Name: how prokaryotes survive without a nucleus
Uploaded: 2023-04-30T10:29:03.000Z
Duration: 1 min 28 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.1.4

Prokaryotic Cells

Los procariotas incluyen arqueas y bacterias, organismos unicelulares simples que carecen de orgánulos unidos a la membrana.
Estos organismos están rodeados por una membrana plasmática selectivamente permeable que encierra componentes celulares, libremente suspendidos en el citoplasma viscoso.
Además de la membrana plasmática, las células bacterianas tienen un nivel adicional de protección en forma de pared celular que ayuda a mantener su forma general y la presión osmótica interna.
La pared celular está formada por peptidoglicano, un polímero de aminoácidos y azúcares.
Algunas bacterias tienen otra capa de defensa llamada cápsula, una capa de polisacáridos que promueve la adhesión de las células a las superficies.
Dentro de la célula, un ADN monocatenario de doble cadena se agrupa en una región central llamada nucleoide, donde puede interactuar con proteínas que flotan libremente.
La mayoría de las bacterias también tienen piezas circulares de ADN que flotan libremente, llamadas plásmidos, que pueden replicarse de forma independiente y conferir ventajas de supervivencia como la resistencia a los antibióticos.
Algunas especies bacterianas pueden contener proteínas específicas y orgánulos unidos a lípidos con funciones distintas.
Por ejemplo, las cianobacterias poseen carboxisomas y tilacoides para recolectar energía luminosa para llevar a cabo la fotosíntesis.

células procariotas

Los procariotas son pequeños organismos unicelulares que incluyen los dominios Archaea y Bacteria. Las bacterias incluyen muchos microorganismos comunes, como Salmonella y E. coli, mientras que Archaea incluye extremófilos que viven en ambientes hostiles, como manantiales volcánicos.

Al igual que las células eucariotas, todas las células procariótas están rodeadas por una membrana plasmática, tienen material genético en forma de ADN circular único, un citoplasma que llena el interior de la célula y ribosomas que sintetizan proteínas. Sin embargo, a diferencia de las células eucariotas, las procariotas carecen de núcleo u otros orgánulos intracelulares unidos a una membrana. Sus componentes celulares flotan libremente dentro del citoplasma, aunque su ADN está agrupado dentro de una región llamada nucleoide.

Dentro del citoplasma, muchos procariotas tienen pequeños fragmentos circulares de ADN bicatenario llamados plásmidos. Estos son distintos del ADN cromosómico de la célula y contienen sólo unos pocos genes especiales que proporcionan a las bacterias ventajas de supervivencia, como la resistencia a los antibióticos. Los plásmidos son autorreplicantes y pueden transmitirse entre células procariotas.

La mayoría de las bacterias tienen una pared celular hecha de peptidoglicano que se encuentra fuera de su membrana plasmática. Protege físicamente la célula y la ayuda a mantener la presión osmótica en diferentes ambientes. Muchas bacterias también tienen una capa de cápsula pegajosa que cubre su pared celular y les permite adherirse a un sustrato o entre sí, brindando así protección adicional.

Si bien las bacterias no tienen orgánulos rodeados de membranas, algunas tienen pliegues de la membrana plasmática que llevan a cabo funciones especializadas, como la fotosíntesis en las cianobacterias. Por lo tanto, aunque los procariotas son células simples en comparación con las eucariotas, tienen algunas estructuras únicas que les ayudan a realizar funciones complejas y les permiten vivir en una amplia variedad de entornos.

Células procariotas

Los procariotas son pequeños organismos unicelulares que incluyen los dominios: arqueas y bacterias. Las bacterias incluyen muchos microorganismos comunes, como ...

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

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 cytoplasm because they do not have membrane-bound intracellular organelles.

Their DNA is clustered in a region called the nucleoid. Many prokaryotes also carry plasmids, which are small, circular, double-stranded DNA molecules. Plasmids are separate from chromosomal DNA and can carry genes that give survival advantages, such as antibiotic resistance. They can also self-replicate and move between prokaryotic cells.

Most bacteria have a cell wall made of peptidoglycan outside the plasma membrane. This wall helps protect the cell and supports osmotic pressure in different environments. Many bacteria also have a sticky capsule that covers the wall and helps them attach to surfaces or to other cells. Some bacteria even have infoldings of the plasma membrane for special jobs, such as photosynthesis in cyanobacteria.

How Prokaryotes Survive Without a Nucleus

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the tree of life - bacteria, archaea, and eukaryotes

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Three Domains on the Tree of Life

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prokaryotic cells

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...

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eukaryotic evolution

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the nucleus

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the dna helix

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genome size and the evolution of new genes

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Genome Size and Gene Evolution

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gene evolution - fast or slow?

Gene Evolution Rates and Selection

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types of genetic transfer between organisms

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key terms and concepts

Learn how prokaryotes survive without a nucleus, from circular DNA and plasmids to peptidoglycan cell walls, capsules, and specialized membrane folds.

How Prokaryotes Survive Without a Nucleus | 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

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Heredity: Inheritance And Variation Of Traits

HS-LS3-1

Tennessee Academic Standards

From Molecules to Organisms: Structures and Processes

BIO1.LS1.1

BIO1.LS1.2

Virginia  Standards of Learning

HIgh School

BIO.3

BIO.3.b

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

Georgia Standards of Excellence

SB4.a

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How Prokaryotes Survive Without a Nucleus

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