Stroma (fluid)Stroma, in botany, refers to the colorless fluid surrounding the grana within the chloroplast. Within the stroma are grana (stacks of thylakoid), the sub-organelles where photosynthesis is started before the chemical changes are completed in the stroma. Photosynthesis occurs in two stages. In the first stage, light-dependent reactions capture the energy of light and use it to make the energy-storage molecules ATP and NADPH. During the second stage, the light-independent reactions use these products to fix carbon by capturing and reducing carbon dioxide.
Signal peptideA signal peptide (sometimes referred to as signal sequence, targeting signal, localization signal, localization sequence, transit peptide, leader sequence or leader peptide) is a short peptide (usually 16-30 amino acids long) present at the N-terminus (or occasionally nonclassically at the C-terminus or internally) of most newly synthesized proteins that are destined toward the secretory pathway. These proteins include those that reside either inside certain organelles (the endoplasmic reticulum, Golgi or endosomes), secreted from the cell, or inserted into most cellular membranes.
ChromoplastChromoplasts are plastids, heterogeneous organelles responsible for pigment synthesis and storage in specific photosynthetic eukaryotes. It is thought that like all other plastids including chloroplasts and leucoplasts they are descended from symbiotic prokaryotes. Chromoplasts are found in fruits, flowers, roots, and stressed and aging leaves, and are responsible for their distinctive colors. This is always associated with a massive increase in the accumulation of carotenoid pigments.
ApicoplastAn apicoplast is a derived non-photosynthetic plastid found in most Apicomplexa, including Toxoplasma gondii, and Plasmodium falciparum and other Plasmodium spp. (parasites causing malaria), but not in others such as Cryptosporidium. It originated from algae through secondary endosymbiosis; there is debate as to whether this was a green or red alga. The apicoplast is surrounded by four membranes within the outermost part of the endomembrane system.
CercozoaCercozoa (now synonymised with Filosa) is a phylum of diverse single-celled eukaryotes. They lack shared morphological characteristics at the microscopic level, and are instead defined by molecular phylogenies of rRNA and actin or polyubiquitin. They were the first major eukaryotic group to be recognized mainly through molecular phylogenies. They are the natural predators of many species of bacteria. They are closely related to the phylum Retaria, comprising amoeboids that usually have complex shells, and together form a supergroup called Rhizaria.
ChlamydomonasChlamydomonas (ˌklæmɪˈdɒmənəs,_-dəˈmoʊ- ) is a genus of green algae consisting of about 150 species of unicellular flagellates, found in stagnant water and on damp soil, in freshwater, seawater, and even in snow as "snow algae". Chlamydomonas is used as a model organism for molecular biology, especially studies of flagellar motility and chloroplast dynamics, biogenesis, and genetics. One of the many striking features of Chlamydomonas is that it contains ion channels (channelrhodopsins) that are directly activated by light.
Photosynthetic pigmentA photosynthetic pigment (accessory pigment; chloroplast pigment; antenna pigment) is a pigment that is present in chloroplasts or photosynthetic bacteria and captures the light energy necessary for photosynthesis. List of photosynthetic pigments (in order of increasing polarity): Carotene: an orange pigment Xanthophyll: a yellow pigment Phaeophytin a: a gray-brown pigment Phaeophytin b: a yellow-brown pigment Chlorophyll a: a blue-green pigment Chlorophyll b: a yellow-green pigment Chlorophyll a is the most common of the six, present in every plant that performs photosynthesis.
LeucoplastLeucoplasts (λευκός leukós "white", πλαστός plastós "formed, molded") are a category of plastid and as such are organelles found in plant cells. They are non-pigmented, in contrast to other plastids such as the chloroplast. Lacking photosynthetic pigments, leucoplasts are not green and are located in non-photosynthetic tissues of plants, such as roots, bulbs and seeds. They may be specialized for bulk storage of starch, lipid or protein and are then known as amyloplasts, elaioplasts, or proteinoplasts (also called aleuroplasts) respectively.
Chlamydomonas reinhardtiiChlamydomonas reinhardtii is a single-cell green alga about 10 micrometres in diameter that swims with two flagella. It has a cell wall made of hydroxyproline-rich glycoproteins, a large cup-shaped chloroplast, a large pyrenoid, and an eyespot that senses light. Chlamydomonas species are widely distributed worldwide in soil and fresh water. Chlamydomonas reinhardtii is an especially well studied biological model organism, partly due to its ease of culturing and the ability to manipulate its genetics.
Autumn leaf colorAutumn leaf color is a phenomenon that affects the normal green leaves of many deciduous trees and shrubs by which they take on, during a few weeks in the autumn season, various shades of yellow, orange, red, purple, and brown. The phenomenon is commonly called autumn colours or autumn foliage in British English and fall colors, fall foliage, or simply foliage in American English. In some areas of Canada and the United States, "leaf peeping" tourism is a major contribution to economic activity.