When solar energy is used to blow up H20 into H+, O2, and e-. This occurs in the lumen of they thylakoid.
After chlorophyll "a" absorbs a photon, what happens to the electron inside of the chlorophyll "a" molecule? What happens to chlorophyll "a" after?
After chlorophyll "a" absorbs a photon, the electron inside of the chlorophyll "a" molecule becomes highly energized and is donated by the chlorophyll "a" molecule to the primary electron acceptor (a protein) in the thylakoid membrane. Then, because chlorophyll "a" donated an electron, it must now gain one to keep the cycle going. It gets this new electron from the splitting of water (photolysis)
What does it take for solar energy to be considered as captured?
when a low energy electron, in a chlorophyll molecule, from photosystem II absorbs a photon.
What do antenna pigments/ accessory pigments do in a photosystem?
They gather light and transfer it to chlorophyll "a" so that chlorophyll "a" actually uses the solar energy.
All the pigments of a photosystem capture and absorb photons. However only 1 pair of chlorophyll molecules can actually USE the solar energy. Which chlorophyll molecule is this and where is it located?
The chlorophyll molecule that can actually use the solar energy is chlorophyll "a" and chlorophyll "a" can be found at the core of the reaction center of a photosystem.
Label the parts:
what does the stroma do for the thylakoids?
It protects them.
Where are the photosystems in stage 1 of photosynthesis generally located?
the cluster of chlorophyll and other pigments (the photosystem) is packed into the thylakoid membrane
What is the difference between photosystem I and II? which one goes first and which goes second?
Photosystem I uses a different form of chlorophyll "a" then photosystem II. Moving on, the one that does its job first is photosystem II and the one that does its job second is photosystem I.
What is a photosystem?
A photosystem is a cluster of pigments.
Very generally, what occurs in the Calvin cycle and where does the Calvin cycle occur? Additionally, What is used by the Calvin cycle to make it work?
In the Calvin cycle, carbon fixation occurs. Carbon fixation is the incorporation of CO2 into organic compounds such as glucose. Moving on, the Calvin cycle occurs in the stroma of the chloroplast and it uses the ATP and NADPH from the light dependent stages of photosynthesis. Also, it uses enzymes for dehydration synthesis and hydrolysis.
Which stage of photosynthesis is light independent? What is another name for this stage?
Stage 3. Another name for this stage is the Calvin cycle.
Where do stages 1 and 2 of photosynthesis occur and what do they require?
Stages 1 and 2 of photosynthesis occur in the thylakoid membranes of the chloroplast and they require chlorophyll.
What are some other names for the light dependent stages 1 and 2 of photosynthesis?
noncyclic photophosphorylation or noncyclic electron flow.
The reactants of photosynthesis are the products of what chemical reaction?
cellular respiration
During reduction of NADP+, what happens? What about during oxidation of NADPH?
In reduction of NADP+, the NADP+ gains electrons, acting as a "high energy glue", allowing for the binding of the NADP+ to a hydrogen atom, forming NADPH. NADPH is now stable and can release energy to the next electron acceptor. Which is what exactly what happens during oxidation of NADPH where electrons "high energy glue" is removed from the NADPH, separating the hydrogen atom for the NADPH, forming NADP+. This NADP+ can be reused in future reduction reactions so that it can become NADPH again.
During reduction of ADP, what happens? What about during oxidation of ATP?
In reduction of ADP, ADP accepts e-, which is a "high energy glue" that ends up binding the ADP to Pi which turns the ADP into ATP, resulting in storage of energy. In oxidation of ATP, ATP releases electrons, removing that "high energy glue", turning the ATP into ADP + Pi which results in energy being released. This same ADP and Pi produced due to the oxidation of ATP can then be used in future reduction reactions to form ATP again.
What is a reducing agent and what is a oxidizing agent?
A reducing agent is a substance that causes reduction in another substance and an oxidizing agent is a substance that causes oxidation in another substance.
What is a redox reaction?
A chemical reaction involving both oxidation and reduction.
m True or false: Electron transfers between 2 substances always involves both oxidation and reduction reactions
True.
What is Oxidation and Reduction?
Oxidation: A reaction in which an atom or a molecule loses electrons
Reduction: A reaction in which an atom or molecule gains electrons
Describe glucose.
It is a transport molecule and it acts as medium-term energy storage in most cells.
What does e- act like in chemical reactions?
High energy glue. Allowing things like ADP and Pi or NADP+ and H to join through its addition (hence why it is considered to be like super glue; due to it, substances can bind.)
How is NADPH formed? How does it then go back to NADP+ and H?
NADP+ accepts 1 hydrogen atom and 2 electrons to form NADPH. Moving on, NADPH is an electron donor so it gives it away its electrons, causing the hydrogen to leave, turning it back into NADP+
What is NADPH? Describe its function.
NADPH, also known as nicotinamide dinucleotide phosphate, is a molecule that can be found at many different stages of photosynthesis and it is involved in energy transfers.
When ATP is formed by combining ADP and Pi, is there more energy stored or released in that chemical reaction? How about when ATP is broken down into ADP and Pi?
there is more energy stored than released when ATP is formed. However, when ATP is broken down to form ADP and Pi, more energy is released then stored/absorbed (this is obvious because the only reason ATP would split into ADP and Pi is to RELEASE energy to other cells)
What is ATP? What is it's function? And, how is it formed?
ATP, also known as Adenosine Triphosphate, is the principal energy-supply molecule for cellular functions of all cells. It provides an immediate source of energy for cellular processes. And, it is formed by the addition of ADP and Pi (phosphate)
Where does photosynthesis mainly take place?
in the thylakoid membrane and the stroma of the chloroplast.
What is paper chromatography? Describe it.
Paper chromatography is a method used to separate different compounds in a solution. As solvent moves up the paper, it will carry dissolved compounds of solution. The compounds will move up the paper at different rates due to their solubility in the solvent and their size. To perform this experiment, one must put the tip of the filter paper in the solvent. Then, as the solvent moves up the paper it will carry the pigments. The smaller the pigments, the further they will travel up the paper and the more soluble the pigments are, the further they will also travel up the paper.
Are lipid droplets and starch grains present in the chloroplast?
Yes. The starch grains are there for gravitropism.
True or false:
Chloroplasts are able to replicate, through division, dependent on their cell.
False: Chloroplasts are able to replicate, through division, INDEPENDENTLY of their cell.
What does the structure of the thylakoid system greatly increase?
It greatly increases the surface area of the thylakoid membrane. Thus, increasing photosynthesis efficiency.
What is the lumen of a thylakoid?
The lumen of a thylakoid is a fluid-filled space inside of the thylakoid that carries out chemiosmosis.
What is the thylakoid membrane and what does it contain?
The thylakoid membrane is a photosynthetic membrane within the chloroplast. It contains the light-gathering pigment molecules and the electron transport chains.
What are lamellae? What do they do?
Lamellae are groups of unstacked thylakoids (elongated thylakoids) that are between the grana. Lamellae exchange resources between thylakoids.
How many grana are in one chloroplast?
60.
what is a grana? How many thylakoids are in each grana?
A stack of thylakoids put on top of one another in the stroma of the chloroplast. Additionally, there are about 30-50 thylakoids within each grana.
What are the thylakoids?
Thylakoids are a system of interconnected flattened membrane sacs. They are the main photosynthesis structure and they form a separate compartment within the stroma of a chloroplast. Thylakoids stack on top of one another forming grana.
What is the stroma?
the stroma is a protein-rich semi liquid material in the interior of the chloroplast.
How many membranes do chloroplasts contain? What are they called?
Chloroplasts contain 2 membranes, the inner and outer membrane.
Sci 10 review: What do the waxy cuticle and the epidermis of a plant protect the plant from?
water loss.
sci 10 review: Where do gases enter and exit a plant?
from the stomata.
Sci 10 review: what does xylem transport and what does phloem transport?
xylem: transports water
phloem: transports sugar
Sci 10 review: describe chloroplasts.
chloroplasts are found in the leaves, they are the primary photosynthetic organs of most plants, and they contain chlorophyll (which captures light for food production).
Why do leaves change color in the fall?
Because in the fall, it gets colder and there is less sunlight. So, the trees recognize that there is less sunlight so they stop spending energy producing and maintaining chlorophyll so they end up sucking the chlorophyll back into their phloem. This then reveals the reds, the yellows, and the browns of the leaves which is due to the xanthophyll's, the carotenoids, and accumulated waste that is left inside of the leaf after the chlorophyll has been sucked back into the phloem.
What color light waves does chlorophyll 'a' reflect and which ones does it absorb?
reflect: green light waves
absorb: red and blue light waves
What creates the difference between the different types of chlorophylls?
The R group they contain.
What do accessory pigments do? Give examples of some of these accessory pigments.
accessory pigments absorb energy that chlorophyll "a" does not absorb. Examples of these accessory pigments include: chlorophyll "b" (also c, d, and e in algae and protistans.), Xanthophyll's (look red/blue/purple), and carotenoids (look orange/yellow)
What is the purpose of photosynthetic organisms having accessory pigments along with chlorophyll "a"?
Chlorophyll "a" can only absorb certain wavelengths of light. These amounts of wavelengths are not enough for the photosynthetic organism to survive. So, accessory pigments are necessary to absorb other wave lengths of light, giving the photosynthetic organism more overall light so that it can produce more glucose for itself to survive.
What pigment do all photosynthetic organisms have?
chlorophyll "a"
What is chlorophyll? What does it do? Where does it get its color from?
Chlorophyll is a light absorbing, green colored pigment (that means it reflects mostly green, maybe some other colors too, but mostly green). The color of this pigment comes from the wavelengths of light reflected. In terms of what chlorophyll does, Chlorophyll absorbs photons and begins the process of photosynthesis.
What is a pigment? What can a difference in pigment chemical structure cause?
It is a cluster of H2, O2, N2, and C all put together. Differences in pigment chemical structures can cause pigments to end up absorbing certain wavelengths of light and reflecting certain wavelengths of light depending on that chemical structure.
Ex. carotenoids will reflect orangy colors while chlorophyll will reflect more greenish colors. This is all due to the differences in chemical structure between carotenoids and chlorophyll.
Visible light is only how much of the total energy from the sun?
3%
How do you measure the energy of a certain light source? What makes light have higher energy and what makes light have lower energy?
By the looking at the distance between the top of the light wavelengths. The higher the distance between peaks, the less energy there is coming from that light source. However, the lower the distance between peaks, the higher the energy that light source contains.
Describe light.
It is a part of electromagnetic radiation (EMR) and it can be described by its wave characteristics or as particles of energy called photons.
Write the chemical formula for photosynthesis:
12H2O+ 6CO2-----> C6H12O6 + 6H20 + 6O2
(light energy)
In which organisms can photosynthesis occur in?
all plants, some algae, some bacteria, some protists (single celled organisms)
What is the purpose of stage 2 of photosynthesis? What are the two processes involved?
The purpose of stage 2 of photosynthesis is to form energy-rich molecules (ATP and NADPH). The two processes involved in stage 2 are H+ build up (ATP), and transfer of electrons (NADPH).
Write the chemical formula for photolysis.
2H20 (L) + energy ----> 4H+ + 4e- + O2(g)
What is photolysis? Where do each of the products of photolysis go?
Photolysis is a process in the plant where the solar energy absorbed by chlorophyll is used to split water into 4H+,2e-, and O2. Photolysis occurs in the thylakoid lumen.
the 2e- replaces the 2e- lost by the chlorophyll "a" molecules in photosystem II
the O2 exits the plant via the stomata in the leaves or is used to make H20 again.
The H+ will stay inside of the lumen of the thylakoid and help produce ATP.
Describe NADPH formation.
After the e- have lost their energy going through the electron transport chain, the e- are transferred from the ETC to photosystem I where they are once again energized by photons of light (exactly the same as the way in photosystem II). After this, the now re-energized e- are transferred to NADP+ where each NADP+ accepts 2e- and 1H+. Thus, reducing NADP+ to form NADPH.
Describe, in detail, how ATP is formed, starting after when the energy from the e- is released as it goes through the ETC which then turns on the H+ protein pumps.
So, due to the buildup of H+ ions inside of the lumen due to the activation of the H+ protein pumps and photolysis, the concentration of positive ions increases, resulting in an electrical gradient forming. Due to this electrical gradient, all the H+ ions end up wanting to do is go out of the thylakoid lumen and into the stroma to balance out the charges. However, the protein pumps only go one way. So, the H+ ions end up having to go through the ATP synthase complex (another tunnel in the thylakoid membrane). In doing so, the H+ ions end up releasing energy which then helps the ATP synthase complex combine ADP and Pi to form ATP.
What is chemiosmosis?
Charged particle movement due to an imbalance of electrical charges.
After the electron has passed the electron transport chain, What happens?
At this point, the e- have lost most of their energy (due to the fact that electrons release energy every time they go from one protein to another in the ETC). So, they end up transferring from the ETC to photosystem I where they are energize again by another photon (the same process as in photosystem II happens again) Then, after the electrons have been charged up again, they are transferred to NADP+ and reduce it into NADPH
When energy from e- is released as it goes from one electron acceptor/donor to another in the ETC, where does this released energy go?
The energy released from e- as it goes through the ETC is used to "turn on" H+ protein pumps in the thylakoid membrane to allow H+ ions to travel from the stroma, across the thylakoid membrane, and build-up in the lumen of the thylakoid. This causes the H+ ion concentration inside the lumen to increase, leading to the build-up of a positive charge.
What is an electron transport chain? as electrons move through the ETC, what happens to them?
It is when e- is passed from one molecular complex (proteins) to the next in a series of REDOX reactions between electron acceptors and donors. As electrons are exchanged from one protein to the next in the ETC, they lose and release energy each in each exchange.
After the two e- are removed from photosystem II and go to the primary electron acceptor, what happens to the electrons next?
They are sent to an electron transport chain.
During photolysis, how many electrons are released from the water molecule?
2.
where does the one carbon from the 2 PGAL that is not used for regeneration of RuBP go to until it can be used for glucose?
A glucose waiting room.
Why do plant use glucose for energy instead of ATP or NADPH?
Because glucose is smaller, less reactive, and has more energy than ATP and NADPH
Describe step 3 of the Calvin cycle (RuBP regeneration). Also, explain why 6 cycles of the Calvin cycle are needed for glucose to be made?
To start off, This step is needed so that the Calvin cycle can continue. And, ATP from the light-dependent reactions is used. In step 3, 5 carbons from the 2 PGAL produced in the Calvin cycle are used to reform RuBP with the help of ATP(5 carbons are used because RuBP is literally a 5 carbon molecule), leaving only one carbon to be used for glucose formation. So, this is why 6 cycles of the Calvin cycle must occur for Glucose to form, because glucose has 6 carbons. So, if you were to only get one carbon from the cycle each time, you would need that cycle to occur 6 times for glucose formation to actually happen.
PGAL has 3 purposes. What are they?
Provide chemical energy for the cell, combine to form glucose which is stored energy for the cell, and it can be recycled to form RuBP to allow the Calvin cycle to happen again.
Describe step 2 of the Calvin cycle.
Each PGA molecule from step 1 of the Calvin cycle accepts energy from ATP and NADPH where then, the 3-C PGA molecules are reduced to form PGAL and water. PGAL is now a stable molecule, and it then combines with another PGAL to form glucose (PGAL= C3H6O3. So, PGAL + PGAL = Glucose.)
Describe step 1 of the Calvin cycle.
In step 1 of the Calvin cycle, RUBP (ribulose biphosphate), a 5 carbon molecule attaches to CO2 coming from the stomata (For this reaction to work, an enzyme named RUBP carboxylase, or Rubisco, is needed.). After RUBP and CO2 combine, it forms a 6 carbon unstable molecule. This 6 carbon molecule is then broken down into two 3 carbon molecules called PGA, which do not have much energy. Due to this lack of energy, ATP and NADPH from stages 1 and 2 supply PGA with energy by reducing it, turning the PGA into PGAL or G3P.
Very generally, describe the 3 steps of the Calvin cycle and what is needed to make each of them function.
1. CO2 fixation and reduction
2. PGAL (G3P) molecules produced
3. Regeneration of RUBP.
Each stage requires enzymes for the cycle to occur.
How many times does CO2 have to go through the Calvin cycle to finally produce glucose? How many ATP and NADPH molecules would be used in one cycle and then to make a full glucose molecule?
CO2 has to go through the Calvin cycle 6 times to produce glucose. For one rep of Calvin cycle, 3 ATP's and 2 NADPH's are consumed per CO2 in one rep of Calvin cycle. However, to make a full glucose molecule, you would have to multiply those numbers by 6 (because it takes 6 reps to make a glucose molecule) meaning that to make one glucose molecule, you need 18 ATP's and 12 NADPH's to consume 6 CO2 molecules.
Where do the needed C,O, and H come from to make glucose?
Carbon- provided by CO2
Oxygen- photolysis of H20 in stage 1 and CO2
Hydrogen- photolysis of H20 in stage 1
What is PGAL/ G3P?
PGAL is a direct product of the Calvin cycle and it is a 3 carbon sugar. It is put together with another PGAL to form glucose in the stroma.
How does CO2 enter the leaf to allow the Calvin cycle to happen? When it enters the Calvin cycle what happens to it?
Through the stomata. When it enters the Calvin cycle it is reduced by ATP and NADPH
Where does the Calvin-Benson cycle take place? What are the reactants of the Calvin cycle, what are the products?
The Calvin-Benson cycle takes place in the stroma of the chloroplast. The reactants of this cycle are ATP, CO2, NADPH, and RUBP. The products are NADP+, H+, ADP, Pi, PGAL (G3P), H20, and RUBP
How is PGAL converted back to RuBP?
through the use of ATP
What is photosynthesis?
-A process that converts solar energy into chemical energy (C6H12O6)
Label the parts: