Questions & Answers > 1.2.7 Practice BIO Q&A_ American High School Academy BIOLOGY MISC. Score 100%

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1.2.7 Practice Kanishka Harnwal 1. Dimensions for cells of various shapes are provided in the table below. Using this information, rank the cells in order from fastest to slowest at procuring nutrients by diffusion from the surrounding medium. Explain your reasoning.

Cells ranked from the fastest to the slowest: Sphere shaped cells Cylinder shapes cells Cube shaped cells Reason: We already know that the time it takes for a cell to conduct diffusion depends on the cells surface area.

The greater the surface area the faster it takes for diffusion to occur. So after calculating the sphere has the greatest surface area while the cube has the lowest.

2. Draw an illustration of a cell showing the direction of movement in or out of the cell for the following molecules: O2, CO2, urea, glucose, phosphate. How are the molecules taken up by the cell used once inside the cell interior?

3. A microbiologist ran some tests on pure enzymes extracted from a pathogenic bacterial strain. She found that Compound Z was a potent inhibitor of an enzyme essential for DNA replication. In subsequent tests, however, when the scientist incubated bacterial cultures in media containing high concentrations of Compound Z, she observed no effect on the bacteria.

Pose a scientific question the scientist might use to pursue additional research on this topic. (3 points)

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The scientific question: Can the bacteria consume/ingest Compound Z? In her test the microbiologist the external effects that Compound Z had on the enzymes. But this does not mean the same results will happen internally. She should get the compound to go inside the cell and then run further tests.

4. Dimethylmercury is a nonpolar volatile liquid that is lethal to animals. Its structure is CH 3-Hg-CH3.

Predict the mechanism and timeframe of passage into cells for dimethylmercury based upon its chemical properties. Draw a diagram to support your explanation. (4 points) Dimethylmercury is nonpolar and enters a cell through passive diffusion. This liquid will pass feely through the lipid bilayer. Next the CH3 lets the Dimethylmercury get deposited under the skin. This is because CH3 is lipophilic and has a relation to fat. When it comes to the time, Dimethylmercury is slow when passing into a cell because it is a large molecule.

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5. A group of cells is placed in a liquid culture medium containing the molecule X and allowed to incubate for several hours. The diagram below shows the final distribution of molecule X in the interior of one cell and in the external liquid surrounding the cell.

Is molecule X undergoing active or passive transport across the cell membrane? Explain. (2 points)

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The molecule X is going through active transport and not passive transport. We can tell because the molecules present in the interior is greater than the number of molecules present in the exterior.

6. Farmlands are often threatened by the application of salt to roads during the winter months.

Explain how the application of salt to the roads could affect crops, based on your knowledge of osmosis. (6 points) The application of salt is very harmful to the surrounding corps. This is because the soil easily absorbs salt using it up in plants. If the plants raise their salt intake than they will eventually die.

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