Biological Sciences
Cells
Cells are the basic structural and functional units of all living organisms. They are enclosed by a membrane and contain genetic material, organelles, and other cellular structures. Cells carry out essential processes such as metabolism, growth, and reproduction, and they can specialize to perform specific functions within multicellular organisms.
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9 Key excerpts on "Cells"
eBook - ePubCancer
Basic Science and Clinical Aspects
- Craig A. Almeida, Sheila A. Barry(Authors)
- 2011(Publication Date)
- Wiley-Blackwell(Publisher)
Cells: the fundamental unit of lifeThe uniformity of Earth’s life, more astonishing than its diversity, is accountable by the high probability that we derived, originally, from some single cell, fertilized in a bolt of lightning as the Earth cooled.Lewis Thomas, physician, researcher, educator, and essayistCHAPTER CONTENTS- Seven hierarchal levels of organization
- Four types of macromolecular polymers
- Cell structure and function
- Relationship between structure and function is important
- Expand your knowledge
- Additional readings
When our bodies work properly we have the tendency to take their complex structure and functions for granted. It is important to realize that the more we know about healthy body function, the better the position we will be in to fix what is wrong when we are ill. This and the following two chapters will provide a basic understanding of the way Cells function normally and how an attack on the body by rogue Cells that divide uncontrollably and function abnormally can result in cancer. This chapter will take a stepwise approach to gradually build a working knowledge of subcellular components in order to understand how they work together as a single entity – the cell. The whole is more than the sum of its parts, and all components of the cell must work together seamlessly to carry out the processes that give rise to what we know as life.SEVEN HIERARCHAL LEVELS OF ORGANIZATIONUsing the stepwise approach to understand how a living organism as complex as a human is put together first requires some knowledge of the seven levels of biological organization (Figure 2.1 ), and there is no better place to start than at the beginning, at the level of the atom.Atoms are the building blocks of all moleculesEverything around us is composed of atoms – the building blocks of matter (Figure 2.1a ). An atom is composed of negatively charged particles called electrons that spin in orbitals around a central nucleus possessing positively charged protons and uncharged neutrons. A chemical or covalent bond can be created between two atoms when their orbitals overlap, allowing their electrons to be shared. A molecule is formed by such bonding of two or more atoms, and when molecules bond with other molecules they can serve as building blocks for the formation of macromolecules such as proteins, carbohydrates, fats, and DNA (Figure 2.1b ). A cell is a collection of atoms, molecules, macromolecules, and macromolecular structures (Figure 2.1c
eBook - PDF- Rathoure, Ashok Kumar(Authors)
- 2021(Publication Date)
- Daya Publishing House(Publisher)
Chapter 1 Introduction to Cell Biology Introduction The earth surrounded by the living and non living things. The living things are regarded as organisms. The living organisms are complicated and highly organized and are composed of many Cells, typically of many types. These Cells possess sub-cellular structures or organelles, which are complex assemblies of very large polymeric molecules or macromolecules. Crucial events in biomineral formation such as compartmentalization, supersaturation, precipitation, export of macromolecules and cessation require a referee who can control these events with precision and fidelity. This job falls to the cell and in particular, a specialized cell, such as an osteoblast, odontoblast, mantle epithelium or bacterium who has evolved or differentiated into a molecular factory that generates and controls the biomineralization process. All organisms are composed of structural and functional units of life called Cells. The study of cell and its organelles is called cytology derived from Greek word kytos meaning container. This includes their physiological properties, their structure organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level. Cell biology research extends to both the great diversity of single celled organisms like bacteria and the many specialized Cells in multicellular organisms like humans. Knowing the composition of Cells and how Cells work is fundamental to all of the biological sciences. Appreciating the similarities and differences between cell types is particularly important to the fields of cell and molecular biology. These fundamental similarities and differences provide a unifying theme, allowing the principles learned from studying one cell type to be extrapolated and generalized to other cell types. Research in cell biology is closely related This ebook is exclusively for this university only.
- Gabrielle I. Edwards, Cynthia Pfirrmann, Barron's Educational Series(Authors)
- 2021(Publication Date)
- Barrons Educational Services(Publisher)
3THE CELL: BASIC UNIT OF LIFE
WHAT YOU WILL LEARN
In this chapter, you will review the structure and function of Cells and the essential roles that Cells play in the life of an organism. SECTIONS IN THIS CHAPTER•The Cell as a Basic Unit•Parts of a Cell•Comparison of Plant and Animal Cells•Organization of Cells and Tissues•Cell Reproduction•Review Exercises•Connecting to Life/Job Skills•Chronology of Famous Names in BiologyThe Cell as a Basic Unit
CELL CONCEPT
The body of a living organism is built of units called Cells. All living things are similar in that they are composed of one or more Cells. The body of a unicellular organism is composed of one cell. Most plants and animals are multicellular, having a body made of numerous Cells.During the years 1838 and 1839, the cell theory was pioneered by two eminent scientists of the day. Matthias Schleiden, a botanist, and Theodor Schwann, a zoologist, combined some of their fundamental ideas about the structure of plants and animals into what has developed into a basic concept of biological thought. The work of Rudolf Virchow completed the cell theory when, in 1858, he established that new Cells could arise only from other living Cells. The cell theory states that (1) that Cells are the basic units of life; (2) that all plants and animals are made of Cells; and (3) that all Cells arise from preexisting Cells.UNIT OF STRUCTURE
Microscopic examination of plant and animal parts indicates that the bodies of living organisms are composed of Cells. Cells provide structure and form to the body. They appear in a variety of shapes: round, concave, rectangular, elongate, tapered, spherical, and others. Cell shape seems to be related to specialized function (Figure 3.1 ).Cells not only vary in shape, they also differ in size. Most plant and animal Cells are quite small, ranging in size between 5 and 50 micrometers in diameter (Figure 3.2 ). Cells are measured in units that are compatible with modern microscopes. (See Table 3.1
eBook - PDFThe Sciences
An Integrated Approach
- James Trefil, Robert M. Hazen(Authors)
- 2022(Publication Date)
- Wiley(Publisher)
These functions cannot be performed by a random collection of atoms; rather, they result from the collective behavior of large numbers of atoms organized into some kind of system. For our purposes, the cell can be considered to be the smallest identifiable unit capable of carrying on the basic tasks that we associate with living things. An enormous number of different kinds of Cells can be found in nature. Cells come in a wide range of sizes and shapes, and perform all sorts of functions. Although typical animal Cells are about one-hundredth of a millimeter (a thousandth of an inch) in diam- eter, they can range in size from bacteria only a few hundred-thousandths of a centimeter across (much too small to see in most light microscopes and smaller than some large mol- ecules) to the yolk portion of an ostrich egg that is much larger than most species of ani- mals. Most Cells are too small to be seen with the unaided eye but are easily studied with a microscope. Cells also come in a wide variety of shapes. Plant Cells are often rectangular or polygo- nal, whereas egg Cells are usually spherical. Bacteria may be rod-shaped or spiral in form, muscle Cells are extremely elongated, nerve Cells sport a complex array of branching fibers, and a sperm cell has a tail-like flagellum that helps it swim. The recognition of common characteristics in this extraordinary collection represents one of the great advances in biology. These differences in shape reflect the differences in the functions that the Cells per- form. Elongated muscle Cells exert forces when they contract. Branching nerve Cells (see Chapter 5) transmit impulses to many other Cells. To fulfill their functions, Cells con- stantly require raw materials and energy to live and reproduce. Living things use two Sunburn! It’s late afternoon at the beach when you notice that the tops of your feet are bright red. You’ve got sunburn. Hours earlier you used sunblock, but you missed those areas.
eBook - PDF- Khushboo Chaudhary(Author)
- 2023(Publication Date)
- Delve Publishing(Publisher)
CELL BIOLOGY CHAPTER1 1. CELLULAR BASIS OF LIFE, EVOLUTION OF CELL THEORY AND ORGANIZATION OF PLANT AND ANIMAL Cells Cellular Basis of Life and Application of Microscope Organisms are made of one or more Cells. Multicellular organisms have a hierarchical organization of Cells, tissues, organs and organ systems that work together to keep the Cells alive. “Cells need a supply of energy and molecules to carry out life processes. Living organisms depend on their environment to survive. Animals, including humans, need a plentiful supply of air, water, nutrients from food, and a suitable temperature to survive. Plants need air, light, water, a suitable temperature, nutrients from soil, and room to grow. All living organisms carry out some characteristic processes that distinguish them from non-living things. Living organisms can move, can respond to the world around them, use food as a source of energy and materials, get rid of waste, grow and can reproduce – though something that is alive will not show all of these life processes all of the time, and in some cases may not show them in an obvious way. All living organisms eventually die. Tissues, organs and systems The bodies of humans and other animals are divided into different parts with different functions, including senses. Humans and some other animals have skeletons and muscles for support, protection and movement. The human digestive system includes Cell Technology 2 the mouth, stomach and intestines. In the human circulatory system, the heart pumps blood around the body through blood vessels. Flowering plants are also divided into parts with different functions. The roots absorb water, which is transported up the stem or trunk to the leaves and flowers. Cells Organisms, living and dead, are made up of Cells. Cells are made of molecules organized into membranes and other structures. Most Cells are too small to be seen with the naked eye but can be seen using a light microscope.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Learning Press(Publisher)
___________________________ WORLD TECHNOLOGIES ___________________________ Chapter- 1 Introduction to Cell Biology Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smal-lest unit of a living organism ___________________________ WORLD TECHNOLOGIES ___________________________ Cells in culture, stained for keratin (red) and DNA (green) The cell is the functional basic unit of life. It was discovered by Robert Hooke and is the functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. Humans have about 100 trillion or 10 14 Cells; a typical cell size is 10 µm and a typical cell mass is 1 nanogram. The largest Cells are about 135 µm in the anterior horn in the spinal cord while granule Cells in the cerebellum, the smallest, can be some 4 µm and the longest cell can reach from the toe to the lower brain stem (Pseudo-unipolar Cells). The largest known Cells are unfertilised ostrich egg Cells which weigh 3.3 pounds. In 1835, before the final cell theory was developed, Jan Evangelista Purkyně observed small granules while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more Cells, that all Cells come from preexisting Cells, that vital functions of an organism occur within Cells, and that all Cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of Cells. The word cell comes from the Latin cellula , meaning, a small room.
eBook - PDFThe Sciences
An Integrated Approach
- James Trefil, Robert M. Hazen(Authors)
- 2016(Publication Date)
- Wiley(Publisher)
hus, biologists recognized that only Cells can produce other Cells and that these tiny objects represent the indivisible units of life—a discovery as fundamental as the discovery of atoms in chemistry and quanta in physics. he cell theory initiated the ield of cell biology, which remains one of the central eforts in biology. STOP THINK & The fact that Cells require energy implies that they do work. What kind of work do Cells do? Observing Cells: The Light Microscope Advances in understanding how Cells work have relied in large part on the development of microscopes. Early microscopes were rather primitive afairs; consequently, scientists were unable to see many details of cell structure. Until the middle part of the twentieth century, FIGURE 21-1 The structure of Cells, the basic unit of all living things, can be seen in this micrograph of cork (magnified approximately 50 times), which is taken from the bark of the cork oak tree. Andrew Syred/Photo Researchers, Inc. 477 21.2 THE CELL THEORY science textbooks often spoke of something called “protoplasm.” his substance was supposed to be a kind of uniform, molasses-like luid that illed Cells. Today, with much better micro- scopes we know that Cells are very complex indeed. Advanced Cells are full of specialized struc- tures, as complicated in their own way as larger life forms such as human beings. In the next chapter we’ll see that the molecules of life play a crucial role in the complex workings of the cell, with each performing a separate vital function. Today, we refer to the luid that takes up the spaces between all this complexity as cytoplasm. Early microscopes and their modern high-tech descendants all operate on the same basic principle shown in Figure 21-2a. Ordinary visible light passes through a specimen, which is often placed between two transparent layers of glass or plastic. he light transmits through a series of lenses so that a magniied image is presented in the eyepiece.
eBook - PDF- Khushboo Chaudhary, Pankaj Kumar Saraswat(Authors)
- 2023(Publication Date)
- Delve Publishing(Publisher)
CELL BIOLOGY CHAPTER3 19. CELLULAR BASIS OF LIFE AND APPLICATION OF MICROSCOPE. Introduction Microbes to mammals are composed of chemical substances from both the inorganic and organic world that appear in roughly the same proportions and perform the same general tasks. The elements are hydrogen, oxygen, nitrogen, carbon, phosphorus, and sulfur normally make up more than 99% of the mass of living Cells and when combined in various ways, form virtually all known organic biomolecules. They are initially utilized in the synthesis of a small number of building blocks that are, in turn, used in the construction of a vast array of vital macromolecules. There are four general classes of macromolecules within living Cells such as nucleic acids, proteins, polysaccharides and lipids. These compounds, which have molecular weights ranging from 1 x 10 3 to 1 x 10 6 , are created through polymerization of building blocks that have molecular weights in the range of 50 to 150 MW. Although many differences do exist between Cells (such as erythrocyte, liver, muscle or fat cell), they all generally contain a greater variety of proteins than any other type of macromolecules, with about 50% of the solid matter of the cell being protein (Scribd, slideshare, molecular-plant- biotechnology, slideplayer, documents, docplayer, bmb.psu, powershow, bioscience, docslide, msluay, scienceprofonlue, biotechuniverse.blogspot). Basic Biology 130 Cells generally contain many more protein molecules than DNA molecules, yet DNA is typically the largest biomolecule in the cell. About 99% of cellular molecules are water molecules, with water normally accounting for approximately 70% of the total wetweight of the cell. Although water is obviously important to the vitality of all living Cells, the bulk of our attention is usually focused on the other 1% of biomolecules.
eBook - PDF- Julianne Zedalis, John Eggebrecht(Authors)
- 2018(Publication Date)
- Openstax(Publisher)
A scan of news headlines—whether reporting on immunizations, a newly discovered species, sports doping, or a genetically-modified food—demonstrates the way biology is active in and important to our everyday world. 34 Chapter 1 | The Study of Life This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 abstract applied science atom basic science biochemistry biology biosphere botany cell community conclusion control deductive reasoning descriptive science discussion ecosystem eukaryote evolution falsifiable homeostasis hypothesis hypothesis-based science inductive reasoning introduction life science macromolecule materials and methods microbiology molecular biology KEY TERMS opening section of a scientific paper that summarizes the research and conclusions form of science that aims to solve real-world problems smallest and most fundamental unit of matter science that seeks to expand knowledge and understanding regardless of the short-term application of that knowledge study of the chemistry of biological organisms the study of living organisms and their interactions with one another and their environments collection of all the ecosystems on Earth study of plants smallest fundamental unit of structure and function in living things set of populations inhabiting a particular area section of a scientific paper that summarizes the importance of the experimental findings part of an experiment that does not change during the experiment form of logical thinking that uses a general inclusive statement to forecast specific results (also, discovery science) form of science that aims to observe, explore, and investigate section of a scientific paper in which the author interprets experimental results, describes how variables may be related, and attempts to explain the phenomenon in question all the living things in a particular area together with the abiotic, nonliving parts of that environment organism with Cells that have nuclei and membrane-bound organelles process of gradual change during which new species arise from older species and some species become extinct able to be disproven by experimental results ability of an organism to maintain constant internal conditions
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