HESI A2 Biology Practice Test

Correct Answer: B

Rationale: Correct Answer: B - Glycolysis occurs in the presence of Oxygen. Rationale: 1. Glycolysis is the initial step in cellular respiration and takes place in the cytoplasm of cells. 2. It does not require oxygen to start but can occur in both aerobic and anaerobic conditions. 3. In the presence of oxygen, the pyruvate produced from glycolysis can enter the citric acid cycle for further ATP production. Summary: A: Incorrect - Glycolysis can occur in the presence of oxygen. C: Incorrect - Fermentation is a separate process from glycolysis. D: Incorrect - Anaerobic respiration involves further steps after glycolysis.

Correct Answer: B

Rationale: Thymine is not present in RNA because thymine is a pyrimidine base found in DNA instead of RNA. RNA contains uracil as its complementary base to adenine, while DNA contains thymine. Adenine, uracil, and cytosine are all present in RNA, making them incorrect choices. Thymine is the only base not present in RNA, making option B the correct answer.

Correct Answer: B

Rationale: Enzymes are typically proteins because they are biological catalysts made up of amino acids. Proteins have specific structures that allow them to bind to substrates and speed up chemical reactions. Fats, sugars, and neurons do not possess the specific structural properties required for enzyme function. Therefore, the correct answer is B (Proteins).

Correct Answer: B

Rationale: Failed to generate a rationale after 5 retries.

Correct Answer: B

Rationale: The correct answer is B: Troposphere, stratosphere, mesosphere, thermosphere, exosphere. Rationale: 1. Troposphere: Closest to the Earth's surface where weather occurs. 2. Stratosphere: Contains the ozone layer, which absorbs UV radiation. 3. Mesosphere: Middle layer where meteors burn up. 4. Thermosphere: Upper layer with high temperatures and auroras. 5. Exosphere: Outermost layer where atmosphere transitions to space. Summary: A: Incorrect order, starts with exosphere which is the outermost layer. C: Incorrect order, mesosphere is placed before troposphere. D: Incorrect order, thermosphere comes before troposphere.