Biology Chapter: Electron Transport and Photosynthesis
46 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What role do high-energy electrons play in the electron transport chain?

High-energy electrons provide the energy needed to drive proton pumps, which create a proton gradient.

Explain how the proton gradient contributes to ATP synthesis.

The proton gradient allows protons to flow back into the matrix/stroma through ATP synthase, driving the phosphorylation of ADP to produce ATP.

What is the function of oxygen in the electron transport chain?

Oxygen acts as the final electron acceptor, allowing the process of electron transport to continue.

Describe the relationship between proton pumps and the generation of a proton gradient.

<p>Proton pumps actively transport protons from the matrix/stroma into the intermembrane space or thylakoid space, establishing a concentration gradient.</p> Signup and view all the answers

What is oxidative phosphorylation and how is it related to the electron transport chain?

<p>Oxidative phosphorylation is the process of ATP generation linked to the electron transport chain and the flow of protons through ATP synthase.</p> Signup and view all the answers

What is the primary function of chloroplasts in plants?

<p>The primary function of chloroplasts is to conduct photosynthesis, absorbing light energy to produce glucose.</p> Signup and view all the answers

How do chloroplasts respond to low light conditions compared to high light intensity?

<p>In low light, chloroplasts distribute evenly throughout the cytoplasm, while in high light, they align in vertical columns against the cell wall.</p> Signup and view all the answers

What is the purpose of using chromatography in studying photosynthetic pigments?

<p>Chromatography separates photosynthetic pigments, allowing for the identification and analysis of their properties.</p> Signup and view all the answers

How is the Rf value calculated in chromatography?

<p>The Rf value is calculated by dividing the distance moved by the pigment from the origin by the distance moved by the solvent front from the origin.</p> Signup and view all the answers

What role do photosynthetic pigments play in the process of photosynthesis?

<p>Photosynthetic pigments absorb specific wavelengths of light, which is essential for converting light energy into chemical energy.</p> Signup and view all the answers

What wavelengths does chlorophyll a predominantly absorb, and how does this relate to its role in photosynthesis?

<p>Chlorophyll a predominantly absorbs light at 435 nm (blue) and 670-680 nm (red), which correlates with the high rate of photosynthesis observed in these regions.</p> Signup and view all the answers

How does the absorption spectrum of chlorophyll b differ from that of chlorophyll a?

<p>Chlorophyll b absorbs light in the blue and orange-yellow regions, whereas chlorophyll a absorbs strongly in the blue and red regions.</p> Signup and view all the answers

Explain the significance of the action spectrum in relation to the absorption spectrum.

<p>The action spectrum demonstrates the rate of photosynthesis across different wavelengths, showing a close correlation with the absorption peaks of chlorophyll pigments.</p> Signup and view all the answers

What role do carotenoids play in plant photosynthesis based on their absorption spectrum?

<p>Carotenoids absorb light in the blue and green regions, complementing chlorophyll by capturing additional light energy for photosynthesis.</p> Signup and view all the answers

Discuss the relationship between light wavelengths absorbed by pigments and the overall efficacy of photosynthesis.

<p>The wavelengths absorbed by pigments like chlorophyll a and b correspond with the highest rates of photosynthesis, indicating their crucial role in energy capture.</p> Signup and view all the answers

What role do the chlorophyll a molecules play in the light-dependent stage of photosynthesis?

<p>Chlorophyll a molecules absorb light energy and release high-energy electrons.</p> Signup and view all the answers

How does cyclic photophosphorylation differ from non-cyclic photophosphorylation?

<p>Cyclic photophosphorylation uses only PSI and recycles electrons back to PSI, while non-cyclic involves both PSI and PSII and does not recycle electrons.</p> Signup and view all the answers

What is the function of the antenna complex in the light-dependent reactions?

<p>The antenna complex captures light energy and transfers it to the reaction center while preventing the escape of this energy.</p> Signup and view all the answers

What happens to the high-energy electrons released by photosystem II during non-cyclic photophosphorylation?

<p>These electrons are transferred to PSI and play a crucial role in forming NADPH.</p> Signup and view all the answers

Explain the significance of photophosphorylation in the context of photosynthesis.

<p>Photophosphorylation is vital as it converts ADP into ATP using light energy, which is essential for powering various cellular processes.</p> Signup and view all the answers

What was the main purpose of Thomas Engelmann's experiment with Spirogyra?

<p>The main purpose was to determine which wavelengths of light are most effective for photosynthesis.</p> Signup and view all the answers

How did Engelmann use a prism in his experiment?

<p>He used a prism to separate white light into its constituent colors to study their effects on photosynthesis.</p> Signup and view all the answers

What did the clustering of aerobic bacteria in blue and red light indicate?

<p>It indicated that these wavelengths are associated with higher rates of oxygen production during photosynthesis.</p> Signup and view all the answers

What role do accessory pigments play in photosynthesis?

<p>Accessory pigments help absorb a broader range of wavelengths, enhancing the light harvesting process.</p> Signup and view all the answers

What is the significance of oxygen production in Engelmann's experiment?

<p>Oxygen production serves as an indicator of photosynthetic activity and helps determine the effectiveness of different light wavelengths.</p> Signup and view all the answers

Where does light harvesting primarily occur in the chloroplasts?

<p>Light harvesting primarily occurs in the antenna complexes within the thylakoid membranes of the chloroplasts.</p> Signup and view all the answers

Why is chlorophyll a considered the primary pigment in photosynthesis?

<p>Chlorophyll a is crucial because it primarily participates in the reaction center of the antenna complexes, directly facilitating photosynthesis.</p> Signup and view all the answers

What conclusion did Engelmann draw from his findings regarding light wavelengths and photosynthesis?

<p>Engelmann concluded that blue and red light are the most effective wavelengths for photosynthesis in <em>Spirogyra</em>.</p> Signup and view all the answers

What is the initial reactant that combines with carbon dioxide in the Calvin cycle?

<p>Ribulose bisphosphate (RuBP)</p> Signup and view all the answers

Identify the two main products of the Calvin cycle after the conversion of glycerate-3-phosphate (GP).

<p>Triose phosphate (TP) and glucose</p> Signup and view all the answers

What enzyme catalyzes the reaction between RuBP and carbon dioxide?

<p>RuBisCo</p> Signup and view all the answers

How is ATP used in the Calvin cycle?

<p>ATP provides the energy needed to convert GP into TP and regenerate RuBP.</p> Signup and view all the answers

What is the significance of the reduced NADP in the Calvin cycle?

<p>Reduced NADP supplies the reducing power needed to convert GP into TP.</p> Signup and view all the answers

What compounds are predominantly observed in the autoradiograph after 5 seconds of exposure?

<p>Glycerate-3-phosphate (GP) and Sugar phosphates/diphosphates.</p> Signup and view all the answers

Explain the significance of comparing autoradiographs from different time intervals.

<p>Comparing autoradiographs of different time intervals helps in understanding the progression and formation of various compounds during the Calvin cycle.</p> Signup and view all the answers

What additional molecules appear in the autoradiograph after 30 seconds?

<p>Amino acids like alanine and glycine, and the disaccharide sucrose.</p> Signup and view all the answers

How does the intensity of spots in the autoradiographs correlate with the amount of compound present?

<p>Darker and larger spots indicate a greater amount of the specific compound present in the sample.</p> Signup and view all the answers

Why do amino acids take longer to form compared to initial products in the Calvin cycle?

<p>Amino acids require the initial formation of compounds like Glycerate-3-phosphate before they can be synthesized, which takes time.</p> Signup and view all the answers

What are the products of photolysis in the thylakoid space?

<p>The products of photolysis are electrons, protons, and oxygen.</p> Signup and view all the answers

How does photolysis contribute to the process of non-cyclic photophosphorylation?

<p>Photolysis provides the electrons needed to replace those lost from PSII during non-cyclic photophosphorylation.</p> Signup and view all the answers

What is the significance of reduced NADP in photosynthesis?

<p>Reduced NADP acts as a reducing power that is essential for the Calvin cycle.</p> Signup and view all the answers

Describe the role of the Z scheme in photosynthesis.

<p>The Z scheme illustrates the flow of electrons through photosystems I and II and highlights the electron transport process.</p> Signup and view all the answers

What happens to oxygen produced during photolysis?

<p>Oxygen diffuses out of the chloroplast as a waste product.</p> Signup and view all the answers

Why are ATP and reduced NADP crucial for the Calvin cycle?

<p>ATP provides the energy and reduced NADP provides the electrons needed to fix carbon dioxide into carbohydrates.</p> Signup and view all the answers

Explain the role of the proton gradient in the process of photophosphorylation.

<p>The proton gradient, generated by the electron transport chain, drives ATP synthesis during photophosphorylation.</p> Signup and view all the answers

Identify the location of photolysis within the chloroplast.

<p>Photolysis occurs in the thylakoid space of the chloroplast.</p> Signup and view all the answers

Flashcards

Electron Transport Chain

A series of protein complexes embedded within the inner mitochondrial membrane or thylakoid membrane that transfer electrons, releasing energy to pump protons across the membrane.

Proton Gradient

A difference in proton concentration across a membrane, with a higher concentration on one side than the other. It's like stored energy that can be used to do work.

ATP Synthase

A membrane protein that uses the energy from the proton gradient to convert ADP and inorganic phosphate into ATP. It's like a turbine capturing the flow of water to generate power.

Oxidative Phosphorylation

The process by which ATP is generated using the energy from the proton gradient. It's like using a dam to generate electricity.

Signup and view all the flashcards

Oxygen

The final electron acceptor in the electron transport chain. It binds to the last electron, completing the process and forming water.

Signup and view all the flashcards

Absorption Spectrum

A graph showing how much light a pigment absorbs at different wavelengths.

Signup and view all the flashcards

Action Spectrum

A graph showing the rate of photosynthesis at different wavelengths of light.

Signup and view all the flashcards

Chlorophyll a

A pigment that absorbs mostly blue and red light; it's key for photosynthesis.

Signup and view all the flashcards

Chlorophyll b

A pigment that absorbs blue and orange-yellow light; it assists chlorophyll a.

Signup and view all the flashcards

Carotenoids

Pigments that absorb blue and green light; they assist in photosynthesis.

Signup and view all the flashcards

Chromatography

A technique used to separate different pigments in a mixture, based on their different affinities for a stationary phase and a mobile phase.

Signup and view all the flashcards

Rf value

The ratio of the distance traveled by a pigment from the origin to the distance traveled by the solvent front from the origin. It's a unique value for each pigment in a given solvent.

Signup and view all the flashcards

Chloroplast

A specialized organelle found in plant cells that's responsible for photosynthesis.

Signup and view all the flashcards

Photosynthetic pigment

Any substance that absorbs light energy at specific wavelengths. Examples include chlorophyll a, chlorophyll b, carotene, and xanthophylls.

Signup and view all the flashcards

Origin

The starting point where a sample is applied on a chromatography paper or strip.

Signup and view all the flashcards

Photophosphorylation

The process of adding a phosphate group to ADP, forming ATP. This specifically refers to the use of light energy in this process.

Signup and view all the flashcards

Cyclic Photophosphorylation

A type of photophosphorylation that uses only Photosystem I (PSI) to generate ATP. Electrons from PSI are cycled back to PSI, creating a continuous loop.

Signup and view all the flashcards

Non-cyclic Photophosphorylation

A type of photophosphorylation that involves both Photosystem I (PSI) and Photosystem II (PSII) to generate ATP and reduce NADP. Electrons travel from PSII to PSI and then to NADP, resulting in ATP and NADPH.

Signup and view all the flashcards

Primary Pigments

chlorophyll molecules that absorb light energy and are located in the reaction center of photosystems. They initiate the flow of electrons in photosynthesis.

Signup and view all the flashcards

Antenna Complex

A complex of chlorophyll molecules and proteins that capture light energy and transfer it to the reaction center. It acts as a light-harvesting antenna.

Signup and view all the flashcards

Engelmann's Experiment

The study of which wavelengths of light are most effective in photosynthesis.

Signup and view all the flashcards

Spirogyra

A photosynthetic organism with spiral-shaped chloroplasts visible under a microscope.

Signup and view all the flashcards

Aerobic Bacteria

Motile bacteria that require oxygen for respiration, often found clustering around areas with high oxygen production.

Signup and view all the flashcards

Photosynthesis

The process of converting light energy into chemical energy, producing glucose and oxygen.

Signup and view all the flashcards

Carotenoids and Xanthophylls

Accessory photosynthetic pigments that absorb wavelengths of light besides those absorbed by chlorophyll a, increasing the range of light energy captured.

Signup and view all the flashcards

What is photolysis?

The splitting of water molecules using light energy, producing protons (H+), electrons, and oxygen.

Signup and view all the flashcards

Where do the electrons from photolysis go?

The electrons are passed to Photosystem II (PSII) to replace those lost during non-cyclic photophosphorylation.

Signup and view all the flashcards

How is ATP produced during non-cyclic photophosphorylation?

The energy stored in the proton gradient is used by ATP synthase to produce ATP.

Signup and view all the flashcards

What is photophosphorylation?

It is the process of generating ATP using the energy from the proton gradient created during non-cyclic photophosphorylation.

Signup and view all the flashcards

What is the Z scheme?

It is a graphical representation of the electron flow during non-cyclic photophosphorylation.

Signup and view all the flashcards

What is reduced NADP?

Reduced NADP is a form of NADP that has gained electrons from PSII.

Signup and view all the flashcards

Why are ATP and reduced NADP important?

They are needed for the light-independent stage (Calvin cycle) to convert carbon dioxide into carbohydrates.

Signup and view all the flashcards

What happens to the oxygen produced during photolysis?

It is a waste product of photosynthesis and diffuses out of the chloroplast.

Signup and view all the flashcards

What is the Calvin Cycle?

The light-independent stage of photosynthesis where carbon dioxide is converted into carbohydrates.

Signup and view all the flashcards

What is the role of RuBisCo in the Calvin Cycle?

RuBisCo catalyzes the reaction of carbon dioxide with RuBP, forming an unstable 6-carbon compound.

Signup and view all the flashcards

What is the purpose of the Calvin Cycle product, triose phosphate (TP)?

The product of the Calvin Cycle that can be converted into glucose, starch, fatty acids, or amino acids.

Signup and view all the flashcards

How do these two molecules from the light-dependent reactions fuel the Calvin Cycle?

Glycerate-3-phosphate (GP) is converted into triose phosphate (TP) using energy from ATP and reducing power from reduced NADPH.

Signup and view all the flashcards

How does the Calvin Cycle regenerate RuBP?

The majority of TP produced is converted back into RuBP, allowing the Calvin cycle to continue.

Signup and view all the flashcards

Autoradiograph Spot Intensity

The intensity of a spot on an autoradiograph represents the quantity of the corresponding molecule. A darker and larger spot indicates a higher concentration of that molecule.

Signup and view all the flashcards

Early Calvin Cycle Products

Glycerate-3-phosphate (GP) and Sugar Phosphates/Diphosphates are the dominant molecules observed in an autoradiograph after 5 seconds of exposing Chlorella to 14CO2. This indicates they are the earliest products of the Calvin cycle.

Signup and view all the flashcards

Calvin Cycle Progression

After 30 seconds, the autoradiograph shows an increase in the amount of GP and TP, indicating their continued production. Additionally, new molecules like amino acids (alanine, glycine) and sucrose appear, showcasing the synthesis of more complex molecules.

Signup and view all the flashcards

Time Dependence in the Calvin Cycle

Comparing autoradiographs taken at various time intervals reveals the sequential formation of molecules during the Calvin cycle. This allows for a clear understanding of the reaction's progression and the time dependence of different product formations.

Signup and view all the flashcards

Delayed Amino Acid Formation

Amino acids like alanine and glycine take longer to form than initial Calvin cycle products like GP and TP because they are synthesized from the earlier products. This shows the stepwise nature of the Calvin cycle.

Signup and view all the flashcards

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser