Essay questions

BIOL 101

Comprehensive Final Exam – Essay Portion

University of Maryland University College

Directions: Please complete the AnswerSheet file electronically and submit it via Assignments by March 6th

at 11:59 PM ET. Save your AnswerSheet in the following format: “LastName FINAL” (e.g., SmithFINAL).

Sources: You may use any electronic or print source from BIOL 101. When appropriate, you may use the

internet to locate additional supporting evidence (look for questions requiring it). AS ALWAYS, BE SURE TO

CITE ANY EXTERNAL RESOURCES YOU USE NEXT TO THE APPROPRIATE QUESTION.

Note: you may not consult any “living” resource in or out of this class, so do not seek assistance from your

peers or any other person. All essays will be run through the anti-plagiarism website, TurnItIn.com, and any

plagiarized material will be given a zero.

This exam is worth 200 points or 20% of your total grade. This section of the exam is essay, which is worth

100 pts (or half of the total points for the final exam). The other half of the final exam is a series of multiple-

choice questions, which is a separate link in our LEO classroom. Read the directions carefully below—you

have some choice in the Essay section. If you have any questions, e-mail me.

SHORT ESSAY QUESTIONS:

Complete all three. Answers should not exceed 1-2 paragraphs for each question. Worth 10 points each.

1. A population of grasshoppers in the Kansas prairie has two color phenotypes, green and brown. Typically, the prairie receives adequate water to maintain healthy, green grass. Assume a bird that

eats grasshoppers moves into the prairie. How will this affect natural selection of the grasshoppers?

How might this change in a drought year?

2. Using material from this class, support the following statement with at least five pieces of evidence: a plant-based (or vegetarian) diet is good for your health and the planet. Be sure to cite any external

evidence you use.

3. DNA and RNA are similar yet distinct components of the cell. Describe three differences between RNA and DNA with respect to their chemical composition and structure. Provide a detailed

description of each characteristic you chose in your response.

ESSAY QUESTIONS:

Pick FIVE to answer—ONE FROM EACH PAIR. Each answer should be approximately 3-4 paragraphs in

length—maximum. Worth 14 points each.

4. Molecules of life and Cells (PICK A OR B TO ANSWER)

A. Pick three animal organelles and compare each one to a department or feature in a grocery or department store. In other words, the organelles in a cell are analogous to various machines

and/or features in a store.

B. List the four “large molecules of life.” Identify their composition and structure, and describe one function they perform in the cell.

5. Combining Micro and Macro concepts (PICK A OR B TO ANSWER)

A. Water is crucial for life as we know it. One of the most important characteristics of water is its ability to act as a solvent. Explain why water is such a good solvent for polar and charged

molecules. In what ways are humans negatively impacting the hydrologic cycle—how might

these effects impact solvency properties in nature? Be specific.

B. Carbon dioxide is a greenhouse gas that is thought to be responsible for global warming. Explain what type of bond(s) carbon forms that are relevant to global warming. How does the

destruction of Earth’s rain forests impact the carbon cycle and contribute to global warming?

6. Genetics and evolution (PICK A OR B TO ANSWER)

A. How can you explain the occurrence of birth defects (caused by altered genes) in children and grandchildren of WWII atomic bomb victims, when the victims themselves were only mildly

affected?

B. During the past 50 years, more than 200 species of insects that attack crop plants have become highly resistant to DDT and other pesticides. Based on what you have learned in this class

regarding evolution, explain the rapid and widespread evolution of resistance. Now that DDT has

been banned in the US, what do you expect to happen to levels of resistance to DDT among

insect populations?

7. Understanding The Scientific Method (PICK A OR B TO ANSWER)

A. Before bringing a new drug to the marketplace, extensive testing is done on the drug by administering the drug to large numbers of individuals. Explain the importance of the scientific

method, sample size, controls and variables in the drug evaluation process.

B. You are interested in how pH affects the functioning of the enzyme, metabolase. Design an experiment that would reveal the ideal pH required for optimal functioning of metabolase.

i. Design a study that will allow you to assess how various pH levels affect metabolase functioning.

ii. Be sure to state your hypothesis, define your controls, describe the materials you will use, and dissect your IV(s) and DV(s).

iii. Conclude with a graphical prediction of your results.

8. Using the Scientific Method to Analyze Research (PICK A OR B TO ANSWER) A. You are a researcher at Stanford University. In between surfing at Mavericks and growing your

own avocados, your lab group is investigating how the speed at which cells complete mitosis

varies based on their location in the body. In one study, you isolated human cells from hair

follicles, the tongue, and the earlobe. Half of your 200 participants are male, and the other half

are female with equal representation from all major racial groups. Look at the data table below

which shows how many minutes, on average, it took for one cell to complete a mitosis cycle.

Male Female

Hair follicle 48.2 mins 29.2 mins

Tongue 12.7 mins 13.1 mins

Earlobe 97.4 mins 94.9 mins

i. What type of study is this (experimental vs. correlational)? Explain how you know. ii. What are the controls, IV(s) and DV(s) in this study?

iii. What can you conclude based on the reported findings? iv. Describe, in detail, how you would improve upon this study if you were to do a follow-up. v. Why might the study of “mitosis speed” be important?

B. The following article was found on USAToday.com. Read it and answer the questions below.

i. What is/are the independent variable(s) in this research? ii. What is/are the dependent variable(s) in this research?

iii. What factor is producing the negative impact on monarch larvae? iv. Name another important insect that genetically-modified corn could affect and suggest the

ultimate repercussions of this effect. (HINT: Think of a beneficial insect to humans.)

v. Explain if the newspaper’s interpretation of the above findings is justified or not? (HINT: Think in terms of correlation vs. experiment and lab vs. field settings.)

Butterfly Experiment Highlights Biotech Hazards By Brian Tokar

Genetically engineered crops threaten monarch butterflies. The headlines spread worldwide this past May, after three researchers at Cornell University published a study confirming what critics of biotechnology have been saying for a decade: that the environmental consequences of genetic engineering would prove to be widespread and very damaging.

This was far from the first study of its kind. After 25 years of research in genetic engineering, over a decade of open-air field tests, and three years

of aggressive promotion of genetically engineered crops in the commercial marketplace, research on the health and environmental effects of

engineered crops is finally beginning to catch up with the industry juggernaut. But while biotech companies pour billions of dollars every year into

developing and marketing new high-tech crop varieties, researchers concerned about the health and environmental consequences of these

technologies face scarce research funds, unrealistic burdens of proof, and sometimes even professional ostracism. For more than two decades,

assertions about the likely ill effects of genetic engineering have been dismissed as mere speculation. As fast-merging “life science” conglomerates

seek to control all aspects of seed production, agricultural chemicals, and pharmaceutical manufacture, their reach is having an ever more chilling

effect on many areas of science.

Dr. Losey and his two colleagues at Cornell University collected pollen from one of the “pest-resistant” corn varieties that is now being

aggressively promoted by Monsanto and other biotech companies. The corn plants are genetically engineered to secrete very high doses of a toxin

naturally produced by the bacterium Bacillus thuringiensis, commonly known as Bt. While short-lived Bt bacteria normally produce this toxin in an

inactive form, which becomes activated only when absorbed into the highly alkaline digestive systems of organisms such as the corn rootworm,

genetically engineered Bt crops produce up to 20 times as much toxin in its activated form in every plant tissue throughout the plant's entire life

cycle.

The Cornell researchers used a simple spatula to apply Bt corn pollen to the leaves of common milkweed, which is the sole food source for

monarch butterflies in their early larval stages throughout much of North America. Three-day-old butterfly larvae were exposed to the treated

milkweed, and others were placed on milkweed leaves that either had no pollen on them, or only pollen from non-genetically engineered corn.

After only four days, 44% of the larvae that were exposed to the Bt pollen died, while both control groups had a 100% survival rate. The surviving

Bt-exposed larvae were also reduced in weight by more than 60%. "These results have potentially profound implications for the conservation of

monarch butterflies," the three researchers wrote in the prestigious British scientific journal Nature. In subsequent public statements, the researchers

instead emphasized the differences between the laboratory and the field.