1.
Select the statement about red blood cells that is incorrect.
Correct Answer
C. Deoxyhemoglobin carries oxygen.
Explanation
The statement "Deoxyhemoglobin carries oxygen" is incorrect. Deoxyhemoglobin is the form of hemoglobin that does not carry oxygen, while oxyhemoglobin is the form that binds to oxygen.
2.
Which dietary component(s) is/are needed for DNA synthesis, and thus greatly influence the production of red blood cells?
Correct Answer
C. Vitamin B12 and folate
Explanation
Vitamin B12 and folate are needed for DNA synthesis and greatly influence the production of red blood cells. These two nutrients play a crucial role in the production and maturation of red blood cells in the bone marrow. They are involved in the synthesis of DNA, which is necessary for the proper division and growth of cells, including red blood cells. Deficiencies in vitamin B12 and folate can lead to impaired DNA synthesis and result in megaloblastic anemia, a condition characterized by the production of large, immature red blood cells. Therefore, ensuring an adequate intake of vitamin B12 and folate is essential for the production of red blood cells.
3.
Which blood cell can be described as being a biconcave disc?
Correct Answer
D. Erythrocyte
Explanation
The correct answer is erythrocyte. Erythrocytes, also known as red blood cells, are biconcave discs. This means that they have a concave shape on both sides, resembling a shallow bowl. This unique shape allows erythrocytes to have a large surface area-to-volume ratio, which is important for their main function of carrying oxygen throughout the body. The biconcave shape also allows erythrocytes to be flexible and squeeze through narrow blood vessels.
4.
Which of the following directly defines the transportation of oxygen?
Correct Answer
B. Oxyhaemoglobin
Explanation
Oxyhaemoglobin directly defines the transportation of oxygen. Oxyhaemoglobin is formed when oxygen molecules bind to haemoglobin in red blood cells. It is the main form in which oxygen is transported from the lungs to the tissues in the body. This process allows for the efficient delivery of oxygen to cells for cellular respiration and energy production.
5.
Red blood cells survive around _____ days.
Correct Answer
A. 120
Explanation
Red blood cells, also known as erythrocytes, have a lifespan of approximately 120 days. They are continuously produced in the bone marrow and are responsible for carrying oxygen to different parts of the body. After around 120 days, they become old and damaged, and are removed from circulation by the spleen and liver. New red blood cells are constantly being produced to replace the old ones, ensuring a healthy supply of oxygen throughout the body.
6.
Erythropoietin appears in the plasma when peripheral tissues, especially the kidneys, are exposed to:
Correct Answer
B. Low oxygen concentrations
Explanation
Erythropoietin is a hormone that is released in response to low oxygen concentrations in the body. When the kidneys and other peripheral tissues detect low oxygen levels, they produce and release erythropoietin into the bloodstream. This hormone then stimulates the production of red blood cells in the bone marrow, which helps to increase the oxygen-carrying capacity of the blood. Therefore, the correct answer is low oxygen concentrations.
7.
Iron is necessary in the diet because it is involved with: [
Correct Answer
A. Hemoglobin production
Explanation
Iron is necessary in the diet because it is involved in hemoglobin production. Hemoglobin is a protein in red blood cells that carries oxygen from the lungs to the rest of the body. Iron is a crucial component of hemoglobin, as it binds to oxygen and allows it to be transported throughout the body. Without sufficient iron, the body cannot produce enough hemoglobin, leading to a condition called iron-deficiency anemia. Therefore, iron is essential for the production of hemoglobin and proper oxygen transport in the body.
8.
The primary site of erythropoiesis in the adult is the:
Correct Answer
C. Bone marrow
Explanation
The bone marrow is the primary site of erythropoiesis in adults. Erythropoiesis is the process of producing red blood cells, and it occurs in the bone marrow. The bone marrow contains stem cells that differentiate into red blood cells, and these cells go on to carry oxygen throughout the body. The kidney and liver also play a role in erythropoiesis, but they are not the primary sites.
9.
Which of the following statements are incorrect : Glucose 6 phosphate dehydrogenase deficiency results in:
Correct Answer
E. Reduction in ATP production
Explanation
Glucose 6 phosphate dehydrogenase deficiency leads to a reduction in NADPH production, which is necessary for maintaining the reduced state of glutathione and protecting erythrocytes from oxidative damage. This deficiency also causes the production of Heinz bodies, which are denatured hemoglobin aggregates that can damage erythrocytes. Both of these factors contribute to the development of hemolytic anemia. However, glucose 6 phosphate dehydrogenase deficiency does not directly affect ATP production, so the statement "reduction in ATP production" is incorrect.
10.
Deoxygenation of haemoglobin can result as a consequence of:
Correct Answer
F. All of the above
Explanation
Deoxygenation of hemoglobin can occur due to multiple factors. Low oxygen levels in the blood can lead to the release of oxygen from hemoglobin. The production of 2,3 BPG (2,3-bisphosphoglycerate) can also cause a decrease in the affinity of hemoglobin for oxygen, leading to its release. Binding of carbon monoxide (CO) to hemoglobin can prevent the binding of oxygen, resulting in deoxygenation. A decrease in pH, such as in acidic conditions, can also cause hemoglobin to release oxygen. High levels of carbon dioxide (CO2) can stimulate the release of oxygen from hemoglobin. Therefore, all of the above factors can contribute to the deoxygenation of hemoglobin.
11.
Sickle cell anaemia occurs because of:
Correct Answer
C. A mutation in beta globin
Explanation
Sickle cell anaemia occurs because of a mutation in beta globin. This mutation causes the red blood cells to become misshapen and rigid, leading to a variety of symptoms such as pain, fatigue, and organ damage. The mutation affects the structure of the haemoglobin molecule, which is responsible for carrying oxygen in the blood. This mutation results in the production of abnormal haemoglobin, known as haemoglobin S, which causes the red blood cells to take on a sickle shape. This abnormal shape makes it difficult for the red blood cells to flow through small blood vessels, leading to a lack of oxygen delivery to tissues and organs.
12.
Circulating mature RBCs lack:
Correct Answer
D. All of the above
Explanation
Circulating mature RBCs lack ribosomes, mitochondria, and a nucleus. This is because during their maturation process, these components are expelled to make space for more hemoglobin, which is essential for oxygen transport. Without ribosomes, RBCs cannot synthesize proteins. Without mitochondria, they cannot generate energy through aerobic respiration. And without a nucleus, RBCs cannot undergo cell division or repair themselves. Therefore, all of the above options are correct.
13.
The part of the hemoglobin molecule that directly interacts with oxygen is:
Correct Answer
D. The iron ion
Explanation
The iron ion is the part of the hemoglobin molecule that directly interacts with oxygen. Hemoglobin is a protein found in red blood cells that carries oxygen throughout the body. The iron ion within the heme group of hemoglobin binds to the oxygen molecule, allowing for oxygen transport in the bloodstream. The interaction between the iron ion and oxygen is crucial for the oxygen-carrying capacity of hemoglobin.