Test Prep OAT Online Practice Questions and Exam Preparation

Test Prep OAT Online Questions & Answers

• Question 151:

  Which of the following possesses a cell wall?

  A. Plants
  B. Bacteria
  C. Fungi
  D. Protists
  E. All of the above
  E. All of the above

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  All of the answer choices do indeed a contain cell wall. The anatomy of the cell of various kingdoms should be known.

• Question 152:

  The reduction of an ester to an aldehyde can be done using which reagent?

  A. DIBALH
  B. Tri-t-butoxyaluminum hydride
  C. Lithium dialkylcuprate
  D. Phosphoylide (Wittig Reaction)
  E. Heat
  A. DIBALH

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  Addition of DIBALH (diisobutylaluminum hydride) indeed reduces an ester to an aldehyde. You should be familiar with all these reagents and know the effects they do to various reagents.

• Question 153:

  Leaves have parallel veins:

  A. Monocots
  B. Nonvascular plants
  C. Gymnosperms
  D. Dicots
  E. Angiosperms
  A. Monocots

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  Monocots differ from dicots in that they have one cotyledon, or embryonic leaf in their embryos. They also have parallel veination, fibrous roots, petals in multiples of three, and a random arrangement of vascular bundles in their stems.

• Question 154:

  A manometer filled with mercury has a higher pressure on the open end, with a difference of 380 mm in the height of the fluid. What is the pressure of the gas in there?

  A. 100,000 Pa
  B. 75,000 Pa
  C. 50,000 Pa
  D. 25,000 Pa
  E. Cannot be determined.
  C. 50,000 Pa

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  In manometers filled with mercury (Hg), the difference in height of the fluid is equivalent to the difference in pressure. There is a difference in 380 mmHg between the pressure inside and outside, which is half of the atmospheric pressure of 760 mmHg, or 1 atm. 1 atm is roughly 100,000 Pa, so the pressure inside is 50,000 Pa.

• Question 155:

  Which of the following holds the greatest bond energy?

  A. HCl
  B. O2
  C. Br2
  D. CN
  E. OH
  D. CN

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  In general, triple bonds > double bonds > single bonds in bond energies. CN is linked via a triple bond: C N

• Question 156:

  Identify the incorrect pairing of hormone to site of secretion:

  A. Glucagon – alpha cells
  B. Angiotensinogen – liver
  C. GnRH – anterior pituitary
  D. TRH – hypothalamus
  E. Oxytocin – posterior pituitary
  C. GnRH – anterior pituitary

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  GnRH is releases from the hypothalamus, not the anterior pituitary.

• Question 157:

  An mRNA strand has the following sequence: 5' CUAUUG 3'. Identify the DNA coding strand:

  A. 5' CAATAG 3'
  B. 5' GAUAAC 3'
  C. 5' CTATTG 3'
  D. 5' CUAUUG 3'
  E. 5' CGCTTA 3'
  C. 5' CTATTG 3'

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  The coding strand is the DNA strand that is not transcribed into mRNA. The coding strand is identical to the mRNA strand, except with T's instead of U's. The template strand (choice 5' CAATAG 3') is what gets transcribed into mRNA. Understand the difference between coding and template strands as well as base-pair rules.

• Question 158:

  Which statement best explains why the work done by a gravitational force on an object does not depend on the path the object takes?

  A. Work depends on the path when there is friction. The longer the path the more energy is required to overcome friction.
  B. Gravitational fields that arise from the interaction between point masses always produce elliptical paths of motion.
  C. A falling object experiences a change in potential energy.
  D. When an object falls down the work done by gravity is positive and when an object is thrown up the work done by gravity is negative.
  C. A falling object experiences a change in potential energy.

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  To determine how much work is done by a gravitational force, you should calculate the change in that object's potential energy = mgh, where m = mass, g = the gravitational acceleration 9.8 m/s2 and h = height. Therefore, the work done only depends on the change in height and not on the path taken. In Answer [Work depends on the path when...], the work done by gravity doesn't have anything to do with friction, so this is not a good explanation. Friction is a separate force. Answer [When an object falls down...], although true, doesn't explain why the work doesn't depend on the path.

• Question 159:

  Which of the following has the higher acidity?

  

  A. Option A
  B. Option B
  C. Option C
  D. Option D
  E. Option E
  C. Option C

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  In phenols, the closer the substituent is to the OH, the stronger the acid (O > M > P). Same applies to electronegative: the more electronegative the halogen is, the stronger the acid (ex. F > Cl > Br). Thus, C is the more electronegative and closer substituent to the OH, making it the more acidic ph.

• Question 160:

  What is the percent composition of potassium in potassium dichromate?

  A. 26.5%
  B. 35.4%
  C. 33.3%
  D. 38.1%
  E. Cannot be determined.
  A. 26.5%

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  The molecular formula of potassium dichromate is K2Cr2O7. To find the percent composition, calculate the weight of the entire molecule:

  (2 × 39 g/mol) + (2 × 52 g/mol) + (7 × 16 g/mol) = 294 g/mol

  Then divide the weight of the potassium in the molecule by the entire molecular weight:

  (2 × 39 g/mol) / 294 g/mol = 0.265

  Multiply ×100 to produce the percentage value: 0.265 × 100 = 26.5%