Name: how xylem moves water in plants
Uploaded: 2026-08-26T08:20:58.626Z
Duration: 2 min 21 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Life Science

SC.912.L.14

SC.912.L.14.7

xylem-and-transpiration-driven-transport-of-resources

Xylem and Transpiration-driven Transport of Resources

Pflanzen nehmen Wasser und
N&#xE4;hrstoffe vom Boden auf,
sei ben&#xF6;tigen diese Substanzen allerdings
sogar in weit entfernten Geweben.
Wie transportieren Pflanzen
diese Substanzen
entgegen die Kr&#xE4;fte der Gravitation?
Wasser und gel&#xF6;ste
Mineralien dringen in die Pflanze
durch durchl&#xE4;ssige Wurzelhaarzellen
in die Epidermis ein und
reisen zum Xylem,
wo die Fl&#xFC;ssigkeit ist,
die als Xylemsaft bezeichnet wird.
Der Saft wird von den
Wurzeln zum Rest der Pflanze
durch Massestr&#xF6;mung verteilt,
einer mit Druck angetriebenen Bewegung von Fl&#xFC;ssigkeit
&#xFC;ber gro&#xDF;e Distanzen hinweg, durch
spezialisierte Transportzellen
im Xylem.
Tracheiden und Tracheen
funktioneren als flexibles
Rohrsystem.
Ihre Zellen haben kein
Zytoplasma und Organellen,
und sie haben undurchl&#xE4;ssige, verholzene
Zellw&#xE4;nde, die dagegen vorbeugen,
dass Xylemsaft ausl&#xE4;uft.
Der prim&#xE4;re Mechanismus, der
Xylemsaft durch die Pflanze
zieht, ist Transpiration
von den Bl&#xE4;ttern.
Luftraum zwischen Mesophyllzellen
in den Bl&#xE4;ttern
werden durchtr&#xE4;nkt
mit Wasserdunst
w&#xE4;hrend des Prozesses
der Photosynthese
und zellul&#xE4;rer Atmung.
Die Luft au&#xDF;erhalb der Pflanze
ist trockener als die Luft
innerhalb den Bl&#xE4;ttern.
Wenn die Stomata ge&#xF6;ffnet
sind, diffundiert Wasserdunst
entlang seinem
Konzentrationsgef&#xE4;lle,
wobei der von den feuchten
Lufttaschen innerhalb des Blattes
zur Atmosph&#xE4;re
au&#xDF;erhalb der Pflanze reist.
Ein Film von fl&#xFC;ssigem Wasser
haftet sich an die Zellwand
jeder Mesophyllzelle,
was den Gasaustausch
w&#xE4;hrend der Photosynthese und
zellul&#xE4;ren Atmung erleichtert.
Wenn Wasserdunst durch
die Stomata austritt, verdunstet ein
Teil des fl&#xFC;ssigen Wassers,
was eine Spannung erzeugt,
mit der das Wasser von den Blattvenen
in die Mesophyllzellen gezogen wird,
um den Film nachzuf&#xFC;llen.
Negativer Druck
in den Blattvenen
zieht dann den Xylemsaft weg von
den Wurzeln, den Stamm hinauf,
und in die Bl&#xE4;tter,
wobei Wasser und Mineralien
durch die Pflanze transportiert werden.

Hae Koo Kim, Joonghyuk Park, Ildoo Hwang. Untersuchung des Wassertransports durch das Xylem-Netzwerk in Gefäßpflanzen. Zeitschrift für experimentelle Botanik. Jahrgang 65, Heft 7. [<a href="https://doi.org/10.1093/jxb/eru075" target="_blank">Quelle</a>]

der durch xylem und transpiration betriebene transport von ressourcen

Das Xylem der Gef&#xE4;&#xDF;pflanzen verteilt das von den Wurzeln aufgenommene Wasser und die gel&#xF6;sten Mineralien in die gesamte Pflanze. Die reifen Zellen, die den Xylemsaft transportieren, leben nicht mehr und die Bewegung des Xylemsaftes ist ein passiver Prozess.
 
 Tracheiden und Gef&#xE4;&#xDF;glieder transportieren Xylemsaft
 
 Tracheiden-Elemente sind die Transportzellen des Xylems. Ihnen fehlen das Zytoplasma und die Organellen, wenn sie reif sind und sind ein als Teil des Apoplasten der Pflanze, weil sie direkt mit dem extrazellul&#xE4;ren Raum verbunden sind. Es gibt zwei Arten der Tracheiden-Elementen: Tracheiden und Gef&#xE4;&#xDF;glieder (Tracheen).
 
 Tracheiden sind l&#xE4;ngliche Zellen mit lignifizierten W&#xE4;nden, die kleine L&#xF6;cher (die T&#xFC;pfel) enthalten, die den Xylemsaft von einer Zelle zur n&#xE4;chsten leiten, wo sich ihre W&#xE4;nde &#xFC;berlappen. Samenlose Gef&#xE4;&#xDF;pflanzen und die meisten Gymnospermen, oder zapfentragende Pflanzen, haben nur Tracheiden, von denen angenommen wird, dass sie sich vor den Tracheen entwickelt haben.
 
 Tracheen sind breite lignifizierte Zellen, die vertikal gestapelt sind und so Gef&#xE4;&#xDF;e bilden. Sie sind durch perforierte Membranen (T&#xFC;pfelmembran) verbunden, das sind spezialisierte Zellstrukturen, durch dessen Hohlr&#xE4;ume der Xylemsaft flie&#xDF;en kann. Der gr&#xF6;&#xDF;ere Durchmesser und die effizientere Struktur der T&#xFC;pfelmembran erm&#xF6;glichen Gef&#xE4;&#xDF;en, die aus Tracheen bestehen, den Transport von einem viel gr&#xF6;&#xDF;erem Volumen des Xylemsafts. Die meisten Angiospermen, oder bl&#xFC;henden Pflanzen, haben sowohl Tracheiden als auch Tracheen.
 
 Der aktive Transport von Mineralien erzeugt einen Gradienten des Wasserdrucks von den Wurzeln zu den Bl&#xE4;ttern
 
 W&#xE4;hrend Wasser passiv in die durchl&#xE4;ssigen Wurzelzellen einer Pflanze gelangt, ist ein aktiver Transport f&#xFC;r Mineralien in das Xylem erforderlich. Die daraus resultierende hohe 
 Konzentration an gel&#xF6;sten Stoffen in den Wurzeln erzeugt einen Gradienten des Druckpotentials von dem Wasser innerhalb des Xylems, wobei ein h&#xF6;herer Druck in den Wurzeln herrscht und ein geringerer an Orten in der Pflanze, wo weniger gel&#xF6;ste Stoffe sind. Das Wasser bewegt sich dann in Richtung des geringeren Druckbereichs; Dieser Gradient tr&#xE4;gt jedoch nur zu gering zu dem gesamten Transport des Safts durch das Xylem bei.
 
 Physikalische Kr&#xE4;fte, die auf Wassermolek&#xFC;le wirken, halten die Fl&#xFC;ssigkeit im Xylem
 
 Der Transport von Xylemsaft durch eine Pflanze wird zum Teil durch die physikalischen Eigenschaften des Wassers erm&#xF6;glicht. Die Koh&#xE4;sionstheorie f&#xFC;r den Transport des Xylemsaftes durch das Xylem wurde erstmals in den 1890er Jahren vorgeschlagen. Der Zusammenhalt zwischen Wassermolek&#xFC;len ist relativ stark, da alle drei Atome eines Wassermolek&#xFC;ls an einer Wasserstoffbindung mit anderen Wassermolek&#xFC;len teilnehmen k&#xF6;nnen. Dies bedeutet, dass ein Transpirationssog in den Bl&#xE4;ttern Wassermolek&#xFC;le im gesamten Xylem beeinflussen kann, wie Glieder in einer Kette, bis hin zu den Wurzeln.
 
 Eine weitere Kraft, die Adh&#xE4;sion, erm&#xF6;glicht es Wassermolek&#xFC;len, an Oberfl&#xE4;chen innerhalb der Pflanze zu kleben, wie z. B. die Zellw&#xE4;nde der Mesophyllzellen im Blatt, wo die Wasseroberfl&#xE4;chenspannung wichtig ist, um Saft aus Blattgef&#xE4;&#xDF;en zu ziehen, wenn Wasserdampf aus den Bl&#xE4;ttern austritt. Die Adh&#xE4;sion der Wassermolek&#xFC;len an den W&#xE4;nden von Xylemgef&#xE4;&#xDF;en verhindert, dass der Saft durch die Wurzeln nach unten und aus der Pflanze sickert, wenn sich die Stomata schlie&#xDF;en und der durch die Transpiration erzeugte Sog aufh&#xF6;rt.

Der durch Xylem und Transpiration betriebene Transport von Ressourcen

The xylem of vascular plants distributes water and dissolved minerals that are taken up by the roots to the rest of the plant. The cells that transport ...

https://cloudfront.jove.com/files/ftp_upload/11098/11098_article_thumb_11098.jpg

Education

Lehre

JoVE Core

Biology

Biologie

Plant Biology

Pflanzenbiologie

Plant Structure, Growth and Function

Pflanzenstruktur, Wachstum und Ernährung

KEY TERMS AND CONCEPTS

KERNBEGRIFFE UND KONZEPTE

how xylem moves water in plants

Xylem moves water and dissolved minerals from the roots to the rest of the plant. The cells that carry xylem sap are dead when mature, so the flow is passive. Xylem transport depends on special tracheary elements, which connect directly with the extracellular space in the apoplast.

There are two main tracheary elements: tracheids and vessel elements. Tracheids are long cells with lignified walls and small pits. These pits let xylem sap move from one cell to the next where the walls overlap. Seedless vascular plants and most gymnosperms have only tracheids, which are thought to have evolved first.

Vessel elements are wider lignified cells that stack to form vessels. Their ends have perforation plates, which contain openings for sap flow. Because of their larger diameter and efficient perforation plates, vessels can move a much larger volume of sap. Most angiosperms have both tracheids and vessel elements.

Water enters the plant passively through permeable root cells, but minerals must be moved into the xylem by active transport. This builds a high solute concentration in the roots. That difference creates a water pressure gradient, with higher pressure in the roots and lower pressure elsewhere in the plant. Water moves toward the lower pressure areas, but this is only a minor part of xylem transport.

Water also moves because of its physical properties. The cohesion-tension hypothesis explains how transpiration in the leaves can pull water through the xylem. Cohesion between water molecules is strong because hydrogen bonding links them together. Adhesion helps water stick to cell walls in the leaf and along the xylem, which supports the pull of sap upward and helps prevent sap from leaking downward when stomata close.

How Xylem Moves Water in Plants

introduction to plant diversity

Plant Adaptations for Life on Land

Plant adaptations for life on land explain how Kingdom Plantae moved from water to land about 410 million years ago. This shift happened when green algae began colonizing a new environment that had not been widely occupied. Land offered more light and carbon dioxide for growth, but it also created major challenges for early plants. One key adaptation was the cuticle, a waxy outer layer that helps prevent water loss. It traps moisture inside the plant. But it also limited direct gas exchange...

non-vascular seedless plants

Nonvascular Plants and Their Life Cycle

Nonvascular plants include some of the earliest plants on Earth. Today, this group includes liverworts, mosses, and hornworts. These plants are also called bryophytes. They have no true roots, leaves, or stems because they lack extensive vascular tissue. Bryophytes reproduce with spores instead of seeds. Their life cycle is dominated by the haploid gametophyte stage, which produces eggs and sperm. The sporophyte stage makes haploid spores that can grow by mitosis into new gametophytes. In many...

seedless vascular plants

Fern Life Cycles and Vascular Tissue

Seedless vascular plants include ferns, horsetails, whisk ferns, and lycophytes. Ferns are the most common example. Whisk ferns and their relatives, along with horsetails, are monilophytes. Lycophytes include club mosses, spikemosses, and quillworts, and none of these are true mosses. Seedless vascular plants differ from nonvascular plants because they have vascular tissue. This tissue includes xylem and phloem, which move water and nutrients through the plant. Most seedless vascular plants...

introduction to seed plants

Seed Plants: Cones, Flowers, and Fruits

Seed plants are land plants that make seeds, use pollen, and have reduced gametophytes. This group includes gymnosperms and angiosperms. Gymnosperms include cycads, Ginkgo biloba, gnetophytes, and conifers. Gymnosperms usually form cones. Pollen cones contain the male gametophytes. Ovulate cones contain the female gametophytes and produce exposed seeds after fertilization. Angiosperms are the most diverse and widespread land plants. They form flowers and fruit, and both structures support...

basic plant anatomy: roots, stems, and leaves

basic-plant-anatomy-roots-stems-and-leaves

Plant Organs and Their Specialized Roles

Plants are built from roots, stems, and leaves, but each organ can change to fit a plant’s environment. These structures may look very different from one species to another. They still carry out the main jobs needed for growth and survival. Roots are usually underground, but that is not always true. Aerial roots grow aboveground. Epiphytic plants, such as orchids, can live without ever touching soil. In strangler figs and banyans, aerial roots begin aboveground, grow downward, and later reach...

plant cells and tissues

Plant Growth and Support Tissues

Plant growth and support tissues help plants grow, protect themselves, and move materials through the body. Plant tissues are groups of similar cells that do related jobs. These tissues combine to form organs such as flowers, fruit, stems, and leaves. Two major kinds of plant tissue are meristematic tissue and permanent tissue. Meristematic tissue is the main growth tissue in plants. It can keep dividing and renewing itself, and every plant cell begins in a meristem. Meristematic tissue is...

meristems and plant growth

Plant Growth from Root and Shoot Tips

Plants grow throughout their lives, and that pattern is called indeterminate growth. This trait sets plants apart from most animals. Some plant parts stop growing, such as leaves and flowers, but roots and stems can keep growing for a long time. Meristems make this ongoing growth possible. A meristem is a plant tissue that contains undifferentiated cells called meristematic cells. When these cells divide, some daughter cells stay in the meristem. That keeps a supply of cells that can keep...

primary and secondary growth in roots and shoots

primary-and-secondary-growth-in-roots-and-shoots

Root and Shoot Growth: Length vs. Width

Root and shoot growth in vascular plants happens in two main ways: primary growth and secondary growth. Primary growth makes roots and shoots longer. Secondary growth makes them thicker. Many woody plants show both kinds of growth, and the two can happen at the same time. Primary growth happens in newer parts of the plant. Secondary growth happens in regions that have already finished primary growth. In roots and shoots, the process starts in apical meristems, which are areas of actively...

morphogenesis

Plant Flowering and Organ Identity

Plant flowering and organ identity shape a plant’s form and structure. These changes depend on growth and cell differentiation, which work together during plant morphogenesis. Precursor cells become specialized cell types, and those cells are organized into tissues and organ systems that support the whole plant. Plant growth and cell differentiation are controlled by hormones. Plant hormones regulate gene expression, often in response to environmental stimuli. Temperature and day length are...

light acquisition

How Plants Maximize Sunlight Capture

Plants need light energy to make glucose, so leaf shape and plant structure help determine how well they capture sunlight. Many modern plants have evolved leaves that are specialized for light capture. Leaf size can vary from just a few millimeters wide to tens of meters wide, depending on the environment. Competition for sunlight has pushed evolution toward larger leaves and taller plants. These changes help plants avoid being shaded by nearby competitors. They also depend on root systems...

water and mineral acquisition

How Roots Absorb Water and Minerals

Roots absorb water and minerals from the soil using specialized tissues. Their branching patterns help them reach more soil, and root hairs on the outer cells increase surface area for contact with the ground. Water enters roots passively because the water concentration in the soil is higher than in root tissue. Minerals move in a different way. They are taken up actively by root cells, which requires energy and transport proteins. Soil particles carry a negative charge, so positive ions...

short-distance transport of resources

Plant Cell Membranes and Water Balance

Plant cell membranes control how water, ions, and other solutes move over short distances. This transport can happen across just 2 to 3 cells, and it begins at the plasma membrane. Small uncharged molecules, such as oxygen, carbon dioxide, and water, can diffuse through the membrane on their own. Ions and larger molecules need transport proteins because of their charge or size. Membrane transport also happens inside plant cells. The central vacuole stores resources and helps manage the cell’s...

xylem and transpiration-driven transport of resources

Xylem moves water and dissolved minerals from the roots to the rest of the plant. The cells that carry xylem sap are dead when mature, so the flow is passive. Xylem transport depends on special tracheary elements, which connect directly with the extracellular space in the apoplast. There are two main tracheary elements: tracheids and vessel elements. Tracheids are long cells with lignified walls and small pits. These pits let xylem sap move from one cell to the next where the walls overlap.

regulation of transpiration by stomata

How Guard Cells Open Plant Stomata

How guard cells open and close plant stomata controls gas exchange in leaves. A stoma is a tiny opening in the leaf epidermis. The word comes from the Greek word for “mouth.” These openings let plants take in carbon dioxide for photosynthesis and release oxygen into the air. Each stoma is surrounded by two guard cells. When these cells take up water, they create an opening. Ion transport controls how much water stays in the guard cells. A trigger causes pumps to move hydrogen ions out of the...

adaptations that reduce water loss

Plant Features That Limit Water Loss

Plant features that limit water loss help plants survive in dry or hot environments. Water is needed for photosynthesis and other cell processes, so plants have evolved several ways to slow evaporation from their leaves. One major barrier is the cuticle, a waxy layer on the leaf epidermis. The epidermis is the outer cell layer, and it makes cutin and other plant waxes that form this hydrophobic coating. The cuticle helps stop water from escaping and also keeps out unwanted solutes. Its...

phloem and sugar transport

How Phloem Moves Sugars in Plants

Phloem moves sugars and other materials through plants. In angiosperms, sugar production is mostly limited to photosynthetic cells in the leaves. These leaves act as sugar sources because they make more sugar than they use. Roots, shoots, flowers, and fruits are usually sugar sinks because they need more sugar than they can make. This movement is called translocation. It carries sugar, hormones, amino acids, and some signaling molecules from source tissues to sink tissues. The transport...

the soil ecosystem

Soil Layers and How Soil Forms

Soil supplies plants with water and inorganic minerals. It is the natural medium for land plants, and its quality depends on both chemical makeup and living organisms in the soil. Healthy soil contains enough air, water, minerals, and organic matter to support plant growth. Soil is made of three major components. Inorganic mineral matter makes up about 40 to 45 percent of soil volume. Organic matter, also called humus, makes up about 5 percent. Water and air fill about 50 percent of the volume.

key elements for plant nutrition

Plant Nutrients: Macro and Micro Needs

Plants need both organic and inorganic nutrients to survive, grow, reproduce, and keep normal cell function. Researchers use hydroponics to study these essential nutrients. In hydroponic culture, plants grow without soil in water-based nutrient solutions. At least 17 nutrients are known to be essential for plants. Plants get these elements from the atmosphere, the soil around their roots, and water. Nine of them are macronutrients, which plants need in larger amounts. These macronutrients are...

the roles of bacteria and fungi in plant nutrition

the-roles-of-bacteria-and-fungi-in-plant-nutrition

How Soil Microbes Help Plants Get Nutrients

Soil microbes help plants get nutrients, water, and protection. Plants can make their own food by photosynthesis, but they still depend on organisms in the soil to get the nutrients they need to work properly. Bacteria and fungi form symbiotic relationships with plants, which helps both partners survive in many environments. The bacteria living in and around plant roots are called the rhizosphere. This community is very diverse. Some bacteria can cause disease, but most help plant health. In...

epiphytes, parasites, and carnivores

Plant Nutritional Adaptations in Nature

Plant nutritional adaptations help some species survive by using fungi, bacteria, or other plants and animals. Many plants also rely on mutualistic partners in the soil. Root-colonizing fungi, such as mycorrhizae, increase root surface area and improve nutrient absorption. Nitrogen-fixing bacteria, such as rhizobia, convert atmospheric nitrogen (N2) into ammonia (NH3), which plants can use to build essential molecules like chlorophyll. These relationships benefit both sides. The plant gets...

the apoplast and symplast

Plant Water Transport Pathways

Plant water transport pathways help roots absorb water and dissolved minerals from the soil. These pathways move materials through plant tissues that support growth and nutrient uptake. The main tissue regions involved are the apoplast and the symplast. The apoplast includes everything outside the plasma membrane of living cells. It contains cell walls, extracellular spaces, xylem, phloem, and tracheids. The symplast is the cytosol of all living plant cells, along with the plasmodesmata that...

key terms and concepts

Learn how xylem transports water and minerals in plants, from tracheids and vessel elements to transpiration pull, cohesion, and adhesion.

How Xylem Moves Water in Plants | 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

Die JoVE-Serie erweckt die Biologie durch über 300 prägnante und leicht verständliche animierte Video-Lektionen zum Leben, die Schlüsselkonzepte der Biologie erklären, sowie durch mehr als 150 Videos von Wissenschaftlern in der Praxis, die aktuelle Forschungsexperimente in den Labors von heute zeigen.

Texas Essential Knowledge and Skills

BIO.12

BIO.12.B

new-york-state-science-learning-standards

New York State Science Learning Standards

Structure and Function

HS-LS1-2.

Georgia Standards of Excellence

9-12

Botany

SBO1.

Transport

What are Cells?

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, ...

Characteristics of Life

Biology is a natural science that studies life and living organisms, including their structure, function, development, interactions, evolution, ...

https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/10647.jpg

Animal and Plant Cell Structure

Animal and plant cells not only differ in their structure, function, and mode of nutrition but also in how they reproduce, specialize, and organize into ...

Eukaryotic Evolution

The endosymbiont theory is the most widely accepted theory of eukaryotic evolution; however, its progression is still somewhat debated. According to the ...

Cell Diversity

The concept of a cell started with microscopic observations of dead cork tissue by Robert Hooke in 1665. Hooke coined the term &#34;cell&#34; based on the ...

Chemistry of the Cell

The cell is chemically composed of water, organic molecules and inorganic ions.
Water
The polarity of the water molecule and its resulting hydrogen ...

Describe the scientific theory of cells (cell theory) and relate the history of its discovery to the process of science.

SC.912.L.14.1

Cell Size

Cell sizes vary widely among and within organisms. Bacterial cells range between 1-10 micrometers (&#x3BC;m)and are considerably smaller than most ...

Eukaryotic Compartmentalization

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 ...

Microtubules

There are three types of cytoskeletal structures in eukaryotic cells&#x2014;microfilaments, intermediate filaments, and microtubules. With a diameter of ...

Peroxisomes

Peroxisomes and mitochondria are two important oxygen-utilizing organelles in eukaryotic cells. Mitochondria carry out cellular respiration&#x2014;the ...

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

In order to maintain tissue organization, many animal cells are surrounded by structural molecules that make up the extracellular matrix (ECM). Together, ...

Tissues

Cells with similar structure and function are grouped into tissues. A group of tissues with a specialized function is called an organ. There are four main ...

Plant Cell Wall

The plant cell wall gives plant cells shape, support, and protection. As a cell matures, its cell wall specializes according to the cell type. For ...

Plasmodesmata

The organs in a multicellular organism&#x2019;s body are made up of tissues formed by cells. To work together cohesively, cells must communicate. One way ...

What are Membranes?

A key characteristic of life is the ability to separate the external environment from the internal space. To do this, cells have evolved semi-permeable ...

Membrane Fluidity

Cell membranes are composed of phospholipids, proteins, and carbohydrates loosely attached to one another through chemical interactions. Molecules are ...

Fluid Mosaic Model

The fluid mosaic model was first proposed as a visual representation of research observations. The model comprises the composition and dynamics of ...

What is an Electrochemical Gradient?

Adenosine triphosphate, or ATP, is considered the primary energy source in cells. However, energy can also be stored in the electrochemical gradient of an ...

Diffusion

Diffusion is the passive movement of substances down their concentration gradients&#x2014;requiring no expenditure of cellular energy. Substances, such as ...

Osmosis

Approximately 60% to 95% of the weight of living organisms is attributed to water. Therefore, maintaining appropriate water balance within cells is of ...

Tonicity in Animals

The tonicity of a solution determines if a cell gains or loses water in that solution. The tonicity depends on the permeability of the cell membrane for ...

Tonicity in Plants

Tonicity describes the capacity of a cell to lose or gain water. It depends on the quantity of solute that does not penetrate the membrane. Tonicity ...

Introduction to Membrane Proteins

The cell membrane, or plasma membrane, is an ever-changing landscape. It is described as a fluid mosaic where various macromolecules are embedded in the ...

Facilitated Transport

The chemical and physical properties of plasma membranes cause them to be selectively permeable. Since plasma membranes have both hydrophobic and ...

Primary Active Transport

In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or ...

Secondary Active Transport

One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this ...

Receptor-mediated Endocytosis

Overview

Receptor-mediated endocytosis is a process through which bulk amounts of specific molecules can be imported into a cell after binding to cell ...

Pinocytosis

Cells use energy-requiring bulk transport mechanisms to transfer large particles, or large amounts of small particles, into or out of the cell. The cells ...

Phagocytosis

Cells pull particles inward and engulf them in spherical vesicles in an energy-requiring process called endocytosis. Phagocytosis (&#x201C;cellular ...

Exocytosis

Exocytosis is used to release material from cells. Like other bulk transport mechanisms, exocytosis requires energy.

While endocytosis takes particles ...

Relate structure to function for the components of plant and animal cells. Explain the role of cell membranes as a highly selective barrier (passive and active transport).

SC.912.L.14.2

Cell Structure

Background
Cells represent the most basic biological units of all organisms, whether it be simple, single-celled organisms like bacteria, or large, ...

Compare and contrast the general structures of plant and animal cells. Compare and contrast the general structures of prokaryotic and eukaryotic cells.

SC.912.L.14.3

Overview of Microscopy Techniques

The early pioneers of microscopy opened a window into the invisible world of microorganisms. In 1830, Joseph Jackson Lister created an essentially modern ...

Introduction to Light Microscopy

The light microscope is an instrument used by researchers in many different fields to magnify specimens to as much as a thousand times their original ...

Overview of Electron Microscopy

The wavelengths of visible light ultimately limit the maximum theoretical resolution of images created by light microscopes. Most light microscopes can ...

Compare and contrast structure and function of various types of microscopes.

SC.912.L.14.4

A. Cells have characteristic structures and functions that make them distinctive.

B. Processes in a cell can be classified broadly as growth, maintenance, reproduction, and homeostasis.

C. Life can be organized in a functional and structural hierarchy ranging from cells to the biosphere.

D. Most multicellular organisms are composed of organ systems whose structures reflect their particular function.

How Xylem Moves Water in Plants

Description

Transcript

Tags

More videos by Standards