Name: peroxisomes and cellular detoxification
Uploaded: 2026-06-01T06:27:54.739Z
Duration: 1 min 30 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

North Carolina K-12 Science Standard Course of Study

9-12

Biology

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms- Structures and Processes

LS.Bio.1.3

Peroxisomes

Peroxisomes are single-membrane-bound organelles with oxidative enzymes that help break down organic molecules.
 
 The shape, number, and size of peroxisomes vary according to the cell type and environmental signals. For example, liver and kidney cells often have lots of peroxisomes because they handle many chemical reactions and detoxification processes.
 
 Peroxisomes can form through the growth and division of existing peroxisomes. They can also form from vesicles that bud off from the endoplasmic reticulum.
 
 Peroxisomal enzymes are imported from the cytoplasm into the peroxisomal matrix through a membrane-associated protein translocation complex involving peroxins or PEX proteins.
 
 These enzymes use molecular oxygen during the beta-oxidation of fatty acids, producing shorter-chain fatty acids and hydrogen peroxide as by-products.
 
 Because hydrogen peroxide is cytotoxic, catalase, a peroxisomal enzyme, rapidly converts it into water and oxygen.
 
 Peroxisomes help with cellular detoxification and lipid metabolism. They also help make lipids such as dolichol and contain enzymes required to make bile acids from cholesterol.

perossisomi

I mitocondri e i perossisomi sono organelli che sono i siti primari di consumo di ossigeno nelle cellule eucariotiche. I mitocondri effettuano la respirazione cellulare, il processo che converte l&#x27;energia dal cibo in ATP, la forma primaria di energia utilizzata dalle cellule. I perossisomi svolgono una variet&#xE0; di funzioni, principalmente abbattere diverse sostanze come gli acidi grassi.

I perossisomi contengono fino a 50 enzimi e sono circondati da una singola membrana. Essi svolgono reazioni ossidative che scompongono le molecole e producono perossido di idrogeno (H2O2) come sottoprodotto. H2O2 &#xE8; tossico per le cellule, ma il perossisoma contiene un enzima,catalasi , che converte H2O2 in acqua e ossigeno innocui. Inoltre, catalasi utilizza H2O2 per abbattere l&#x27;alcol nel fegato in aldeide e acqua. Tuttavia, poich&#xE9; H2O2 &#xE8; prodotto in quantit&#xE0; molto basse nel corpo, altri enzimi degradano principalmente l&#x27;alcol.

Una funzione critica del perossisoma &#xE8; quella di abbattere gli acidi grassi in un processo chiamato ossidazione. Il prodotto risultante, l&#x27;acetil-CoA, viene rilasciato nel citosol e pu&#xF2; viaggiare verso i mitocondri, dove viene utilizzato per produrre ATP. Nelle cellule dei mammiferi, i mitocondri effettuano anche l&#x27;ossidazione, cos&#xEC; come l&#x27;utilizzo di prodotti dal catabolismo di altre fonti di energia, come il glucosio, per produrre ATP.

I mitocondri sono circondati da una doppia membrana: una membrana esterna liscia e una membrana interna che ha molte pieghe chiamate creste. All&#x27;interno della membrana interna &#xE8; una regione chiamata matrice. Durante la respirazione cellulare, il piruvato dalla ripartizione del glucosio nel citoplasma viaggia nella matrice, dove entra nel ciclo dell&#x27;acido citrico. Quindi, la fosfororilazione ossidativa attraverso la catena di trasporto degli elettroni si verifica nella membrana interna dei mitocondri, con conseguente produzione di una quantit&#xE0; significativa di ATP. La cresta aumenta la superficie della membrana interna, fornendo pi&#xF9; regioni per la produzione di ATP.

Sia i perossisomi che i mitocondri sono auto-replicanti, ma i mitocondri hanno inoltre il loro DNA e ribosomi, consentendo loro di produrre le loro proteine. I mitocondri e i perossisomi sono entrambi altamente concentrati nelle cellule dove sono pi&#xF9; necessari. Ad esempio, le cellule del fegato, che scompongono le sostanze tossiche nel sangue, hanno un elevato numero di perossisomi, e le cellule muscolari, che hanno un grande fabbisogno energetico, sono ricche di mitocondri.

Perossisomi

Peroxisomes and mitochondria are two important oxygen-utilizing organelles in eukaryotic cells. Mitochondria carry out cellular respiration&#x2014;the ...

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Education

Didattica

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Biologia

Cellular Processes

Processi cellulari

Cell Structure and Function

Struttura e funzione della cellula

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

peroxisomes and cellular detoxification

Peroxisomes and mitochondria are two important oxygen-utilizing organelles in eukaryotic cells. Mitochondria carry out cellular respiration, which turns energy from food into ATP. Peroxisomes focus on breaking down substances such as fatty acids and other materials the cell needs to process.

A peroxisome is a single membrane-bound organelle. It helps with lipid metabolism and chemical detoxification. Enzymes inside peroxisomes move hydrogen atoms from molecules to oxygen. This reaction produces hydrogen peroxide, or H2O2.

Peroxisomes also help neutralize poisons such as alcohol. They take part in reactions that remove free radicals as well. Although they make toxic H2O2 during these reactions, they also contain enzymes that break H2O2 into water and oxygen. The cell can then release these products safely into the cytoplasm.

These organelles act like tiny sewage treatment plants inside cells. They help prevent harmful substances from causing damage. Liver cells contain especially large numbers of peroxisomes because the liver detoxifies the blood before it travels through the body. Kidney cells also contain many peroxisomes for blood detoxification.

Mitochondria have a different internal structure. They are surrounded by a double membrane. The outer membrane is smooth, and the inner membrane has folds called cristae. The space inside the inner membrane is the matrix.

During cellular respiration, pyruvate from glucose breakdown in the cytoplasm moves into the matrix. There, it enters the citric acid cycle. Oxidative phosphorylation then takes place in the inner membrane through the electron transport chain, producing a large amount of ATP. The cristae increase the surface area of the inner membrane and create more space for ATP production.

Both peroxisomes and mitochondria can replicate on their own. Mitochondria also have their own DNA and ribosomes, which lets them make some of their proteins. These organelles are concentrated in cells that need them most. Liver cells have many peroxisomes, while muscle cells, which need lots of energy, are rich in mitochondria.

Peroxisomes and Cellular Detoxification

what are cells?

Cell Membrane, DNA, and Organelles

Cells are the basic units of life, from a bacterium made of one cell to a human made of trillions. Even though organisms can differ greatly, their cells share key features that support life. A cell has a plasma membrane, which is a lipid bilayer that separates the cytoplasm from the outside environment. It also contains DNA, the genetic material that carries instructions for the cell. In prokaryotic cells, DNA is found in a region called the nucleoid. In eukaryotic cells, DNA is enclosed...

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cytoplasm

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ER in Protein and Lipid Transport

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ribosomes

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peroxisomes

Peroxisomes and mitochondria are two important oxygen-utilizing organelles in eukaryotic cells. Mitochondria carry out cellular respiration, which turns energy from food into ATP. Peroxisomes focus on breaking down substances such as fatty acids and other materials the cell needs to process. A peroxisome is a single membrane-bound organelle. It helps with lipid metabolism and chemical detoxification. Enzymes inside peroxisomes move hydrogen atoms from molecules to oxygen. This reaction...

microtubules

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the nucleus

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the extracellular matrix

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gap junctions

Connexins and Cell-to-Cell Signaling

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tissues

Body Tissues and Their Jobs

Body tissues are groups of cells with similar structure and function. When different tissues work together, they form an organ with a specialized job. Vertebrates have four main tissue types: epithelial, connective, muscle, and nervous tissue. Epithelial tissue is made of thin sheets of cells. It covers the skin and lines internal organs and body cavities. These cells are tightly packed, so they help protect against injury, infection, and water loss. Epithelial tissue may be simple, with one...

key terms and concepts

Explore how peroxisomes detoxify harmful substances, break down fatty acids, and work alongside mitochondria in high school cell biology.

Peroxisomes and Cellular Detoxification | JoVE K12

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Pennsylvania State Academic Standards

Life Science

Structure and Function

3.1.9-12.A

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Ohio’s Learning Standards and Model Curriculum

Cells

Cell structure and function

Virginia  Standards of Learning

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BIO.3

BIO.3.a

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HS+B.L1U1.4

Alabama Course of Study Science

From Molecules to Organisms: Structures and Processes

9-12.B.1.1

Florida Department of Education

SC.912.L.14

SC.912.L.14.2

SC.912.L.14.3

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Peroxisomes and Cellular Detoxification

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