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

Клетки эукариотов содержат многочисленные внутренние отделения, ограниченные мембраной органеллы, позволяющие очень специфическим функциям проявляться в микросредах, защищённых и от цитоплазматического интерьера, и от внеклеточного окружения. Например, ядро требует наличия контролируемых условий для точного регулирования генов внутри. Поэтому оно окружено двойной мембраной, ядерной оболочкой с порами, контролирующими, какие молекулы могут попасть и остаться, как мРНК.Кроме того, некоторые белки требуют окислительной среды и должны быть изолированы от цитозоли, которая восстанавливает их. Таким образом, рибосомы производят эти белки в эндоплазматическом ретикулуме, где они также могут пройти критические изменения. Последующие движения происходят даже внутри маленьких химических микрокосмов, называемых везикулами, на пути в их пункты назначения.Другие органеллы, такие как пероксисомы, обеспечивают защиту от их собственных вредных побочных продуктов, Таких как пероксид водорода, путём секвестирования ферментов, которые преобразуют токсичные соединения в безвредные молекулы, такие как вода. Аналогично, лизосомы сегрегируют ферменты, но по другой причине, для защиты реакций пищеварения, которые требуют уровня pH намного ниже предоставленного цитоплазмой. Митохондрии также кислые внутри между двумя их мембранами, что помогает производить энергию.В целом, эукариотическое разделение поддерживает действия, которые, в противном случае, были бы несовместимы если бы выполнялись одновременно, без какой-либо формы сдерживания.

Габальдон, Тони и Александрос А. Питтис. "Происхождение и эволюция метаболической субклеточной компартментализации у эукариот." Биохимия 119 (декабрь 2015 г.): 262–68. [<a href="https://doi.org/10.1016/j.biochi.2015.03.021" target="__blank">Источник</a>]

Эукариотическая компартментализация

Одной из отличительных особенностей эукариотических клеток является то, что они содержат мембранные органеллы, такие как ядро и митохондрии, которые выполняют определенные функции. Так как биологические мембраны проницаемы только для небольшого количества веществ, мембрана вокруг органеллы создает отсек с контролируемыми условиями внутри. Эти микроокантироны часто отличаются от окружающей среды окружающего цитозола и адаптированы к конкретным функциям органеллы.

Например, лизосомы-органеллы в клетках животных, которые переваривают молекулы и клеточный мусор, поддерживают среду, которая является более кислой, чем окружающий цитозол, потому что ее ферменты требуют более низкого рН для реакций катализа. Аналогичным образом, рН регулируется в митохондриях, что помогает им выполнять свою функцию производства энергии.

Кроме того, некоторые белки требуют окислительной среды для правильного складывания и обработки, но цитозол, как правило, редуктивный. Таким образом, эти белки производятся рибосомы в эндоплазматической ретикулум (ER), который поддерживает необходимую окружающую среду. Белки часто затем транспортируются внутри клетки через мембранные пузырьки.

Генетический материал эукариотических клеток разобщен внутри ядра, которое окружено двойной мембраной, называемой ядерной оболочкой. Небольшие поры в оболочке контролируют, какие молекулы или ионы могут войти или покинуть ядро. Например, РНК-мессенджер (мРНК) выходит из ядра через эти поры, чтобы перенести генетические инструкции, закодированные в ДНК, в рибосомы, где они могут быть переведены в белок.

Органеллы также могут защитить клетку, сдерживая и нейтрализуя опасные вещества. Например, пероксисомы выполняют окислительные реакции, которые производят перекись водорода, который является токсичным для клеток, но они также содержат ферменты, которые преобразуют его в безвредный кислород и воду. Таким образом, разнообразие позволяет эукариотическим клеткам выполнять различные функции, которые в противном случае были бы несовместимы с точки зрения их необходимой среды или суб-продуктов производства.

Одной из отличительных особенностей эукариотических клеток является то, что они содержат мембранно-связанные органеллы, такие как ядро и митохондрии, которые несут ...

Education

JoVE Core

Биология

Cellular Processes

Клеточные процессы

Cell Structure and Function

Строение и функции клетки

KEY TERMS AND CONCEPTS

ОСНОВНЫЕ ТЕРМИНЫ И ПОНЯТИЯ

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

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

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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introduction-to-mechanisms-of-enzyme-catalysis

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LS.Bio.1.2

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Cell Size

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One of the distinguishing features of eukaryotic cells is that they contain membrane-bound organelles, such as the nucleus and mitochondria, that carry ...

Prokaryotic Cells

Prokaryotes are small unicellular organisms that include the domains&#x2014;Archaea and Bacteria. Bacteria include many common organisms, such as ...

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

Overview of the Cytoskeleton
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Cell Structure

Background
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overview-of-myosin-structure-and-function

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Microtubules

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Types of Intermediate Filaments

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Gap Junctions

Multicellular organisms employ a variety of ways for cells to communicate with each other. Gap junctions are specialized proteins that form pores between ...

The Extracellular Matrix

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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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