Biology unit 1&2 chapter 3 answers Essay
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There must be a higher concentration of wastes in the dialysis tube than in the surroundings. Wastes must therefore be constantly removed from the surroundings to maintain a concentration gradient.
b) What special features does it have?
If the surrounding solution was not changed, the concentration gradient would become smaller and smaller until diffusion would no longer occur and the same amount of wastes would leave the dialysis tubing as wound enter it. 2.
3. When epithelial cells such as human cheek cells, are studied under a microscope, they are mounted on a slide to which a drop of ‘normal’ saline (salt) solution, rather than tap water, has been added.
Explain why this is the best method for preparing these cells.
If the person drank the sea water, cells in digestive system would be surrounded by a hypotonic solution and would lose water. Cells would become dehydrated and cease to function.
4. Under what natural conditions might plant cells become plasmolysis?
There will be a net movement of water into the Amoeba in freshwater environment.
5. Two cells have the same internal concentration of sugar solution. They are both placed in distilled water. Even though both cells expand over time, one expands faster than the other. What are some reasons for this observation?
The disease will cause severe diarrhea. Human body will be infected with bacterium when drinking contaminated water, and sticks to the intestinal lining. . Intestinal cells start secreting sodium and chloride ions into the
intestinal fluid. This upsets the balance of fluids, causing a net movement of water out of the intestinal cells into the surrounding fluid which is then excreted with faces, causing diarrhea. Dehydration of body cells may eventually kill infected people.
6. After eating a packet of slated potato chips your lips often feel dry. Explain why?
Blood glucose levels are measured in mill moles of glucose per liter of blood (mmol/L). The normal level is around 5 mmol/L. A 5% solution of glucose is roughly equivalent to the normal level of glucose in the blood. If this concentration drastically increases (20%), body cells may be in danger of losing water by osmosis. Increased thirst and excessive urination are two of the symptoms of diabetes, a condition in which the amount of blood sugar rises to unacceptable levels.
7. A student places a living cell into a drop of liquid contains less than 5% sugar. a) Make a hypothesis to explain what caused the change in sugar concentration outside the living cell. It is hypothesis a living cell being placed into a drop of liquid contains less than 5% sugar can cause the sugar concentration outside the living cell.
8. A particle that has been drawn into a cell by phagocytosis is not truly inside the cell. Explain the statement.
If salt levels rise, water tends to move from the root tissue in citrus trees to the surroundings by osmosis. There is a lack of water for photosynthesis, causing smaller yields of citrus fruit.