Скачать или смотреть Mitochondria structure and function double membrane bonded organelles

1. Definition

Mitochondria are double-membrane cellular organelles, often called the “powerhouse of the cell” because they produce ATP (adenosine triphosphate), the main energy currency of the cell.


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2. Structure

Outer membrane: Smooth membrane containing proteins called porins that allow small molecules to pass.

Inner membrane: Folded into structures called cristae, which increase the surface area. It contains proteins for the electron transport chain and ATP synthase.

Intermembrane space: The region between the outer and inner membranes where protons accumulate to create an electrochemical gradient.

Matrix: Gel-like material inside the inner membrane. It contains enzymes for the citric acid cycle (Krebs cycle), mitochondrial DNA, and 70S ribosomes.



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3. Unique Features

Possesses its own circular DNA.

Contains 70S ribosomes (similar to bacterial ribosomes).

Can synthesize some of its own proteins and enzymes.

Capable of self-replication.

According to the Endosymbiotic Theory, mitochondria originated from ancient bacteria that entered early eukaryotic cells.



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4. Functions

ATP production via oxidative phosphorylation.

Site of the citric acid cycle (Krebs cycle).

Regulation of apoptosis (programmed cell death).

Calcium storage and regulation.

Heat production through non-shivering thermogenesis (especially in brown adipose tissue).



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