Which anemia is classified as not being able to use iron properly to synthesize hemoglobin because of an inherited cause.

Correct Answer: D

Rationale: The correct answer is D: Sideroblastic anemia. This type of anemia is characterized by the bone marrow's inability to use iron properly for hemoglobin synthesis due to an inherited cause. Sideroblastic anemia is specifically associated with defects in heme synthesis, leading to the accumulation of iron in mitochondria. A: Iron deficiency anemia is caused by a lack of iron intake or absorption. B: Hypochromic anemia refers to anemia with abnormally low levels of hemoglobin in red blood cells. C: Aplastic anemia is due to bone marrow failure, leading to decreased production of all blood cell types.

Correct Answer: A

Rationale: The correct answer is A: Tense. In the tense form of the hemoglobin (Hb) molecule, the binding of oxygen is hindered, leading to low oxygen affinity. This form occurs in tissues where oxygen is needed, promoting oxygen release. The relaxed form (choice B) has higher oxygen affinity, favoring oxygen binding. Arterial (choice C) and venous (choice D) refer to the oxygen saturation levels in blood, not directly related to the oxygen affinity of Hb molecules.

Correct Answer: C

Rationale: The correct answer is C: Polarizing microscopy. Polarizing microscopy is valuable in identifying crystals that rotate light because it can distinguish between isotropic and anisotropic materials, such as crystals. When polarized light passes through an anisotropic material like crystal, the light waves are split into ordinary and extraordinary rays, causing the crystals to rotate light. This phenomenon, known as birefringence, is observed under polarizing microscopy. Incorrect Choices: A: Compound brightfield microscopy does not provide the necessary contrast to identify crystals that rotate light. B: Darkfield microscopy is used for observing light scattering, not for identifying crystals that rotate light. D: Phase-contrast microscopy is used to enhance contrast in transparent samples, not specifically for identifying crystals that rotate light.

Correct Answer: D

Rationale: The correct answer is D: Liver. During midfetal life, the liver is the primary source of blood cells. The rationale behind this is that the liver is the major site of hematopoiesis during this developmental stage, producing red blood cells, white blood cells, and platelets. The liver's hematopoietic function gradually declines as the bone marrow takes over this role postnatally. Explanation for why other choices are incorrect: A: Bone marrow - While bone marrow becomes the primary site of hematopoiesis in adults, during midfetal life, it is not the main source of blood cells. B: Spleen - The spleen plays a role in blood filtration and immune response, but it is not the primary source of blood cells during midfetal life. C: Lymph Nodes - Lymph nodes are important for immune function and lymphocyte production, but they do not serve as the primary source of blood cells during midfetal life.

Correct Answer: C

Rationale: The correct answer is C: Glycoprotein. Glycoproteins are the most common type of protein found in the cell membrane because they play crucial roles in cell signaling, adhesion, and recognition. They have sugar molecules attached to them, which help in cell-cell interactions. Lipoproteins (choice A) have lipids attached to them and are found in cell membranes but are not as common as glycoproteins. Mucoproteins (choice B) are proteins with carbohydrate chains but are not as prevalent in cell membranes. Nucleoproteins (choice D) are proteins associated with nucleic acids and are not typically found in the cell membrane.