Nokea
What is the function of ribosomes?
- A. Packaging and transporting proteins
- B. Storing genetic material
- C. Controlling cell division
- D. Synthesizing proteins
Correct Answer: D
Rationale: The correct answer is D: Synthesizing proteins. Ribosomes are cellular organelles responsible for protein synthesis. They read the messenger RNA (mRNA) and utilize the information to assemble amino acids into proteins through a process known as translation. Choice A, packaging and transporting proteins, is incorrect as this function is typically performed by the Golgi apparatus and vesicles. Choice B, storing genetic material, is incorrect as genetic material is usually stored in the nucleus in the form of DNA. Choice C, controlling cell division, is incorrect as this function is primarily regulated by the cell cycle checkpoints and specific proteins involved in cell cycle regulation.
You may also like to solve these questions
During antibiotic use, bacteria can evolve resistance. This is an example of:
- A. Coevolution (two species influencing each other's evolution)
- B. Convergent evolution (unrelated organisms evolving similar traits)
- C. Macroevolution (large-scale evolutionary change)
- D. Artificial selection acting on a natural process
Correct Answer: D
Rationale: The process of bacteria evolving resistance to antibiotics due to the selective pressure exerted by the antibiotics is an example of artificial selection (human intervention selecting for certain traits) acting on a natural process (bacterial evolution). Antibiotic use creates a selective pressure that favors the survival and reproduction of bacteria with resistance traits, leading to the evolution of antibiotic-resistant strains.
- Coevolution (option A) refers to the influence of two species on each other's evolution, which is not the case in the scenario described in the question.
- Convergent evolution (option B) involves unrelated organisms evolving similar traits due to similar environmental pressures, which is not directly applicable to the situation of bacteria evolving resistance to antibiotics.
- Macroevolution (option C) refers to large-scale evolutionary changes over long periods, which is not specifically demonstrated in the context of bacteria evolving resistance during antibiotic use.
Which type of white blood cell directly attacks and destroys pathogens like bacteria and viruses?
- A. Neutrophils
- B. Lymphocytes
- C. Monocytes
- D. Eosinophils
Correct Answer: A
Rationale: Neutrophils are a type of white blood cell that plays a crucial role in the immune system's response to infections. They are phagocytes, meaning they engulf and destroy pathogens like bacteria and viruses. Neutrophils are the most abundant type of white blood cell and are known for their rapid response to infections, making them the primary cell type that directly attacks and destroys pathogens. Lymphocytes, although important in adaptive immunity, are not primarily responsible for directly attacking and destroying pathogens. Monocytes are involved in phagocytosis and immune response regulation but are not the primary cell type for direct pathogen destruction like neutrophils. Eosinophils are mainly involved in combating multicellular parasites and are not the primary cell type for targeting bacteria and viruses.
Salts are formed by the reaction between:
- A. Two acids
- B. An acid and a base
- C. Two bases
- D. A metal and a nonmetal only
Correct Answer: B
Rationale: Salts are formed by the reaction between an acid and a base. This reaction is known as a neutralization reaction. In this reaction, the acid donates a proton (H+) to the base, resulting in the formation of water and a salt as the products. Choice A is incorrect because salts are not formed by the reaction of two acids. Choice C is incorrect as salts are not produced by the reaction of two bases. Choice D is incorrect because while salts can be formed from the reaction between a metal and a nonmetal, it is not the only way salts are produced.
Which of the following is NOT a common symptom of lactose intolerance?
- A. Gas
- B. Bloating
- C. Diarrhea
- D. Nausea
Correct Answer: D
Rationale: A) Gas: Gas is a common symptom of lactose intolerance. When lactose is not properly digested, it can ferment in the colon, leading to the production of gas.
B) Bloating: Bloating is another common symptom of lactose intolerance. The buildup of gas in the digestive system can cause bloating and discomfort.
C) Diarrhea: Diarrhea is a common symptom of lactose intolerance. When lactose is not broken down in the small intestine, it can draw excess water into the colon, resulting in diarrhea.
D) Nausea: Nausea is not a common symptom of lactose intolerance. While some individuals may experience mild stomach discomfort or cramps, nausea is not typically associated with lactose intolerance.
What is the net ionic equation for the reaction: 2HCl(aq) + Ba(OH)2(aq) → 2H2O(l) + BaCl2(aq)?
- A. 2H+(aq) + 2OH-(aq) → 2H2O(l)
- B. 2HCl(aq) + Ba(OH)2(aq) → BaCl2(aq) + 2H2O(l)
- C. 2H+(aq) + Ba2+(aq) → Ba2+(aq) + 2H+(aq)
- D. Ba(OH)2(aq) + HCl(aq) → BaCl2(aq) + 2H2O(l)
Correct Answer: A
Rationale: In the given reaction, the complete ionic equation is: 2H+(aq) + 2Cl-(aq) + Ba2+(aq) + 2OH-(aq) → 2H2O(l) + Ba2+(aq) + 2Cl-(aq). Spectator ions (Ba2+ and Cl-) do not participate in the net ionic equation, which simplifies to: 2H+(aq) + 2OH-(aq) → 2H2O(l). This equation represents the significant species involved in the reaction, showcasing the formation of water from the combination of hydrogen ions and hydroxide ions, resulting in the production of water molecules.