Fall 1999

Lecture Exam 3 -- KEY

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! Mark your answers on the Scantron form provided, using only a #2 lead pencil. If you erase an answer, make sure you erase it completely, 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. Even if it is a turkey. Not this time. Sorry.

Good luck.

You have been kidnapped by unfriendly aliens from the planet Zorgo and taken away in their flying saucer. As if that weren't bad enough, the Zorgonians are using you for hideous medical experiments.

1. The aliens implant some sort of tiny robot probe in the collecting duct of a nephron. What organ is this a part of?
kidney

2. The probe then "goes with the flow" from the nephron directly to the
ureter

3. The aliens implant another robotic probe in the right atrium of your heart. It travels with your normal circulation into your
right ventricle

4. The probe then radios a message to the aliens: It tried to go back into the right atrium, but found its way blocked by a structure called a
valve

5. Carried away by the blood, the probe is then whisked out of your heart to the lungs by way of a large vessel called the ________.
pulmonary artery

6. Passing through the lungs, the probe then reports that oxygen is entering the blood. Oxygen molecules were being picked up and carried by a ______ molecule called ________.
protein; hemoglobin

7. The probe analyzed one of these oxygen-carrying molecules. Unfortunately, the probe ended up bending the molecule out of shape, and then it no longer functioned properly. In other words, the probe __________ the molecule.
denatured

8. By scanning the insides of your blood cells, the probe is able to determine that this molecule was directly made by organelles known as
ribosomes

9. The probe also reports that oxygen is entering your blood by way of millions of small, thin-walled sacs in your lungs, called
alveoli

10. Completing its observations of your lungs, the probe returns to your heart via normal circulation. It finds itself in the thickest-walled, most powerful chamber of your heart, the
left ventricle

11. The aliens insert a third probe into- well, let's just say that it provides information on the functions of the small intestine. The probe reports that molecules are present that cause other molecules to be broken down into smaller ones. These are
enzymes

12. The probe reports that two types of molecules have been partly broken down already, before they reach the small intestine. These types are
proteins and starches [Remember that the enzyme amylase in saliva breaks down starches, and pepsin in the stomach begins the breakdown of proteins.]

13. The probe reports that it is having trouble staying in place, because rhythmic, regularly spaced muscle contractions are pushing it through the small intestine. These contractions are known as
peristalsis

14. Studying the muscle in your small intestine, the probe reports that part of it is made up of a protein called myosin. Myosin is actually made up of many polymer strands wound around each other, in an arrangement that looks something like a bundle of sticks. This arrangement is myosin's
quaternary structure

15. The probe analyzes a myosin molecule and discovers that it is made up of amino acids strung together. Each amino acid has two groups of atoms that act as the "hooks" to link them together in a chain. These "hooks" are the
amino and carboxyl groups

16. The probe also discovers that the inner lining of your small intestine is covered with miniscule bumps called
villi

17. To contract, the myosin molecules have to break down an "energy carrier" molecule and use the energy released in order to change shape. This carrier molecule is
ATP

18. Passing out of the small intestine into the large intestine, the probe reports that the large intestine is absorbing ___ from digested food.
water

19. The picture at the right shows an onion root cell in the process of dividing. What phase is it in?
anaphase

20. The cell pictured above has already duplicated its DNA before it even began to divide. The part of its life in which a cell duplicates its DNA is the
S phase

21. If the cell above were destined to give rise to gametes (eggs or sperm) it would divide by
meiosis

22. Which of these is NOT a difference between DNA and RNA?
RNA is made of amino acids; DNA is made of nucleotides

23. Suppose that, despondent over your grade in this class, you slip the poison cyanide into your roommate's coffee, in the mistaken belief that you get a 4.0 average if your roommate dies. Cyanide blocks the activity of the electron transport chain. What would your roommate no longer be able to do?
make ATP in the mitochondria [But s/he could still make ATP by glycolysis, in the cytoplasm.]

24. Suppose that your roommate detected the cyanide in his or her coffee, and dumped it on the nearest potted plant. What part of photosynthesis might be affected directly?
light-dependent reactions [Because those also involve an electron transport chain!]

25. In the movie Star Wars: Episode I, the Jedi knight Qui-Gon Jinn tells young Anakin Skywalker that there are tiny symbiotic life forms called "midiclorions" living inside everyone's cells. These life forms give people the ability to use the Force. What was Qui-Gon really talking about, and what do your own "midiclorions" actually do?
mitochondria-carry out respiration

26. All of the following pieces of evidence support the theory that "midiclorions" evolved from symbiotic prokaryotes EXCEPT:
eukaryotes can't survive without midiclorions [Think: they can't survive without a cell membrane, either, but that doesn't mean that the cell membrane is a symbiont. . . And anyway, there are a few eukaryotes that do just fine without "midiclorions", a.k.a. mitochondria.]

27. Think of a single eukaryote cell as a metaphorical factory. What phrase best describes the function of the Golgi body?
"Packing and Shipping Department"

28. What phrase best describes the function of the rough ER?
"Assembly Line"

29. Hämmerling's experiments with the giant single-celled green alga Acetabularia, the "mermaid's parasol" or"mermaid's wineglass" alga, showed that
the nucleus contains hereditary information

30. The fluid part of blood, or filtrate, passes from the capillaries of the ___ into the ___ via Bowman's capsule.
glomerulus; loop of Henle

31. In hot weather, a plant has to close its stomata in order to keep from losing too much water. However, this causes _____ to build up in the leaves, which can result in an inefficient "short circuit" of photosynthesis known as _____________.
oxygen; photorespiration

32. Hemophilia is a genetic disease. An affected person's blood does not clot; such a person can bleed to death from a small cut. The gene for a common type of hemophilia is located on the X chromosome. We say that hemophilia is
sex-linked

33. The shape of the DNA molecule was ultimately worked out by
Watson and Crick

34. The protein insulin is made up of amino acids linked together as follows: methionine - alanine - leucine - tryptophan - methionine - histidine - leucine. . . This is insulin's
primary structure

35. Certain herbicides block the light-independent reactions of photosynthesis from happening, but leave the light-dependent reactions alone. What would a plant produce if it were treated with this herbicide and provided with water and light?
ATP, NADPH, and O₂

36. Suppose you woke up one morning lying in a hotel bathtub full of ice, with a dreadful ache in your lower back, and found a note telling you that your kidneys had been removed. Why would it be a really, really bad idea to react to this horrible news by drinking three liters of water?
You wouldn't be able to dispose of excess water.

37."Chargaff's Rule" states that, in any given sample of DNA, the amounts of

A=T and G=C

The diagram below depicts a certain process inside a eukaryotic cell. Use the diagram to answer questions 38-42.

38. What cellular structure is object #1?
nuclear membrane

39. What type of bonds are holding together the subunits that make up object #4?
peptide

40. What type of molecule is object #5?
transfer RNA

41. What is object #3? ribosome

42. What is the name for the entire process diagrammed above?
translation

43. What is the ultimate source of the electrons that plants use in photosynthesis?
water

44. In 1928, Fred Griffith showed that a harmless strain of pneumonia bacteria could be converted into a lethal strain, by means of
an unknown "transforming principle" [Remember, no one at the time knew that the "transforming principle" was DNA. Hershey and Chase, and also Oswald Avery and his team, were the ones who showed that, decades later.]

45. How many possible DNA triplet codons are there?
64

46. Rosalind Franklin showed that DNA was a helically-shaped molecule with certain dimensions, using the technique of
X-ray diffraction

47. In the graph at the right, what does x represent?
activation energy

48. Which property of phospholipids makes them able to form bilayer membranes?
They have hydrophilic "heads" and hydrophobic "tails."

49. Given the following sequence of bases on a strand of DNA:
GTAACGATTCCCATACG
Which of these base sequences represents a complementary strand of DNA?
CATTGCTAAGGGTATGC

50. Who wrote Beethoven's Ninth Symphony?
Ludwig van Beethoven