Name: how organelles keep cells working
Uploaded: 2023-04-30T10:29:11.000Z
Duration: 1 min 37 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.1.4

Eukaryotic Compartmentalization

Les cellules eucaryotes contiennent de nombreux organites liés à une membrane qui permettent à des fonctions cellulaires spécifiques de se produire dans des microenvironnements distincts, protégés de l’intérieur du cytoplasme ainsi que de l’environnement extracellulaire.
Par exemple, les complexes de pores nucléaires intégrés dans l’enveloppe nucléaire contrôlent le transport des molécules à l’intérieur et à l’extérieur du noyau. Cela aide à maintenir des conditions contrôlées à l’intérieur du noyau pour réguler les processus critiques, tels que l’expression des gènes.
De plus, certaines protéines nécessitent un environnement oxydatif et doivent être isolées du cytosol réducteur. De telles protéines sont produites et modifiées chimiquement dans le réticulum endoplasmique avant d’être transportées vers leur destination finale via de petits microcosmes chimiques appelés vésicules.
D’autres organites, tels que les peroxysomes, offrent une protection en séquestrant des enzymes qui convertissent leurs propres sous-produits toxiques, comme le peroxyde d’hydrogène, en molécules inoffensives, telles que l’eau.
De même, les lysosomes séparent du cytosol les enzymes digestives qui fonctionnent à un pH très bas.
L’environnement acide entre les deux membranes d’une mitochondrie aide à produire de l’énergie sous forme d’ATP.
Dans l’ensemble, la compartimentation eucaryote soutient des actions qui seraient autrement incompatibles si elles étaient menées simultanément sans une certaine forme de confinement.

compartimentation eucaryote

L’une des caractéristiques distinctives des cellules eucaryotes est qu’elles contiennent des organites liées à la membrane, comme le noyau et les mitochondries, qui remplissent des fonctions spécialisées. Étant donné que les membranes biologiques ne sont que sélectivement perméables aux solutés, elles contribuent à créer un compartiment aux conditions contrôlées à l’intérieur d’un organite. Ces microenvironnements sont adaptés aux fonctions spécifiques des organites et aident à les isoler du cytosol environnant.

Par exemple, les lysosomes des cellules animales maintiennent un environnement acide par rapport au cytosol environnant. Cela aide les enzymes lysosomales à digérer les débris cellulaires. De même, la régulation du pH au sein des mitochondries contribue à la synthèse des molécules énergétiques.

De plus, certaines protéines nécessitent un environnement oxydatif pour un repliement et un traitement corrects, mais le cytosol est généralement réducteur. Par conséquent, ces protéines sont produites par les ribosomes du réticulum endoplasmique (RE), qui maintiennent l’environnement nécessaire. Les protéines sont ensuite transportées vers leur destination finale dans la cellule via des vésicules liées à la membrane.

Le matériel génétique des cellules eucaryotes est compartimenté au sein du noyau, entouré d’une double membrane appelée enveloppe nucléaire. Les petits pores de l'enveloppe contrôlent les molécules ou les ions qui peuvent entrer ou sortir du noyau. Par exemple, l’ARN messager (ARNm) quitte le noyau par ces pores pour transporter les instructions génétiques codées dans l’ADN vers les ribosomes, où elles peuvent être traduites en protéines.

Par conséquent, la compartimentation permet l’exécution de nombreuses fonctions différentes avec une plus grande efficacité au sein de la même cellule en concentrant les composants requis dans un espace confiné et en les séparant du reste de la cellule.

Compartimentation Eucaryote

L’une des caractéristiques distinctives des cellules eucaryotes est qu’elles contiennent des organites liés à une membrane, tels que le noyau et les mitochondries, qui portent ...

Education

Enseignement

JoVE Core

Cell Biology

Biologie cellulaire

Unit 1

Unité 1

Cells, Genomes, and Evolution

Cellules, génomes et évolution

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

how organelles keep cells working

Eukaryotic cells keep their organelles separate so each part can do a specific job. Organelles such as the nucleus and mitochondria are surrounded by membranes. These membranes are selectively permeable, which means they control what enters and leaves. That control creates small internal environments with conditions suited to each organelle.

These controlled spaces help organelles work more efficiently. In animal cells, lysosomes keep an acidic environment that helps their enzymes digest cellular debris. Mitochondria also rely on pH control to help make energy molecules. Some proteins need an oxidizing environment to fold and process correctly, so they are made by ribosomes in the endoplasmic reticulum, or ER, instead of in the cytosol, which is usually reductive.

After proteins are made, membrane-bound vesicles move them to their final location in the cell. The nucleus also shows how compartmentalization supports cell function. It holds the cell’s genetic material inside a double membrane called the nuclear envelope. Small pores in this envelope control what can enter or leave, and messenger RNA, or mRNA, exits through these pores to carry DNA instructions to ribosomes for protein synthesis. By keeping key materials in the right place, compartmentalization lets one cell carry out many tasks at the same time.

How Organelles Keep Cells Working

what are cells?

Cells as the Building Blocks of Life

Cells are the basic building blocks of life. A bacterium can be a single cell, while a human is made of trillions of cells. Even with this range, cells share key features that support life. A living cell has a plasma membrane. This is a bilayer of lipids that separates the cytoplasm inside the cell from the outside environment. A cell also carries genetic information in the form of DNA. In prokaryotic cells, DNA is found in a region called the nucleoid. In eukaryotic cells, DNA is enclosed...

the tree of life - bacteria, archaea, and eukaryotes

the-tree-of-life-bacteria-archaea-and-eukaryotes

Three Domains on the Tree of Life

The tree of life shows how living things are grouped into three domains: Bacteria, Archaea, and Eukaryotes. This classification helps explain the major branches of life and how they are related. Bacteria and Archaea are both single-celled organisms, but they are not the same. Eukaryotes include organisms with more complex cells, such as plants, animals, and fungi. Together, these three domains give a broad picture of life on Earth. Understanding the tree of life helps students compare cell...

prokaryotic cells

How Prokaryotes Survive Without a Nucleus

Prokaryotes are small unicellular organisms that live without a nucleus. They include the domains Archaea and Bacteria. Bacteria include common microbes such as Salmonella and E. coli, while Archaea include extremophiles that live in harsh places like volcanic springs. Prokaryotic cells still share several basic features with eukaryotic cells. They have a plasma membrane, cytoplasm, ribosomes, and genetic material in the form of single, circular DNA. Their cell parts float freely in the...

eukaryotic compartmentalization

Eukaryotic cells keep their organelles separate so each part can do a specific job. Organelles such as the nucleus and mitochondria are surrounded by membranes. These membranes are selectively permeable, which means they control what enters and leaves. That control creates small internal environments with conditions suited to each organelle. These controlled spaces help organelles work more efficiently. In animal cells, lysosomes keep an acidic environment that helps their enzymes digest...

eukaryotic evolution

How Eukaryotic Cells Became Complex

Eukaryotic cells became complex through a debated evolutionary path that likely involved endosymbiosis. The most accepted model is the endosymbiont theory, which explains how organelles such as mitochondria and chloroplasts may have entered an ancestral cell. Other ideas include the nucleus-first hypothesis, the mitochondria-first hypothesis, and the eukaryote-first hypothesis. The nucleus-first hypothesis says an ancestral prokaryote first formed a membrane around its DNA, creating the...

animal and plant cell structure

Plant vs Animal Cell Division and Specialization

Plant and animal cells differ in how they divide, organize into tissues, and specialize for different jobs. Both cell types divide by mitosis in non-gametic cells and by meiosis in gametic cells, but the details are not the same. These differences help explain how each cell type supports growth and reproduction. During cell division, animal cells use centrosomes to organize spindle fibers and separate chromosomes. Plant cells do not have centrosomes. Instead, they use a microtubule-organizing...

cytoplasm

Cytoplasm and the Cell’s Internal Support

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. This fluid helps keep the cell organized and supports many cellular activities. The cytoplasm is also where protein synthesis and protein folding take place. The watery cytosol helps proteins fold correctly. In a folded protein, hydrophobic amino acid side chains tend to stay buried in the core, while...

the nucleus

Nuclear DNA, Chromatin, and Nucleoli

The nucleus is a membrane-bound organelle that stores chromosomal DNA and helps control what proteins a eukaryotic cell makes. It acts as the cell’s control center. DNA in mitochondria and chloroplasts is different because it mainly supports functions specific to those organelles. Inside the nucleus, DNA is wrapped around proteins called histones. This DNA-protein complex is called chromatin. During interphase, when the cell is not dividing, chromatin stays loosely arranged so the DNA is easy...

the dna helix

How DNA Structure Was Discovered

DNA is the genetic material that passes traits from one generation to the next in organisms and most viruses. It is made of two strands of nucleotides that twist into a spring-like double helix. The shape is not perfectly even. It also has repeating grooves called the major groove and the minor groove. The major groove forms where the sugar-phosphate backbones are farther apart. This wider space gives DNA-binding proteins, including transcription factors, better access to the bases. The minor...

the central dogma

DNA to Protein: RNA’s Role

DNA to protein flow depends on RNA as the link between genetic information and the amino acids that build proteins. Early scientists knew that DNA stores the information for cell functions and that proteins carry out most of those functions. For a long time, they did not know how the code in DNA became a working protein. At first, many people thought one gene was changed directly into its protein. Two findings in eukaryotic cells challenged that idea. Protein production does not happen in the...

mutations

Mutations in DNA and Inherited Disease

Mutations are changes in the DNA sequence. They can happen on their own during DNA copying, or they can be caused by environmental factors. Scientists describe mutations in several ways, including whether they change the amino acid sequence of a protein, how much DNA they affect, and whether they occur in somatic cells or germline cells. Some mutations are point mutations. A point mutation changes a single nucleotide in DNA. Other mutations are chromosomal alterations, which change the number...

genome size and the evolution of new genes

genome-size-and-the-evolution-of-new-genes

Genome Size and Gene Evolution

Genome size and gene evolution are linked through changes in DNA sequence and genome structure. Some genes can arise from parts of the genome that were not coding before, while others come from changes to existing genes. These shifts help explain how new genetic material can appear over time. A genome is the full set of DNA in an organism. Its size can change as DNA is added, removed, or rearranged. The transcript highlights that genome size is not fixed, and that these changes can shape the...

gene families

Shared Origins of Gene Families

Gene families are groups of related genes that share a common origin. They form when genes are copied and then change over time. These related genes can be found within the same genome. The video also connects gene families to homologous genes and orthologous genes. Homologous genes are genes with a shared evolutionary origin. Orthologous genes are homologous genes found in different species. Gene families help show how these relationships are used to study evolution and related gene functions.

gene evolution - fast or slow?

Gene Evolution Rates and Selection

Gene evolution can happen at different rates, and natural selection helps shape those changes. Some genes change slowly because important DNA changes are removed over time. Other genes can change more quickly when different mutations are kept in a population. The rate of evolution depends on how a gene is used and how strongly it is affected by selection. Genes with essential jobs often stay more similar across species. Genes under weaker pressure may show more variation and may evolve faster.<br...

types of genetic transfer between organisms

types-of-genetic-transfer-between-organisms

Vertical and Horizontal Gene Transfer

Genetic transfer between organisms happens in two main ways: vertical gene transfer and horizontal gene transfer. These two routes explain how hereditary material moves from one generation to the next or between organisms that are not parent and offspring. Vertical gene transfer passes genes from parent to offspring during reproduction. This is the usual way genetic information is inherited in living things. Horizontal gene transfer moves genetic material between organisms outside of...

key terms and concepts

Learn how eukaryotic organelles use membranes, pH control, and nuclear pores to create the right conditions for digestion, energy use, and protein synthesis.

How Organelles Keep Cells Working | JoVE K12

cell biology

JoVE Core Biologie cellulaire illustre les processus cellulaires complexes dans des leçons vidéos complètes mais faciles à comprendre. Cette collection se concentre sur les composants et fonctions essentiels de la cellule ; cela inclut les organelles et les membranes ainsi que le transport et le métabolisme énergétique cellulaire. Elle est complétée par nos vidéos de scientifiques à l'action qui démontrent l'application de la biologie cellulaire dans des expériences concrètes.

Louisiana Student Standards for Science

High School

Life Sciences

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance And Variation Of Traits

HS-LS3-1

Tennessee Academic Standards

From Molecules to Organisms: Structures and Processes

BIO1.LS1.2

Virginia  Standards of Learning

HIgh School

BIO.6

BIO.6.a

Life Science

LS.3

LS.3.b

Florida Department of Education

SC.912.L.15

SC.912.L.15.6

Texas Essential Knowledge and Skills

BIO.5

BIO.5.B

Georgia Standards of Excellence

SB4.a

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introduction-to-mechanisms-of-enzyme-catalysis

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LS.Bio.1.2

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Cells are the smallest and basic units of life, whether it is a single cell that forms the entire organism, e.g., in a bacterium or trillions of them, ...

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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

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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

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

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ExpandImmediately before the experiment, wash and peel onion bulbs for the class.
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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.

LS.Bio.1.3

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

How Organelles Keep Cells Working

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