<h2 class="documentFirstHeading">Summary</h2>
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<h3 class="para"><b class="emphasis">The Discovery of Cells</b></h3>
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<li class="item">All living organisms are made of cells.</li>
<li class="item">Cells are very small therefore magnifying instruments such as lenses and microscopes are used to view them.</li>
<li class="item">By using a <a data-lesson="light" data-subject="biology" data-tutorial="sensory-systems" href="https://app.ulearngo.com/biology/sensory-systems/light">light</a> microscope the simple features of cells can be studied. The light microscope uses a beam of light focused by various glass lenses.</li>
<li class="item">Electron microscopes have higher power of magnification than the ordinary light microscope, therefore allowing us to see very small structures inside the cells. These microscopes use a beam of <a data-lesson="electron-shells-and-bohr-model" data-subject="biology" data-tutorial="chemical-foundation-of-life" href="https://app.ulearngo.com/biology/chemical-foundation-of-life/electron-shells-and-bohr-model">electrons</a> focused by electromagnets to magnify objects instead of light rays and lenses.</li>
<li class="item">Robert Hooke (1665) used a light microscope to examine non-living cork cells.</li>
<li class="item">Antonie van Leeuwenhoek was the first person to observe living cells using a microscope.</li>
<li class="item">The development of <a data-lesson="cell-theory-intro" data-subject="biology" data-tutorial="introducing-the-cell" href="https://app.ulearngo.com/biology/introducing-the-cell/cell-theory-intro">cell theory</a> was from the study of microscopic cells.</li>
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<h3 class="para"><b class="emphasis">Cell Structure and Function</b></h3>
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<li class="item">All cells have the same basic structure. They are all surrounded by a cell membrane and contain <a data-lesson="cytoplasm" data-subject="biology" data-tutorial="introducing-the-cell" href="https://app.ulearngo.com/biology/introducing-the-cell/cytoplasm">cytoplasm</a> and organelles.</li>
<li class="item">Cells have different sizes, shapes and structures in order to carry out specialised functions.</li>
<li class="item">The cell membrane is made of <a data-lesson="phospholipids-and-steroids" data-subject="biology" data-tutorial="biological-macromolecules" href="https://app.ulearngo.com/biology/biological-macromolecules/phospholipids-and-steroids">phospholipids</a> and proteins and controls substances which move in and out of the cell.</li>
<li class="item">The structure of the cell membrane is referred to as the Fluid Mosaic Model.</li>
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<li class="item">The <a data-lesson="nucleus-2" data-subject="biology" data-tutorial="cell-biology" href="https://app.ulearngo.com/biology/cell-biology/nucleus-2">nucleus</a> is made up of a nuclear membrane with nucleopores, chromatin material and the nucleolus inside the nucleoplasm.</li>
<li class="item">Mitochondria release chemical <a data-lesson="types-of-energy" data-subject="biology" data-tutorial="cell-metabolism" href="https://app.ulearngo.com/biology/cell-metabolism/types-of-energy">potential energy</a> (ATP) for the cell during cellular respiration.</li>
<li class="item">Ribosomes are important for protein production.</li>
<li class="item">Cytoplasm is used for storage and circulation of various materials.</li>
<li class="item">Endoplasmic reticulum transports substances from one part of the cell to another.</li>
<li class="item">The Golgi body modifies, secretes, packages and distributes various organic <a data-lesson="first-organic-molecules" data-subject="biology" data-tutorial="evolution-overview" href="https://app.ulearngo.com/biology/evolution-overview/first-organic-molecules">molecules</a> (proteins and lipids) around the cell.</li>
<li class="item">Vacuoles are used for storage. In <a data-lesson="summarizing-asexual-reproduction" data-subject="biology" data-tutorial="plant-reproduction" href="https://app.ulearngo.com/biology/plant-reproduction/summarizing-asexual-reproduction">plant</a> cells these are large, whilst in animal cells, if present, are very small.</li>
<li class="item">Lysosomes are mainly found in animal cells.</li>
<li class="item">Centrioles are only found in animal cells.</li>
<li class="item">The <a data-lesson="cell-wall" data-subject="biology" data-tutorial="introducing-the-cell" href="https://app.ulearngo.com/biology/introducing-the-cell/cell-wall">cell wall</a> is found only in plant cells and is made up of cellulose. The cell wall gives the <a data-lesson="nutritional-adaptations-of-plants" data-subject="biology" data-tutorial="soil-plant-nutrition" href="https://app.ulearngo.com/biology/soil-plant-nutrition/nutritional-adaptations-of-plants">plants</a> shape, support and protection.</li>
<li class="item">Plastids are found only in plant cells. There are three types of plastids:

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<li class="item">chloroplasts contain chlorophyll and their function is the production of <a data-lesson="ingestion" data-subject="biology" data-tutorial="digestive-system" href="https://app.ulearngo.com/biology/digestive-system/ingestion">food</a> by photosynthesis</li>
<li class="item">chromoplasts give colour to <a data-lesson="development-of-fruit-and-fruit-types" data-subject="biology" data-tutorial="plant-reproduction" href="https://app.ulearngo.com/biology/plant-reproduction/development-of-fruit-and-fruit-types">fruits</a> and flowers</li>
<li class="item">leucoplasts are white and are used mainly for starch storage</li>
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Summary and Main Ideas

Biology studies life and living organisms. Biology can be divided into different sections that cover the morphology, physiology, anatomy, behavior, and so on of living organisms.

Biology

Discover the fascinating world of cells and explore topics such as microscopy, cell theory, membrane models, transport processes, organelles, and the cell cycle.


Summary and Main Ideas

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