Introduction to Mitochondria

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Questions and Answers

What is the primary role of mitochondria in the cell?

DNA replication

Protein synthesis

ATP production (correct)

Cell division

Mitochondrial DNA is inherited equally from both parents.

False

What process do mitochondria trigger to initiate programmed cell death?

apoptosis

The space between the outer and inner membranes of the mitochondria is called the ______.

intermembrane space Signup and view all the answers

Which of the following functions is NOT associated with mitochondria?

DNA synthesis Signup and view all the answers

Match the following features of mitochondria with their descriptions:

Cristae = Inner membrane folds that increase surface area Matrix = Space where the TCA cycle occurs Outer membrane = Barrier containing enzymes for large molecules Intermembrane space = Space between the inner and outer membranes Signup and view all the answers

Mitochondria assist in glycolysis by producing the majority of ATP.

False Signup and view all the answers

What is the name of the protein involved in heat production within brown adipose tissue?

thermogenin Signup and view all the answers

What is the primary energy molecule produced by mitochondria?

ATP Signup and view all the answers

Mitochondrial diseases can be inherited from both the mother and father.

False Signup and view all the answers

What process occurs in the electron transport chain to produce ATP?

oxidative phosphorylation Signup and view all the answers

Mitochondria contain folds called __________, which increase the surface area for ATP production.

cristae Signup and view all the answers

Which of the following cells would most likely contain a high number of mitochondria?

Skeletal muscle cells Signup and view all the answers

Match the following mitochondrial features with their functions:

Outer mitochondrial membrane = Encases the mitochondria Cristae = Increases surface area for ATP production Matrix = Contains enzymes for the Krebs cycle Proton gradient = Powers ATP synthase to produce ATP Signup and view all the answers

The inner mitochondrial membrane is impervious to protons.

False Signup and view all the answers

What unique feature does mitochondrial DNA have compared to nuclear DNA?

circular structure Signup and view all the answers

Study Notes

Mitochondria Introduction

Mitochondria were discovered after the nucleus.
Also known as the "powerhouse of the cell" because it produces ATP, the energy currency of the cell.
Mitochondria has a double membrane structure, with an outer membrane and an inner membrane with a space between called the intermembrane space.
Mitochondria are double-membrane-bound organelles.

Mitochondria Functions

ATP Production: Oxidative phosphorylation, a process occurring in the electron transport chain, is the primary source of ATP production in mitochondria.
Cellular Differentiation: Mitochondria plays a role in regulating cell growth, division, and the cell cycle.
Apoptosis: Mitochondria trigger programmed cell death (apoptosis) by releasing enzymes that initiate the process.
Heat Production: Thermogenin, a protein found in brown adipose tissue (brown fat), is involved in heat production.
Heme Synthesis: Mitochondria is involved in the synthesis of heme, a component of hemoglobin.
Cell Signaling: Mitochondria interacts with other cellular components, including the nucleus, and participates in various cellular signaling pathways.
Glycolysis: Produces a small amount of ATP in the cytosol, a necessary process for cellular respiration. But it also has roles within mitochondria.

Mitochondria Structure

Outer membrane: Forms a barrier between the cytosol and the mitochondria, contains enzymes and pores for large molecules.
Inner membrane: Holds molecules essential for ATP synthesis and the electron transport chain. Contains ATP synthase for ATP production.
Intermembrane space: The space between the two membranes.
Cristae: The inner membrane folds into cristae, increasing the surface area for ATP synthesis.
Matrix: The space inside the inner membrane, where ATP is generated. Contains enzymes for the TCA cycle (Krebs cycle).
Protons are pumped from the matrix to the intermembrane space, creating a proton gradient. This gradient powers ATP synthase for ATP production.

Mitochondria DNA

Mitochondrial DNA (mtDNA) is similar to bacterial DNA.
mtDNA is circular.
mtDNA is inherited exclusively from the mother.
Sperm's mitochondria remain outside the egg during fertilization.
Mature red blood cells lack both a nucleus and mitochondria.
Hepatocytes (liver cells) have high concentrations of mitochondria due to their metabolic activity (over 2,000 per cell).
mtDNA replicates independently from the nucleus, known as cytoplasmic or extra-nuclear inheritance. This supports the endosymbiotic theory, suggesting mitochondria originated from bacteria engulfed by early eukaryotic cells.

Comparison of Apoptosis and Necrosis

Apoptosis (programmed cell death): A natural, controlled process essential for cell turnover.
Necrosis (cell murder): Uncontrolled, abnormal cell death caused by injuries or diseases. It involves inflammation and cell lysis unlike Apoptosis.

Additional Information

Mitochondrial diseases are inherited from the mother due to the exclusive maternal inheritance of mitochondrial DNA.
Mitochondria are critical for cell function and survival; it provides cellular energy and regulates cell growth, division, and death.
Mature red blood cells lack a nucleus and mitochondria as they are specialized for oxygen transport.
Glycolysis occurs in the cytosol and produces a small amount of ATP, along with the main source from the mitochondria.

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Description

Explore the fascinating world of mitochondria, the powerhouse of the cell. This quiz delves into the structure and essential functions of mitochondria, including ATP production, cellular differentiation, and apoptosis. Test your understanding of how mitochondria contribute to vital cellular processes.