Nokea
What is the main component that gives bones their rigidity and hardness?
- A. Collagen
- B. Calcium phosphate
- C. Cartilage
- D. Ligaments
Correct Answer: B
Rationale: Calcium phosphate is the main component that gives bones their rigidity and hardness. It combines with calcium hydroxide to form hydroxyapatite crystals, which provide strength and structure to bones. Collagen, on the other hand, provides flexibility and tensile strength. Cartilage is a type of connective tissue found in joints, and ligaments are fibrous tissues that connect bones to other bones, but they do not contribute to the rigidity and hardness of bones.
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Which of the following is an example of a zoonotic disease?
- A. The common cold
- B. Influenza (the flu)
- C. Malaria
- D. HIV/AIDS
Correct Answer: B
Rationale: A zoonotic disease is a disease that can be transmitted from animals to humans. Influenza is an example of a zoonotic disease as it can be transmitted from animals such as birds and pigs to humans. The common cold (option A) is caused by human rhinoviruses and is not considered a zoonotic disease. Malaria (option C) is transmitted through the bite of infected mosquitoes and is not considered a zoonotic disease. HIV/AIDS (option D) is caused by the human immunodeficiency virus and is not considered a zoonotic disease.
What is the mass number of an element?
- A. The number of protons in an atom's nucleus.
- B. The number of neutrons in an atom's nucleus.
- C. The number of electrons in an atom's valence shell.
- D. The number of isotopes of an element.
Correct Answer: B
Rationale: The mass number of an element represents the total number of protons and neutrons in an atom's nucleus. It specifically focuses on the number of neutrons in an atom's nucleus, which contributes to the overall mass of the atom. Therefore, the mass number is not solely determined by the number of protons, electrons, or isotopes. Choice A is incorrect because it refers to the atomic number, which is the number of protons in an atom's nucleus. Choice C is incorrect as the number of electrons in the valence shell is related to the atom's reactivity and bonding behavior, not the mass number. Choice D is incorrect because the mass number does not represent the number of isotopes of an element, but rather the sum of protons and neutrons in an atom's nucleus. Thus, option B, the number of neutrons in an atom's nucleus, is the correct choice.
Antibodies, crucial for immune defense, are produced by:
- A. Neutrophils
- B. Lymphocytes
- C. Monocytes
- D. Basophils
Correct Answer: B
Rationale: Antibodies are produced by a specific type of lymphocyte known as B cells. B cells are a critical component of the adaptive immune system and are responsible for producing antibodies in response to pathogens. Neutrophils, monocytes, and basophils are types of white blood cells that are part of the innate immune response and do not have the function of producing antibodies. Neutrophils are primarily involved in phagocytosis, monocytes differentiate into macrophages and dendritic cells for antigen presentation, while basophils are involved in allergic reactions and parasitic infections.
Which of the following is a functional group commonly found in alcohols?
- A. Carbonyl
- B. Hydroxyl
- C. Amine
- D. Ester
Correct Answer: B
Rationale: The hydroxyl functional group (OH) is commonly found in alcohols, giving them their characteristic properties. Alcohols are organic compounds that contain a hydroxyl group bonded to a carbon atom. The other choices, carbonyl, amine, and ester, are associated with different functional groups commonly found in other types of organic compounds. Carbonyl groups consist of a carbon atom double-bonded to an oxygen atom. Amines contain a nitrogen atom bonded to hydrogen atoms. Esters consist of a carbonyl group bonded to an alkoxyl group. Therefore, the correct answer is 'Hydroxyl (B),' as it specifically relates to the functional group present in alcohols, distinguishing it from the other options.
Where in the cell are proteins modified, sorted, and packaged for transport?
- A. Ribosomes
- B. Golgi apparatus
- C. Endoplasmic reticulum (ER)
- D. Lysosomes
Correct Answer: B
Rationale: The Golgi apparatus is the cellular organelle responsible for modifying, sorting, and packaging proteins for transport within the cell or for secretion outside the cell. Ribosomes are not involved in modifying, sorting, or packaging proteins; they are responsible for protein synthesis. The endoplasmic reticulum (ER) is primarily involved in protein synthesis and folding, rather than modification and packaging for transport. Lysosomes function in breaking down cellular waste rather than modifying, sorting, or packaging proteins for transport.