Name: nuclear dna, chromatin, and nucleoli
Uploaded: 2023-04-30T10:29:41.000Z
Duration: 1 min 25 s
Channel: JoVE

K12 Standards

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

NC 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.1.5

The Nucleus

En las células eucariotas, el núcleo es un orgánulo unido a la membrana que alberga la información genética de la célula: el ADN.
Sin embargo, la organización del ADN dentro del núcleo depende de la fase del ciclo celular.
Por ejemplo, cuando la célula no se está dividiendo, los complejos de proteínas del ADN, conocidos como fibras de cromatina, están suspendidos sin apretar en el nucleoplasma, lo que permite un fácil acceso a la replicación del ADN y a las enzimas de transcripción.
Por el contrario, cuando la célula está a punto de dividirse, las fibras de cromatina se comprimen en cromosomas.
El nucléolo es una región distinta dentro del núcleo especializada para el ensamblaje de los ribosomas, complejos ARN-proteína responsables de la traducción de proteínas.
El núcleo está rodeado por una barrera de doble membrana, la envoltura nuclear, que está revestida con complejos de poros nucleares o NPC.
Estas NPC controlan el intercambio de moléculas entre el núcleo y el citoplasma.
Si bien la mayoría de las células del cuerpo tienen un núcleo, algunas, como los glóbulos rojos, están anucleadas, es decir, carecen de núcleo. Mientras que otras, como las células del músculo esquelético, son multinucleadas debido a necesidades estructurales y funcionales.

el núcleo

El núcleo es un orgánulo rodeado de membrana que actúa como centro de control en una célula eucariota. Contiene ADN cromosómico, que controla la expresión genética y regula con precisión la producción de proteínas dentro de la célula. Por el contrario, el ADN del interior de las mitocondrias y del cloroplasto sólo lleva a cabo funciones específicas de esos orgánulos.

Disposición del ADN dentro del núcleo.

La regulación de la expresión genética dentro del núcleo depende de muchos factores, incluida la estructura del ADN. El ADN del núcleo está envuelto alrededor de proteínas llamadas histonas, creando un complejo ADN-proteína llamado cromatina. Cuando las células no se dividen, es decir, durante la interfase, la cromatina se organiza de forma difusa. Esto permite un fácil acceso al ADN durante la transcripción. Cuando la célula eucariota está a punto de dividirse, la cromatina se condensa estrechamente en cromosomas lineales distintos, que pueden segregarse fácilmente en células hijas.

Nucléolos

El nucléolo es un orgánulo sin membrana que se forma alrededor de los loci cromosómicos del ARN ribosómico dentro del núcleo. Por tanto, los nucléolos son el sitio para la síntesis de ARNr y el ensamblaje de subunidades ribosómicas. Posteriormente, estas subunidades se exportan fuera del núcleo para ensamblarse en ribosomas completamente funcionales.

Estructuras subnucleares adicionales

El núcleo también contiene muchos otros cuerpos nucleares, como los cuerpos de Cajal, las motas y las paraspeckles. Estos cuerpos nucleares ayudan a compartimentar espacialmente el entorno nuclear y crear sitios distintos para reacciones biológicas específicas. Además, su estructura sin membranas permite un mejor intercambio de contenidos con el nucleoplasma.

El núcleo

El núcleo es un orgánulo unido a la membrana que actúa como centro de control en una célula eucariota. Contiene ADN cromosómico, que controla la expresión génica ...

Education

Educación

JoVE Core

Cell Biology

Biología Celular

Unit 1

Unidad 1

Cells, Genomes, and Evolution

Células, genomas y evolución

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

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 to access for transcription. As a eukaryotic cell prepares to divide, the chromatin condenses into distinct, linear chromosomes that can be separated into daughter cells.

The nucleus also contains the nucleolus, which is a membrane-less organelle. It forms around chromosomal regions that contain ribosomal RNA, or rRNA. The nucleolus is the site of rRNA synthesis and the assembly of ribosomal subunits. These subunits later leave the nucleus and join together to form functional ribosomes.

Other nuclear bodies are present as well. Cajal bodies, speckles, and paraspeckles help organize the nuclear space into regions for specific biological reactions. Their membrane-less structure also allows materials to move more easily with the nucleoplasm, the fluid inside the nucleus.

Nuclear DNA, Chromatin, and Nucleoli

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

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eukaryotic evolution

How Eukaryotic Cells Became Complex

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animal and plant cell structure

Plant vs Animal Cell Division and Specialization

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cytoplasm

Cytoplasm and the Cell’s Internal Support

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the nucleus

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

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the central dogma

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mutations

Mutations in DNA and Inherited Disease

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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

Explore how nuclear DNA is packed as chromatin, condenses into chromosomes, and how the nucleolus makes rRNA and ribosomal subunits in eukaryotic cells.

Nuclear DNA, Chromatin, and Nucleoli | JoVE K12

cell biology

JoVE Core Biología Celular ilustra procesos celulares complejos mediante completos vídeos animados fáciles de entender. Esta colección se centra en los componentes esenciales de las células y su funcionamiento, incluyendo los orgánulos y las membranas, el transporte celular y el metabolismo energético celular. Todo este material se complementa con los vídeos de científicos en acción, que muestran la aplicación de la biología celular en experimentos reales de investigación.

Louisiana Student Standards for Science

High School

Life Sciences

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance And Variation Of Traits

HS-LS3-1

Virginia  Standards of Learning

HIgh School

BIO.2

BIO.2.d

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

From Molecules to Organisms: Structures and Processes

B-LS1-1.

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Biomolecules
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lipid-derived-compounds-in-the-human-body

Lipid-derived Compounds in the Human Body

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Protein Organization

Globular Proteins

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Protein Denaturation

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ATP Energy Storage and Release

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LS.Bio.1.1

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Catalytically Perfect Enzymes

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introduction-to-mechanisms-of-enzyme-catalysis

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Cooperative Allosteric Transitions

Ribozymes

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LS.Bio.1.2

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Cytoplasm

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Ribosomes

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Lysosomes

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Peroxisomes

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Introduction to the Cytoskeleton

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overview-of-myosin-structure-and-function

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Plasmodesmata

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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

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, ...

Construct explanations to compare prokaryotic and eukaryotic cells in terms of structures and degree of complexity.

LS.Bio.1.4

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

Nuclear DNA, Chromatin, and Nucleoli

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