Regents Review Part D

1. Regents ReviewPart D

2. Diffusion Through A Membrane Key Terms • Diffusion • Selectively permeable • Indicators • Dialysis tubing • Starch • Glucose • Starch indicator • Glucose indicator • Controls • Cytoplasm • Cell membrane • Cell wall • Osmosis • Wet mount • Cover slip

3. Key Points I 1. Molecules tend to move from high to low concentration without the use of energy (diffusion). 2. Membranes may allow some molecules to pass through while not allowing others (selectively permeable). 3. Indicators are used to show the presence of certain kinds of molecules.

4. Recap 1. A model cell is made using a plastic membrane (usually dialysis tubing) containing starch and glucose. The bag is sealed with string. 2. Starch indicator (iodine) is placed in solution outside the ‘cell’. 3. Because of the differences in concentration, starch indicator diffuses in and glucose diffuses out. Starch ‘wants’ to, but cannot diffuse out because the molecule is too large to pass through the membrane.

5. 4. Starch (milky white) + starch indicator (brown) = blue-black color 5. The inside of the bag turns blue-black while the outside stays brown, proving that indicator went in, but starch did not leave.

6. 6. Glucose indicator (Benedict's solution) (blue) + glucose (clear) + HEAT = eventually turns orange 7. Testing the fluid outside the ‘cell’ shows glucose has left. This is tested by placing fluid from outside into a test tube, adding indicator solution, and heating the mixture. 8. You may prove that #6 is true by testing (heating) indicator alone and also testing indicator + starch. Both of these controls result in a blue color (no change).

7. Analysis 1. Glucose and starch indicator may pass through the membrane. Starch may not. This is because starch is a much larger molecule than glucose or starch indicator. 2. This shows the importance of breaking down large molecules inside the digestive system in order for nutrients to enter the bloodstream.

8. The diagram below represents a laboratory setup used by a student during an investigation of diffusion. Which statement best explains why the liquid in tube A will rise over a period of time? (1) The starch concentrations are equal on both sides of the membrane. (2) The water will pass from a region of lower starch concentration to one of higher starch concentration. (3) Water and starch volumes are the same in both tubes A and B. (4) The fluids in both tubes A and B will change from a higher temperature to a lower temperature.

9. A laboratory setup for a demonstration is represented in the diagram below. Describe how an indicator can be used to determine if starch diffuses through the membrane into the beaker. In your answer, be sure to include: • the procedure used [1] • how to interpret the results [1] Example of a 2 credit response Add starch indicator solution to the water in the beaker. If the indicator solution changes color, then starch is present (no color change, no starch).

10. The diagram illustrates an investigation carried out in a laboratory activity on diffusion. The beaker and the artificial cell also contain water. Predict what would happen over time by showing the location of molecules I, G, and S in diagram B below. [3] 1 pt for I’s both inside and outside of the cell 1 pt for G’s both inside and outside of the cell 1 pt for S’s inside the cell I G S S G G I S S I G I

11. State what is observed when there is a positive test for starch using the starch indicator. [1] Example of an acceptable response Color changes from amber to blue black

12. Glucose indicator was added to a beaker of an unknown liquid. Starch indicator was added to a different beaker containing the same unknown liquid. The color of the indicator solutions before they were added to the beakers and the color of the contents of the beakers after adding the indicator solution are recorded in the chart below. Which carbohydrate is present in the unknown liquid? Support your answer. [1] Example of an acceptable response Starch - Color change in beaker 2

13. A laboratory setup of a model cell is shown in the diagram below. Which observation would most likely be made 24 hours later? (1) The contents of the model cell have changed color. (2) The diameter of the model cell has increased. (3) The model cell has become smaller. (4) The amount of distilled water in the beaker has increased.

14. Key Points II 1. Basic parts of the cell that are easily seen under the microscope are the cytoplasm, cell membrane, and cell wall (in plants). 2. Molecules tend to move from high to low concentration without the use of energy (diffusion). 3. Diffusion of water molecules is particularly important and has the special name of osmosis. 4. The balance of water molecules inside and outside the cell is extremely important for the survival of all organisms, including humans.

15. Recap 1. Make a wet mount slide of a thin section of red onion cells. 2. The cells are examined under the light (compound) microscope. 3. It is important to see that the cell membrane and cytoplasm completely fill the space within the cell wall.

16. Recap 4. Place a 10% salt solution under the cover slip. This is done by putting a drop of salt solution next to one edge of the cover slip, then absorbing water from the opposite side of the slip using a paper towel.

17. Recap 5. Observe the cells in the salt solution. It is important to see that the cytoplasm and cell membrane have shriveled up inside the cell wall. This is due to water molecules leaving the cell and entering the salty (low water) solution.

18. Recap 6. Place distilled water under the cover slip using the technique described in #4 above. 7. Observe the cells in distilled water. It is important to see that the cytoplasm and cell membrane have swollen back to fill the entire space available within the cell wall.

19. Analysis 1. Cells placed in very salty solutions will lose water, causing them to collapse and possibly lose the ability to complete life functions. 2. Cells placed in very watery solutions will tend to gain water, which causes them to swell and might cause them to burst/break open, destroying the cell. Note that this did not happen in the plant cells because the cell wall prevents the cell membrane from easily expanding. 3. Freshwater creatures, particularly single-celled organisms, must cope with too much water entering the cells. They use their contractile vacuoles if single celled to pump out this water. Saltwater organisms tend to have the opposite problem and must try to reclaim lost water.

20. The diagram illustrates what happens when a particular solution is added to a wet-mount slide containing red onion cells being observed using a compound light microscope. Identify a process that caused the change in the cells. [1] • Acceptable response • Osmosis • Diffusion • Passive Transport To observe the cells on this slide it is best to start out using the (1) high-power objective and focus using the coarse adjustment, only (2) low-power objective and focus using the fine adjustment, only (3) high-power objective and focus using the fine adjustment (4) low-power objective and focus using the coarse adjustment

21. The diagram below represents a plant cell in tap water as seen with a compound light microscope. Which diagram best represents the appearance of the cell after it has been placed in a 15% salt solution for two minutes?

22. Relationships and Biodiversity Key Terms • Biodiversity • Gel Electrophoresis • Evolutionary relationships • Molecular Evidence • Habitat Destruction • Structural Evidence • Chromatography • Human Impact • DNA • Cladograms* • Extinct • Amino Acids • Transcription • Translation • Enzymes

23. Key Points 1. The diversity of life on the planet has been created through the process of evolution by means of natural selection. Differences between or within species is called biodiversity. 2. Through natural selection, organisms have evolved to lessen competition, and therefore fill a wide array of niches. This biodiversity increases the stability of ecosystems. 3. Biodiversity has important benefits to mankind, including development of new food sources and medicines; as providing aesthetic beauty. Ecosystem destruction leads to the loss of genetic biodiversity and increases the chance that an ecosystem will become less stable and collapse.

24. Recap 1. Seven tests are conducted to determine the relatedness of Samples X,Y, and Z to Botanacurus. They are as follows: a. Structural Characteristics of Plants b. Structural Characteristics of Seeds c. Structural Characteristics of Stems (Internal Microscopic Structures) Examine cross sections of the stems. Look for a scattered arrangement of bundles or a circular arrangement of bundles.

25. Recap • d. Paper Chromatography to Separate Plant Pigments • Using clean, separate pipettes for each sample, transfer two drops of each plant extract to a piece of chromatography paper, two cm above the bottom. Label the top of the paper with the proper sample names. • Place the paper into a cup of water, 1 cm deep. The water should NOT touch the spots of plant extract. • Keep checking the sample to make sure the water does not reach the labeled top part of the paper. When the water is done rising, check the colors and relative amounts of pigments and record this in the data table.

26. Recap e. Indicator Test for Enzyme M Placing a scoop of the indicator powder into 4 depressions of the well tray, check the extracts for the presence of Enzyme M. A fizzing reaction indicates that Enzyme M is present in the extract. f. Gel Electrophoresis (simulated) to Compare DNA Obtain colored paper strips representing portions of DNA molecules. The sequence of bases are representative of molecules isolated from Botanacurus and Species X,Y, and Z. A simulated restriction enzyme will be used to cut between C and G of the sequences to produce different sized portions of the DNA. These will be placed on a simulated gel plate to compare the relatedness of B. curus to X, Y, and Z.

27. Recap g. Translating the DNA Code to Make a Protein Using the DNA codons, create the complementary messenger RNA, remembering that the DNA base A specifies the RNA base U (*T is replaced with U in RNA). Using the Universal Genetic Code table, translate the mRNA base sequences into the correct amino acid sequences of the protein.

28. Analysis 1. This lab has 7 tests used to determine the relatedness of 4 plant samples. Remember that scientists use a variety of evidence to determine evolutionary relationships, including cell types, structural morphology, DNA, behavior, embryology, and fossils. The more criteria that are shared between organisms, the more likely they are closely related. 2. Relatedness can be shown using a “branching tree diagram”, or cladogram. Organisms that are closely related have a more recent common ancestor and will be closer together on the same branch. 3. Botanacurus shares the most characteristics with Sample Z, making this sample the most closely related. These characteristics included the presence of Enzyme M, the same pigments blue, yellow, and pink, scattered bundles, no difference in the amino acid sequences, and the same DNA banding pattern.

29. Analysis 4. The evidence that should receive the most emphasis when determining the relatedness would be the molecular or genetic evidence, as many things can look similar structurally, but would be unlikely to share the same DNA sequence if they are not truly closely related. (DNA, RNA, protein) 5. The loss of even a single species (extinction) can have major implications for mankind and natural ecosystems. 6. Scientists use gel electrophoresis to separate DNA fragments. Negatively charged DNA molecules migrate through the gel like material towards the positively charged pole. The smaller molecules migrate more rapidly through the gel than the larger ones do. Electricity must be turned on to propel the fragments through the gel and restriction enzymes must cut the fragments so they fit through the gel. Wells are holes in the gel where the DNA fragments are placed.

30. Which evolutionary tree best represents the information in the chart?

31. State one way the information obtained by this technique can be used. [1] • acceptable responses • to determine evolutionary relationship • screening for a genetic disorder • To determine paternity • to dsetermine whether the hospital mixed up the babies • To identify suspects in criminal investigations. The results of which laboratory technique are represented in the diagram? (1) chromatography (2) manipulation of genes (3) genetic engineering (4) gel electrophoresis

32. The DNA of three different species of birds was analyzed to help determine if there is an evolutionary relationship between these species. The diagram shows the results of this analysis. Identify the technique normally used to separate the DNA fragments to produce the patterns shown in the diagram. [1] • acceptable responses • electrophoresis • gel electrophoresis

33. The chart below contains amino acid sequences for part of a protein that is found in the feathers on each of these three species of birds. • State one way this data supports the inference that these three bird species may be closely related. • Since they have similar amino acid sequences, they may be closely related. • Since they have amino acid sequences that are very much alike, the species have similar DNA. • State one type of additional information that could be used to determine if these three species are closely related. [1] • comparing embryos, cytology, comparing fossils, comparing bone structure, additional sequence studies.

34. In preparation for an electrophoresis procedure, enzymes are added to DNA in order to ___________. (1) convert the DNA into gel (2) cut the DNA into fragments (3) change the color of the DNA (4) produce longer sections of DNA Paper chromatography is a laboratory technique that is used to __________________. (1) separate different molecules from one another (2) stain cell organelles (3) indicate the pH of a substance (4) compare relative cell sizes

35. A marathon runner frequently experiences muscle cramps while running. If he stops running and rests, the cramps eventually go away. The cramping in the muscles most likely results from ______________. (1) lack of adequate oxygen supply to the muscle (2) the runner running too slowly (3) the runner warming up before running (4) increased glucose production in the muscle

36. Based on these data, which two plant species appear to be most closely related? Support your answer. [1] • A and C have the most characteristics in common • A and C have the same type of chlorophyll present • What additional information could be gathered to support your answer? [1] • Structure of protein molecules • type of enzymes present • DNA sequences • other physical characteristics • State one reason why scientists might want to know if two plant species are closely related. [1] • two related species may be used to produce substances for medicines • a related plant may produce a cheaper version of a substance.

37. Acceptable responses include: — The pigeon shares characteristics with all of the other organisms. — Organisms A and C also lay eggs.

38. In an investigation, DNA samples from four organisms, A, B, C, and D, were cut into fragments. The number of bases in the resulting DNA fragments for each sample is shown below. Draw lines to represent the position of the fragments from each DNA sample when electrophoresis is completed. [1] Which two DNA samples are the most similar? Support your answer using data from this investigation. [1] B and D because they have the most fragments in common

39. The Beaks of Finches Key Terms • Variation • Competition • Struggle for Survival • Adaptation • Environment • Selecting Agent • Migration

40. Key Points 1. Species evolve over time. Evolution is a result of the interactions between: a. The potential for a species to increase its population b. Genetic variation of offspring due to mutation and genetic recombination. c. A limited amount of resources in the environment (ex. food, space, mates, etc.) d. Selection by the environment of those individuals that are better able to survive and produce viable offspring (“survival of the fittest”)

41. Key Points 2. Some characteristics / variations give individuals an advantage over others in surviving and reproducing. The offspring of these “better adapted” individuals will be more likely to survive and reproduce than those of other individuals. The proportion / frequency of individuals with favorable characteristics will increase. 3. Variation in a population increases the likelihood that at least some individuals will survive the changing environmental conditions.

42. Recap 1. In teams of two, students will simulate foraging for food by finches in an island environment. 2. The beak variations of finches will be represented by a variety of tools (tweezers, spoons, pliers, etc.) 3. In Round One, students simulate feeding on small seeds. Each student will remove seeds alone, without competition from other students. 4. The winners of Round One stay on their original island while the losers migrate to a different food source (large seeds). In Round Two, the same procedure will be followed. 5. The winning teams proceed to Round Three and the losing teams are eliminated.

43. Analysis 1. Competitionfor food should have had an adverse effect on feeding success. 2. There were fewer survivors at the end of Round Three due to increased competition. 3. The following components of Natural Selection were simulated: a. Variation: different beaks, different size seeds b. Competition: more than one bird feeding at one bowl c. Struggle for survival: each bird trying to get enough food to survive d. Adaptation: particular characteristics of “beaks” e. Environment: students, seeds, dishes are part of environment f. Selecting agent: type of “beak” and / or type of seed available

44. * Be sure you study the diagram that shows the variations in beaks of Galapagos Island finches. The diagram represents the types of beaks, the function of the beaks, and the type of food the finches eat.

45. The only finch that is completely carnivorous has a beak adapted for __________________. (1) probing, only (2) probing and edge crushing (3) probing and biting (4) biting and edge crushing

46. Which two finches would compete the least for food? (1) small ground finch and large ground finch (2) large ground finch and sharp-billed ground finch (3) small tree finch and medium ground finch (4) vegetarian finch and small ground finch

47. Evolutionary changes have been observed in beak size in a population of medium ground finches in the Galapagos Islands. Given a choice of small and large seeds, the medium ground finch eats mostly small seeds, which are easier to crush. However, during dry years, all seeds are in short supply. Small seeds are quickly consumed, so the birds are left with a diet of large seeds. Studies have shown that this change in diet may be related to an increase in the average size of the beak of the medium ground finch. The most likely explanation for the increase in average beak size of the medium ground finch is that the ________________. (1) trait is inherited and birds with larger beaks have greater reproductive success (2) birds acquired larger beaks due to the added exercise of feeding on large seeds (3) birds interbred with a larger-beaked species and passed on the trait (4) lack of small seeds caused a mutation which resulted in a larger beak In exceptionally dry years, what most likely happens in a population of medium ground finches? (1) There is increased cooperation between the birds. (2) Birds with large beaks prey on birds with small beaks. (3) The finches develop parasitic relationships with mammals. (4) There is increased competition for a limited number of small seeds.

48. Making Connections Key Terms • Pulse Rate • Muscle fatigue • Homeostasis • Hypothesis • Independent variable • Dependent variable • Control Trial • Sample size • Histogram

49. Key Points I 1. In order to find a hypothesis, one looks for patterns. For example, we did not see a connection between pulse rate and height, but we did see a connection between pulse rate and exercise. 2. Graphs and data tables present data in a clear, organized way that is easy to understand. 3. Pulse rate increases during exercise because the cells need to be provided with more food and oxygen and more wastes are produced which need to be transported to the lungs (CO2) and the kidneys (urea). 4. Muscles become fatigued, tired, due to waste products building up in them. The waste product lactic acid produces muscle fatigue. 5. Organ systems interact in order to maintain homeostasis.

50. Recap 1. Students found their average pulse rates after three trials. 2. Class results were graphed in a connected bar graph called a histogram. 3. Pulse rates were found to increase after exercising. 4. A clothespin was squeezed rapidly for one minute. The number of times that it was squeezed was recorded. 5. The clothespin was squeezed the same way for another minute. The second time produced a lesser number of squeezes for most people due to muscle fatigue.