Nokea
Which of the following is an example of an aromatic compound?
- A. Ethanol
- B. Toluene
- C. Acetone
- D. Butanal
Correct Answer: B
Rationale: Toluene is an aromatic compound due to its benzene ring structure, which satisfies the criteria of aromaticity. Aromatic compounds contain conjugated pi electrons in a ring structure, providing extra stability. Ethanol, acetone, and butanal are not aromatic compounds as they do not possess a benzene ring or meet the aromaticity criteria. Ethanol is an alcohol, acetone is a ketone, and butanal is an aldehyde, none of which have the characteristic benzene ring structure of aromatic compounds.
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Which of the following is a common property of bases?
- A. Conductivity in aqueous solutions
- B. Sour taste
- C. Reactivity with metals to produce hydrogen gas
- D. Turns red litmus paper blue
Correct Answer: D
Rationale: Bases are substances that can accept protons or donate hydroxide ions in a chemical reaction. One common property of bases is that they turn red litmus paper blue. This is a classic test to distinguish between acids (which turn blue litmus paper red) and bases. Conductivity in aqueous solutions (Option A) is a property of both acids and bases, but not unique to bases alone. Sour taste (Option B) is a property commonly associated with acids, not bases. Reactivity with metals to produce hydrogen gas (Option C) is a property of acids, particularly strong acids, but not bases.
What is the term for the tiny particles that make up atoms?
- A. Protons
- B. Electrons
- C. Neutrons
- D. Subatomic particles
Correct Answer: D
Rationale: The correct answer is 'Subatomic particles.' Subatomic particles are the tiny components that constitute atoms, including protons, neutrons, and electrons. Protons and neutrons are located in the nucleus of an atom, while electrons revolve around the nucleus. Choices A, B, and C specifically refer to individual subatomic particles but do not encompass the complete range of particles within an atom.
Cartilage is a flexible connective tissue found in the:
- A. Center of long bones
- B. Joints between bones
- C. Muscle tissue
- D. Walls of blood vessels
Correct Answer: B
Rationale: Cartilage is a flexible connective tissue found in the joints between bones. It provides cushioning and support for the bones, allowing smooth movement and reducing friction between them. Cartilage acts as a shock absorber and helps maintain the structural integrity of the joints. Choices A, C, and D are incorrect because cartilage is not typically found in the center of long bones, muscle tissue, or the walls of blood vessels. Cartilage primarily functions in providing structural support and flexibility in joints.
What is the building block of RNA?
- A. Amino acid
- B. Nucleotide
- C. Protein
- D. Fatty acid
Correct Answer: B
Rationale: Nucleotide: Nucleotides are the building blocks of RNA. A nucleotide consists of a nitrogenous base (adenine, guanine, cytosine, or uracil in RNA), a sugar (ribose in RNA), and a phosphate group. A) Amino acid: Amino acids are the building blocks of proteins, not RNA. C) Protein: Proteins are made up of amino acids, not nucleotides. D) Fatty acid: Fatty acids are components of lipids, not RNA.
In the context of cholesterol levels, LDL cholesterol is often referred to as:
- A. HDL or "good" cholesterol.
- B. LDL or "bad" cholesterol.
- C. Total cholesterol, encompassing both LDL and HDL.
- D. VLDL, a type of triglyceride transported in the bloodstream.
Correct Answer: B
Rationale: LDL cholesterol is often referred to as "bad" cholesterol because high levels of LDL can lead to plaque buildup in the arteries, increasing the risk of heart disease and stroke. LDL cholesterol is considered harmful as it contributes to the formation of plaque in blood vessels, whereas HDL cholesterol helps remove LDL from the arteries. Choice A is incorrect because HDL is known as "good" cholesterol, which helps remove LDL cholesterol from the bloodstream. Choice C is incorrect as it refers to total cholesterol, which includes LDL, HDL, and other lipids. Choice D is incorrect as VLDL is a different type of lipoprotein that carries triglycerides and is not specifically related to LDL cholesterol.