HESI A2
HESI A2 Biology Practice Test
1. Which of the following shows how information is transformed to make a protein?
- A. DNA-RNA-protein
- B. gene-chromosome-protein
- C. ATP-amino acid-protein
- D. RNA-DNA-protein
Correct answer: A
Rationale: The correct sequence of events for protein synthesis is that DNA is transcribed into RNA, which is then translated into a protein. This process is known as the central dogma of molecular biology. In this sequence, DNA serves as the template for RNA synthesis (transcription), and the RNA serves as the template for protein synthesis (translation). Choice B is incorrect as genes are segments of DNA that code for proteins, and chromosomes are structures that contain DNA. Choice C is incorrect as ATP is an energy molecule and amino acids are the building blocks of proteins, but they are not directly involved in the synthesis process. Choice D is incorrect because RNA is first transcribed from DNA and then used as a template to produce proteins.
2. Where is the ovary located in a flowering plant?
- A. Anther
- B. Pistil
- C. Stamen
- D. Calyx
Correct answer: B
Rationale: The ovary is located in the pistil of a flowering plant. The pistil is the female reproductive part of the flower, and it consists of the ovary, style, and stigma. The ovary contains ovules, which develop into seeds after fertilization. Choice A, 'Anther,' is incorrect because the anther is the part of the flower's stamen that produces pollen. Choice C, 'Stamen,' is incorrect because the stamen is the male reproductive part of the flower, consisting of the anther and filament. Choice D, 'Calyx,' is incorrect because the calyx is the outermost whorl of a flower, composed of sepals that protect the flower bud.
3. What happens during anaphase?
- A. Chromosomes move to opposite ends of the spindle.
- B. Nuclear membrane and nucleoli disintegrate.
- C. Chromatids line up at the center of the spindle.
- D. Nuclear membrane and nucleoli form.
Correct answer: A
Rationale: During anaphase, the sister chromatids, joined at the centromere, separate and move towards opposite ends of the spindle apparatus. This movement ensures that each daughter cell receives an identical set of chromosomes. Choice B is incorrect as the disintegration of the nuclear membrane and nucleoli occurs during prophase. Choice C is incorrect as chromatids align at the center of the spindle during metaphase, not anaphase. Choice D is incorrect as the formation of the nuclear membrane and nucleoli occurs during telophase, not anaphase.
4. What is the classification of organisms into different categories based on their physical characteristics and presumed natural relationship?
- A. Biology
- B. Taxonomy
- C. Grouping
- D. Nomenclature
Correct answer: B
Rationale: Taxonomy is the correct answer. Taxonomy is the branch of biology that deals with the classification of organisms into different categories based on their physical characteristics and presumed natural relationship. It involves naming and categorizing organisms into hierarchical groups to show their evolutionary relationships. Choice A, 'Biology,' is incorrect as it is the broader field of science that encompasses the study of living organisms. Choice C, 'Grouping,' is incorrect as it is a general term that does not specifically refer to the systematic classification of organisms. Choice D, 'Nomenclature,' is incorrect as it refers to the system of naming organisms rather than the classification based on physical characteristics and natural relationships.
5. Which structure controls the passage of substances into and out of the cell?
- A. Vacuole
- B. Cell Membrane
- C. Nuclear Membrane
- D. Cytoplasm
Correct answer: B
Rationale: The correct answer is the Cell Membrane. The cell membrane acts as a barrier that controls the passage of substances into and out of the cell. It is selectively permeable, allowing only certain molecules to pass through. Vacuole (Choice A), Nuclear Membrane (Choice C), and Cytoplasm (Choice D) do not primarily regulate the passage of substances in and out of the cell. Vacuoles are responsible for storage, the nuclear membrane surrounds the nucleus providing protection, and the cytoplasm is the fluid where organelles are suspended.
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