background preloader

Mitosis: An Interactive Animation

Mitosis: An Interactive Animation
This animation demonstrates the stages of mitosis in an animal cell. Use the control buttons along the bottom to run the complete animation. Click on any intermediate stage (for example, Anaphase), and see a representative still frame. Interphase: Cells may appear inactive during this stage, but they are quite the opposite. Prophase: During this first mitotic stage, the nucleolus fades and chromatin (replicated DNA and associated proteins) condenses into chromosomes. Prometaphase: In this stage the nuclear envelope breaks down so there is no longer a recognizable nucleus. Metaphase: Tension applied by the spindle fibers aligns all chromosomes in one plane at the center of the cell. Anaphase: Spindle fibers shorten, the kinetochores separate, and the chromatids (daughter chromosomes) are pulled apart and begin moving to the cell poles. Telophase: The daughter chromosomes arrive at the poles and the spindle fibers that have pulled them apart disappear. Related:  Reproduction

Meiosis: An Interactive Animation Diploid Cell (2N): From a preceding mitotic division, the Oogonium (Spermatogonium) enters meiosis with DIPLOID (2N) chromosomes but TETRAPLOID (4N) DNA. Chromosomes then duplicate to produce SISTER CHROMATIDS (or HOMOLOGOUS DYADS). Prophase I: Dyad pairs align to create "TETRADS", non-sister chromatids connect and trade sections at a "CHIASMA", a process called "CROSSING OVER". Metaphase I: SPINDLE FIBERS attach to each dyad at the KINETOCHORE. Anaphase I: Chiasmata break apart and sister chromatids begin migrating toward opposite poles. Telophase I: CLEAVAGE FURROW forms beginning the process of CYTOKINESIS (cell division). Prophase II: Spindle formation begins and centrosomes begin moving toward poles. Metaphase II: Tension from spindle fibers aligns chromosomes at the metaphase plate. Anaphase II: CHROMATIDS separate and begin moving to the poles. Telophase II: CLEAVAGE FURROW forms beginning CYTOKINESIS. Gamete (1N): NUCLEAR ENVELOPES form and chromosomes disperse as CHROMATIN.

Physics Flash Animations We have been increasingly using Flash animations for illustrating Physics content. This page provides access to those animations which may be of general interest. The animations will appear in a separate window. The animations are sorted by category, and the file size of each animation is included in the listing. In addition, I have prepared a small tutorial in using Flash to do Physics animations. LInks to versions of these animations in other languages, other links, and license information appear towards the bottom of this page. The Animations There are 99 animations listed below. Other Languages and Links These animations have been translated into Catalan, Spanish and Basque: En aquest enllaç podeu trobar la versió al català de les animacions Flash de Física. Many animations have been translated into Greek by Vangelis Koltsakis. Most animations have been translated into Hungarian by Sandor Nagy, Eötvös Loránd University.

Skeletal System – Posterior (Back) View [Continued from above] . . . calcium, iron, and energy in the form of fat. Finally, the skeleton grows throughout childhood and provides a framework for the rest of the body to grow along with it. Skeletal System Anatomy The skeletal system in an adult body is made up of 206 individual bones. SkullHyoidAuditory ossiclesRibsSternumVertebral column The appendicular skeleton is made up of 126 bones in the folowing regions: Upper limbsLower limbsPelvic girdlePectoral (shoulder) girdle SkullThe skull is composed of 22 bones that are fused together except for the mandible. The bones of the superior portion of the skull are known as the cranium and protect the brain from damage. Hyoid and Auditory OssiclesThe hyoid is a small, U-shaped bone found just inferior to the mandible. The malleus, incus, and stapes—known collectively as the auditory ossicles—are the smallest bones in the body. VertebraeTwenty-six vertebrae form the vertebral column of the human body. Long. Skeletal System Physiology

Cell Function: Mitosis Eventually cells need to duplicate. There are two main methods of replication, mitosis and meiosis. This tutorial will talk about mitosis. The big idea to remember is that mitosis is the simple duplication of a cell and all of its parts. Beyond the idea that two identical cells are created, there are certain steps in the process. We suppose it would be good to know what happens during those phases. Metaphase: Now all of the pieces are aligning themselves for the big split. Anaphase: Here we go! Telophase: Now the division is finishing up. Interphase: This is the normal state of a cell. pacific ocean plate tectonic evolution The Pacific Ocean is the world's largest ocean, covering nearly one-half of the globe. Though huge, the Pacific is getting smaller. It was once much wider when all the continents were joined together in the supercontinent, Pangea. The Pacific ocean basin is getting smaller because the Atlantic Ocean is opening and North America and South America are moving westward. Most of the Pacific Ocean is underlain by the Pacific plate. Though the Pacific Ocean is ancient, the Pacific plate is relatively young. The modern Pacific plate was formed nearly 180 million years ago. The Pacific Ocean floor, shown in rainbow colors according to age, continues to grow along the East Pacific Rise. This animation is available on CD-ROM in Quicktime format. This page uses a java applet that displays a VR model. (c) PALEOMAP Project, 2002.

Interval Training: Good Exercise For All Ages Cell Function: Meiosis What are the big ideas here? There are two cell divisions. Mitosis has one division and meiosis has two divisions. You still have to remember PMATI, but now you do it twice. Meiosis happens when it's time to reproduce an organism. As we said, meiosis happens when it's time to reproduce. That second division divides the number of chromosomes in half. MEIOSIS I: This is basically like the PMATI of a regular mitosis. This crossing over is an exchange of genes. MEIOSIS II: In Prophase II the DNA that remains in the cell begins to condense and form short chromosomes. Telophase II shows the DNA completely pulled to the sides and the cell membrane begins to pinch. Or search the sites for a specific topic.

Ripple tank circular wave reflection Ripple tank: circular wave reflection Added by David Fairhurst on Feb 6, 2008 An interactive animation demonstrating circular wave reflection in a ripple tank. Click in the water to generate a circular wave that undergoes reflection at the tank boundary. This resource is from the unit Bouncing Waves which is part of Absorb Physics. The full Absorb Physics course normally sells for £400 - but you can get it free for your school! All you need to do is ask your colleagues in the maths department to try our new Sumdog games...

Muscular System - Muscles of the Human Body [Continued from above] . . . Muscle TypesThere are three types of muscle tissue: Visceral, cardiac, and skeletal. Visceral Muscle. Visceral muscle is found inside of organs like the stomach, intestines, and blood vessels. The weakest of all muscle tissues, visceral muscle makes organs contract to move substances through the organ. Because visceral muscle is controlled by the unconscious part of the brain, it is known as involuntary muscle—it cannot be directly controlled by the conscious mind. Gross Anatomy of a Skeletal MuscleMost skeletal muscles are attached to two bones through tendons. Muscles move by shortening their length, pulling on tendons, and moving bones closer to each other. Names of Skeletal MusclesSkeletal muscles are named based on many different factors, including their location, origin and insertion, number of origins, shape, size, direction, and function. Location. The sarcolemma is the cell membrane of muscle fibers. Thick filaments.

Asexual Reproduction vs Sexual Reproduction - Difference and Comparison | Diffen Moon Jellies has two main stages in its life cycle – polyp stage (asexual reproduction) & medusa stage (sexual reproduction) Types There are several different types of asexual reproduction. These include budding, where the offspring grows out of the body of the parent, and gemmules, where the parent releases a specialized mass of cells that will become a new individual. There are two types of sexual reproduction. Syngamy is the permanent fusion of two haploid gametes to create a zygote. Process Asexual reproduction is reproduction that occurs without any interaction between two different members of a species. Cell division in asexual and sexual reproduction Sexual reproduction is reproduction that requires a male and a female of the same species to contribute genetic material. Examples Asexual reproduction is used by many plants, e.g. spider plants, bacteria, hydra, yeast, and jellyfish. Sexual reproduction is used by most mammals, fish, reptiles, birds and insects. References

Related: