14. The physiologist J. Soum surgically sealed off an air sac of a pigeon and injected carbon monoxide into it. What did he observe and conclude from this experiment?
(A) The bird died demonstrating the toxicity of this gas.
(B) The bird was fine, demonstrating this gas is not actually toxic.
(C) The bird died, indicating diffusion of gases across the air sac into the blood.
(D) The bird showed no ill effects, indicating diffusion of gases from the air sac into the blood.
(E) The bird showed no ill effects, indicating gases do not diffuse from the air sac into the blood.

10. Why is there a need to produce Okazaki fragments on the lagging strand, but NOT on the leading strand of DNA? (A) It is substantially more efficient to make several shorter strands rather than one longer strand of DNA. (B) The two parental strands of DNA are antiparallel and DNA polymerase makes DNA in the 5’ to 3’ direction only. (C) There lacks enough DNA ligase for bonding Okazaki fragments together if they were produced from both parental strands. (D) By having one leading strand and one lagging strand the cell can limit the amount of DNA polymerase used for chromosomal replication. (E) It is faster to make several smaller fragments than one larger fragment.

11. When observing the skeleton of a snake, you see the remains of hip and hind leg bones associated with four legged animals. These bones are called (A) convergent traits. (B) vestigial structures. (C) homologous structures. (D) analogous structures. (E) both homologous and analogous structures.

12. The group of protists to which humans are most closely related is: (A) Rhizaria. (B) the choanoflagellates. (C) slime molds. (D) Foraminifera. (E) Stramenopila.

13. Which of the following is NOT a defining trait of the phylum Chordata? (A) notochord (B) dorsal hollow nerve cord (C) pharyngeal slits (D) post anal tail (E) protostome development

15. Humans cannot survive at sea by drinking salt water. However, marine vertebrates such as sea turtles and various sea birds can survive by drinking salt water. What DO they have that humans DO NOT? (A) kidneys that are extremely good at producing a concentrated urine. (B) body fluid concentrations that are similar to or greater than those of seawater. (C) the ability to secrete salts and wastes into their intestinal contents like an insect. (D) They use ammonia as their primary nitrogenous waste. (E) salt glands.

16. Which of the following is NOT a feature of apoptosis? (A) formation of apoptotic body (B) DNA fragmentation (C) cell swelling (D) activation of caspases (E) release of cytochrome C from mitochondria

17. A nonsense suppressor tRNA may have the anticodon (A) 5'-CAU-3' (B) 5'-UAA-3' (C) 5'-UUA-3' (D) 5'-CCC-3' (E) 5'-UAG-3'

18. Which of the following accurately gives the distribution of phenotypes produced from a cross of purple dwarf pea plants that are heterozygous for flower color and plant height? (A) 27 purple dwarf; 28 purple tall; 31 white dwarf; 29 white tall (B) 63 purple dwarf; 28 purple tall; 27 white dwarf; 7 white tall (C) 132 purple dwarf; 138 white tall (D) 54 purple dwarf; 6 white tall (E) 100% purple dwarf

19. Which of the following components and conditions increases membrane fluidity? (A) phospholipids with long, saturated fatty acyl chains (B) phospholipids with short, unsaturated fatty acyl chains (C) lower temperatures (D) cholesterol at the usual concentrations found in biomembranes (E) lipid rafts

20. A 400-bp covalently closed circular DNA with a linking number of 35 has 5 negative supercoils. When the linking number of this DNA is changed to 38 by a topoisomerase, this DNA will have (A) 3 positive supercoils. (B) 3 negative supercoils. (C) 2 positive supercoil. (D) 2 negative supercoils. (E) relaxed.