Chirality (chemistry)In chemistry, a molecule or ion is called chiral (ˈkaɪrəl) if it cannot be superposed on its by any combination of rotations, translations, and some conformational changes. This geometric property is called chirality (kaɪˈrælɪti). The terms are derived from Ancient Greek χείρ (cheir) 'hand'; which is the canonical example of an object with this property. A chiral molecule or ion exists in two stereoisomers that are mirror images of each other, called enantiomers; they are often distinguished as either "right-handed" or "left-handed" by their absolute configuration or some other criterion.
Copy editingCopy editing (also known as copyediting and manuscript editing) is the process of revising written material (copy) to improve readability and fitness, as well as ensuring that a text is free of grammatical and factual errors. The Chicago Manual of Style states that manuscript editing encompasses "simple mechanical corrections (mechanical editing) through sentence-level interventions (line, or stylistic, editing) to substantial remedial work on literary style and clarity, disorganized passages, baggy prose, muddled tables and figures, and the like (substantive editing)".
Color theoryIn the visual arts, color theory is the body of practical guidance for color mixing and the visual effects of a specific color combination. Color terminology based on the color wheel and its geometry separates colors into primary color, secondary color, and tertiary color. The understanding of color theory dates to antiquity. Aristotle (d. 322 BCE) and Claudius Ptolemy (d. 168 CE) already discussed which and how colors can be produced by mixing other colors. The influence of light on color was investigated and revealed further by al-Kindi (d.
Web designWeb design encompasses many different skills and disciplines in the production and maintenance of websites. The different areas of web design include web graphic design; user interface design (UI design); authoring, including standardised code and proprietary software; user experience design (UX design); and search engine optimization. Often many individuals will work in teams covering different aspects of the design process, although some designers will cover them all.
Subtractive colorSubtractive color or subtractive color mixing predicts the spectral power distribution of light after it passes through successive layers of partially absorbing media. This idealized model is the essential principle of how dyes and pigments are used in color printing and photography, where the perception of color is elicited after white light passes through microscopic "stacks" of partially absorbing media allowing some wavelengths of light to reach the eye and not others, and also in painting, whether the colors are mixed or applied in successive layers.
Cyclin-dependent kinase 1Cyclin-dependent kinase 1 also known as CDK1 or cell division cycle protein 2 homolog is a highly conserved protein that functions as a serine/threonine protein kinase, and is a key player in cell cycle regulation. It has been highly studied in the budding yeast S. cerevisiae, and the fission yeast S. pombe, where it is encoded by genes cdc28 and cdc2, respectively. With its cyclin partners, Cdk1 forms complexes that phosphorylate a variety of target substrates (over 75 have been identified in budding yeast); phosphorylation of these proteins leads to cell cycle progression.
TimeTime is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantify rates of change of quantities in material reality or in the conscious experience. Time is often referred to as a fourth dimension, along with three spatial dimensions.
Optical rotationOptical rotation, also known as polarization rotation or circular birefringence, is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circular birefringence and circular dichroism are the manifestations of optical activity. Optical activity occurs only in chiral materials, those lacking microscopic mirror symmetry. Unlike other sources of birefringence which alter a beam's state of polarization, optical activity can be observed in fluids.
Cyclin-dependent kinase 2Cyclin-dependent kinase 2, also known as cell division protein kinase 2, or Cdk2, is an enzyme that in humans is encoded by the CDK2 gene. The protein encoded by this gene is a member of the cyclin-dependent kinase family of Ser/Thr protein kinases. This protein kinase is highly similar to the gene products of S. cerevisiae cdc28, and S. pombe cdc2, also known as Cdk1 in humans. It is a catalytic subunit of the cyclin-dependent kinase complex, whose activity is restricted to the G1-S phase of the cell cycle, where cells make proteins necessary for mitosis and replicate their DNA.
G proteinG proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their activity is regulated by factors that control their ability to bind to and hydrolyze guanosine triphosphate (GTP) to guanosine diphosphate (GDP). When they are bound to GTP, they are 'on', and, when they are bound to GDP, they are 'off'. G proteins belong to the larger group of enzymes called GTPases.
Cell cortexThe cell cortex, also known as the actin cortex, cortical cytoskeleton or actomyosin cortex, is a specialized layer of cytoplasmic proteins on the inner face of the cell membrane. It functions as a modulator of membrane behavior and cell surface properties. In most eukaryotic cells lacking a cell wall, the cortex is an actin-rich network consisting of F-actin filaments, myosin motors, and actin-binding proteins. The actomyosin cortex is attached to the cell membrane via membrane-anchoring proteins called ERM proteins that plays a central role in cell shape control.
Cyclin-dependent kinaseCyclin-dependent kinases (CDKs) are the families of protein kinases first discovered for their role in regulating the cell cycle. They are also involved in regulating transcription, mRNA processing, and the differentiation of nerve cells. They are present in all known eukaryotes, and their regulatory function in the cell cycle has been evolutionarily conserved. In fact, yeast cells can proliferate normally when their CDK gene has been replaced with the homologous human gene.
