OAT Online Practice Questions and Answers

Correct Answer: D

Since this is a head-on elastic collision, you could use conservation of kinetic energy and momentum to actually solve this problem. However, in this case, you only need to think through the answers to arrive at a correct conclusion. Clearly the ball after it's struck won't be going 0 m/s. And since this is an elastic collision, and it is hit by a much larger ball, it must be going faster than the larger ball was originally moving. Therefore, the ball will be moving at more than 10 m/s. If this were an inelastic collision where the balls stuck together, the ball would final velocity would be less than 10 m/s.

Correct Answer: A

Begin by finding a common base root. Left side is 31(x − 3); right is 32(3x − 7). The 3's cancel out on both sides, and you have: 1(x − 3) = 2(3x − 7). Simplifying gives:

x – 3 = 6x − 14 −3 = 5x − 14 11 = 5x x = 2.2

Correct Answer: E

All of the above are accurate statements.

Correct Answer: D

Helicase is an enzyme that functions in unpackaging or separating 2 things (e.x. DNA strands).

Correct Answer: A

This is the most correct answer choice.

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.

Correct Answer: C

The gastrula is formed from the blastocyst, which contains a bilayered embryonic disc. One layer of this disc's inner cell mass further subdivides into the epiblast and the hypoblast, resulting in the three primary germ layers (endoderm, mesoderm, ectoderm).

Correct Answer: B

Guanine pairs up with Cytosine. So, if 20% of the DNA stand is Guanine, it means 20% of it is Cytosine. Thus, the 60% left is made up of Adenine and Thymine. Since Adenine pairs up with Thymine, it must be evenly split into 30:30. Thus, 30% is composed of Thymine.

Correct Answer: B

Understanding how to solve these type of problems where a benzene has various substituents that alter its pH depends on understanding electron-withdrawing substituents (fluorine and chlorine) and electron-donating substituents (hydroxyl and methyl, with the former being more powerful). The electron-donating substituents destabilize the nitrogen's lone pair of electrons, thus increasing its reactivity and making it more basic (less acidic).

Correct Answer: D

This is a Wolff-Kishner reaction, that basically removes a carbonyl, leaving a methylene. Know the reaction itself and the name.