Nokea
What is the name for the hard, protective protein that makes up hair and nails?
- A. Collagen
- B. Keratin
- C. Elastin
- D. Fibrin
Correct Answer: B
Rationale: Keratin is the correct answer as it is the hard, protective protein that comprises hair and nails. Collagen is a different type of protein found in connective tissues, providing structure and support. Elastin imparts elasticity to tissues, allowing them to stretch and recoil. Fibrin is a protein involved in the blood clotting process and is not related to the structure of hair and nails. Therefore, choices A, C, and D are incorrect in the context of the question.
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Who is credited with the discovery of nuclear fission?
- A. Marie Curie
- B. Albert Einstein
- C. Enrico Fermi
- D. Ernest Rutherford
Correct Answer: C
Rationale: Enrico Fermi is credited with the discovery of nuclear fission. In 1934, Fermi bombarded uranium with neutrons, leading to the splitting of the uranium nucleus and the release of energy. This groundbreaking discovery laid the foundation for the development of nuclear power and weapons. Marie Curie is known for her pioneering research on radioactivity, but she did not discover nuclear fission. Albert Einstein made significant contributions to physics, including the theory of relativity, but he was not credited with the discovery of nuclear fission. Ernest Rutherford conducted the famous gold foil experiment and made contributions to the understanding of the atom's structure, but he did not discover nuclear fission.
What is the functional group present in aldehydes?
- A. Hydroxyl
- B. Carbonyl
- C. Ester
- D. Amine
Correct Answer: B
Rationale: The correct answer is B: Carbonyl. Aldehydes contain the functional group -CHO, which is a carbonyl group where a carbon atom is double-bonded to an oxygen atom and single-bonded to a hydrogen atom. This distinguishes aldehydes from other functional groups. Choice A, Hydroxyl (-OH), is not characteristic of aldehydes as it is found in alcohols. Choice C, Ester (-COOR), and choice D, Amine (-NH2), represent different functional groups not typically found in aldehydes. Therefore, the correct functional group present in aldehydes is the carbonyl group.
What is the technical term for the free edges of your fingernails and toenails?
- A. Lunula (The lunula is the white crescent moon shape at the base of the nail)
- B. Matrix (The matrix is the area under the nail where new nail cells are produced)
- C. Hyponychium (This is the skin under the free edge of the nail)
- D. Free edge
Correct Answer: C
Rationale: The correct answer is C, hyponychium. The hyponychium is the skin under the free edge of the nail, responsible for sealing the nail to the fingertip and protecting the nail bed from bacteria and debris. The lunula (choice A) refers to the white crescent moon shape at the base of the nail. The matrix (choice B) is the area under the nail where new nail cells are produced. The free edge (choice D) is the part of the nail that extends beyond the fingertip or toe.
Which of the following is the smallest part of an element that can still be recognized as that element?
- A. Electron
- B. Proton
- C. Neutron
- D. Atom
Correct Answer: D
Rationale: An atom is the smallest unit of matter that retains the chemical properties of an element. It consists of a nucleus containing protons and neutrons, surrounded by electrons that orbit the nucleus. The number of protons in the nucleus defines the atomic number of the element, and the number of neutrons determines the isotope of the element. While electrons, protons, and neutrons are fundamental particles, an atom as a whole is the smallest part of an element that maintains its unique identity. Electrons are negatively charged particles orbiting the nucleus, protons are positively charged particles in the nucleus, and neutrons are neutral particles in the nucleus. Therefore, the correct answer is 'D: Atom.'
Where are most of the body's immune cells located?
- A. Blood
- B. Brain
- C. Skin
- D. Large intestine
Correct Answer: A
Rationale: - The majority of the body's immune cells are located in the blood. Immune cells, such as white blood cells (leukocytes), circulate throughout the body via the bloodstream to detect and fight off infections and foreign invaders.
- While immune cells are also present in other parts of the body like the lymph nodes, spleen, and bone marrow, the blood serves as a primary conduit for immune cells to travel to different tissues and organs to carry out their functions.
- The brain (option B) is protected by the blood-brain barrier, which limits the entry of immune cells into the brain to prevent inflammation and damage.
- The skin (option C) contains immune cells like Langerhans cells that help protect against pathogens, but the largest concentration of immune cells is found in the blood.
- The large intestine (option D) also houses a significant amount of immune cells due to its role in interacting with the external environment through the gut-associated lymphoid tissue, but the primary location for most of the body's immune cells is the blood.