HESI A2 Practice Test Biology

Correct Answer: A

Rationale: The correct answer is A: mitochondria. Bacterial cells do not contain mitochondria because they are prokaryotic cells, lacking membrane-bound organelles like mitochondria. Mitochondria are found in eukaryotic cells and are responsible for producing energy in the form of ATP through cellular respiration. The other choices - DNA, vesicles, and ribosomes - are all present in bacterial cells. DNA is the genetic material, vesicles are involved in transport, and ribosomes are responsible for protein synthesis.

Correct Answer: C

Rationale: The correct answer is C: ribosome. Ribosomes are the organelles responsible for organizing protein synthesis. They are the site where proteins are assembled based on instructions from the cell's DNA. Ribosomes can be found in the cytoplasm and on the endoplasmic reticulum. Mitochondria (A) are responsible for energy production, the nucleus (B) contains genetic material but does not directly organize protein synthesis, and vacuoles (D) are primarily involved in storage and maintaining cell structure. Therefore, the ribosome is the only organelle directly involved in protein synthesis among the choices provided.

Correct Answer: B

Rationale: The correct answer is B: Sexual reproduction and asexual reproduction. Sexual reproduction involves the fusion of gametes from two parents to create offspring with genetic variation. Asexual reproduction involves a single parent producing genetically identical offspring. Option A is incorrect because binary fission is a form of asexual reproduction, not sexual reproduction. Option C is incorrect because binary fission is a specific type of asexual reproduction, not the only category. Option D is incorrect because mitosis is a cell division process within asexual reproduction, but it is not a category of cell reproduction on its own.

Correct Answer: D

Rationale: The correct answer is D: DNA. DNA is not directly involved in translation. Translation is the process of synthesizing proteins from mRNA using tRNA and ribosomes. DNA serves as the template for transcription, where mRNA is synthesized. Once mRNA is formed, it carries the genetic information from DNA to the ribosome for translation. tRNA brings in amino acids based on the codons on the mRNA, and the ribosome facilitates the assembly of amino acids into a polypeptide chain. Therefore, DNA is not directly involved in the actual process of translation, making it the correct answer.

Correct Answer: A

Rationale: The second part of an organism's scientific name is the species. In binomial nomenclature, developed by Carl Linnaeus, the scientific name consists of two parts: the genus and the species. The genus is the broader category that encompasses multiple species, while the species is the specific name unique to that particular organism within the genus. Therefore, the correct answer is A: species. Option B: phylum is incorrect as it is a higher taxonomic rank above the genus and species. Option C: population is incorrect as it refers to a group of organisms of the same species in a particular area. Option D: kingdom is incorrect as it is the highest taxonomic rank, encompassing all living organisms categorized into five kingdoms.