Phagocytosis is not a characteristic of which groups?

Correct Answer: D

Rationale: Phagocytosis is a process where cells engulf and digest particles. Archaea lack membrane-bound organelles, including phagosomes, making phagocytosis impossible. Protozoans, algae, and fungi have the necessary cellular structures for phagocytosis. Therefore, the correct answer is D. Protozoans, algae, and fungi can perform phagocytosis due to their cellular structure and function, making choices A, B, and C incorrect.

Correct Answer: B

Rationale: The correct answer is B: cell walls. Microorganisms, such as bacteria and archaea, do not have mitochondria or chloroplasts. ATP synthesis in microorganisms primarily occurs in the cell walls through processes like glycolysis and fermentation. Cytoplasmic membranes are involved in electron transport and ATP synthesis in prokaryotic cells, not cell walls. Chloroplasts are only present in photosynthetic organisms, not in microorganisms.

Correct Answer: A

Rationale: Rationale: A: Emphysema is characterized by the destruction of alveolar walls and loss of elasticity of the lungs, leading to air trapping and difficulty exhaling. This results in reduced gas exchange and airflow limitation. B: Bronchospasms are more commonly associated with conditions like asthma, not emphysema. C: Abnormal growth of epithelial cells is seen in conditions like lung cancer, not emphysema. D: Excessive mucus production is characteristic of conditions like chronic bronchitis, not emphysema. Summary: The correct answer is A because emphysema specifically involves the loss of elasticity of the lungs due to destruction of alveoli, leading to impaired airflow. Choices B, C, and D are incorrect as they describe features more indicative of other respiratory conditions.

Correct Answer: A

Rationale: The correct answer is A because a codon is a triplet of nucleotides in mRNA that corresponds to a specific amino acid during protein synthesis. To be a codon, the triplet must be in the same reading frame as the start codon (AUG) to maintain the correct reading of the genetic code. Choice B is incorrect because codons are typically consecutive in mRNA. Choice C is incorrect as tRNA sequences are not codons. Choice D is incorrect because all codons correspond to specific amino acids.

Correct Answer: D

Rationale: The correct answer is D: Recombinant DNA. Recombinant DNA refers to the DNA molecule formed by combining DNA from different sources. In genetic engineering, this is created by inserting a foreign DNA fragment into a vector DNA, resulting in a new DNA molecule. Plasmid DNA (A) is a small, circular DNA found in bacteria. Vector DNA (B) is a carrier molecule used to transport foreign DNA into a host cell. Insert DNA (C) is the DNA fragment that is inserted into a vector. Therefore, choice D is the correct answer as it specifically refers to the combined DNA molecule formed in genetic engineering.