Which of the following is not a product of the Krebs cycle?

Correct Answer: B

Rationale: The correct answer is B: oxygen. Oxygen is not a product of the Krebs cycle. During the Krebs cycle, carbon dioxide, adenosine triphosphate (ATP), and energy carriers like NADH and FADH2 are produced. Carbon dioxide is a byproduct of the cycle, ATP is a form of energy produced, and energy carriers play a crucial role in transferring energy within the cell. Therefore, oxygen is the only option that is not a product of the Krebs cycle, making it the correct answer.

Correct Answer: A

Rationale: The correct answer is 'species.' In binomial nomenclature, the second part of an organism's scientific name represents its species. The species name is a unique identifier within the genus and helps differentiate between different organisms within the same genus. Choices B, C, and D are incorrect. Phylum is a taxonomic rank higher than species, population refers to a group of organisms of the same species living in the same area, and kingdom is a taxonomic rank higher than genus.

Correct Answer: B

Rationale: The correct answer is B: 'They are not water soluble.' Lipids are not water-soluble, which distinguishes them from other organic molecules. Choice A is incorrect because lipids are not indivisible; they can be broken down into fatty acids and glycerol. Choice C is incorrect as lipids do not necessarily contain zinc; they are a diverse group of molecules. Choice D is incorrect because lipids do not form long proteins; proteins are made up of amino acids, not lipids.

Correct Answer: A

Rationale: The correct answer is A: mitochondria. Mitochondria are not found in bacterial cells. Bacterial cells lack membrane-bound organelles like mitochondria, which are commonly found in eukaryotic cells. Choices B, C, and D are all components that can be found within a bacterial cell. Bacterial cells contain DNA as their genetic material, vesicles for various cellular functions, and ribosomes for protein synthesis. Therefore, the presence of mitochondria is the distinguishing factor that is not found in bacterial cells, making option A the correct answer.

Correct Answer: B

Rationale: The Golgi apparatus is the correct answer because it functions to transport materials from the endoplasmic reticulum throughout the cell. Ribosomes are responsible for protein synthesis, not transportation of materials. Lysosomes contain enzymes for digestion and waste removal, not for transporting materials. Vacuoles are primarily involved in storage, waste disposal, and maintaining turgor pressure, not in transporting materials from the endoplasmic reticulum.