Name: cell organelles and microenvironments
Uploaded: 2025-11-18T06:54:45.000Z
Duration: 1 min 46 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

Eukaryotic Compartmentalization

Eukaryontische Zellen enthalten zahlreiche innere Teilbereiche.
 Membrangebundene Organellen, die es ermöglichen, dass sehr spezifische Funktionen in Mikroumgebungen auftreten, die sowohl vor dem zytoplasmatischen Inneren als auch vor der extrazellulären Umgebung geschützt sind.
 Zum Beispiel benötigt der Kern kontrollierte Bedingungen für eine präzise Regulation der darin enthaltenen Gene.
 Daher ist es von einer Doppelmembran umgeben.
 Die Kernhülle.
 Mit Poren zur Kontrolle, welche Moleküle, wie etwa MRNAs ein- und austreten können.
 Darüber hinaus erfordern einige Proteine eine oxidative Umgebung und müssen aus dem Cytosol isoliert werden, welches reduktiv ist.
 Somit produzieren Ribosomen diese Proteine im endoplasmatischen Retikulum, wo sie auch kritische Modifikationen eingehen können.
 Nachfolgende Bewegungen finden sogar innerhalb kleiner chemischer Mikrokosmen statt, die als Vesikel bezeichnet werden, während sie sich auf dem Weg zu ihrem endgültigen Bestimmungsort befinden.
 Andere Organellen wie Peroxisomen schützen vor ihren eigenen schädlichen Nebenprodukten wie Wasserstoffperoxid, indem sie Enzyme absondern, die toxische Verbindungen in harmlose Moleküle wie Wasser umwandeln.
 In ähnlicher Weise trennen Lysosomen Enzyme, jedoch aus einem anderen Grund.
 Zum Schutz von Verdauungsreaktionen, die einen viel niedrigeren pH-Wert als die Zytoplasma-Häfen erfordern.
 Mitochondrien haben auch saure Innenräume zwischen ihren beiden Membranen, die zur Energieerzeugung beitragen.
 Insgesamt unterstützt die eukaryotische Kompartimentierung Aktionen, die andernfalls unvereinbar wären, wenn sie gleichzeitig ohne irgendeine Form von Eindämmung ausgeführt würden.

Gabaldón, Toni und Alexandros A. Pittis. "Ursprung und Evolution der metabolischen subzellulären Kompartimentierung in Eukaryoten." Biochimie 119 (Dezember 2015): 262–68. [<a href="https://doi.org/10.1016/j.biochi.2015.03.021" target="__blank">Quelle</a>]

die eukaryotische kompartimentierung

Eukaryotische Zellen zeichnen sich unter anderem besonders dadurch aus, dass sie membrangebundene Organellen wie z.B. den Kern und die Mitochondrien enthalten. Diese Organellen erfüllen bestimmte Funktionen. Da biologische Membranen nur für wenige Stoffe durchlässig sind, schafft die Membran um ein Organell ein Kompartiment mit kontrollierten Bedingungen im Inneren. Diese Mikroumgebungen unterscheiden sich oft von der Umgebung des umgebenden Zytosols und sind auf die spezifischen Funktionen der Organelle zugeschnitten.
 
 Lysosomen sind hier ein passendes Beispiel. Es handelt sich um Organellen in tierischen Zellen, die Moleküle und Zellabfälle verdauen. Sie müssen eine Umgebung aufrechterhalten, die saurer ist als das umgebende Zytosol, da ihre Enzyme einen niedrigeren pH-Wert benötigen, um Reaktionen zu katalysieren. In ähnlicher Weise wird der pH-Wert auch in den Mitochondrien reguliert. Das hilft ihnen dabei, ihre Funktion der Energieproduktion erfüllen zu können.
 
 Zusätzlich benötigen einige Proteine eine oxidative Umgebung für die korrekte Faltung und Verarbeitung. Das Zytosol ist jedoch im Allgemeinen reduktiv. Daher werden diese Proteine von Ribosomen im Endoplasmatischen Retikulum (ER) produziert, das die notwendige Umgebung aufrechterhält. Die Proteine werden dann oft innerhalb der Zelle durch membrangebundene Vesikel transportiert.
 
 Das genetische Material von eukaryotischen Zellen ist noch einmal innerhalb des Zellkerns unterteilt. Dieser ist von einer Doppelmembran, der so genannten Kernhülle umgeben. Kleine Poren in der Hülle steuern, welche Moleküle oder Ionen in den Kern ein- oder austreten können. Durch diese Poren verlässt zum Beispiel die Boten-RNA (mRNA) den Kern, um die in der DNA kodierten genetischen Anweisungen zu den Ribosomen zu bringen, wo sie in Proteine übersetzt werden können.
 
 Organellen können eine Zelle auch schützen, indem sie gefährliche Substanzen aufnehmen und neutralisieren. Zum Beispiel führen Peroxisomen Oxidationsreaktionen durch, die Wasserstoffperoxid produzieren, das für Zellen giftig ist. Sie enthalten aber auch Enzyme, die es in unschädlichen Sauerstoff und Wasser umwandeln. Durch die Kompartimentierung können eukaryotischen Zellen also eine Vielzahl von Funktionen ausüben, die sonst in Bezug auf die benötigten Umgebungen oder die entstehenden Nebenprodukte nicht miteinander vereinbar wären.

Die eukaryotische Kompartimentierung

Eines der Unterscheidungsmerkmale eukaryotischer Zellen ist, dass sie membrangebundene Organellen wie den Zellkern und die Mitochondrien enthalten, die ...

Education

Lehre

JoVE Core

Biologie

Cellular Processes

Zelluläre Prozesse

Cell Structure and Function

Zellstruktur und Zellfunktion

KEY TERMS AND CONCEPTS

KERNBEGRIFFE UND KONZEPTE

cell organelles and microenvironments

Eukaryotic cells use membrane-bound organelles to keep cell processes organized. The nucleus and mitochondria are two key examples. Because biological membranes are selectively permeable, they create controlled spaces inside each organelle. These small microenvironments support specialized jobs and separate them from the surrounding cytosol.

Different organelles maintain different internal conditions. In animal cells, lysosomes keep an acidic environment that helps their enzymes digest cellular debris. Mitochondria also regulate pH, which supports the synthesis of energy molecules. These conditions show how compartmentalization helps each organelle work efficiently.

Some proteins need an oxidative environment to fold and be processed correctly. The cytosol is usually reductive, so these proteins are made by ribosomes in the endoplasmic reticulum, or ER. The ER provides the needed environment, and vesicles move the proteins to their final destination. This transport system helps direct proteins to the right place in the cell.

The nucleus also depends on compartmentalization. It holds the cell’s genetic material inside a double membrane called the nuclear envelope. Small pores in the envelope control what enters and leaves the nucleus. Messenger RNA, or mRNA, exits through these pores and carries DNA instructions to ribosomes for protein synthesis. Overall, compartmentalization lets one cell carry out many functions with greater efficiency by concentrating needed materials in separate spaces.

Cell Organelles and Microenvironments

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...

cell size

Why Cell Size Is Limited

Cell size is limited by surface area and diffusion. Cells vary widely in size, both between organisms and within the same organism. Bacterial cells are usually 1 to 10 micrometers wide, and the smallest bacteria can be 0.1 micrometers in diameter. That is about a thousand times smaller than most eukaryotic cells, which are typically 10 to 100 micrometers across. A cell takes in nutrients and water through diffusion across the plasma membrane or through channels in the membrane. The membrane...

eukaryotic compartmentalization

Eukaryotic cells use membrane-bound organelles to keep cell processes organized. The nucleus and mitochondria are two key examples. Because biological membranes are selectively permeable, they create controlled spaces inside each organelle. These small microenvironments support specialized jobs and separate them from the surrounding cytosol. Different organelles maintain different internal conditions. In animal cells, lysosomes keep an acidic environment that helps their enzymes digest...

prokaryotic cells

Prokaryotic Cell Structures

Prokaryotic cells are small, single-celled organisms found in the domains Archaea and Bacteria. Bacteria include familiar species such as Salmonella and E. coli. Archaea include extremophiles, which are organisms that live in harsh environments like volcanic springs. Prokaryotic cells share several basic features with eukaryotic cells. They are surrounded by a plasma membrane, contain cytoplasm, and have ribosomes that make proteins. Their genetic material is a single, circular DNA molecule.

cytoplasm

Cytoplasm and the Cell’s Internal Framework

The cytoplasm is the cell’s internal space that holds organelles and the cytoskeleton. It is suspended in the cytosol, an aqueous fluid made of water, ions, salts, and many organic molecules. Together, these parts create the environment where key cell activities happen. The cytoplasm is also a major site for protein synthesis and folding. The water-based cytosol helps proteins fold correctly. Hydrophobic amino acid side chains tend to hide in the protein core, while hydrophilic amino acids...

endoplasmic reticulum

ER in Protein and Lipid Transport

The endoplasmic reticulum is a membrane network in eukaryotic cells. It is continuous with the outer membrane of the nucleus. This connection helps link nuclear and cytoplasmic processes and supports efficient movement inside the cell. mRNA can move from the nucleus to ribosomes, which helps protein synthesis happen efficiently. The ER is a major site for making, processing, and distributing biomolecules. The rough endoplasmic reticulum has ribosomes attached to its surface. These ribosomes...

ribosomes

How Ribosomes Build Proteins

Ribosomes build proteins by reading messenger RNA, or mRNA, and linking amino acids in the right order. Both prokaryotic and eukaryotic cells contain ribosomes. Cells that make large amounts of protein, such as secretory cells in the human pancreas, can have millions of them. Ribosomes are made of ribosomal RNA, or rRNA, and proteins. In eukaryotic cells, rRNA is transcribed from genes in the nucleolus, a part of the nucleus that specializes in making ribosomes. There, rRNA combines with...

golgi apparatus

Protein Sorting in the Golgi Apparatus

The Golgi apparatus sorts and modifies proteins after they leave the endoplasmic reticulum (ER). Properly folded and assembled proteins are packaged into vesicles, or small membrane sacs, and moved by microtubule-based motor proteins. These vesicles can fuse into vesicular tubular clusters before reaching the Golgi, which often looks like a ribbon-shaped organelle in eukaryotic cells. Vesicles enter the cis face of the Golgi, the side facing the ER. They pass through a set of pancake-shaped...

peroxisomes

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...

microtubules

Microtubules in Cells and Cell Movement

Microtubules are cytoskeletal fibers that help cells keep their shape, move materials, and divide. They are the thickest of the three main cytoskeletal structures in eukaryotic cells, with a diameter of about 25 nm. Along with microfilaments and intermediate filaments, they form the internal support network of the cell. Microtubules are hollow tubes built from tubulin proteins. Each tubulin molecule is a heterodimer, which means it has two different parts: α-tubulin and β-tubulin. These dimers...

plant cell wall

Plant Cell Walls in Growth and Support

Plant cell walls help plant cells keep their shape, stay protected, and remain supported. As a cell matures, its wall can change based on the cell type. Parenchyma cells in leaves usually have only a thin primary cell wall. These walls are part of how different plant cells take on different jobs. Collenchyma and sclerenchyma cells are found mostly in the outer layers of stems and leaves. Collenchyma cells add strength by partially thickening the primary cell wall. Sclerenchyma cells provide...

plasmodesmata

Plasmodesmata and Plant Cell Communication

Plasmodesmata are the connections that let plant cells communicate directly. These tiny passageways link neighboring cells through the cell wall and help tissues work together in a multicellular plant. Cells in multicellular organisms must communicate to function as a unit. One way they do this is through intercellular junctions, which are contact points between adjacent cells. Fungal, plant, and animal cells all have intercellular junctions, but the types differ. In animal cells, the main...

the nucleus

Nuclear DNA and Cell Control

The nucleus is the control center of a eukaryotic cell. It is a membrane-bound organelle that contains chromosomal DNA. That DNA helps control gene expression and regulate protein production in the cell. Not all cellular DNA has the same role. The DNA in mitochondria and chloroplasts supports functions that are specific to those organelles. Inside the nucleus, DNA structure also affects how genes are regulated. Nuclear DNA is wrapped around proteins called histones. This forms chromatin, a...

the extracellular matrix

How ECM Supports Animal Tissues

The extracellular matrix (ECM) supports animal tissues by surrounding cells with structural molecules. It helps maintain tissue organization and gives tissues their specific physical properties. The ECM includes a gel-like ground substance, fibrous components, and many molecules with different jobs. A major part of the ECM is made of glycosaminoglycans, or GAGs. These polysaccharides fill much of the extracellular space and can take up a large volume for their mass. That makes the matrix...

gap junctions

Connexins and Cell-to-Cell Signaling

Gap junctions help animal cells send signals and share small materials with nearby cells. They are made of special proteins that form pores between neighboring cells and connect their cytoplasm. Through these channels, cells can exchange ions and other small molecules. These communication channels are found in many invertebrate and vertebrate species. They support important processes such as cell differentiation and development. They are also linked to human diseases, including disorders of...

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

Learn how membrane-bound organelles create controlled microenvironments in eukaryotic cells, from acidic lysosomes to the nucleus and mRNA export.

Cell Organelles and Microenvironments | JoVE K12

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Pennsylvania State Academic Standards

Life Science

Structure and Function

3.1.9-12.A

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Cells

Cell structure and function

Virginia  Standards of Learning

HIgh School

BIO.3

BIO.3.a

Arizona Science Standards

High School

HS+B.L1

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

SC.912.L.14.5

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LS.Bio.1.2

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Prokaryotic Cells

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Cytoplasm

The cytoplasm consists of organelles and a framework of protein scaffolds called the cytoskeleton suspended in an aqueous solution, the cytosol. The ...

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression ...

Endoplasmic Reticulum

Endoplasmic ReticulumThe endoplasmic reticulum (ER) is an extensive network of membranous sacs and tubules in eukaryotic cells, continuous with the outer ...

Ribosomes

Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that ...

Golgi Apparatus

As they leave the Endoplasmic Reticulum (ER), properly folded and assembled proteins are selectively packaged into vesicles. These vesicles are ...

Lysosomes

Lysosomes are membrane-enclosed spherical sacs derived from the Golgi apparatus. The most important function of the lysosome is degrading macromolecules ...

Peroxisomes

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Introduction to the Cytoskeleton

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Background
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Gap Junctions

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Use models to explain how the structure of organelles determines its function and supports overall cell processes.

Analyze how the relationship between structure and function supports life processes within organisms.

Cell Organelles and Microenvironments

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