Test Prep Test Prep Certifications OAT Questions & Answers

• Question 71:

  Organisms that utilize solar energy to exist are called:

  A. Apotrophic

  B. Autotrophic

  C. Heterotrophic

  D. Chemotrophic

  E. Mixotrophic

  Correct Answer: B

  Autotrophic organisms use sunlight as a source of energy (ex. plants). It is recommended one knows the basic definition of autotrophic, heterotrophic, chemotrophic etc. and examples of each.

• Question 72:

  Which of the following statements regarding chemiosmosis in mitochondria is not correct?

  A. ATP synthase is powered by protons flowing through membrane channels.

  B. Energy from ATP is used to transport protons to the intermembrane space.

  C. Energy from the electron transport chain is used to transport protons to the intermembrane space.

  D. An electrical gradient and a pH gradient both exist across the inner membrane.

  E. The waste product of chemiosmosis is water.

  Correct Answer: B

  Proteins in the inner membrane of the mitochondrion accept high-energy electrons from NAD and FADH2, and in turn transport protons from the matrix to the intermembrane space. The high proton concentration in the intermembrane space creates a gradient which is harnessed by ATP synthase to produce ATP.

• Question 73:

  Which of the following bonds requires the highest energy to denature in DNA?

  A. Adenine – Thymine

  B. Guanine – Adenine

  C. Cytosine – Guanine

  D. Adenine – Uracil

  E. All require equal strength

  Correct Answer: C

  Cytosine – Guanine bond is composed of a triple hydrogen bond. Adenine – Thymine is composed of a double hydrogen bond, thus taking less energy to break apart those 2 bonds. Adenine – Uracil is applicable to RNA. Adenine – Guanine does not occur in DNA.

• Question 74:

  Which of the following is true of enzymes?

  A. Enzymes effect the G' of a reaction.

  B. Enzymes effect the equilibrium of a reaction.

  C. Enzymes effect the activation energy of a reaction.

  D. A and C are true.

  E. All of the above are true.

  Correct Answer: C

• Question 75:

  Which of the following are not functions of bones in the human body?

  A. Movement

  B. Protection

  C. Hematopoiesis

  D. Reservoir of minerals

  E. All of the above are correct functions.

  Correct Answer: E

  Bone acts as levers in the body that conducts movement via the attached muscles. Bone also serves a protection function of internal organs (ex. skull protects the brain, vertebra protects the spinal cord). Hematopoiesis occurs in the bone marrow of the bone. Bone is also a reservoir of minerals as it contains approximately 99% of the body's calcium and 85% of the body's phosphorus.

• Question 76:

  A double-stranded DNA molecule consists of 20% Guanine. What percentage does Thymine represent in this stand?

  A. 20%

  B. 30%

  C. 40%

  D. 60%

  E. 80%

  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.

• Question 77:

  Which of the following paracrine signaling molecules increases gastric acid production in the stomach?

  A. Somatostatin

  B. Prostaglandins

  C. Histamine

  D. GIP

  E. None of the above

  Correct Answer: C

  Histamine induces gastric acid secretion in the stomach. Somatostatins inhibit gastric acid secretion, as does GIP.

• Question 78:

  Which of the following statements about pulmonary circulation is false?

  A. Pulmonary artery carries oxygen-rich blood from the right ventricle.

  B. It receives the entire cardiac output.

  C. It has low vascular resistance.

  D. Gas exchange occurs at capillaries on alveolar surface.

  E. Pulmonary vein carries oxygen-rich blood to the left atrium.

  Correct Answer: A

  The pulmonary artery is carrying oxygen-POOR blood from the right ventricle, going to the lungs to pick up oxygen, and continuing to the left atrium of the heart as the pulmonary vein.

• Question 79:

  Which of the following functions is the kidneys NOT responsible for?

  A. Excretion

  B. Tissue osmolarity homeostasis

  C. Producing hormones (endocrine function)

  D. Plasma pH homeostasis

  E. Kidney is responsible for all of the above.

  Correct Answer: E

  Kidney has functions in all of the answer choices.

• Question 80:

  A segment of DNA contains the following code: ATGGCGCCTTA. What would the sequence of its transcribed mRNA be?

  A. ATTCCGCGGTA

  B. TACCGCGGAAT

  C. UACCGCGGAAU

  D. AUCCGCGGAAT

  E. ATGGCGCCTTA

  Correct Answer: C