computerages Posted October 22, 2004 Posted October 22, 2004 Hello everyone! What are three statements of the CELL THEORY? Why can we reasonbly sure sure that the cell theory is true? What is the difference between a PROKARYOTE and a EUKARYOTE? What are the similarities between PROKARYOTE and EUKARYOTE cells? What is the function of the CELL WALL? Why is cell wall found mostly in plants? What is the job of the nucleus? Thanks!
Primarygun Posted October 22, 2004 Posted October 22, 2004 Cells are the basic and structural unit of an organism. Cell wall protects, gives shape and support the cell. Nucleus contain genetic materials responsible for heredity and it controls all activities of the cell. Hope it help for some of the questions!
Sorcerer Posted October 22, 2004 Posted October 22, 2004 Hello everyone! What are three statements of the CELL THEORY? Why can we reasonbly sure sure that the cell theory is true? What is the difference between a PROKARYOTE and a EUKARYOTE? What are the similarities between PROKARYOTE and EUKARYOTE cells? What is the function of the CELL WALL? Why is cell wall found mostly in plants? What is the job of the nucleus? Thanks! Dunno if I should just give you all the answers.... don't you have a text book? Hmmmmmm Cell theory: Not sure but I think it would be - -The cell is the lowest level of structure capable of performing all the activities of life. -All cells come from other cells -The ability of cells to divide to form new cells is the basis for all reproduction and for the growth and repair of multicellular organisms. You can answer the why yourself, its a good question. What is the difference between a PROKARYOTE and a EUKARYOTE? Eukaryotes have membrane bound organelles such as mitochondria and chloroplasts (in plants), they also have a membrane bound neucleus which contains the cells DNA. Prokaryotes do not have these. There are more differences if you want to find them out yourself. What are the similarities between PROKARYOTE and EUKARYOTE cells? They both have cell membranes, both use DNA to code gentic information, both transcribe DNA to mRNA which is then translated into proteins via ribosomes and tRNA. Well the similarities go on and on.... basically anything thats not a difference is a similarity. What is the function of the CELL WALL? The cell wall is structural support which allows the cell to maintain turgor pressure and prevents lysis under extreme hypo or hypertonic conditions. Why is cell wall found mostly in plants? Because plants need it to regulate turgor pressure and maintain structural support to hold the leaves in place for efficient photosynthesis. They also require cell walls to build structures such as xylem (water carrying vessels) and bark (protection). What is the job of the nucleus? The nucleus contains the cells DNA, its "job" is to maintain the DNA in a functioning state eg repair mutations, transcribe mRNA and export it to the cytoplasm and copy DNA for when mitosis (cell division) takes place.
Sorcerer Posted October 23, 2004 Posted October 23, 2004 Ooops, lysis will only occur in a cell not bounded by a cell wall under hypotonic conditions. This is because the cell will burst as water rushes into the cell via osmosis in order to reach equilbrium. In a hypertonic solution the cell will become shriveled. A cell which is bounded by a cell wall will become plasmolysed in a hypertonic solution, this is where the cell membrane seperates from the cell wall. It will be flaccid in an isotonic solution, this means soft or limp, and turgid in a hypotonic solution.
computerages Posted November 13, 2004 Author Posted November 13, 2004 Thanks for all the relpies, and all the answers!! Thanks again for the help!!
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