ____________ ____________ ____________ then molecules outside the Photosystem
Primary Electron Acceptor
Water enters plants through the ___________, traveling up the stem and to the leaves, through the Xylem making up Vascular Bundles
Roots
Water enters through the roots, traveling up the stem and to the leaves, through the __________ making up ___________ ____________
Xylem
Vascular Bundles
Carbon Dioxide enters the plant from the atmosphere (0.3%) through microscopic pores called ____________ in the underside of leaves
Stomata
How does Water and Carbon Dioxide enter leaf cells?
Diffusion
What is the equation for noncyclic photophosphorylation?
Water + Light -> NADPH + Oxygen + ATP
Noncyclic Photophosphorylation is what kind of reaction?
Light-Dependent Reactions
Step 1 of Noncyclic Photophosphorylation is….
Light goes to Photosystem 1, transferring the energy from the light photon into an electron in one of the pigment molecules
After the energy from the photon is transferred to an electron, it is passed to the…
Primary Electron Acceptor
After the electrons are passed to the Primary Electron Acceptor, it is then passed to…
Ferredoxin
After electrons are passed to Ferredoxin it is then passed to…
NADP Reductase
NADP Reductase reduces _____________ to _____________
NADP+
NADPH
What is a problem with Photosystem 1 in light-dependent reactions?
Photosystem 1 will run out of electrons and eventually shut down
What is Step 2 in Noncyclic Phosphorylation?
Light hits Photosystem 2, transferring the energy in the photon to an electron in a pigment
Energy in electrons, not electron itself, is passed to…
P680 (Photosystem 2 - reaction center)
After energy in electrons is passed to Photosystem 2, it passes electrons to the….
Electron Transport Chain
After electrons go to the Electron Transport Chain, they go to…
Photosystem 1
The Primary Electron Acceptor and the Redox Chain is all a part of the…
Electron Transport Chain
What is Chemiosmotic Theory?
Electrons passing through the Electron Transport Chain are used to pump H+ ions from the Stroma into the Thylakoid’s lumen
In Chemiosmotic Theory, Hydrogen ions diffuse down concentration gradient and pass through…..
ATP Synthase
In ATP Synthase, the H+ ions diffuse back into the _________ through ATP Synthase making ATP
Stroma
ATP Synthase rotates as H+ ions pass, coupling H+ flow with…
ADP Phosphorylation
What kind of protein is ATP Synthase?
Multimeric Protein
ATP Synthase consists of a base embedded in the ____________ ___________, a shaft, and a rotating head
Thylakoid Membrane
The shaft rotates as H+ ions pass between the ___ and ___ subunits in the base
a and c
The ____ degree rotation in ATP Synthase causes conformational changes in the head
120
ATP Synthase: In one conformation, the Beta subunit binds what two things?
ADP and Phosphate
ATP Synthase: In the second conformation, ADP and Phosphate are forced together, making…
ATP
ATP Synthase: In the third conformation, ATP is…
released
ATP Synthase: ______________ _________ flow is coupled to ATP Synthesis
Hydrogen Ion
The light absorbed by Photosystem 2 is also used to split ____________, generating oxygen gas (diffuses through the stroma)
Water
Hydrogen ions are added and them pumped into the…
Thylakoid
Major Products of Light-Dependent Reactions:
- ATP
- NADPH
- Oxygen
Photosystem 2, with the ET Chain and ATP Synthase, makes large quantities of…
ATP
Photosystem 1 makes large quantities of…
NADPH
Photosystem 2 receives replacement electrons from ____________, when it is split
Water
Photosystem 1 receives replacement electrons from the…., via PS 2
ET Chain
When levels of NADPH are high but ATP is low, plants can use…
Cyclic Electron Flow
PS1 then passes high energy electrons to FD then to the front of the Electron Transport Chain instead of…
NADP Reductase
Cyclic Electron flow passes high energy electrons through the … to make ATP without producing NADPH
Electron Transport Chain
CEF is used to produce more ATP since next step uses ___ ATP and ____ NADPH to convert one CO2 to Sugar
18
12
What are light-independent reactions also called?
Calvin-Benson Cycle
In the first step of the Calvin Benson Cycle, CO2 added to RuBP (Ribulose Bisphosphate) to yield 2 molecules of…
3PG (3-Phosphoglycerate)
What is the enzyme used in step 1 of the Calvin Benson Cycle?
Ribulose Bisphosphate Carboxylase-Oxygenase
In step 2 of the calvin benson cycle, reduction and phosphorylation of 3PG to G3P (Glyceraldehyde 3-Phosphate) using what two things?
NADPH and ATP
In step three of the calvin benson cycle, regeneration of RuBP (Pentose Phosphate Pathway) from ______, to continue the cycle
G3P
For every 6 Carbon Dioxide entering the cycle, 6 Carbons of _______________ or one _______________ are produced
Carbohydrate
Glucose
Other organic molecules are synthesized from the ______________ produced in photosynthesis
Carbohydrates
In photorespiration, Ribulose Bisphosphate Carboxylase-Oxygenase, in the absence of Carbon Dioxide adds ___________ to RuBP
Oxygen
Photorespiration Product: One molecule of 3PG and one molecule of _____________ which is respired (broken down using oxygen) but producing no ATP, reducing the pool of cellular carbohydrates when the plant should be storing sugars
Glycolate
What are the conditions for photorespiration?
Hot, Still, or Dry conditions
C4 Photosynthesis is a solution for….
Photorespiration
Carbon Dioxide is added to ______ by PEP Carboxylase making Oxaloacetate (a 4-Carbon Compound)
PEP
Oxaloacetate breaks down to what to things that are then used in C3 Photosynthesis?
Pyruvate and Carbon Dioxide
Oxaloacetate is converted to…
Malate
Malate is transported to….
Bundle-Sheath Cells
Malate breaks down to what two things that are then used in C3 Photosynthesis?
Pyruvate and Carbon Dioxide
Pyruvate is phosphorylated (with ATP) to what in order to continue the cycle?
PEP
Carbon dioxide “capture” occurs in what type of cells?
Mesophyll Cells
Oxaloacetate is transferred to what cells where it generates Carbon Dioxide for C3 Photosynthesis?
Bundle Sheath Cells
Carbon Dioxide is pumped into what kind of cells?
Bundle Sheath Cells
What kind of pathway is in Mesophyll Cells within the leaf?
C3
What type of cells in C3 plants have no photosynthesis and is not surrounded completely by Mesophyll Cells?
Bundle Sheath Cells
In C4 plants, what kind of cell has a C4 CO2 pump but no C3 pathway or photosynthesis?
Mesophyll Cells
What kind of cell has a C3 pathway and are completely surrounded by Mesophyll Cells?
Bundle Sheath Cells
Crassulacean Acid Metabolism (CAM) is found in what kind of plants?
Desert Plants
A CAM plant is a modification from what kind of plants?
C4
When does photosynthesis take place in a CAM plant?
Night
CAM plants: formation of ___________________ which is stored until day
Oxaloacetate
At night in CAM plants, CO2 is stored as…
Oxaloacetate
During the day in CAM plants, CO2 is released for…
Photosynthesis
In CAM plants, at night the stroma can be open to capture CO2 without losing much…
Water Vapor
In CAM plants, during the day, the stroma are closed to prevent…
desiccation
Why do plants produce and store carbohydrates?
To be able to break them down for energy when needed (EX: night and winter)
How does Carbon Dioxide for photosynthesis enter the leaf?
By diffusion through the stoma
Where in a C3 plant does C Photosynthesis take place?
Mesophyll Cells
High energy electrons from photosystem 1 are passed to what in order to be passed out of the photosystem?
P700
In light dependent reactions of photosynthesis, water is split. What is produced directly as a result of this reaction?
Oxygen
Where does Photosystem 1 directly pass electrons during Noncyclic Photosphosphorylation?
Feredoxin
Where in a cell do the light dependent reactions take place?
In the thylakoid of the chloroplast
Where in a cell does the Calvin-Benson cycle take place?
Stroma of the Chloroplast
The high energy electrons passed from Photosystem 1 are used for what in the Calvin Benson cycle?
reduce 3PG
What is the first product of the Calvin Benson Cycle that can be isolated?
3PG
What is the first product that can be isolated and identified in C4 Photosynthesis?
Oxaloacetate
What is an inhibitor of Phosphofructokinase?
ATP
Where in the cell is G3P produced during Cellular respiration?
In the cytoplasm
What is produced in the Krebs Cycle?
Carbon Dioxide
When protons diffuse down their concentration gradient through ATP synthase in aerobic respiration, where do they go?
Matrix of mitochondria
What four things does the Krebs Cycle of Aerobic Respiration produce?
- GTP/ATP
- NADH
- CO2
- FADH2
Where in an animal cell would Citrate be found?
matrix of mitochondria
What is produced by substrate level phosphorylation in Glycolysis?
GTP
During lactate fermentation, the electrons from NADH are passed directly to…
Pyruvate
When the last acceptor of electrons in the mitochondrial electron transport chain receives electrons from cytochrome oxidase, what is produced?
water
The epidermal growth factor allows transcription factions in the nucleus to be phosphorylated and activate many genes that produce proteins to stimulate…
cell division
What can diffuse across cellular membranes, enter the nucleus, and bind directly to genes?
Steroids Hormones
What is known to bind to and open calcium channels?
Inositol Phosphate