CH 10- Photosynthesis
For AP Biology Students This set describes the cellular process of photosynthesis at an AP Biology level of analysis. This set is used in reference to Campbell/Reece's Biology Eighth Edition.
Terms in this set (55)
What process converts solar energy into chemical energy?
What are organisms that can sustain themselves without eating anything derived from other organisms and that are the producers for the biosphere?
Autotrophs (auto= self and troph=feeder)
What are organisms that use solar energy to make organic molecules from H20 and CO2? What are examples?
-Most all of plants are photoautotrophs, but other examples can be seen in this picture
What are organisms that obtain their organic material from other organisms?
Heterotrophs (Hetero= different, troph= feeder)
-make up consumers of the bioshpere
Where is the major location of Photosynthesis?
What drives the synthesis of organic molecules?
light energy absorbed by chlorophyll in the chloroplast
What are the microscopic pores where CO2 enters and O2 exits the leaf, which is on the bottom of most plants (top for water lilies)?
What are the interior tissues of leaves where chloroplasts are mainly found?
What is the chloroplast's anatomy?
1. Stroma: it is like the cytoplasm of the chloroplast (I jokingly call it "chloroplasm"); it is where the Calvin Cycle takes place
2. Thylakoids: little disks that are stacked up to help facilitate the light reaction
3. Granum/Grana: stacks of thylakoids
4. Thylakoid Membrane: the lipid bilayer surrounding the thylakoid
5. Thylakoid space: the space trapped inside thylakoids
What is the Photosynthesis Equation?
*the weird symbol is meant to be an arrow --->
How is photosynthesis a redox reaction?
Water is oxidized (hydrogen is lost making 6O2) and CO2 is reduced (hydrogen is gained making glucose)
What are the two stages of Photosynthesis? Brief summary?
1. Light Reactions (in thylakoid, Splits water, releases O2, Reduces NADP+ to NADPH, generates ATP via phosphorylation) AKA the "photo" part
2. Calvin Cycle (in stroma, forms glucose using CO2 ATP and NADPH from Light reactions) AKA the "synthesis" part
*Here is a helpful picture illustrating the overview of photosynthesis: Figure 10.5
What is the process of incorporating CO2 into organic molecules?
What is the entire range of electromagnetic energy AKA radiation?
What consists of wavelengths that produce the colors we see?
What are the discrete particles that make up light?
photons (light behaves like little photon particle in wavelengths)
What happens to wavelengths that are not absorbed?
they are reflected or transmitted
Why do leaves appear green?
because chlorophyll reflects and transmits green light (it doesn't absorb green light well)
What instrument measures a pigment's ability to absorb various wavelengths by sending light through pigments and measuring the fraction of light transmitted at each wavelength?
What is a graph plotting a pigment's light absorption as opposed to wavelength?
What is a graph that profiles the relative effectiveness of wavelengths of radiation in a driving process?
What types of light work best for photosynthesis?
Violet-blue and red work best for photosynthesis
What did Engelmann's experiment do?
Engelmann was the first to come up with an action spectrum by using photosynthetic algae and aerobic bacteria.
-Areas receiving wavelengths favorable to photosynthesis produced more O2 as a product
-The aerobic bacteria measured O2 production and thus photosynthesis rates by clustering along the algae with the most O2 and thus with the highest photosynthesis rate
What is the main photosynthetic pigment?
What pigment broadens the spectrum used for photosynthesis?
What pigments absorb excessive light that would damage the chlorophyll?
-they are one of several accessory pigments that dominate in the fall (and add colors to the leaves)
What happens when a pigment absorbs light?
electrons go from a grounded state to an excited state, which is unstable
What happens when excited electrons fall back to the ground?
photons are given off in an afterglow called fluorescence
What are pigment molecules bound to proteins?
(green= pigment molecules)
In the light reactions, what are reaction-center complexes surrounded by light-harvesting complexes?
*Note: a reaction-center complex is just a type of protein complex
What funnels the energy of photons to the reaction center?
the light-harvesting complexes
What accepts an excited electron from chlorophyll a?
a primary electron acceptor (it is the big square) and it is inside the reaction-center
Here is a VERY helpful diagram pulling all of this together: Figure 10.12
Here is a metaphor for how photons excite pigments
Where are photosystems located? How many are there?
2 distinct photosystems
What photosystem functions first and is the best at absorbing light at a wavelength of 680 nm?
Photosystem II or PS II
*Only named PS II because it was discovered 2nd
What photosystem functions second and is the bast at absorbing light at a wavelength of 700nm?
Photosystem I or PS I
What are the two possible routes for electron flow in photosynthesis?
cyclic and linear
What is the primary pathway involving both photosystems that produces ATP and NADPH using light energy?
linear electron flow
*This is illustrated in Figure 10.13-5
What happens after the electron falls from the primary electron acceptor? (LINEAR)
each electron falls down an electron transport chain
**This is because electrons are charged and need to use proteins to travel through the membrane
Where is does the electron from the PS II's primary acceptor fall to? (LINEAR)
a cytochrome complex to produce ATP
What does the energy released by the fall drive the creation of? (LINEAR)
a proton gradient across the thylakoid membrane
What drives ATP synthesis? (LINEAR)
Diffusion of H+ (protons) across the membrane through ATP synthase
Where is does the electron from the PS I's primary acceptor fall to? (LINEAR)
the protein ferredoxin (Fd)
From ferredoxin, where are the electrons then transferred? (LINEAR)
to NADP+ and then it is reduced to NADPH (available for the Calvin Cycle)
Need to know about Linear Electron Flow:
2 ETC (1st for ATP, 2nd for NADPH)
2 Products: ATP and NADPH
Here is a VERY VERY helpful picture outlining the Light reactions: Figure 10.17
How water fits in to the photosystems:
1. Light excites the chlorophyll a pigments causing a cascade of excitement eventually exciting a pair of chlorophyll a molecules in PS II reaction-complex called the P680 pair
2. An excited electron from the P680 pair is then transferred to the Primary acceptor
3.1 An enzyme catalyzes the splitting of water into 2 protons (H+), 2 electrons, and 1/2O2
3.2 The two electrons are supplied one by one to the P680 pair that just lost an electron to the primary acceptor
3.3 The 1/2O2 immediately binds with another 1/2O2 generated by the splitting of another water molecule, which is eventually released as a waste
4. The "photoexcited" electrons pass from the Primary acceptor of the PSII into the first ETC
5.1 The two protons from the split water molecule builds up inside the thylakoid space thus creating an electrochemical gradient
5.2 The protons pass through ATP synthase to form ATP
*Fun Fact: P680, when it loses an electron is in a state referred to as P680+. P680+ is the strongest known biological oxidizing (adding electrons) agent; the "hole" left by the lost electron must be filled, which greatly facilitates the transfer of electrons from the split water molecule
What flow uses only photosystem I and produces ATP, but not NADPH? What is it used for?
Cyclic Electron flow
-used to generate surplus ATP to satisfy higher demands in the Calvin Cycle
Need to know about Cyclic Electron Flow:
1 Product: ATP
What kind of organisms use Cyclic Electron flow?
primitive bacteria, plants, and cyanobacteria
How is cyclic electron flow linked to the Endosymbiotic theory?
1. Scientists thought that chloroplasts and mitochondria originated from bacteria
2. Cyclic electron flow is thought to have evolved before linear electron flow
3. Some organisms have PS I but not PS II so they only can have cyclic electron flow
Along which membranes does chemiosmosis occur in PS and CR?
PS: thylakoid membranes
What different sources of energy are used in PS and CR to produce ATP
PS: Photophosphorylation to get energy from light (to make ATP to drive the Dark Cycle)
CR: Oxidative Phosphorylation to get energy from food (to make ATP for cellular use)
On what side of the thylakoid membrane are ATP and NADPH produced?
the side facing the stroma
YOU MIGHT ALSO LIKE...
Core Topic 2 Molecular Biology | IB Biology Guide
Chapter 10- Photosynthesis
Chapter Ten Biology
OTHER SETS BY THIS CREATOR
L6- Thinking & Language
L5- Learning and Memory
Lecture #4- Sensation and Perception
L3- Genes, ANS, Sleep, & Consciousness
THIS SET IS OFTEN IN FOLDERS WITH...
Biology Proteins & Enzymes
Campbell's Biology Chapters 8-10 Vocabulary
Biology-Proteins, Carbs, Nucleic Acid, Lipids
Campbell Biology: Ninth Edition - Chapter Ch 17: From Gene to Protein (vocabulary)