HONORS BIOCHEMISTRY 2014-2015 MIDTERM EXAM STUDY GUIDE

Use the following practice questions to help you prepare for our midterm exam. These questions DO NOT cover ALL of the content that you may be expected to know for the midterm; rather they represent a series of the types of questions you might be expected to answer.

As always, use your UNIT STUDY GUIDES, ONLINE REVIEW GAMES, and your BIOCHEMISTRY JOURNAL to review the full range of information and skills that you may be expected to display on the midterm.

YOU SHOULD REVIEW ALL EXPERIMENTS WE HAVE PERFORMED AS DESCRIBED IN YOUR LAB JOURNAL; INCLUDING THE pGLO BACTERIAL TRANSFORMATION LAB; BOTH CELLSERV LABS (Comparing L-929 and IMR-90 cells lab and HeLa cells chromosome spread lab); and THE ENZYME LAB.

BE PREPARED TO ANALYZE A DESCRIBED EXPERIMENT, INCLUDING IDENTIFYING THE INDEPENDENT VARIABLE AND DEPENDENT VARIABLE, AN ANALYSIS OF THE VALIDITY OF A GIVEN PROCEDURE, AND INTERPRETATION OF ANY DATA. See, for example your CAPT TASK: ENZYMES!!! HANDOUT ….

UNIT I: Enhancing and Evolving to “Perfection”?

NATURAL SELECTION AND EVIDENCES FOR EVOLUTION:

1. Explain Darwin’s Theory of Evolution by Natural Selection. Write a series of steps to explain the process of evolution.

2. A small population of fish lives in a grey bottom pond. Two phenotypes exist, a dark brown variation, and a grey variation. Cats enter the environment and begin hunting the fish. Over time what will likely happen to the population of fish? Explain WHAT, WHY and HOW.

3. Evaluate WHY variation is important in a population of a species. Predict what can happen to a species in a changing environment if the members of that species do not express any genetic variations.

4. Explain HOW genetic variation is generated in a population. 5. Compare and contrast analogous structures and homologous structures. If two animals have analogous

structures, what does that imply about their ancestry? What if two animals have homologous structures? 6. Give an example of a structure that is homologous to a bat’s wing. 7. Give an example of a vestigial structure. Explain WHY such structures are still present in a species even though

they have no function in that species. 8. The evolutionary tree to the

right depicts the evolution of foxes and dogs as determined from biochemical evidence. Provide THREE distinct conclusions that can be made about the evolution of these species based upon the DATA in the figure. For each conclusion, provide information about both the species and the timeframe (in millions of years) involved.

ANTIBIOTIC RESITANCE:

9. WHY do some antibiotics that worked 20 years ago fail to cure bacterial infections today? Please explain in terms of antibiotic resistance, mutation and the process of natural selection.

10. Your friend was given an antibiotic for strep throat. The prescription indicates that she should take the antibiotics for two weeks. After three days she is feeling fine and asks you if she should stop taking the antibiotic and save the pills for the next time she has a sore throat. What advice should you give your friend?

11. Describe the transformation procedure we used to create antibiotic resistant E. coli bacteria in the pGLO bacterial transformation lab. a) For an overview see: http://www.phschool.com/science/biology_place/labbench/lab6/concepts1.html. b) Then complete the lab analysis questions found online at:

http://www.phschool.com/science/biology_place/labbench/lab6/test2.html c) Finally, complete the Self-Quiz located at:

http://www.phschool.com/science/biology_place/labbench/lab6/quiz1.html 12. Which type of infection(s) is/are treatable with antibiotics? 13. Describe tuberculosis as an infectious disease. What pathogen causes it? How is it transmitted? 14. Describe and compare eukaryotic cells versus prokaryotic cells, including similarities and differences. 15. Describe and compare animal cells, plant cells, and bacterial cells, including similarities and differences. 16. Identify and describe FOUR features found in ALL cells, and therefore common to both prokaryotic and

eukaryotic cells.

DNA STRUCTURE:

17. Compare and contrast the nucleic acids DNA and RNA. How are they alike? How are they different? 18. Describe in general terms HOW the information in DNA is used to direct the synthesis of a protein. In your

answer, use and explain the following terms (given in alphabetical order): amino acid, codon, cytoplasm, DNA, mRNA, nucleus, polypeptide/protein, ribosome, RNA polymerase, transcription, and translation.

19. Using your knowledge of protein synthesis and the Universal Table of the Genetic Code given below, determine the amino acid sequence of the protein that would result from the following DNA sequence:

TACCGACTCGGACTATGCAACATT

20. LABEL the diagram of a double-stranded DNA molecule below to indicate its structural components. Use the following terms: base pair, deoxyribose sugar, hydrogen bond, nitrogen base, nucleotide, and phosphate. Write in the complementary base sequence present on the second strand.

21. Explain the process of DNA replication used to make copies of this molecule of DNA. 22. If the bases in DNA are the same in all organisms, what accounts for the large diversity of life on the planet? 23. Calculate: If a given piece of double stranded DNA contains 32% adenine, what are the percentages of each of

the other three nitrogenous bases in that piece of DNA? 24. Describe and compare point mutations versus frameshift mutations, including similarities and differences. 25. Change this sentence: “The fat cat ran far.” to make a point mutation. Make a different change to cause a

frameshift mutation. 26. Explain WHY a single nucleotide base change in a DNA sequence may NOT result in a change in the amino acid

sequence of a protein.

INHERITANCE:

27. A cell with 64 chromosomes undergoes meiosis (meiotic cell division). What is the chromosome number in the daughter cells? How many daughter cells are produced?

28. A cell with 64 chromosomes undergoes mitosis (mitotic cell division). What is the chromosome number in the daughter cells? How many daughter cells are produced?

29. Which cells are generated by meiosis? Which are generated by mitosis? 30. Identify and explain THREE ways that meiosis and sexual reproduction increase genetic variation, and explain

why mitotic cell division to generate somatic cells (body cells) does not generate such variation. 31. If an organism has 80 chromosomes, HOW would nondisjunction affect the resulting daughter cells during

meiosis? Provide a specific example of a human genetic disorder resulting from nondisjunction. 32. What does it mean to be “haploid”? What cells in a human are haploid? 33. What does it mean to be “diploid”? What cells in a human are diploid? 34. An organism has 64 TOTAL chromosomes. What is the haploid number? What is its diploid number? 35. Exposure to cigarette smoke has caused a mutation in the lung of a human. Would this mutation be passed on to

the human’s offspring? Why or why not?

36. Analyze the karyotype to the right. a) Which sex is this person? b) Does this person have Down Syndrome? c) HOW can you tell (what evidence are you

using to answer each question)?

37. A couple has a female child with Tay Sachs disease (a severe and deadly neurological disorder), and 3 unaffected children. Neither parent nor any of the four biological grandparents of the affected child has had the disease. a) What mode of inheritance does Tay Sachs disease show? b) Show the Punnett Square depicting the cross between this couple. c) What percentage of their children will have Tay Sachs disease? d) What percentage will be heterozygous carriers for Tay Sachs disease? e) Compare and contrast genetic disorders and infectious diseases. How are they alike? How are they

different? 38. Identify all possible modes of inheritance (autosomal dominant or autosomal recessive) for the traits depicted in

the following pedigrees. Explain how you arrived at your conclusions using evidence from each pedigree. In your response refer to specific individuals in each pedigree by number.

C

A B

GENETICALLY MODIFIED ORGANISMS:

39. Evaluate: What are some benefits (PROS) to the use of genetically modified foods? Provide at least THREE arguments, supported with details and specifics, in favor of the use of GMFs.

40. Evaluate: What are some risks (CONS) to the use of genetically modified foods? Provide at least THREE arguments, supported with details and specifics, against of the use of GMFs.

UNIT II: Causes and Treatment of Cancer

THE CELL CYCLE AND CANCER:

41. Evaluate: In what way is cancer a disease of cell division? 42. Compare and contrast normal versus cancer cells. How are they alike? How are they different? Refer to you

Biochemistry Journal entries for the L-929 and IMR-90 cell observations lab (CellServ Kit 1) AND THE BACKGROUND READING HANDOUT THEREFORE; and the HeLa cell lab (CellServ Kit 4). a) Explain what is meant by saying a cell is “transformed”. b) Identify and describe at least THREE factors that can result in the formation of “transformed” cells. c) Identify and describe at least FOUR differences between normal and “transformed” cells. d) Which cells show density-dependent inhibition of their cell division and which ones don’t? e) How does the morphology (structure and shape) of normal and “transformed” cells differ? f) How do the chromosome numbers of normal and “transformed” cells differ? ?

43. With reference to the diagram to the below: a) Describe the mitotic cell cycle . In your answer, define and explain the following terms: Interphase, G1

phase, S phase, G2 phase, Mitotic phase, DNA replication, Mitosis, and Cytokinesis. Describe the major events occurring during each phase.

b) Describe the THREE major “checkpoints” that regulate the progression of the cell cycle. Identify the THREE major “checkpoints;” that regulate the progression of the cell cycle, describe WHEN each occurs, and explain HOW each regulates the cell cycle (What is the checkpoint “checking” for? Under what conditions will the cell cycle proceed? Under which conditions will the cell cycle NOT proceed?).

44. With reference to the diagram below explain how DNA replication and the movement of chromosomes during mitosis produce daughter cells that are genetically identical to the parent cell.

45. Compare and contrast proto-oncogenes and oncogenes. How are they alike? How are they different? Explain HOW they relate to the regulation of the cell cycle.

46. Compare and contrast oncogenes and tumor suppressor genes. How are they alike? How are they different? Explain HOW they relate to the regulation of the cell cycle.

47. Identify THREE environmental factors known to cause a dramatic increase in the relative risk of developing cancer.

RADIATION AND MUTATIONS:

48. Describe the relationship between wavelength, frequency, and energy within the electromagnetic spectrum. 49. List the wave types within the electromagnetic spectrum in order from lowest energy to highest energy. 50. Identify which of the wave type(s) within the electromagnetic spectrum is/are potentially ionizing radiation.

51. Complete the following table to compare alpha (α), beta (β), and gamma () radiation in terms of particle emitted (if any), size and charge of the emission, ionizing ability, and penetrating capacity.

Radiation type

Particle emission

Size Charge Ionizing ability Penetrating capacity

Alpha (α)

Beta (β)

Gamma ()

52. Evaluate the relative risk associated with exposure to alpha (α), beta (β), and gamma () radiation.

SUPPORT YOUR ANALYSIS WITH SPECIFICS FROM THE TABLE ABOVE.

53. You must be able to complete balanced nuclear decay equations for nuclear reactions. Practice with these… a) The alpha decay of iridium-174 b) The beta decay of platinum-199 c) The alpha decay of radon-198 d) The beta decay of uranium -237

54. Describe and compare the effect of alpha (α), beta (β), and gamma () decay on the atomic mass and atomic number of a decaying radioisotope.

CELLULAR AGING AND CANCER:

55. With reference to the diagram to the right, describe oxidation and reduction in terms of the movement of electrons (e-). In your answer use and define the terms oxidation, reduction, oxidizing agent, and reducing agent.

56. Identify the oxidizing agent and reducing agent in a redox

reaction. Practice with these: Label each of the “redox” reactions shown below to:

I. Show the proper use of oxidation numbers; II. Show the movement of electrons (as labelled

on the reactants)(1 point); III. Identify the oxidizing agent and reducing agent (1 point); and IV. Identify the substance being reduced and the substance being oxidized (1 point).

a) 2 H2(g) + O2(g) 2 H2O(g)

b) 2 Mg(s) + O2(g) 2 MgO(s)

c) Zn(s) + Fe2+(aq) Zn2+(aq) + Fe(s)

d) Cl2(g) + 2 K(s) 2 KCl(s)

e) 3 Sn2+(aq) + 2 Al(s) 3 Sn(s) + 2 Al3+(aq)

ENZYMES:

57. Describe the function of enzymes. In your answer, explain the terms catalyst and activation energy (EA). 58. Explain WHY enzymes are so specific in their functions. In your answer, explain the terms substrate and active

site. 59. Describe what is meant by saying an enzyme is “denatured.” Describe how being denatured affects an enzyme’s

function and WHY. 60. Describe THREE environmental factors that can impact the reaction rate of an enzyme catalyzed reaction and

explain WHY they have this effect.