Mitosis in Real Cells. To study mitosis, biologists often look at particular cells. Remember, that mitosis occurs only in areas of growth, so finding a good spot to study it can be challenging. Two specimens are commonly used by biologists to study mitosis: the blastula of a whitefish and the root tip of an onion. The whitefish embryo is a good place to look at mitosis because these cells are rapidly dividing as the fish embryo is growing.
The onion root is also a good place because this is the area where the plant is growing. Remember that when cells divide, each new cell needs an exact copy of the DNA in the parent cell. Mitosis can take several hours to complete. Tasks: View slide images of a whitefish blastula and an onion root to see cells in various stages of mitosis. You may want to print this page out to answer the questions on it, or just answer questions (#1-5) on your own paper. Review the stages of mitosis at: Introduction: 1. 2. 3. View Cells 4. Video Clips for Biology! Lab 2—Mitosis Slides. The Red Queen | Science | Classroom Resources | PBS Learning Media. Many say that our culture is obsessed with sex, and uses sexual references to sell everything from fragrances to cars.
And wouldn't life be dull without it? Yet from the viewpoint of evolutionary theory, sex isn't the most efficient way of reproducing. In fact, scientists have been asking for decades, why does sexual reproduction even exist? If the goal of life is spreading one's genes far and wide, asexually reproducing organisms seem to have the edge. They do not have to invest time and energy finding a mate. Asexual individuals can pass on their genes twice as fast as those reproducing sexually, because they pass on all their genes -- and only their genes.
When reproduction is sexual, half of the genes handed on to the next generation are those of the other parent. There are many hypotheses but, until recently, little hard evidence on the advantages of sex. Meiosis with Crossing Over. Unit 3 Review - Mitosis and Meiosis. Evolution: Library: The Red Queen. Mitosis and Meiosis - Comparison Chart, Video and Pictures | Diffen.
Cells divide and reproduce in two ways: mitosis and meiosis. Mitosis is a process of cell division that results in two genetically identical daughter cells developing from a single parent cell. Meiosis, on the other hand, is the division of a germ cell involving two fissions of the nucleus and giving rise to four gametes, or sex cells, each possessing half the number of chromosomes of the original cell. Mitosis is used by single-celled organisms to reproduce; it is also used for the organic growth of tissues, fibers, and membranes. Meiosis is found in sexual reproduction of organisms. The male and female sex cells (i.e., egg and sperm) are the end result of meiosis; they combine to create new, genetically different offspring. Differences in Purpose Though both types of cell division are found in many animals, plants, and fungi, mitosis is more common than meiosis and has a wider variety of functions.
A diagram showing the differences between meiosis and mitosis. Mitosis and Meiosis Stages. 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. 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. Advantages and Disadvantages References. Sexual Reproduction and Meiosis NOTES.pdf. Sexual vs. Asexual Reproduction. 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. You also need to remember that four cells are created where there was originally one. That's four (4) cells with half of the amount of DNA needed by a cell. When a cell goes through meiosis, it's not concerned about creating another working cell. 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. 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.
It duplicates its DNA and the two new cells (daughter cells) have the same pieces and genetic code. Two identical copies come from one original. Start with one; get two that are the same. 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. 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. This is the longest period of the complete cell cycle during which DNA replicates, the centrioles divide, and proteins are actively produced. For a complete description of the events during Interphase, read about the Cell Cycle.
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. Cancer cells reproduce relatively quickly in culture. 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. Tension from spindle fibers aligns the tetrads at the cell equator. 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.
Animation: Comparison of Meiosis and Mitosis (Quiz 1) Genetics and Meiosis Games and Virtual Labs. Genetics and Meiosis Genes are passed on from one generation to the next! Learn how this occurs through fun, interactive games and activities that explore genetics and meiosis! Genetics Video Games, Virtual Labs & Activities Snurfle Meiosis and Genetics 2: Diversity and Dihybrid Crosses When Snurfles reproduce, their offspring can have a lot of different traits (lots of diversity). But how? Snurfle Meiosis and Genetics Snurfles, just like any other organism, must reproduce in order to continue as a species! Meiosis Battle Pong!! Fire comets at your opponent, dodge asteroids, and keep the ball in play in this fresh twist on the classic game of Pong, all while reviewing Meiosis!
Mitosis and Meiosis: 'Interactive demonstrations' Mitosis and Meiosis.