Photosynthesis Quiz Flashcards
(39 cards)
1
Q
Formula of Photosynthesis
A
- Carbon Dioxide + Water (Energy From Light) = Glucose + Oxygen
- 6CO2 + 6H2O + Light Energy → C6H12O6 + 6O2
2
Q
Chloroplast
A
- An organelle in the plant cell that is in charge of photosynthesis.
- Contains chlorophyll
3
Q
Parts of a Chloroplast
A
Thylakoid, Stroma, Granna, Outer Membrane, Inner Membrane, Thylakoid Lumen, Lamella
4
Q
Stroma
A
- The interior space of the chloroplast made up of protein-rich semiliquid material.
- This is where Light-Independent Reactions/ Calvin Cycle occur
5
Q
Thylakoid
A
- Flattend, disk- like sacs with a thykaloid membrane enclosing a thylakoid lumen.
- Site of light-dependent reactions
6
Q
Granna
A
- (singular: granum) stacks of
thylakoids
7
Q
ATP
A
- Supplies energy from the cell (Adenosine Triphosphate)
- A molecule containing three high-energy phosphate bonds that acts as the primary energy-transferring molecule in living organisms
- Used by all living things (Plants & Animals)
- Provides an immediate source of energy for cellular processes, such as growth and movement
- Formed by the addition of an inorganic phosphate group (Pi) to a molecule of lower-energy ADP
- Energy is stored when ATP is formed from a phosphate group and ADP. This energy can be released when needed by the reversal of this reaction.
8
Q
ADP
A
- Adenosine diphosphate
- A molecule containing two high-energy phosphate bonds that may be formed by breaking one of the phosphate bonds in ATP
9
Q
Metabolism
A
All chemical reactions that occur within a cell to support and sustain life functions
10
Q
Anabolic Metabolic Pathways
A
Synthesize larger molecules from smaller ones
11
Q
Catabolic Metabolic Pathways
A
- Break down larger molecules into smaller ones and release energy
- Think of Cat Noir’s catalysm
12
Q
Oxidation
A
- LEO the lion
- Loses Electron
13
Q
Reduction
A
- Says GER
- Gain Electrons
- Compounds contain more energy in ther reduced form than in their oxidized form.
- Energy-rich molecules (such as glucose) are in their reduced form
- Molecules in their reduced form contain a large amount of availabe energy are siad to have reduicng power
14
Q
Pigments
A
- Molecules that absorb specific wavelengths of light and are essential for capturing the energy from sunlight to drive the photosynthetic process.
- Chlorophyll a is the main pigment, while accessory pigments like chlorophyll b and carotenoids help absorb more wavelengths of light to increase the efficiency of photosynthesis.
15
Q
Photon
A
A packet of light
16
Q
Why do plants look green?
A
Plants look green because they reflect the green colour.
Chlorophyll does not do well in cold temperature that is why there is a colour change in fall.
16
Q
Chlorophyll
A
- The light-absorbing green-coloured pigment that begins the process of photosynthesis
- Chlorophyll a (blue-green) and chlorophyll b (yellow-green) are two common forms.
17
Q
List the Two Main Parts of Photosynthesis
A
- Light-Dependent Reactions
- Light- Independent Reactions
18
Q
Photosystem
A
- Embeded in the membrane of the thylakoid
- There are 2 types: Photosystem I & Photosystem II
- Chlorophyll and other pigments are arranged in cluster called PSI and PSII
- Pigment molecules, including approx. a dozen chlorophyll and carotenoid molecules
- A molecule that ACCEPTS an electron
- A specialized electron-accepting chlorophyll a molecule called the reaction centre
19
Q
Summary of Light Dependent Reaction
A
- Light-dependent reactions harness light energy to drive electron transport & proton pumping in order to convert light energy into ATP and to produce NADPH, which is a molecule that has a high reducing power (G.E.R)
- The MAIN goal is to make ATP & NADPH
20
Q
Step 1 of LIGHT DEPENDENT REACTION
A
- Sunlight hits the leaf (Specifically in PSII)o
- Chlorophyll (Green pigment) absorbs the light photon, and the reaction center receives the energy, and an electron in the reaction center is “excited,” meaning it reaches a higher energy level.
21
Q
Step 2 of LIGHT DEPENDENT REACTION
A
- The “excited” electron is passed on to an electron accpeting molecule.
- Electron leaves PSII and goes to the electron acceptor site
- This electron must be replaced in PSII before PSII can absorb MORE energy to excite another electron
21
Q
Replacement of Electron in PSII
A
- The NEW electron comed from a water molecule
- Water molecule is split in a series of reactions that release electrons, hydrogen ions, and oxygen atoms
- This process is called PHOTOLYSIS
* This is where the oxygen that plants releases come from
22
Q
Step 3 of LIGHT DEPENDENT REACTIONS
A
- From the electron acceptor the energized electron is transferred along a series of electron-carrying molecules
- These molecules are referred to as an electron transport system (ETS) or electron transport chain (ETC)
- With each transfer along the electron transport system, the electron releases a small amount of energy
- This released energy is used to push hydrogen ions from the stroma across the thylakoid membrane and into the thylakoid space
22
Energy Passed From Electron Transport System
- Stored temporarily in a hydrogen ion concentration gradient across the thylakoid membrane
- The energy will later be used to generate ATP from ADP
23
Photosystem I
* Scientist discovered it first BUT it is the second step of the LD reaction
* While the electron left the reaction centre in PSII and passed through the electron transport system, light energy was absorbed by PSI
24
What Goes On In PSI?
* Quite similar to PSII
* Light energy is transferred to a reaction centre, where it excites an electron
- An electron is passed to a high-energy electron acceptor site
- The lost electron is replaced by an electron that has reached the end of the electron transport system from photosystem II
25
The Final Step of LIGHT DEPEENDENT REACTION
* The final electron that was received by the electron-acceptor from PSI is used to reduce NADP+ to create NADPH
* NADP+ is converted into NADPH when Hydrogen ion and 2 electrons are added
* The reducing power of NADPH will be used to in the LIGHT-INDEPENDENT reactions
26
Chemiosmosis
* A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.
* Occurs in the **light-dependent reactions** in the thylakoid membrane of the chloroplasts
* GOAL: To produce ATP to power the Calvin Cycle
27
Making ATP: Chemiosmosis
| Ms. Brozic's version of the notes
- When hydrogen ions are forced from the **stroma** to the **thylakoid space**, they **CANNOT** diffuse back across the membrane because the membrane is impermeable to these charged particles
- Special structures called **ATP Synthase** provide a pathway for the hydrogen ions to move down their concentration gradient
- The pathways is linked to a mechanism that bonds a free phosphate group to an ADP molecule to form ATP
- As the hydrogen ions move down their concentration gradient through the ATP synthase, the energy of the gradient is used to generate ATP molecules
28
Step-By-Step Process for Chemiosmosis
* Light energy excites electrons in Photosystem II.
* Excited electrons travel through the (ETC).
* Water (H₂O) is split (photolysis) to:
* Replace electrons in PSII
* Release H⁺ ions into the thylakoid space.
* Produce oxygen (O₂) as a byproduct.
* Energy from the moving electrons is used to pump more H⁺ ions into the thylakoid space, increasing proton concentration inside.
* A proton gradient is established:
* High H⁺ concentration inside thylakoid.
* Low H⁺ concentration in the stroma.
* Protons (H⁺) flow back into the stroma through ATP synthase (a protein channel).
* The flow of protons spins ATP synthase, providing energy to form:
* ADP + Pi → ATP
* ATP is released into the stroma and used in the Calvin Cycle to make glucose.
29
Summary of Light-Independent Reactions
* It can happen anytime, day or night
* Once there is enough ***NADPH & ATP*** in the stroma **(Made from LD Reactions)** the energy of these molecules can be used to create glucose in the presence or absence of light.
* Happens in the **STROMA**
30
Calvin-Benson Cycle
* Series of reaction where **carbohydrates** are syntehsized
* AKA Calvin Cycle
31
List the Stages of the Calvin Cycle
* Carbon Fixation
* Reduction
* Regeneration of RuBP
32
Calvin's Cycle Stage 1: **Fixing Carbon**
- A carbon atom (One singular carbon atom) in carbon dioxide is chemically bonded to a 5-carbon compound called ribulose bisphosphate (RubBP) for short
- When the carbon combines with RuBP, it makes a 6-carbon molecule
- These 6-carbon molecules are very unstable and immediately break down into 2 identical, stable 3-carbon molecules
- Plants that do this stage are called C3 plants
33
Calvin's Cycle Stage 2: **Reduction**
- The 3-carbon molecules that were just formed are in a low-energy state
- To convert them into a high-energy state, they are first activated by ATP and then reduced by NADPH
- The result is 2 molecules of PGAL (glyceraldehyde-3-phosphate, sometimes abbreviated G3P)
34
Calvin's Cycle Stage 3: **Replacing RuBP**
* Most of the **reduced** PGAL molecules are sued to make more RuBP
* Requires energy (ATP) to break down and reform the 5-carbon chemical bonds in RuBP from the PGAL molecules
- This ATP come from the light-dependent reactions
34
PGAL molecules (G3P)
- In their reduced **(High-energy state)**, some of the PGAL molecules leave the cycle and may be used to make glucose
- The remaining PGAL molecules move on to the third stage of the cycle
35
Making Glucose
- Plants must go through the Calvin Cycle 6 times to make 1 molecule of glucose
- 12 molecules of PGAL are produced from 6 cycles of the Calvin Cycle
- 10 of these molecules are used to regenerate RuBP
- 2 of these molecules are used to make glucose
