Energy Generation in Mitochondria and Chloroplasts

These flashcards cover key concepts related to energy generation in mitochondria and chloroplasts, including oxidative phosphorylation, photosynthesis, key terms, and functions of organelles.

What process occurs in mitochondria to generate ATP using the energy released from NADH oxidation?

Oxidative phosphorylation.

How do cells obtain energy from organic molecules?

Through oxidative phosphorylation.

What is the role of chloroplasts in photosynthesis?

To capture sunlight and convert it into chemical energy.

What are the two major energy-generating systems in cells?

Mitochondria and chloroplasts.

What kind of gradient is established during oxidative phosphorylation?

A proton gradient.

What does ATP synthase do?

It produces ATP using the energy stored in the electrochemical proton gradient.

Where are mitochondria particularly concentrated in cells?

In regions with high ATP utilization, such as muscle cells.

What is the function of the cytochrome c oxidase complex?

To reduce molecular oxygen to water.

What are the primary products of glycolysis?

2 ATP and 2 NADH.

In which part of the mitochondrion does the citric acid cycle occur?

In the mitochondrial matrix.

What is the genetic disorder associated with mitochondrial dysfunction called?

Myoclonic epilepsy with ragged red fibers (MERRF).

How is MERRF inherited?

It is inherited maternally; mothers transmit the mutation to all offspring.

What type of proton gradient is created during ATP synthesis in mitochondria?

Electrochemical proton gradient.

What is the main function of the antenna complex in chloroplasts?

To absorb light energy.

What are the two main stages of photosynthesis?

Light reactions and the Calvin cycle (light-independent reactions).

What is photophosphorylation?

The process of generating ATP from ADP using the energy derived from light.

What is the purpose of nitrogen fixation?

To convert atmospheric nitrogen into a usable form for plants.

What are thylakoids?

Membrane-bound structures within chloroplasts where light-dependent reactions occur.

What molecule acts as the primary energy carrier in cells?

ATP (adenosine triphosphate).

What role do chlorophyll molecules play in photosynthesis?

They absorb light energy necessary for the photosynthesis process.

What is chemiosmotic coupling?

The coupling of proton transport across a membrane to ATP synthesis.

What is oxidative phosphorylation primarily responsible for in eukaryotic cells?

Producing most of the ATP used by cells.

Why do plants appear green?

Because chlorophyll absorbs red and blue light but reflects green light.

What are reactive oxygen species (ROS) involved in?

Cell signaling.

How does the energy yield of NADH produced in the mitochondrial matrix compare to that produced in the cytosol?

NADH from the matrix yields more ATP.

What is the main function of the light reactions in photosynthesis?

To convert solar energy into chemical energy in the form of ATP and NADPH.

What do the products of the citric acid cycle contribute to in oxidative phosphorylation?

They provide high-energy electrons necessary for ATP production.

What is the consequence of mitochondrial DNA mutations?

They can lead to various mitochondrial disorders.

Which complex in the electron transport chain is responsible for pumping protons into the intermembrane space?

The NADH dehydrogenase complex.

What is the function of plastoquinone in chloroplasts?

To transfer electrons from photosystem II to the cytochrome b6-f complex.

During photosynthesis, what process uses ATP and NADPH to convert CO2 into sugars?

Carbon fixation.

What contributes to the proton motive force in mitochondria?

The electrochemical gradient of protons across the inner mitochondrial membrane.

What type of cells contain chloroplasts?

Plant cells and some algae.

How do mitochondria regulate apoptosis?

By releasing molecules that trigger cell death pathways.

What are the two compartments found in mitochondria?

The outer membrane and the inner membrane.

Which light wavelengths do chlorophyll preferentially absorb?

Around 430 nm (blue) and 660 nm (red).

What processes occur in both mitochondria and chloroplasts?

Electron transport and ATP synthesis.

What intermediate is produced during glycolysis?

Pyruvate.

What happens to the glyceraldehyde 3-phosphate produced during the Calvin cycle?

It can be used to regenerate ribulose 1,5-bisphosphate or transported out of the chloroplast.

How many ATP molecules can be produced from the complete oxidation of one glucose molecule?

Up to 30 ATP molecules.

What is the primary purpose of the thylakoid membrane?

To conduct the light-dependent reactions of photosynthesis.

What do the light-independent reactions of photosynthesis require?

ATP and NADPH produced during light reactions.

What kind of proteins are involved in the transport of electrons in mitochondrial oxidative phosphorylation?

Enzyme complexes.

What is one of the key roles of mitochondria in biosynthesis?

Provision of precursors for amino acids and fatty acids.

What is significant about the mitochondrial inner membrane?

It is where the electron transport chain and ATP synthase are located.

What is the role of the respiratory enzyme complex?

To facilitate electron transfer and proton pumping.

What are photosystems composed of?

Chlorophyll molecules and proteins.

What is generated by the splitting of water in photosynthesis?

Oxygen.

What does a steep proton gradient across the mitochondrial membrane create?

A proton motive force.

What is the primary function of the Calvin cycle?

To convert CO2 into organic compounds like sugars.

What substance signifies the high energy potential of electrons generated by photosynthesis?

NADPH.

What type of organisms perform photosynthesis?

Plants, algae, and some bacteria.

What is the final product of the electron transport chain in mitochondria?

Water.

What signals the beginning of ATP synthesis in mitochondria?

The flow of protons back into the mitochondrial matrix.

What is the main precursor for the synthesis of heme and iron-sulfur clusters?

Intermediates from the citric acid cycle.

What happens during the light reactions of photosynthesis?

Light energy is converted to chemical energy in the form of ATP and NADPH.

How do light-dependent reactions produce ATP?

Through chemiosmosis driven by a proton gradient.

What structure in a chloroplast contains both ATP synthase and proton pumps?

Thylakoid membrane.

What is an important characteristic of the chloroplast's inner membrane?

It is impermeable to NADPH and ATP produced during photosynthesis.

From where are the electrons for the light reactions derived?

From water molecules.

What is facilitated by the presence of magnesium in chlorophyll?

Absorption of light energy.

Which compound is used to measure the energy yield from complete glucose oxidation?

ATP.

What happens to the energy-rich products generated by chloroplasts?

They are exported to the cytosol for cellular respiration.

What is the significance of an electron transport chain?

To create a proton gradient necessary for ATP synthesis.

What is the relationship between photosynthesis and cellular respiration?

Products of one are reactants of the other, forming a cycle.

What are grana in chloroplasts?

Stacks of thylakoids where light reactions occur.

What is the basic function of the Calvin cycle?

To reduce carbon dioxide and produce sugars.

What cellular process uses both ATP and NADPH?

The Calvin cycle for carbon fixation.

What occurs in the mitochondrion's matrix during cellular respiration?

Conversion of pyruvate to acetyl CoA.

Which enzyme in mitochondria is responsible for regenerating NAD+ during glycolysis?

NADH dehydrogenase.

What determines the efficiency of cellular respiration?

The utilization of organic molecules to produce ATP.

What roles do both mitochondria and chloroplasts share?

Energy transformation and storage.

What happens to a molecule of glucose in glycolysis?

It is converted into two molecules of pyruvate.

What process of photosynthesis produces oxygen?

The light-dependent reactions.

Differentiate between photosystem II and photosystem I.

Photosystem II absorbs light at 680 nm and is involved in water splitting, while Photosystem I absorbs at 700 nm and aids in NADPH formation.

State the reactants of Calvin cycle. What is the starting material?

The reactants of the Calvin cycle are carbon dioxide, ATP, and NADPH, with ribulose bisphosphate (RuBP) as the starting material.

What stage of photosynthesis involves water? How is it used or released?

Water is involved in the light-dependent reactions of photosynthesis, where it is split (photolysis) to release oxygen and provide electrons for the electron transport chain.

What components are housed by the thylakoid membrane?

The thylakoid membrane houses chlorophyll, electron transport proteins, and various other pigments essential for capturing light energy during photosynthesis.

How is NADH different from NADPH for a plant cell?

NADH is used mainly in cellular respiration for energy production, while NADPH is primarily involved in the Calvin cycle and acts as a reducing agent, providing electrons for biosynthetic reactions.

What is the ultimate product of photosynthesis?

The ultimate product of photosynthesis is glucose, a sugar that serves as an energy source for the plant and can be converted into other organic compounds.

What of the photosystems make ATP? NADPH? Which cell location are these ultimately used?

The light reactions of photosynthesis, specifically Photosystem II and Photosystem I, produce ATP and NADPH, which are ultimately used in the Calvin cycle located in the stroma of the chloroplast.

What enzyme is the main actor in Calvin cycle? What are its substrates?

The main enzyme in the Calvin cycle is RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase), which catalyzes the fixation of carbon dioxide into ribulose-1,5-bisphosphate (RuBP) as its substrate.

During the light-dependent reactions of photosynthesis, water is split to:

ATP and NADPH.

In chloroplasts, the light-dependent reactions occur in the:

thylakoid membranes, where chlorophyll captures light energy.

Which process occurs during the Calvin cycle?

fixation od carbon dioxide into organic molecules

which molecule in the calvin cycle is used to synthesize starch and sucrose?

The molecule in the Calvin cycle that is used to synthesize starch and sucrose is glyceraldehyde-3-phosphate (G3P).

the process by which photosynthetic organism use light energy for ATP production is

known as photophosphorylation.

Continuous carbon assimilation is made possible at the regeneration of?

ribulose 1,5 bisphosphate (RuBP)

Pryuvate becomes acetylene coA where in the mitochondria?

This process occurs in the mitochondrial matrix, where pyruvate is converted to acetyl coenzyme A (acetyl CoA) before entering the citric acid cycle.