Weismann‚ who noted that two cell divisions were necessary to transform one diploid cell into four haploid cells if the number of chromosomes had to be maintained. In 1911 the American geneticist Thomas Hunt Morgan observed crossover in Drosophila melanogaster meiosis and provided the first genetic evidence that genes are transmitted on chromosomes. The term meiosis was introduced to biology by J.B. Farmer and J.E.S. Moore in 1905 Meiosis i/maɪˈoʊsɨs/ is a special type of cell division necessary for
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Cell phones are the most essential devices used in the 21st century. People are using cell phones now more than ever. The first cellular device was invented in the 1940’s and they have been used till this day. The design is very unique‚ making it top dollar in the store. The development of the cellular device has helped better the people of the United States and throughout the world. Today cell phones are much more modified and abstract in the way their being used. Communication is now distributed
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Should Your Child Have a Cell Phone? From My Secure Cyberspace Kids love mobile phones‚ but they need to learn how to use them responsibly. In recent years‚ mobile phones have become extremely popular with young people. More than half of American teenagers now own a cell phone‚ and this number is growing quickly. Also‚ the age at which kids are getting cell phones is dropping‚ and many elementary school-aged children now carry cell phones. This trend is even more marked in countries outside the
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Hey little guy they call me the nucleus of an animal cell and lucky you I’m going to be your mentor and I’m going to teach you about me. So welcome as a new Ribosome organelle in the cell world‚ I’m going to make you familiar with your new home. We are going to start off with the Cell Membrane. The Cell Membrane is the selective barrier that’s surrounding the cell. Since you’re a newbie you need to know that the cell membrane allows only certain things to pass into it‚ but that’s only if it’s made
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------------------------------------------------- Cell phones Imagine being able to talk to someone that is across the world with a push of a button. Seems a little far-fetched? Well‚ there is such a device that allows you to do that. It is called the cell phone. Cell phones are devices that enable people to talk to others no matter how far away they are from each other. They can be on opposite sides of the planet and they still will be able to talk to each other. Many people nowadays use cell phones very frequently for
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Ch. 1: Biology: Exploring Life 1) Slides 1 and 2: What is the main difference between physiological adaptation (as in sense‚ respond and adapt to the environment) and evolutionary adaptation? Evolutionary adaptation occurs over generations. Evolutionary adaptation does involve genetic change but it’s the change in traits as a result of genetic change that drives natural selection and evolutionary adaptation (just genetic change alone won’t drive evolutionary change). Physiological adaptation is
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Cell Fusion Introduction: The fusion of cells is a fundamental biological event that is essential for a variety of developmental and homeostatic processes. The importance of cell-cell fusion during development and disease is displayed in a variety of biological processes including‚ but not limited to‚ fertilization‚ development of tissues‚ the immune response‚ and aspects of tissue regeneration due to stem cells (Chen and Olson‚ 2005). Fertilization‚ which is the fusion of sperm and egg‚
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Chapter 1 Cell Theory- in the 18th century‚ two scientists came up with the cell theory. Schleiden and Schwen. 3 corollaries of the cell theory: -all cells are alike in chemical composition -all cells store and process information in the same way -all cells arise from other cell through cell division 5 types of different Microscopes 1. Light Microscope- produces 2-D image Direct descendants of Hooks scope> take two lenses to a light source> used this to magnify images up to 1‚000 fold.
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1 Hypothesis If you soak an egg in vinegar‚ then the shell will deteriorate and loose centimeters off of it’s circumference. Data and Observations Time (hrs) Observations Circumference (cm) 0 1. The egg is whole‚ and has not lost color. 2. The egg was immediately surrounded by bubbles. 3. 14 cm 4. 24 1. The egg appears to have a little bit of color missing. 2. The egg remains firm. 3. 15.5cm 4. 48 1. The eggs shell is beginning to disappear. 2. The shell of the egg is cracking
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a) Using a human cell of your choice‚ describe how organelles work together to make and secrete a protein (LO1. AC 1.1) An epithelial cell in the thyroid gland‚ called a thyrocyte forms spherical follicles that produce a protein called thyroglobulin. This is a globular protein that has a functional role in metabolism. The protein is used by the thyroid gland to produce thyroid hormones; thyroxine (T4) is an example of one of the hormones created. Thyroxine is formed by iodine binding to tyrosine
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