Test Prep Test Prep Certifications OAT Questions & Answers

• Question 91:

  In ferns, the joining of egg and sperm produces a zygote, which will grow into the:

  A. Gametophyte

  B. Sporophyte

  C. Seedling

  D. Sporangium

  E. Spore

  Correct Answer: B

  In ferns, the mature diploid plant is called a sporophyte. Sporophytes undergo meiosis to produce spores, which develop into gametophytes, which produce gametes.

• Question 92:

  Cyanide is a poison that binds to the active site of the enzyme cytochrome c and prevents its activity. Cyanide is a(n)

  A. Prosthetic group

  B. Cofactor

  C. Reverse regulator

  D. Coenzyme

  E. Inhibitor

  Correct Answer: E

  Enzyme inhibitors attach to an enzyme and block substrates from entering the active site, thereby preventing enzyme activity. As stated in the question, cyanide is a poison that irreversibly binds to an enzyme and blocks its active site, thus fitting the definition of an enzyme inhibitor.

• Question 93:

  In photosynthesis, high-energy electrons move through electron transport chains to produce ATP and NADPH. Which of the following provides the energy to create high energy electrons?

  A. O2

  B. Light

  C. Water

  D. NADP+

  E. NADH

  Correct Answer: B

  Electrons trapped by the chlorophyll P680 molecule in photosystem II are energized by light. They are then transferred to electron acceptors in an electron transport chain.

• Question 94:

  Which of the following molecules is thought to have acted as the first enzyme in early life on earth?

  A. Protein

  B. RNA

  C. Triglycerides

  D. Phospholipids

  E. DNA

  Correct Answer: B

  Some RNA molecules in extant organisms have enzymatic activity; for example, the formation of peptide bonds on ribosomes is catalyzed by an RNA molecule. This and other information have led scientists to believe that the most likely molecules to first demonstrate enzymatic activity were RNA molecules.

• Question 95:

  The breakdown of a disaccharide releases energy which is stored as ATP. This is an example of a(n):

  A. Thermodynamic reaction

  B. Exothermic reaction

  C. Combination reaction

  D. Replacement reaction

  E. Endothermic reaction

  Correct Answer: B

  An exothermic reaction releases energy, whereas an endothermic reaction requires energy. The breakdown of a chemical compound is an example of a decomposition reaction (AB ?gt; A + B). A combination reaction (A + B ?gt; AB) is the reverse of a decomposition reaction, and a replacement (displacement) reaction is one where compound breaks apart and forms a new compound plus a free reactant (AB + C ?gt;AC + B or AB + CD ?gt; AD + CB).

• Question 96:

  Which of the following hormones is released by the posterior pituitary?

  A. FSH

  B. LH

  C. Oxytocin

  D. ACTH

  E. Prolactin

  Correct Answer: C

  All the other hormones in the answer choices are hormones of the anterior pituitary.

• Question 97:

  An optometrist examines a patient's eyes and discovers high pressure associated with the aqueous humor. These symptoms are closely associated with...

  A. Myopia

  B. Hyperopia

  C. Cataract

  D. Glaucoma

  E. Astigmatism

  Correct Answer: D

  Myopia is nearsightedness and Hyperopia is farsightedness, both in relation to the image and the retina. Astigmatism is caused by an irregular shape of the cornea and finally Cataracts is cloudiness in the lens. Glaucoma is the increased pressure in the eye.

• Question 98:

  Eukaryotes undergoing aerobic respiration yield how much ATP per glucose molecule?

  A. 2

  B. 4

  C. 36

  D. 38

  E. 40

  Correct Answer: C

  Eukaryotes produce 36 ATP per glucose molecule via aerobic respiration. 4 are produced via substrate-level phosphorylation and 32 ATP are produced via oxidative phosphorylation. Prokaryotes on the other hand yield 38 ATP.

• Question 99:

  Which of the following is the IUPAC name of this compound?

  

  A. 8-Bromo-6,6-diethyldecane

  B. 5-Bromo-3-ethyl-5-pentylheptane

  C. 1-Bromo-1,3,3-triethyloctane

  D. 3-Bromo-5,5-diethyldecane

  E. 3-Bromo-5,5-diethyldec-5-ene

  Correct Answer: D

  Nomenclature rules states that:

  1) Find the longest and continuous chain

  2) Number the carbons starting at the side with the closest substituent

  3) In listing the substituents, list them in alphabetical order.

• Question 100:

  A dog learns that if it does not bite its bone toy, it will receive treats. This example is best categorized under:

  A. Positive reinforcement

  B. Negative reinforcement

  C. Positive punishment

  D. Negative punishment

  E. Extinction

  Correct Answer: B

  Negative reinforcement relates the lack of an action or behavior with a reward (in this case, the lack of biting the toy). If it was positive reinforcement, the scenario would have the dog receiving a treat for biting the toy.