Page 1. Name: 1) State one factor that influences which molecules can pass through the cell membrane of a human cell.

Transcription

1 Name: 1) State one factor that influences which molecules can pass through the cell membrane of a human cell Page 1 2) Molecules A and B are both organic molecules found in many cells. When tested, it is found that molecule A cannot pass through a cell membrane, but molecule B easily passes through. State one way the two molecules could differ that would account for the difference in the ability to pass through the cell membrane. 3) If vegetables become wilted, they can often be made crisp again by soaking them in water. However, they may lose a few nutrients during this process. Using the concept of diffusion and concentration, state why some nutrients would leave the plant cell.

2 Page 2 4) Elodea is a plant that lives in freshwater. The diagram below represents one Elodea leaf cell in its normal freshwater environment. Predict how the contents of the Elodea cell would change if the cell was placed in saltwater for several minutes by completing the diagram below, "Elodea cell in saltwater." Label the location of the cell membrane. 5) In an experiment to test the effect of light on plant growth, a student used two marigold plants of the same age. The plants were grown in separate pots. One pot was exposed to sunlight, the other to artificial light. All other conditions were kept the same. The height of each plant was measured at the start and at the end of the experiment. The student's data are shown in the table below. The student concluded that all plants grow more rapidly in sunlight than in artificial light. Discuss whether this conclusion is valid. Your answer must include at least: (1) the significance of the difference in the results shown in the data table (2) the significance of the number of individual plants used in the experiment (3) the significance of the number of species of plants used in the experiment

3 Page 3 6) Many people who are in favor of alternative medicine claim that large doses of vitamin C introduced into a vein speed up the healing of surgical wounds. Describe an experiment to test this hypothesis. Your answer must include at least: (1) the difference between the experimental group of subjects and the control group (2) two conditions that must be kept constant in both groups (3) data that should be collected (4) an example of experimental results that would support the hypothesis 7) A student wants to shorten the ripening time for tomato plants. He predicts that the more water the plants receive, the faster they will ripen. To test this prediction he grows 10 tomato plants in a sunny garden with dry soil, and 10 tomato plants in a garden with moist soil. He then records the time it takes for tomatoes to ripen on the plants in each garden location. Using one or more complete sentences, state one error the student made in the design of this experiment. 8) All living things carry out a variety of life functions such as coordination, excretion, digestion, circulation, and synthesis. Select two of the life functions listed above. Define the two life functions you selected and explain how they interact to keep an organism alive. 9) An unknown microorganism was observed with a compound light microscope. Identify the structure that, if observed in the organism, would indicate that it is an autotroph.

4 10) Explain how carbohydrates provide energy for life functions Page 4 11) The diagram below represents a human enzyme and four types of molecules present in a solution in a flask. Which molecule would most likely react with the enzyme? [Explain your answer.]

5 Page 5 12) The bark of trees around Manchester, England, was mostly light in color before the Industrial Revolution. Light-colored peppered moths that rested on the trees were camouflaged against bird predators, while dark-colored peppered moths were easily preyed upon. After a few years of industrialization, the tree bark became darkened from pollution. The table below represents a change in the number of light and dark-colored moths within the peppered moth population over a period of 6 years from the beginning of industrialization. Using the information in the data table, construct a line graph following the directions below. (a) (b) (c) Mark an appropriate scale on the axis labeled "End of Year". Mark an appropriate scale on the axis labeled "Number of Moths". Plot the data for the number of light moths on the grid. Surround each point with a small circle and connect the points. EXAMPLE: (d) Plot the data for the number of dark moths on the grid. Surround each point with a small triangle and connect the points. EXAMPLE:

6 Page 6 13) (a) (b) (c) Choose one of the given processes. Identify the source of the energy in the process you chose in part (a). Identify where the energy ends up at the completion of the process selected. 14) The skeletal system of an animal is shown in the photograph below. List three systems, other than the skeletal system, the animal had when alive that helped it to survive. Describe how each of these three systems contributed to maintaining homeostasis.

7 Questions 15 and 16 refer to the following: Page 7 The diagram below illustrates one type of cellular communication. 15) In region F, there is a space between nerve cells C and D. Cell D is usually stimulated to respond by A) a chemical produced by cell C moving to cell D B) the movement of material through a blood vessel that forms between cell C and cell D C) the movement of a virus from cell C to cell D D) the flow of blood out of cell C to cell D 16) If a stimulus is received by the cells at A, the cells at E will most likely use energy obtained from a reaction between A) water and carbon dioxide B) ATP and pathogens C) glucose and oxygen D) fats and enzymes Questions 17 through 19 refer to the following: 17) Which letter indicates a structure that secretes a hormone that promotes maturation of gametes?

8 18) Which letter indicates a structure that is not involved in the production or delivery of gametes? Page 8 19) Structures B and E provide nutrients and fluid for the gametes. Why are these substances necessary for fertilization? 20) On a television talk show, a guest claims that people who exercise vigorously for 15 minutes or more every day are able to solve math problems more rapidly than people who have no vigorous exercise in their daily routine. Describe a controlled experiment that could be conducted to test this claim. In your description, be sure to: (1) state the purpose of the experiment (2) state why the sample to be used should be large (3) describe how the experimental group will be treated and how the control group will be treated (4) state the specific data to be collected during the experiment (5) state one way to determine if the results support the claim