Which of the following is produced by Natural Killer Cells to create pores for target cell rupture?

Correct Answer: C

Rationale: The correct answer is C, Perforin. Natural Killer cells release perforin, which forms pores in the membrane of target cells, leading to their lysis. Interferon (choice A) is a protein released by cells in response to viral infections, apoptosis (choice B) is programmed cell death, and antibodies (choice D) are produced by B cells to neutralize pathogens but are not directly involved in creating pores for cell rupture like perforin.

Correct Answer: B

Rationale: The correct answer is B: Hydrogen bond. Hydrogen bonds are responsible for holding water molecules together. In a water molecule, the oxygen atom is slightly negative, and the hydrogen atoms are slightly positive, creating a partial positive and negative charge. This polarity allows hydrogen bonds to form between adjacent water molecules. Covalent bonds involve the sharing of electrons, ionic bonds involve transfer of electrons between ions, and peptide bonds are specific to linking amino acids in proteins, which are not relevant to water molecule interactions.

Correct Answer: B

Rationale: Vitamin D is the correct answer. When the skin is exposed to sunlight, it triggers a process where a form of cholesterol in the skin is converted into vitamin D. This vitamin plays a crucial role in aiding calcium absorption in the gut, which is essential for maintaining strong and healthy bones. Vitamin A (Choice A) is important for vision and immune function but is not produced by sunlight exposure. Vitamin K (Choice C) is known for its role in blood clotting and bone metabolism, but it is not produced by sunlight. Vitamin E (Choice D) is an antioxidant that protects cells from damage but is not synthesized in the skin through sunlight exposure.

Correct Answer: B

Rationale: The correct answer is Iron. Iron is essential for the formation of hemoglobin, the protein in red blood cells that binds and transports oxygen throughout the body. Calcium (Choice A), Potassium (Choice C), and Sodium (Choice D) are not directly involved in the formation of hemoglobin and its oxygen-carrying function.

Correct Answer: C

Rationale: The correct answer is the humerus. The humerus is the long bone located in the upper arm, between the shoulder and elbow. Option A, Femur, is incorrect as it is the long bone found in the thigh. Option B, Tibia, is incorrect as it is a long bone found in the lower leg. Option D, Radius, is incorrect as it is a bone located in the forearm, not the upper arm.