[Portrait of King Carlos I of Portugal]

Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...

The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ultimately to photosystem I (PSI) through the electron transport chain. The pigments responsible for caputirng the light energy in photosystems include chlorophyll a, chlorophyll b, and carotenoids.
The pigment molecules are arranged across  two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...

Photosystems are multiprotein complexes that form the functional units of photosynthesis in plants, algae, and cyanobacteria. They are found embedded in the membrane of tiny sac-like structures called thylakoids placed inside the chloroplast.
Functioning of Photosystems
Photosystems contain many pigment molecules, such as chlorophylls and carotenoids, arranged in a particular organization across two domains — the antenna complex and the reaction center. The main aim of the pigment molecules...

Inspection is the initial step in assessing the cardiovascular system. It involves a detailed visual examination that provides crucial information about a patient's circulatory and cardiac health. This systematic process, conducted from head to toe, helps identify signs of cardiovascular conditions by observing physical appearance, skin and mucous membranes, jugular and carotid pulsations, chest symmetry, and the condition of the extremities.
Head and Neck

The penis serves a dual role in sexual reproduction and urination. It consists of three main regions: the glans penis, the body, and the root, each with distinct functions and unique anatomical features.
Anatomy of the Penis
The glans penis, or the head, is the terminal part of the penis and houses the external urethral orifice, the exit point for urine and semen. Covered by the prepuce, or foreskin, the glans is noted for its sensitivity and plays a key role in sexual pleasure. The body of the...

The microscopic anatomy of the liver is a complex and intricate system that comprises numerous structural units known as liver lobules, each of which is comparable in size to a sesame seed. These hexagonal structures consist of plates of liver cells or hepatocytes, which are characterized by their versatility and abundance of cellular apparatus like rough and smooth ER, Golgi apparatus, peroxisomes, and mitochondria.
Hepatocytes perform a variety of essential functions. They secrete...