Mitochondria Structure and Functions

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Questions and Answers

What is the primary function of the inner membrane of mitochondria?

Is involved in the production of mitochondrial DNA

Regulates the movement of molecules selectively (correct)

Allows free movement of all molecules

Contains the proton gradient for ATP synthesis

Which of the following best describes the cristae in mitochondria?

The area where glucose is synthesized

Invaginations that increase surface area for reactions (correct)

Fluid-filled space containing DNA

The outermost layer of the organelle

From which source does mitochondrial DNA primarily originate?

Maternal DNA only (correct)

Primarily from nuclear DNA

Only from paternal DNA

Both parents equally

What is produced as a byproduct during the electron transport chain in mitochondria?

Reactive oxygen species (ROS) Signup and view all the answers

What sustains the proton gradient required for ATP production in mitochondria?

Pumping of protons into the intermembrane space Signup and view all the answers

Which cycle takes place in the mitochondrial matrix and produces high-energy electron carriers?

Krebs Cycle Signup and view all the answers

What is the role of ribosomes found in the mitochondrial matrix?

To synthesize proteins from RNA Signup and view all the answers

Which of the following processes occurs in the mitochondrial matrix?

Fatty acid oxidation Signup and view all the answers

What is produced by the Krebs cycle?

NADH and FADH2 Signup and view all the answers

Which process is involved in the detoxification of ammonia?

Urea cycle Signup and view all the answers

What is the primary role of cytochrome C in mitochondria?

Trigger apoptosis Signup and view all the answers

What percentage of mitochondrial proteins are synthesized in the mitochondria itself?

15% Signup and view all the answers

Which process synthesizes glucose from non-carbohydrate sources?

Gluconeogenesis Signup and view all the answers

What is the significance of mitochondrial DNA (mtDNA)?

It is crucial for protein synthesis and mitochondrial replication. Signup and view all the answers

During apoptosis, the levels of which protein decrease to allow cytochrome C release?

Bcl-2 Signup and view all the answers

What do the mitochondria and ribosomes resemble, indicating their prokaryotic origin?

70S ribosomes Signup and view all the answers

Study Notes

Inner Mitochondrial Membrane Function

The inner membrane of mitochondria is the site of electron transport and ATP production.
It is impermeable to most molecules, requiring specific transport proteins for passage.

Cristae Description

The cristae are folded invaginations of the inner mitochondrial membrane, increasing its surface area.
This enhances the efficiency of ATP production by providing more space for electron transport and ATP synthase.

Mitochondrial DNA Origin

Mitochondrial DNA (mtDNA) is primarily inherited maternally.

Electron Transport Chain Byproduct

Water (H2O) is produced as a byproduct during the electron transport chain in mitochondria.
This occurs as the final electron acceptor, oxygen, is reduced.

Proton Gradient Maintenance

The electron transport chain pumps protons (H+) from the mitochondrial matrix across the inner membrane into the intermembrane space, generating the proton gradient.
This gradient is essential for ATP production by ATP synthase.

Mitochondrial Matrix Cycle

The Krebs cycle (or citric acid cycle) takes place in the mitochondrial matrix.
This cycle generates high-energy electron carriers, such as NADH and FADH2, which are essential for the electron transport chain.

Mitochondrial Ribosome Function

The ribosomes found in the mitochondrial matrix are responsible for synthesizing mitochondrial proteins.

Mitochondrial Matrix Processes

Krebs cycle, fatty acid oxidation, and amino acid catabolism all occur in the mitochondrial matrix.

Krebs Cycle Output

The Krebs cycle produces ATP, NADH, FADH2, and CO2.
These products are essential for ATP production and other metabolic processes.

Ammonia Detoxification

The urea cycle, which detoxifies ammonia, occurs primarily in the liver.
Mitochondria play a role in ammonia detoxification by converting ammonia to urea.

Cytochrome C Role

Cytochrome C is a crucial protein in the electron transport chain.
It acts as an electron carrier and helps maintain the proton gradient essential for ATP production.

Mitochondrial Protein Synthesis

Only about 5% of mitochondrial proteins are synthesized within the mitochondria itself.
The rest are encoded by nuclear DNA and imported from the cytoplasm.

Gluconeogenesis

Gluconeogenesis is the process of synthesizing glucose from non-carbohydrate sources, such as amino acids and glycerol.
This process occurs in the liver and kidneys and utilizes energy generated by mitochondria.

Mitochondrial DNA Significance

mtDNA plays a significant role in cellular energy production and is essential for the proper functioning of mitochondria.
It is also used in tracing ancestry and studying evolutionary relationships.

Apoptosis Protein Level Decrease

During apoptosis, Bcl-2 protein levels decrease, allowing cytochrome C to be released from the mitochondria.
This event triggers a cascade of events leading to programmed cell death.

Mitochondrial-Ribosomal Resemblance

Mitochondria and ribosomes share structural similarities with bacteria.
This suggests that they likely originated from endosymbiotic bacteria that were engulfed by early eukaryotic cells.

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Description

Explore the fascinating structure and functions of mitochondria in this quiz. Discover the roles of various mitochondrial components including the outer and inner membranes, cristae, and mitochondrial DNA. Test your knowledge on how these organelles contribute to cellular processes.