JoVE Science Education > Membranen und zellulärer Transport

Kapitel 5

Membranen und zellulärer Transport

Kostenlose Probe

Free access at this time

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 ...

Kostenlose Probe

Free access at this time

Fließfähigkeit der Zellmembran

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

Kostenlose Probe

Free access at this time

Das Flüssig-Mosaik-Modell

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

Kostenlose Probe

Free access at this time

Was ist ein elektrochemischer 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 ...

Kostenlose Probe

Free access at this time

Diffusion

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

Kostenlose Probe

Free access at this time

Osmose

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

Kostenlose Probe

Free access at this time

Tonizität in Tieren

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 ...

Kostenlose Probe

Free access at this time

Tonizität in Pflanzen

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 ...

Kostenlose Probe

Free access at this time

Proteintypen

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 ...

Kostenlose Probe

Free access at this time

Erleichterter Transport

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

Kostenlose Probe

Free access at this time

Primärer aktiver Transport

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

Kostenlose Probe

Free access at this time

Sekundärer aktiver 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 ...

Kostenlose Probe

Free access at this time

Rezeptorvermittelte Endozytose

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

Kostenlose Probe

Free access at this time

Pinozytose

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 ...

Kostenlose Probe

Free access at this time

Phagozytose

Cells pull particles inward and engulf them in spherical vesicles in an energy-requiring process called endocytosis. Phagocytosis (“cellular eating”) ...

Kostenlose Probe

Free access at this time

Exozytose

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