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Life Processes!! - Coggle Diagram
Life Processes!!
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Cell Structure
Most cells contain; nucleus, cytoplasm and cell surface membrane.
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Cytoplasm: living material that makes up a cell is called a cytoplasm, it has a texture rather like sloppy jelly. Not made up of one substance but is a complex material made of many different structures. Those structures are called organelles.
Largest organelle is the nucleus. Nearly all cells have a nucleus, and few which don't are usually dead or don't live for very long.
The nucleus controls the activities of the cell and contains chromosomes which carry genetic material, or genes.
The DNA remains in the nucleus but the instructions for making proteins are carried out of the nucleus to the cytoplasm where proteins are assembled on tiny structures called ribosomes.
Cell Membrane:also called cell surface membrane. This is a thin layer on the surface of the cell, it forms a boundary between the cytoplasm of the cell and the outside.
It is not a complete barrier, some chemicals can pass into the cell and others can pass out. The membrane is partially permeable.
It can also control the movement of some substances, it is selectively permeable.
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Enzymes
Cells contain hundreds of different enzymes, each catalysing a different reaction. This is how the activities of a cell are controlled, the nucleus contains the genes, which control the production of enzymes, which then catalyse the reaction in the cytoplasm.
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Necessary because temperatures inside organisms are low and without catalysts most of reactions that happen in cells would be far to slow to allow life to go on.
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Temperature
As the enzyme is heated up to the optimum temperature, the rise in temperature increases the rate of reaction
Higher temperatures give the molecules of the enzyme and the substrate more kinetic energy so they collide more often. Reactions will happen more often.
However beyond optimum temperature they temperature (heat) destroys the enzyme. The enzyme is denatured.
pH
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Almost most enzymes work best at a neutral pH and most enzymes have evolved to work best at this pH.
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Stem Cells
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Embryonic stem cells: found in early stage of development of the embryo. Can differentiate into any type of cell.
Adult stem cells: found in certain adult tissues such as bone marrow, skin and the lining of the intestine. have lost the ability differentiate into any type of cell but can form a number of specialised tissues
The use of stem cells to treat or prevent a disease, or to repair damaged tissues is called stem cell therapy
Scientists are able to isolate and culture embryonic stem cells, these are obtained from clinics where parents choose to donate their unused embryos for research.