This exam consists of 50 multiple-choice questions. Each one has only one right answer. Read each question and all possible answers carefully before answering.

Please mark your answers on the Scantron form provided, using only #2 lead pencil. If you erase an answer, make sure you erase it fully, or the machine may mark it incorrect. Check carefully to ensure that your answers are on the correct rows on the Scantron form.

Turn in both the Scantron form and the test paper when you are finished. Make sure your name is on both. You may write on the test paper if you wish, but anything you write on the test paper will not be graded.

Good luck.

For the WWW version, I have added commentary on some of the correct answers in blue.

The first nine questions deal with the exciting field of cheesemaking.

1. You start making cheese by adding organisms known as Lactobacillus to milk. Lactobacillus are microscopic, single-celled organisms that don't have a nucleus, which makes them

prokaryotes

2. Lactobacillus break down sugars in milk, producing a small amount of ATP plus lactic acid. This process is an example of

fermentation

3. The next step is to add an enzyme called rennet which causes certain molecules in the milk to clump together and curdle. If you heat the milk too high when you add rennet, the rennet won't work, probably because it's been

denatured

4. If you overheated your rennet, you would cause its ____ to change, which would destroy its ability to curdle milk.

tertiary structure

5. To make sharp Italian cheeses such as Parmesan, you have to add an enzyme called capilase as well as rennet. Capilase breaks down lipids in milk, such as

fats

6. If you were making blue cheese, you would add Penicillium roqueforti at this stage, which would produce blue streaks and a strong flavor in your cheese. Penicillium roqueforti is a living organism (a fungus), but if you didn't already know this, how could you tell?

all of the above
i.e.: It grows, takes in matter and energy, interacts with its environment, and reproduces.

7. Penicillium roqueforti in blue cheese has cell walls made up of chitin (pronounced "kite-in") which is a

carbohydrate

8. The drug gramidicin A (too poisonous to use on humans) allows protons to flow freely across the inner membrane of mitochondria, as if it had "punched holes" in this membrane. What direct effect does this have on a cell?

Cell can no longer make ATP by proton flow through ATP synthetase
"Cell can no longer make any ATP" was not the right answer, because even with mitochondria knocked out, a cell can make a little ATP by glycolysis. In this case, the Krebs cycle would also still work, and that would also produce a little ATP.

9. The poison cyanide blocks the electron transport chain used in respiration. Would you predict that cyanide might also be poisonous to plants?

Yes, because photosynthesis also involves electron transport

10. Nerve cells have a distinctive star-like or bush-like shape. They keep their shape because they have internal supporting filaments that make up the

cytoskeleton

11. To function, nerve cells must have many sodium ions (Na⁺) outside the cell and very few inside the cell. What process does the cell carry out so that this can happen?

active transport
If it didn't carry out active transport, you'd either get sodium flowing back into the cell, or water flowing out of the cell, until the concentration was equal on both sides. A nerve cell has to actively pump sodium out to maintain its proper state.

12. Muscle cells from the leg and thigh of a chicken are packed with mitochondria. However, the breast and wing muscles of a chicken have fewer mitochondria. What does this mean for the chicken?

its breast muscle cells get tired faster
Even if you didn't know about mitochondria, you could get this one right from knowing something about chickens. I mean, chickens walk around all day, but have you ever seen a chicken soaring through the sky for hours?

13. Why do plants need water?

chlorophyll splits water as a source of electrons

14. Part of the function of a kidney is to get rid of excess water in the body. Knowing this, which of these organisms would you predict should have the largest kidney relative to its body size?

a largemouth bass in Lake Conway
The bass was the only animal living in fresh water. If you live in water that has less dissolved stuff in it than your own cells have, what happens? That's right: water flows into you! And freshwater fish have large kidneys, because they have to expend a fair amount of energy pumping excess water out.

15. A eukaryotic cell's DNA is arranged in linear strips or pieces called

chromosomes

16. An atom is surrounded by one or more electrons that "orbit" its nucleus. These electrons cannot "orbit" just anywhere, but are confined to particular regions of space called

orbitals

17. Using the standard abbreviations, the four most common elements that make up living things are

CHON

18. The stage of respiration in which carbon dioxide is given off and a lot of NADH is produced is

the Krebs cycle

Look at this diagram of an amino acid molecule.

19. What do the lines connecting the letters represent?

covalent bonds

20. Which part of the amino acid molecule is important for forming peptide bonds?

2 and 3 only
2 is the amino group, and 3 is the carboxyl group. Peptide bonds link the carboxyl group of one amino acid with the amino group of another.

21. The part of the molecule called the R-group is

1

22. The part labeled 1 of this amino acid does not have any weak positive or negative electrical charges. This makes it

nonpolar

23. A cell's transport proteins and recognition proteins can both be found

in the plasma membrane

24. Prunes contain large amounts of a sugar called sorbitol. What class of molecules does sorbitol belong to?

carbohydrates
If it's a sugar, it's a carbohydrate, by definition.

25. Sorbitol is hard for your intestines to absorb, and so it tends to stay in your intestine. If you eat a lot of prunes, what happens?

water moves into your intestine by osmosis
And that means you get a case of the . . . well, never mind.

26. Which of these descriptions of the protein hemoglobin describes its quaternary structure?

Hemoglobin is made up of four subunits, each of which is a single polypeptide.

27. Which of these descriptions of the protein hemoglobin describes its secondary structure?

Hemoglobin polypeptides have several areas that are coiled up in a helix shape.

28. The molecule that actually "harvests" light energy in plants is

chlorophyll

29. The molecules that store information in living systems are

nucleic acids

30. A statement about how some aspect of the world might work, that is testable but hasn't been tested yet, is

a hypothesis

31. Water molecules' ability to form hydrogen bonds with other water molecules accounts for

all of the above
i.e.: Water's cohesion, heat capacity, solvent properties, and the fact that ice floats

32. What do enzymes do?

lower the activation energy of a chemical reaction

33. Sometimes sick people report feeling better after taking "medicines" that are known to be useless. This is

the placebo effect

34. Which of these statements is an example of the argument from ignorance?

"UFOs must exist. No one's ever proven that they don't."
"We don't know whether UFOs exist or not" is a statement of ignorance, but it is not an argument from ignorance -- it's not meant to argue for the existence of UFOs.

35. The gasoline additive MTBE (methyl tert-butyl ether) poses an environmental problem: It dissolves very well in water, it may be toxic, it tastes bad, and it is very difficult to get rid of, making it a water quality nightmare. Certain bacteria have an enzyme which allows them to break down MTBE. However, the same enzyme also breaks down the molecule benzene (which is also a pollutant). Both benzene and MTBE apparently bind to the same active site on the same enzyme, and so high levels of one block the enzyme's ability to break down the other. This blocking effect is

competitive inhibition

36. The process of glycolysis involves breaking down a molecule of glucose into two molecules of ___.

pyruvate

37. If a eukaryotic cell were thought of as a factory, what would be the assembly line?

rough endoplasmic reticulum

38. If a eukaryotic cell were thought of as a factory, what would be the "Packing and Shipping Department"?

Golgi body

39. All of the following are lipids EXCEPT:

cellulose

40. RuBisCO is

the enzyme that attaches CO₂ to a five-carbon sugar molecule in photosynthesis

The next nine questions all concern statements taken from actual tabloid newspapers. Evaluate these statements according to your knowledge of the nature of science and of sound reasoning:

41. One person claims that taking garlic capsules improved her sex life. (Weekly World News, 2/26/2001)

This sounds like an argument from insufficient evidence.
One person's experience doesn't mean it will work for everyone.

42. [A psychic prediction:] "TV's Xena, Lucy Lawless, will start a new career as an opera singer. Her first album Warrior Aria will go platinum."(Sun, 12/26/2000)

This is a scientific statement because it's testable.
How do we test it? Wait and see if it comes true!

43. [In an article claiming that U.S. Senators are part of a Satan-worshipping cult:] "According to their belief, the Lord creates all the trouble in the world, and Lucifer is a true friend of mankind who has been falsely represented as the Prince of Evil." (Weekly World News, 2/26/2001)

This is an unscientific statement because it deals with matters of religion and/or morality.
I mean, how do we test it? Sacrifice someone to Satan and ask him if it's true? Play a bunch of Led Zeppelin records backwards?

44. "SCIENCE PROVES HOME REMEDIES REALLY WORK!" (Sun, 12/26/2000)

This is false, because science doesn't prove anything.

45. "The Last Days [the end of the world] will begin on January 1 of next year [2001]. . ."(Sun, 12/26/2000)

This is a scientific statement because it's testable.
Again: how do we test it? Wait and see if it comes true! I presume it didn't come true, but there's still time. . . .

46. "With META-BIOLOGICAL DIETARY SUPPLEMENT, you lose pounds and inches SAFELY. . . . Thousands of men and women across America have tried this amazing breakthrough formula. . . " (Weekly World News, 2/26/2001)

This sounds like an argument from popularity.

47. "Doctors recommend one or two cloves of garlic. . . to reduce the frequency and severity of asthma attacks." (Weekly World News, 2/26/2001)

This is an argument from authority.
The fact that the people in white coats recommend something doesn't necessarily mean it works.

48. [A psychic writes this advice to a reader:] "Evil spirits have invaded your dreams and they're trying to get you executed."

This is an unscientific statement because it's too subjective.

49. [In an article about newly discovered aliens from outer space] "Maybe they're as dumb as wooden spoons, or as smart, or smarter, than humans." (Sun, 12/26/2000)

This is an unscientific statement because it's too vague to be tested.
I mean, are they dumb, smart, really smart, or what? We need an exact statement that we could test.

50. What city is UCA located in?

Conway