Cell Size and Scale Some cells are visible to the unaided eye The smallest objects that the unaided human eye can see are about 0.1 mm long. That means that under the right conditions, you might be able to see an ameoba proteus, a human egg, and a paramecium without using magnification. A magnifying glass can help you to see them more clearly, but they will still look tiny. Smaller cells are easily visible under a light microscope. It's even possible to make out structures within the cell, such as the nucleus, mitochondria and chloroplasts. Plate Tectonics Quicktime versionAVI version Animated gifs Last 750 million years: [1.04 MB] [506 KB] [261 KB] Last 750 million years in reverse: [1.04 MB] [506 KB] Cell Models: An Interactive Animation The cells of protozoa, higher plants and animals are highly structured. These cells tend to be larger than the cells of bacteria, and have developed specialized packaging and transport mechanisms that may be necessary to support their larger size. Use the Interactive animation of plant and animal cells to learn about their respective organelles. : The nucleus is the most obvious organelle in any eukaryotic cell. It is enclosed in a double membrane and communicates with the surrounding cytosol via numerous nuclear pores.
Parts of the Cell - Cells Alive! For life all cells have basic needs. Cells have diverged in their structure and function to accommodate these survival requirements. Here are some KEY TERMS to help you think, explore and search for similarities and significant differences that have become the characteristics of eukaryote (animal, plant) and prokaryotic (bacteria) cells. Examples might be searching: eukaryote prokaryote reproduction or animal plant cell energy. Reproduction / cell division Energy trapping, storage and consumption Form / shape / structure Cell specialization Compartmentalization of cell functions Communication within and beyond the cell Cell / organism survival Cell nucleus HeLa cells stained for the cell nucleus DNA with the BlueHoechst dye. The central and rightmost cell are in interphase, thus their entire nuclei are labeled. On the left, a cell is going through mitosis and its DNA has condensed.
Tectonic Plates The edges of these plates, where they move against each other, are sites of intense geologic activity, such as earthquakes, volcanoes, and mountain building. Plate tectonics is a relatively new theory and it wasn't until the 1960's that Geologists, with the help of ocean surveys, began to understand what goes on beneath our feet. Where is the Evidence for Plate Tectonics? It is hard to imagine that these great big solid slabs of rock could wander around the globe.
Plant Cell Vs. Animal Cell The bodies of both plants and animals are made up of cells. Although the basic structure and most of the features are the same, there are many points of differences between the two. The primary differences between both cells arise because of the fact that plants have to produce their own food by photosynthesis. Another important distinguishing factor is that plants have to support their own weight, which animals do by means of their skeleton. To perform these two important functions, plant cells and animal cells produce different kinds of organelles, that create a variation between the two types of cells. The various structures within a cell are called organelles. Solar-powered sea slug harnesses stolen plant genes - life - 24 November 2008 Video: Watch a sea slug eat algae to nab some of its chloroplasts, and the genes that keep them functioning It's the ultimate form of solar power: eat a plant, become photosynthetic. Now researchers have found how one animal does just that. Elysia chlorotica is a lurid green sea slug, with a gelatinous leaf-shaped body, that lives along the Atlantic seaboard of the US. What sets it apart from most other sea slugs is its ability to run on solar power. Mary Rumpho of the University of Maine, is an expert on E. chlorotica and has now discovered how the sea slug gets this ability: it photosynthesises with genes "stolen" from the algae it eats.
The Cytoskeleton Cells contain elaborate arrays of protein fibers that serve such functions as: establishing cell shape providing mechanical strength locomotion chromosome separation in mitosis and meiosisintracellular transport of organelles The cytoskeleton is made up of three kinds of protein filaments: Actin filaments (also called microfilaments) Intermediate filaments and Microtubules Actin Filaments Monomers of the protein actin polymerize to form long, thin fibers. These are about 8 nm in diameter and, being the thinnest of the cytoskeletal filaments, are also called microfilaments. (In skeletal muscle fibers they are called "thin" filaments.) 5 Must-Have Tools for a Killer Presentation A presentation is one of the best ways to convey ideas, especially for visual learners and thinkers. While many of us grew up creating class presentations with Microsoft heavyweight PowerPoint, sometimes you want to illustrate your ideas with a little more flair. Below, we present to you five sweet digital alternatives to PowerPoint for when you need more than just static words on a screen.
Rwanda’s rainforest renewal : National Parks, Africa When choosing Rwanda as a holiday destination, many people are keen to see the country’s rare primates and learn about its dark past. But those who work in the tourism industry are keen to show visitors a new Rwanda. Not one that is dismissive of its history – but one that offers more than museums and gorillas. Related article: Experiences that make time stand still For the last seven years, the Rwanda Development Board (RDB) has been focusing on the rainforest 200km to the west of capital city Kigali in a bid to attract adventurous travellers.
Plant & Animal WebQuest Plant & Animal WebQuest Introduction Cells, what are they? What do they do? What are they made of? How do they work? Membranes Organize Cellular Complexity Membranes organize proteins and other molecules enabling the cell to run much more efficiently than if everything were floating freely. Mitochondrial membranes, for example, keep protein assembly lines together for efficient energy production. And the lysosome safely holds enzymes that would destroy essential proteins if released into the cytoplasm. Membrane-enclosed vesicles form packages for cargo so that they may quickly and efficiently reach their destinations.