Phagocytosis Figure (Figure 17.21). Reprinted from OpenStax Microbiology (p. 712), by N. Parker, M. Shneegurt, A.-h. Thi Tu, B. M. Forester, and P. Lister, 2016, Rice University. Copyright 2016 by Rice University. Available at: https://openstax.org/books/microbiology/pages/17-4-pathogen-recognition-and-phagocytosis

Phagocytosis Figure

The membrane vesicle containing the pathogen after the phagocyte wraps around the pathogen and undergoes membrane invagination

Phagosome

Phagocytosis, meaning "cell eating," is a type of endocytosis where large particles or other cells are engulfed by a folding of the plasma membrane, enclosing the particle in a pocket that pinches off to form a vacuole that completely surrounds it within the cell.

University of Notre Dame

Google

After pathogen recognition and binding, the pathogen is put into a vesicle and brought into a phagocyte (phagocytosis). After the phagocyte is engulfed, lysosomal enzymes digest the pathogen. Reactive oxygen species from respiratory bursts and reactive nitrogen compounds can also degrade pathogens. Waste leftover from degradation is excreted as well as processed by leukocytes. This processing allows key antigens to be presented on the cell surface for adaptive immune responses.

Leukocyte: Pathogen Degradation

Active transport occurs when cells move molecules across the plasma membrane against their concentration gradients, effectively moving them "uphill" from an area of lower concentration to an area of higher concentration. This process requires an input of energy, typically adenosine triphosphate (ATP) or other forms of energy. Due to this significant energy requirement, the membrane structures that facilitate active transport are often referred to as "pumps."

Active Transport

The plasma membrane of eukaryotic cells is a phospholipid bilayer with embedded peripheral and integral proteins. Similar to prokaryotic plasma membranes, its components move within the plane of the membrane according to the fluid mosaic model, but unlike prokaryotic membranes, it contains sterols and specialized lipids.

Eukaryotic Plasma Membrane

OpenStax Concepts of Biology provides the necessary breadth and depth for core Biology concepts.

Link: https://openstax.org/details/books/concepts-biology/

OpenStax Biology 2nd Edition

https://openstax.org/details/books/microbiology/

Microbiology covers the scope and sequence requirements for a single-semester microbiology course for non-majors. The book presents the core concepts of microbiology with a focus on applications for careers in allied health. The pedagogical features of the text make the material interesting and accessible while maintaining the career-application focus and scientific rigor inherent in the subject matter. Microbiology’s art program enhances students’ understanding of concepts through clear and effective illustrations, diagrams, and photographs.

Microbiology is produced through a collaborative publishing agreement between OpenStax and the American Society for Microbiology Press. The book aligns with the curriculum guidelines of the American Society for Microbiology.

OpenStax Microbiology Textbook

Phagocytosis

The sodium-potassium pump is an active transport protein in the plasma membrane that is crucial for maintaining a cell's resting potential. It moves ions against their concentration gradients by breaking down ATP into ADP for energy. Specifically, the pump expels sodium ions (Na+) from the cytoplasm to the extracellular fluid, where their concentration is higher, and imports potassium ions (K+) from the extracellular fluid into the cytoplasm. In neurons, this unequal exchange expels three positively charged sodium ions for every two positively charged potassium ions it brings in, creating a net negative charge inside the cell.

Sodium-Potassium Pump

Endocytosis is a eukaryotic transport mechanism where substances are internalized by the cell through plasma membrane invagination, which pinches off to form a vacuole or vesicle.

Endocytosis

Eukaryotic plasma membranes contain sterols, including cholesterol, that alter membrane fluidity, distinguishing them from prokaryotic membranes.

Eukaryotic Membrane Sterols

Sphingolipids are specialized lipids found in many eukaryotic cell membranes that are thought to play a role in maintaining membrane stability, signal transduction pathways, and cell-to-cell communication.

Learn Before

Related

Learn After