Chapter 4 The Cell Membrane, Cytoskeleton, and Cell
... place a tea bag in a cup of hot water. Compounds in the tea leaves dissolve gradually and diffuse throughout the cup. The tea is at first concentrated near the bag, but the brownish color eventually spreads to create a uniform brew. The natural tendency of a substance to move from where it is highly ...
... place a tea bag in a cup of hot water. Compounds in the tea leaves dissolve gradually and diffuse throughout the cup. The tea is at first concentrated near the bag, but the brownish color eventually spreads to create a uniform brew. The natural tendency of a substance to move from where it is highly ...
Concepts of Biology
... The microscopes we use today are far more complex than those used in the 1600s by Antony van Leeuwenhoek, a Dutch shopkeeper who had great skill in crafting lenses. Despite the limitations of his now-ancient lenses, van Leeuwenhoek observed the movements of protists (a type of single-celled organism ...
... The microscopes we use today are far more complex than those used in the 1600s by Antony van Leeuwenhoek, a Dutch shopkeeper who had great skill in crafting lenses. Despite the limitations of his now-ancient lenses, van Leeuwenhoek observed the movements of protists (a type of single-celled organism ...
3 | cell structure and function
... Cell Theory The microscopes we use today are far more complex than those used in the 1600s by Antony van Leeuwenhoek, a Dutch shopkeeper who had great skill in crafting lenses. Despite the limitations of his now-ancient lenses, van Leeuwenhoek observed the movements of protists (a type of single-cel ...
... Cell Theory The microscopes we use today are far more complex than those used in the 1600s by Antony van Leeuwenhoek, a Dutch shopkeeper who had great skill in crafting lenses. Despite the limitations of his now-ancient lenses, van Leeuwenhoek observed the movements of protists (a type of single-cel ...
Cytoskeletal Elements in Bacteria
... Tubulin filaments also serve as tracks for the transport of intracellular vesicles and other cargo, which are moved through cells by motor proteins that have a defined direction of movement on microtubules. Actin forms a two-stranded, right-handed helical filament with an axial rise of 5.4 nm per monom ...
... Tubulin filaments also serve as tracks for the transport of intracellular vesicles and other cargo, which are moved through cells by motor proteins that have a defined direction of movement on microtubules. Actin forms a two-stranded, right-handed helical filament with an axial rise of 5.4 nm per monom ...
Teacher Guide for Amplify Cell Structure and Function Module
... • Conducting the investigation Allow students to conduct their own investigation. If they need help, use guiding questions to help students make observations: How do this molecule and this organelle interact? Is the molecule bouncing off of the organelle (no interaction)? Is the molecule going into ...
... • Conducting the investigation Allow students to conduct their own investigation. If they need help, use guiding questions to help students make observations: How do this molecule and this organelle interact? Is the molecule bouncing off of the organelle (no interaction)? Is the molecule going into ...
Divergent Roles for Maize PAN1 and PAN2 Receptor
... nucleus to the site of GMC contact and the formation of a pronounced enrichment of cortical F-actin at that site. Subsequently, SMCs divide asymmetrically to produce subsidiary cells flanking the GMC, which in turn divides to produce a guard cell pair (Galatis and Apostolakos, 2004). In pan1 and pan2 ...
... nucleus to the site of GMC contact and the formation of a pronounced enrichment of cortical F-actin at that site. Subsequently, SMCs divide asymmetrically to produce subsidiary cells flanking the GMC, which in turn divides to produce a guard cell pair (Galatis and Apostolakos, 2004). In pan1 and pan2 ...
The Pathogen-Actin Connection: A Platform for Defense Signaling in
... (60). In plants, a causal link has yet to be established between the activation of MAPK signaling and the regulation of the actin cytoskeleton; however, a number of studies have independently investigated functional and regulatory processes that potentially link MAPK signaling and cortical actin dyn ...
... (60). In plants, a causal link has yet to be established between the activation of MAPK signaling and the regulation of the actin cytoskeleton; however, a number of studies have independently investigated functional and regulatory processes that potentially link MAPK signaling and cortical actin dyn ...
Isoflavone and Pterocarpan Malonylglucosides and ß -l,3
... pan malonylglucosides of chickpea has not been proven clearly until yet. Apart from the accumulation of phytoalexins the synthesis of pathogenesis-related proteins is an especially prominent reaction of plants after microbial infection or elicitation [18]. Recent in vestigations have identified dif ...
... pan malonylglucosides of chickpea has not been proven clearly until yet. Apart from the accumulation of phytoalexins the synthesis of pathogenesis-related proteins is an especially prominent reaction of plants after microbial infection or elicitation [18]. Recent in vestigations have identified dif ...
Interplay between cell growth and cell cycle in
... Turgor-driven cell expansion Cytoplasmic growth and the cell cycle provide the building blocks required for plant growth, but the space that can be occupied by these building blocks is constrained by the cell walls. Cell enlargement requires that the walls yield to the cell’s turgor pressure and cel ...
... Turgor-driven cell expansion Cytoplasmic growth and the cell cycle provide the building blocks required for plant growth, but the space that can be occupied by these building blocks is constrained by the cell walls. Cell enlargement requires that the walls yield to the cell’s turgor pressure and cel ...
Treadmilling by FtsZ filaments drives peptidoglycan
... FtsAZ circumferential motions could be coupled to the insertion of new PG. Next, we investigated the mechanism driving FtsAZ/Pbp2B motion. The coupled, circumferential motions of FtsAZ/Pbp2B appear similar to MreB/Pbp2A, the filament/enzyme system required for elongation of rod-shaped bacteria where ...
... FtsAZ circumferential motions could be coupled to the insertion of new PG. Next, we investigated the mechanism driving FtsAZ/Pbp2B motion. The coupled, circumferential motions of FtsAZ/Pbp2B appear similar to MreB/Pbp2A, the filament/enzyme system required for elongation of rod-shaped bacteria where ...
The Submicroscopic Structure of the Drosophila Egg
... in the cell membranes is not fully established (see below). The bulk of the oocyte cytoplasm has the same appearance as that of the nurse cells; it consists of a finely granular ground substance containing mitochondria, alpha-granules, and tubular elements. The periplasm retains essentially this con ...
... in the cell membranes is not fully established (see below). The bulk of the oocyte cytoplasm has the same appearance as that of the nurse cells; it consists of a finely granular ground substance containing mitochondria, alpha-granules, and tubular elements. The periplasm retains essentially this con ...
Interesting Facts - Raleigh Charter High School
... asexual reproduction where the paramecium splits itself down the middle, making two new paramecium. They perform sexual reproduction only under stressful conditions. Two paramecium bind forming a cytoplasmic bridge between them. Then the micronucleus of the paramecium undergoes meiosis. Four nuclei ...
... asexual reproduction where the paramecium splits itself down the middle, making two new paramecium. They perform sexual reproduction only under stressful conditions. Two paramecium bind forming a cytoplasmic bridge between them. Then the micronucleus of the paramecium undergoes meiosis. Four nuclei ...
silicone rubber in a parallel plate flow chamber in the
... summarized studies reporting increased as well as decreased growth rates of bacteria on surfaces as compared to planktonic bacteria, while increased adhesion of metabolically active cells was also found. The mechanisms of surface-associated changes in bacterial behaviour are probably related to nutr ...
... summarized studies reporting increased as well as decreased growth rates of bacteria on surfaces as compared to planktonic bacteria, while increased adhesion of metabolically active cells was also found. The mechanisms of surface-associated changes in bacterial behaviour are probably related to nutr ...
silicone rubber in a parallel plate flow chamber in the absence and
... summarized studies reporting increased as well as decreased growth rates of bacteria on surfaces as compared to planktonic bacteria, while increased adhesion of metabolically active cells was also found. The mechanisms of surface-associated changes in bacterial behaviour are probably related to nutr ...
... summarized studies reporting increased as well as decreased growth rates of bacteria on surfaces as compared to planktonic bacteria, while increased adhesion of metabolically active cells was also found. The mechanisms of surface-associated changes in bacterial behaviour are probably related to nutr ...
Protein Sorting to the Storage Vacuoles of Plants: A Critical Appraisal
... VSR-PS1 from peas does not possess a dileucine motif, it does have a tyrosine-based sorting motif, YMPL, and this has recently been shown to interact with mA-adaptin, one of the five m-adaptins from Arabidopsis (25). As this adaptin is part of an AP1-like complex and localizes to the TGN (25), it in ...
... VSR-PS1 from peas does not possess a dileucine motif, it does have a tyrosine-based sorting motif, YMPL, and this has recently been shown to interact with mA-adaptin, one of the five m-adaptins from Arabidopsis (25). As this adaptin is part of an AP1-like complex and localizes to the TGN (25), it in ...
Tansley review - Professor Gero Steinberg
... The MTs are hollow cylinders consisting of 13–15 protofilaments, each made of numerous α/β-tubulin dimers (Fig. 2). In vivo, MT formation usually begins at microtubule-organizing centers (MTOCs). These centers are often located at the nucleus, such as the spindle pole body (SPB) (Fig. 3a, S. cerevis ...
... The MTs are hollow cylinders consisting of 13–15 protofilaments, each made of numerous α/β-tubulin dimers (Fig. 2). In vivo, MT formation usually begins at microtubule-organizing centers (MTOCs). These centers are often located at the nucleus, such as the spindle pole body (SPB) (Fig. 3a, S. cerevis ...
On the so-called "Sexual" Method of Spore
... For various reasons, it seemed to me that the process which Schaudinn (1902) and others—including myself (1908)—were driven to regard as a form of conjugation, was, perhaps, capable of being interpreted in some other way. After much idle guessing, I concluded that the only method of throwing light u ...
... For various reasons, it seemed to me that the process which Schaudinn (1902) and others—including myself (1908)—were driven to regard as a form of conjugation, was, perhaps, capable of being interpreted in some other way. After much idle guessing, I concluded that the only method of throwing light u ...
Understanding Lignification: Challenges Beyond
... After their biosynthesis, monolignols must be transported to the cell wall where they undergo oxidation and polymerization to form lignin. In contrast to our detailed knowledge of monolignol biosynthesis, we know little about how these compounds are moved from the cytoplasm to the cell wall. The tra ...
... After their biosynthesis, monolignols must be transported to the cell wall where they undergo oxidation and polymerization to form lignin. In contrast to our detailed knowledge of monolignol biosynthesis, we know little about how these compounds are moved from the cytoplasm to the cell wall. The tra ...
Processing of a Wheat Light-Harvesting Chlorophyll a/b Protein
... were made in vitro and were destined for the thylakoids. Labeled polypeptides synthesized in the reticulocyte lysate using RNA transcribed from the SPt-whAB1.6 construct were incubated with pea chloroplasts, which were then either treated or not treated with thermolysin before lysis. Tl~ermolysin ha ...
... were made in vitro and were destined for the thylakoids. Labeled polypeptides synthesized in the reticulocyte lysate using RNA transcribed from the SPt-whAB1.6 construct were incubated with pea chloroplasts, which were then either treated or not treated with thermolysin before lysis. Tl~ermolysin ha ...
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... recently provided significant insight into deciphering the complexities of the plant cell wall [1–6]. The current, yet rapidly evolving, working model of the cell wall is one of a fibrous composite of polymers, primarily polysaccharides and glycoproteins, which are incorporated into specific loci of ...
... recently provided significant insight into deciphering the complexities of the plant cell wall [1–6]. The current, yet rapidly evolving, working model of the cell wall is one of a fibrous composite of polymers, primarily polysaccharides and glycoproteins, which are incorporated into specific loci of ...
Penium margaritaceum: A Unicellular Model Organism for
... recently provided significant insight into deciphering the complexities of the plant cell wall [1–6]. The current, yet rapidly evolving, working model of the cell wall is one of a fibrous composite of polymers, primarily polysaccharides and glycoproteins, which are incorporated into specific loci of ...
... recently provided significant insight into deciphering the complexities of the plant cell wall [1–6]. The current, yet rapidly evolving, working model of the cell wall is one of a fibrous composite of polymers, primarily polysaccharides and glycoproteins, which are incorporated into specific loci of ...
Membrane traffic and fusion at post-Golgi compartments
... trafficking pathway (purple-colored), there is a controversy over the precise location where VSR recycling occurs (pale purple-colored dashed line). There are different populations of RAB-F-positive endosomes, but their origin is unknown. There is no clear evidence for multiple secretory pathways to ...
... trafficking pathway (purple-colored), there is a controversy over the precise location where VSR recycling occurs (pale purple-colored dashed line). There are different populations of RAB-F-positive endosomes, but their origin is unknown. There is no clear evidence for multiple secretory pathways to ...
Osmoregulation in Halophilic Bacteria
... Despite the abundance of NaCl in the typical haloarchaeal environment, halophilic archaea keep the cytoplasm relatively free of sodium. Instead, potassium accumulates in the cell (as proven for Haloferax volcanii through an energy-dependent potassium uptake system) and, together with its counterion ...
... Despite the abundance of NaCl in the typical haloarchaeal environment, halophilic archaea keep the cytoplasm relatively free of sodium. Instead, potassium accumulates in the cell (as proven for Haloferax volcanii through an energy-dependent potassium uptake system) and, together with its counterion ...
Myosin binding proteins - Journal of Cell Science
... myosin is polymerized in vitro at physiological stoichiometries with MyBP-C, the resulting thick filaments are slightly longer and more regular than in the absence of MyBP-C (Koretz, 1979; Davis, 1988). The presence of MyBP-C reduces the critical concentration required for myosin polymerization sugg ...
... myosin is polymerized in vitro at physiological stoichiometries with MyBP-C, the resulting thick filaments are slightly longer and more regular than in the absence of MyBP-C (Koretz, 1979; Davis, 1988). The presence of MyBP-C reduces the critical concentration required for myosin polymerization sugg ...
Cytoplasmic streaming
Cytoplasmic streaming, also called protoplasmic streaming and cyclosis, is the directed flow of cytosol (the liquid component of the cytoplasm) and organelles around large fungal and plant cells through the mediation of actin. This movement aids in the delivery of organelles, nutrients, metabolites, genetic information, and other materials to all parts of the cell. Cytoplasmic streaming occurs along actin filaments in the cytoskeleton of the cell.Cytoplasmic streaming was first discovered in the 1830s. The scientific breakthrough assisted scientists in developing an understanding of the different roles of cells and how they function as the basic operating systems of life.This process occurs through the operation of motor proteins called myosins.These proteins use energy of adenosine triphosphate (ATP) to act as a molecular motor, which slides along actin filaments. This works in a manner that tows the organelles and other cytoplasmic contents in the same direction. Myosin proteins consist of two conjoined proteins. If one protein remains attached to the substrate, the substance acted upon by the protein, such as a microfilament, has the ability to move organelles through the cytoplasm.The green alga genus Chara and other genera in the Division Charophyta, such as Coleochaete, are thought to be the closest relatives of land plants. These haploid organisms contain some of the largest plant cells on earth, a single cell of which can reach up to 10 cm in length. The large size of these cells demands an efficient means to distribute resources, which is enabled via cytoplasmic streaming.Cytoplasmic streaming is strongly dependent upon intracellular pH and temperature. It has been observed that the effect of temperature on cytoplasmic streaming created linear variance and dependence at different high temperatures in comparison to low temperatures. This process is complicated, with temperature alterations in the system increasing its efficiency, with other factors such as the transport of ions across the membrane being simultaneously affected. This is due to cells homeostasis depending upon active transport which may be affected at some critical temperatures.In plant cells, chloroplasts may be moved around with the stream, possibly to a position of optimum light absorption for photosynthesis. The rate of motion is usually affected by light exposure, temperature, and pH levels.In reference to pH, because actin and myosin are both proteins, strong dependence on pH is expected. The optimal pH at which cytoplasmic streaming is highest, is achieved at neutral pH and decreases at both low and high pH.The flow of cytoplasm may be stopped by:Adding Lugol's iodine solutionAdding Cytochalasin D (dissolved in dimethyl sulfoxide)↑ ↑ ↑ ↑ ↑ ↑