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

K12 Standards

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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

As células eucarióticas contêm numerosos compartimentos internos, organelos ligados à membrana, permitindo que funções muito específicas possam ocorrer dentro de microambientes, protegidos ambos do interior e do exterior citoplasmático circundante. Por exemplo, o núcleo requer condições controladas para regulamentação precisa dos genes dentro. Portanto, está cercado por uma membrana dupla, o envelope nuclear, com poros para controlar quais moléculas podem entrar e sair, como mRNAs.Além disso, algumas proteínas requerem um ambiente oxidativo e devem ser isoladas do citosol, que é redutor. Assim, os ribossomas produzem essas proteínas dentro do retículo endoplasmático, onde elas também podem sofrer modificações críticas. Movimentos subsequentes até acontecem dentro de pequenos microcosmos químicos, chamados vesículas, enquanto faz os caminhos para os seus destinos.Outras organelos, como peroxissomas, fornecem proteção de seus próprios subprodutos prejudiciais, como o peróxido de hidrogénio, sequestrando enzimas que convertem compostos tóxicos em moléculas inofensivas, como a água. Da mesma forma, os lisossomas segregam enzimas, mas por um motivo diferente, para proteger reações digestivas que requerem um pH muito mais baixo do que o citoplasma abriga. As mitocôndrias também têm interiores ácidos entre suas duas membranas, que ajudam a produzir energia.No geral, a compartimentalização eucariótica apoia ações que de outra forma seriam incompatíveis se realizadas simultaneamente, sem alguma forma de contenção.

Gabaldón, Toni e Alexandros A. Pittis. "Origem e evolução da compartimentalização subcelular metabólica em eucariotos." Biochimie 119 (dezembro de 2015): 262–68. [<a href="https://doi.org/10.1016/j.biochi.2015.03.021" target="__blank">Fonte</a>]

compartimentalização eucariótica

Uma das características que distinguem as células eucarióticas é que elas têm organelos ligados a membrana—como o núcleo e as mitocôndrias—que realizam funções específicas. Uma vez que as membranas biológicas são apenas permeáveis a um pequeno número de substâncias, a membrana ao redor de um organelo cria um compartimento com condições controladas no seu interior. Esses microambientes são muitas vezes distintos do ambiente do citosol circundante e são adaptados às funções específicas do organelo.
 
 Por exemplo, os lisossomas—organelos em células animais que digerem moléculas e detritos celulares—mantêm um ambiente mais ácido que o citosol circundante, porque as suas enzimas requerem um pH mais baixo para catalisar reações. Da mesma forma, o pH é regulado dentro das mitocôndrias, ajudando a realizar sua função de produção de energia.
 
 Além disso, algumas proteínas requerem um ambiente oxidativo para enovelamento e processamento adequados, mas o citosol é geralmente redutivo. Portanto, essas proteínas são produzidas por ribossomas no retículo endoplasmático (ER), o que mantém o ambiente necessário. As proteínas são frequentemente transportadas dentro da célula através de vesículas ligadas a membrana.
 
 O material genético das células eucarióticas é compartimentalizado dentro do núcleo, que é cercado por uma dupla membrana chamada de envelope nuclear. Pequenos poros no envelope controlam que moléculas ou iões podem entrar ou sair do núcleo. Por exemplo, o RNA mensageiro (mRNA) sai do núcleo através desses poros para levar as instruções genéticas codificadas no DNA para os ribossomas, onde podem ser traduzidos em proteínas.
 
 Organelos também podem proteger uma célula contendo e neutralizando substâncias perigosas. Por exemplo, os peroxissomas realizam reações de oxidação que produzem peróxido de hidrogénio—que é tóxico para as células—mas também contêm enzimas que o convertem em oxigénio e água inofensivos. Portanto, a compartimentalização permite que as células eucarióticas realizem uma variedade de funções diferentes que de outra forma seriam incompatíveis em termos dos seus ambientes ou subprodutos produzidos.

Compartimentalização Eucariótica

Uma das características distintivas das células eucarióticas é que elas contêm organelas ligadas à membrana, como o núcleo e as mitocôndrias, que carregam ...

Education

JoVE Core

Biologia

Cellular Processes

Processos Celulares

Cell Structure and Function

Estrutura e Função Celular

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

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

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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.a

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HS+B.L1

HS+B.L1U1.4

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From Molecules to Organisms: Structures and Processes

9-12.B.1.1

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SC.912.L.14

SC.912.L.14.2

SC.912.L.14.3

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LS.Bio.1.2

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Prokaryotic Cells

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Cytoplasm

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The Nucleus

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Endoplasmic Reticulum

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

Ribosomes

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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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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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