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Cells can divide in three ways, binary fission, mitosis, and meiosis. Prokaryotes reproduce by binary fission in which the cell basically divides in half. The single, circular DNA, attached to the plasma membrane, duplicates, and the cell begins to grow. Continued growth of the cell separates the chromosomes, and eventually the plasma membrane and cell wall pinch in and create two new cells. Eukaryotes go through a cycle, including interphase and the mitotic phase. Interphase is divided into four stages, G1, S, G2, and M. In G1, cell growth takes place. The organelles get larger and the cell prepares for mitosis. The reproduction of DNA and the replication of chromosomes occur in the S phase, and final preparations for occur in the G2 phase. Actual occurs in M phase (mitosis). Mitosis has four sub-phases, prophase, metaphase, anaphase, and telophase. In prophase, the nucleoli disappears and the chromatin fibers become discrete chromosomes. The mitotic spindle also beings to form and the centrioles begin to move towards opposite ends of the cell. Also occurring later in prophase, the nuclear envelope fragments, and the microtubles attach to the kinetochores and overlap. In Metaphase, the chromosomes line up along the metaphase plate. The centromeres are all aligned and the sister chromatids straddle the metaphase plate. Anaphase beings when ...
Acupuncture is a Chinese medical practice that treats illness and provides local anesthesia by the insertion of needles at predetermined sites of the body. Acupuncture may also follow many other forms. The word acupuncture comes from the Latin word acus, meaning needle, and pungere, meaning puncture. The Chinese call acupuncture Chen Chiu. On do...
In today?s era there exists a medium, which like never before is becoming a medium of communication and interaction between humans, namely the World Wide Web. This old but yet new medium is expanding and changing rapidly, thus making it close to impossible to control. The World Wide Web is offering more to society now than it ever has before, cre...
Involvement of K+ in Leaf Movements During Suntracking Introduction Many plants orient their leaves in response to directional light signals. Heliotropic movements, or movements that are affected by the sun, are common among plants belonging to the families Malvaceae, Fabaceae, Nyctaginaceae, and Oxalidaceae. The leaves of many plants, including C...
What is a stem cell? Stem cells have the ability to divide for indefinite periods in culture and to give rise to specialized cells. They are best described in the context of normal human development. Human development begins when a sperm fertilizes an egg and creates a single cell that has the potential to form an entire organism. This fertilize...
Glycolysis, the Universal Process | Anaerobic Pathways | Aerobic Respiration Glycolysis, the Universal Process | Nine reactions, each catalyzed by a specific enzyme, makeup the process we call glycolysis. ALL organisms have glycolysis occurring in their cytoplasm. At steps 1 and 3 ATP is converted into ADP, inputting energy into the reaction as wel...
