HESI A2
HESI A2 Practice Test Biology
1. During protein synthesis, what process uses an RNA strand to produce a complementary strand of DNA?
- A. Transcription
- B. Translation
- C. Transfer synthesis
- D. Codon synthesis
Correct answer: A
Rationale: The correct answer is 'Transcription.' During transcription, an RNA strand is used to produce a complementary strand of DNA. This process is essential for converting the genetic information stored in DNA into RNA. Choice B, 'Translation,' is incorrect as it involves the synthesis of proteins from mRNA. Choice C, 'Transfer synthesis,' is not a recognized term in molecular biology. Choice D, 'Codon synthesis,' is also incorrect as it does not refer to the process of using an RNA strand to produce a complementary DNA strand.
2. Genes control heredity in man and other organisms. This gene is ___
- A. A segment of DNA
- B. A bead-like structure on the chromosomes
- C. A protein molecule
- D. A segment of RNA
Correct answer: A
Rationale: Genes are sections of DNA that contain instructions for building and operating living organisms. These sections of DNA contain the genetic information that is passed on from one generation to the next. Genes are composed of specific sequences of nucleotides within the DNA molecule. Therefore, genes are best described as segments of DNA. Choice A is correct. Choice B is incorrect because genes are not bead-like structures on chromosomes but specific sequences of DNA. Choice C is incorrect because genes are not protein molecules but rather sequences of nucleotides. Choice D is incorrect because genes are not segments of RNA but DNA.
3. Which color of light is least effective at driving photosynthesis?
- A. Violet
- B. Green
- C. Orange
- D. Red
Correct answer: B
Rationale: Green light is the least effective at driving photosynthesis because chlorophyll, the primary pigment responsible for absorbing light in plants, does not absorb green light well. Instead, chlorophyll absorbs more effectively in the blue and red regions of the light spectrum. Therefore, green light is relatively less efficient in promoting photosynthesis compared to violet, orange, and red light. Violet light, although at the shorter wavelength end of the spectrum, can still drive photosynthesis better than green light. Orange and red light are more efficiently absorbed by chlorophyll, making them more effective in driving the process of photosynthesis.
4. Which component of the cell contributes to the protection, communication, and passage of substances into and out of the cell?
- A. Nucleus
- B. Cell membrane
- C. Endoplasmic reticulum
- D. Cytoplasm
Correct answer: B
Rationale: The correct answer is the cell membrane. The cell membrane is responsible for protecting the cell, facilitating communication with the external environment, and regulating the passage of substances into and out of the cell. The nucleus (Choice A) is the control center of the cell and houses the genetic material but is not primarily involved in these functions. The endoplasmic reticulum (Choice C) is involved in protein synthesis and lipid metabolism, not primarily in protection or communication. The cytoplasm (Choice D) is the gel-like substance that fills the cell but does not specifically contribute to protection, communication, or substance passage.
5. Within the biological hierarchical system of organization, which of the following is least inclusive?
- A. phylum
- B. order
- C. kingdom
- D. species
Correct answer: D
Rationale: The correct answer is 'D: species.' In the biological hierarchical system of organization, a species is the least inclusive level. A species consists of organisms that share similar characteristics and can interbreed to produce fertile offspring. On the other hand, a phylum, order, and kingdom are more inclusive classifications that encompass multiple species. Phylum groups together related classes, order groups together related families, and kingdom groups together related phyla. Therefore, species is the least inclusive category within the biological hierarchical system.
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