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Introduction to Cells, DNA, and Viruses
Published in Patricia G. Melloy, Viruses and Society, 2023
One of the biggest functions of the cell is to produce proteins to do particular jobs for cells and the body as a whole. Because humans contain so many kinds of cells, we have separation of function for different groups of cells, which are organized into tissues, organs, and organ systems. Cells duplicate themselves when they are actively dividing. Cells go through a series of steps known as the cell cycle, in which the cell prepares for DNA synthesis, then copies its DNA, then separates the DNA in the form of the chromosomes moving to opposite sides of the cell (see Figure 1.1). The cell then completes nuclear division followed by separation of the cytoplasmic contents, resulting in two cells. This process is known as mitosis. Not all cells are actively dividing, but cell division is critical during development as well as to replenish worn-out tissues in an adult organism. When cells do a particular job for the body, they need to create proteins encoded in the DNA. Cells come in many shapes and sizes, but what they all have in common is the procedure needed to convert the hereditary material to functional protein in the body.
Cellular and Immunobiology
Published in Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple, Basic Urological Sciences, 2021
Masood Moghul, Sarah McClelland, Prabhakar Rajan
Cytoplasm: gel-like substance which forms majority of the cellular volume (90%).Contains specialised subunits (organelles), cytoskeletal fibres, free molecules, proteins, carbohydrates, lipids, and DNA/RNA.
The cell and tissues
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
All cells have the same basic structure, with a plasma membrane, a nucleus and cytoplasm. The cytoplasm consists of an aqueous fluid, the cytosol, which contains a range of organelles (e.g., mitochondria, ribosomes and endoplasmic reticulum), inclusions and electrolytes (see Figure 3.1). Exceptions to this general cell structure are erythrocytes (red blood cells) and corneocytes (the cells on the surface of the epidermis of the skin), which do not contain nuclei. A third variation is found in cells of skeletal muscle, which are multinucleate, i.e., each muscle cell has more than one nucleus. There are significant differences in shape and size of cells, depending on the particular tissue type and their function. Some neurons (nerve cells) have axons that are over one metre long, whereas red blood cells are only 7µm in diameter and 2µm deep. Some types of cell have more of one type of organelle, e.g., muscle cells have many mitochondria, as they need to produce large quantities of energy.
Bio-acoustic signaling; exploring the potential of sound as a mediator of low-dose radiation and stress responses in the environment
Published in International Journal of Radiation Biology, 2022
Bruno F. E. Matarèse, Jigar Lad, Colin Seymour, Paul N. Schofield, Carmel Mothersill
The details of a plant acoustic perception apparatus are as yet unknown but it has been suggested they may similar to the way outer hair cells function in mammals, by altering membrane potentials of subcellular structures. Altering cell membrane and cell wall potentials have been shown to produce acoustic waves from kHz to THz range (Gagliano et al. 2012b), myosin is also believed to be involved as it can produce mechanical vibrations within cells by sliding against actin filaments (Gagliano 2013). These vibrations can then propagate through cytoplasm and create a vibrational cascade with surrounding cells causing cytoplasmic streaming. A process known as coherent excitation, where multiple cells work collectively could also produce sound signals in frequencies between 150 and 200kHz (Gagliano 2013). We discuss hypotheses for potential mechanisms below. At the range of frequencies most often described it is likely that any plant to plant signal transmission will occur at a very short distance given air movement and acoustic attenuation but in a natural context it is not possible to rule out transmission underground or at the interface of substrate and air via soil water and mass where signals might be expected to travel much further.
Lipogenic stromal cells as members of the foam-cell population in human atherosclerosis: Immunocytochemical and ultrastructural assessment of 6 cases
Published in Ultrastructural Pathology, 2022
Yong-Xin Ru, Zhang Xue-Bin, Xiao-Ling Yan, Dong Shu-Xu, Zhang Yongqiang, Li Ying, Liu Jing, Brian Eyden
Throughout the following descriptions of the cells in the CAPs, it has been necessary to address the question of terminology in terms of using “foamy” cytoplasm, or “vacuolated” cytoplasm. Traditionally, foamy cytoplasm refers to the presence of clear, usually rounded inclusions in the cytoplasm. Mostly, these have been regarded as or shown to be of lipid, but in the case of foamy cytoplasm as seen in the H&E section of wax-embedded tissue, it is impossible to know whether the clear cytoplasmic inclusions are membrane-bound vacuoles or lipidic inclusions. Therefore, we have avoided the term “vacuolated cytoplasm” and have preferred “foamy cytoplasm” unless we have shown by Oil Red O staining or TEM a true lipid content. Sometimes the context of the discussion demanded use of the term, “foam cell/lipid-laden cell.”
Development of computational model for cell dose and DNA damage quantification of multicellular system
Published in International Journal of Radiation Biology, 2019
Ruirui Liu, Tianyu Zhao, Maciej H. Swat, Francisco J. Reynoso, Kathryn A. Higley
In this work, a module, CellMaker, which is a simulation program, was developed in C++ to create a computational multicellular system. This is the first step of the multicellular simulation. It is necessary to make an accurate representation of the multicellular geometry as the cell and its relative arrangement are the basic building blocks of the realistic tissue, and include all microstructures and contents in which all the physical and biological interactions take place. In this work, we propose a 3D cellular model including two cellular compartments: the nucleus and the cytoplasm. These are the most important compartments due to their dominant volume with respect to other organelles, and where most secondary electrons that inflicted DNA damage are most likely to originate from. In addition, the nucleus contains the DNA, which plays a central role in the simulation and should be modeled explicitly in the cell model. Other cellular organelles, such as mitochondria, are embedded within the cytoplasm and are not radiologically different in terms of cross-section data and subsequent secondary electron generation. Hence, the cytoplasm was treated as representative of all other cellular organelles inside it.