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Question 1
Incorrect
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One of the cells of the bone marrow that are responsible for forming the various forms of differentiated blood cells are called?
Your Answer: Progenitor cell
Correct Answer: Hematopoietic stem cell
Explanation:Hematopoietic stem cells (HSCs) or hemocytoblasts are the stem cells that give rise to all the other blood cells through the process of haematopoiesis. They are derived from mesoderm and located in the red bone marrow, which is contained in the core of most bones.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 2
Correct
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What is the function of Activated protein C?
Your Answer: Inactivates factor Va
Explanation:Activated Protein C (APC) is a crucial protein in the regulation of blood coagulation. Its primary functions include:
- Inactivating Factor Va: APC inactivates Factor Va, which is a cofactor for the conversion of prothrombin to thrombin by Factor Xa. By inactivating Factor Va, APC reduces thrombin formation, thereby acting as an anticoagulant.
- Inactivating Factor VIIIa: APC also inactivates Factor VIIIa, another cofactor that assists Factor IXa in the conversion of Factor X to Factor Xa. This further contributes to its anticoagulant effect.
These actions help to regulate blood clotting and prevent excessive thrombosis.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 3
Correct
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Regarding transportation of iron in the body, the process in which iron is transported from the enterocyte into the blood occurs using which transporter protein:
Your Answer: Ferroportin
Explanation:Divalent metal transporter 1 (DMT1) transport several divalent metals including iron across the enterocyte’s cell membrane into the cell. The cell can then release it into the body via the only known iron exporter in mammals, ferroportin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 4
Correct
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Where is the most erythropoietin produced?
Your Answer: Kidneys
Explanation:Erythropoietin is produced by interstitial fibroblasts in the kidney in close association with peritubular capillary and proximal convoluted tubule. It is also produced in perisinusoidal cells in the liver. While liver production predominates in the fetal and perinatal period, renal production is predominant during adulthood.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 5
Correct
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Which of the following is true regarding platelets?
Your Answer: Normally have a half-life of about 8 days
Explanation:Platelets have no cell nucleus: they are fragments of cytoplasm that are derived from the megakaryocytes of the bone marrow, and then enter the circulation. They have a half life of 5-9 days.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 6
Incorrect
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Select one true statement about haemoglobin synthesis…
Your Answer: Involves the combination of iron in the ferric (fe3+) state with protoporphyrin to form haem.
Correct Answer: Occurs in the cytosol of developing red cells.
Explanation:Haemoglobin (Hb) is synthesized in a complex series of steps. The haem part is synthesized in a series of steps in the mitochondria and the cytosol of immature red blood cells, while the globin protein parts are synthesized by ribosomes in the cytosol. Production of Hb continues in the cell throughout its early development from the proerythroblast to the reticulocyte in the bone marrow.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 7
Correct
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5-methyltetrahydrofolate (Methyl THF) is converted to THF with the help of which of the following?
Your Answer: B 12
Explanation:MTR, also known as methionine synthase, is a methyltransferase enzyme, which uses the Vitamin B12 to transfer a methyl group from 5-methyltetrahydrofolate to homocysteine, thereby generating tetrahydrofolate (THF) and methionine. This functionality is lost in vitamin B12 deficiency, resulting in an increased homocysteine level and the trapping of folate as 5-methyl-tetrahydrofolate, from which THF (the active form of folate) cannot be recovered. THF plays an important role in DNA synthesis so reduced availability of THF results in ineffective production of cells with rapid turnover, in particular red blood cells, and also intestinal wall cells which are responsible for absorption.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 8
Correct
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One of the functions of the spleen with regards to red blood cells is:
Your Answer: To filter and remove aged and abnormal red blood cells
Explanation:The spleen plays important roles in regard to red blood cells (also referred to as erythrocytes) and the immune system. It removes old red blood cells and holds a reserve of blood, which can be valuable in case of haemorrhagic shock, and also recycles iron. As a part of the mononuclear phagocyte system, it metabolizes haemoglobin removed from senescent erythrocytes. The globin portion of haemoglobin is degraded to its constitutive amino acids, and the haem portion is metabolized to bilirubin, which is removed in the liver.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 9
Correct
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In adults, the major site of haematopoiesis is?
Your Answer: The axial skeleton
Explanation:Bone marrow is the flexible tissue in the interior of bones. In humans, red blood cells are produced by cores of bone marrow in the heads of long bones.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 10
Incorrect
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The process in which tissue thromboplastin activates factor VII is best known as:
Your Answer: The intrinsic pathway
Correct Answer: The extrinsic pathway
Explanation:In the tissue factor pathway (extrinsic), following damage to the blood vessel, FVII leaves the circulation and comes into contact with tissue factor (TF) expressed on tissue-factor-bearing cells (stromal fibroblasts and leukocytes), forming an activated complex (TF-FVIIa).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 11
Correct
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The following occurs as a result of 2,3 Bisphosphoglycerate binding to deoxyhaemoglobin
Your Answer: A reduction in deoxyhaemoglobin's affinity for oxygen
Explanation:2,3-BPG acts as a heteroallosteric effector of haemoglobin, lowering haemoglobin’s affinity for oxygen by binding preferentially to deoxyhaemoglobin. An increased concentration of BPG in red blood cells favours formation of the T, low-affinity state of haemoglobin and so the oxygen-binding curve will shift to the right.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 12
Incorrect
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All of the following are Vitamin K-dependent clotting factors except:
Your Answer: Factor II
Correct Answer: Factor XI
Explanation:Activated Vitamin K is used to gamma carboxylate (and thus activate) certain enzymes involved in coagulation: Factors II, VII, IX, X, and protein C and protein S. Inability to activate the clotting cascade via these factors leads to the bleeding symptoms
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This question is part of the following fields:
- Haematology
- Medicine
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Question 13
Correct
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Which vitamin plays a major role in the metabolism of many amino acids?
Your Answer: Vitamin B6
Explanation:Vitamin B6 is part of the vitamin B group, and its active form, pyridoxal 5′-phosphate (PLP) serves as a coenzyme in many enzyme reactions in amino acid, glucose, and lipid metabolism.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 14
Correct
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Question 15
Correct
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Platelets are stored in this body organ.
Your Answer: Spleen
Explanation:Megakaryocyte and platelet production is regulated by thrombopoietin. Each megakaryocyte produces between 1,000 and 3,000 platelets during its lifetime. An average of 1011 platelets are produced daily in a healthy adult. Reserve platelets are stored in the spleen, and are released when needed by splenic contraction induced by the sympathetic nervous system.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 16
Incorrect
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The intrinsic pathway of coagulation is activated by which of the following?
Your Answer: Activation of factor viii
Correct Answer: Collagen fibers underlying the endothelium
Explanation:The contact activation (intrinsic) pathway begins with formation of the primary complex on collagen by high-molecular-weight kininogen (HMWK), prekallikrein, and FXII (Hageman factor).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 17
Correct
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Where is intrinsic factor secreted?
Your Answer: Gastric parietal cells
Explanation:Intrinsic factor (IF), also known as gastric intrinsic factor (GIF), is a glycoprotein produced by the parietal cells of the stomach. It is necessary for the absorption of vitamin B12 (cobalamin) later on in the small intestine.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 18
Correct
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Where is Vitamin B 12 absorbed?
Your Answer: Terminal ileum
Explanation:Protein-bound vitamin B12 must be released from the proteins by the action of digestive proteases in both the stomach and small intestine. Gastric acid releases the vitamin from food particles; therefore antacid and acid-blocking medications (especially proton-pump inhibitors) may inhibit absorption of B12. B12 must be attached to Intrinsic Factor (IF) for it to be efficiently absorbed, as receptors on the enterocytes in the terminal ileum of the small bowel only recognize the B12-IF complex; in addition, intrinsic factor protects the vitamin from catabolism by intestinal bacteria.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 19
Correct
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The structure of haemoglobin A in adults includes
Your Answer: Haem, globin polypeptide chains α and β
Explanation:Haemoglobin A (HbA), also known as adult haemoglobin or α2β2, is the most common human haemoglobin tetramer, comprising over 97% of the total red blood cell haemoglobin. It consists of two alpha chains and two beta chains.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 20
Correct
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Which of the following foods contain Vitamin B 12?
Your Answer: Liver, meat
Explanation:No fungi, plants, nor animals (including humans) are capable of producing vitamin B12. Only bacteria and archaea have the enzymes needed for its synthesis. Proved food sources of B12 are animal products (meat, fish, dairy products).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 21
Incorrect
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Which of the following is matched correctly with regard to stem cells of the bone marrow?
Your Answer: None of the above
Correct Answer: Hemopoietic stem cells - basophils
Explanation:Hematopoietic stem cells (HSCs) or hemocytoblasts are the stem cells that give rise to all the other blood cells through the process of haematopoiesis. They give rise to both the myeloid and lymphoid lineages of blood cells. (Myeloid cells include monocytes, macrophages, neutrophils, basophils, eosinophils, erythrocytes, dendritic cells, and megakaryocytes or platelets. Lymphoid cells include T cells, B cells, and natural killer cells.)
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This question is part of the following fields:
- Haematology
- Medicine
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Question 22
Correct
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Which statement is correct about the clinical state of methemoglobinemia?
Your Answer: May arise due to a hereditary deficiency of NADH.
Explanation:Methaemoglobin is a form of haemoglobin that contains ferric [Fe3+] iron and has a decreased ability to bind oxygen. Spontaneously formed methaemoglobin is normally reduced by protective enzyme systems, e.g., NADH methaemoglobin reductase, hence a deficiency of NADH may result in increased levels of methaemoglobin
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This question is part of the following fields:
- Haematology
- Medicine
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Question 23
Correct
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With regard to the spleen which of the following has the correct match?
Your Answer: Periarteriolar lymphoid sheets - T lymphocytes
Explanation:The spleen consists of:Red pulp – responsible for mechanical filtration of red blood cells. Red pulp contains sinusoids, which are filled with blood, splenic cords of reticular fibers and a marginal zoneWhite pulp – responsible for active immune response through humoral and cell-mediated pathways. Composed of nodules, called Malpighian corpuscles. These are composed of: lymphoid follicles, rich in B-lymphocytes and periarteriolar lymphoid sheaths, rich in T-lymphocytes
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This question is part of the following fields:
- Haematology
- Medicine
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Question 24
Incorrect
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From which of the following can niacin be synthesized in humans
Your Answer: Thiamine
Correct Answer: Tryptophan
Explanation:Niacin, is also known as vitamin B3. The liver can synthesize niacin from the essential amino acid tryptophan, requiring 60 mg of tryptophan to make one mg of niacin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 25
Incorrect
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Which statement about antithrombin III is true?
Your Answer: Activity is decreased in endothelial injury.
Correct Answer: It inhibits particularly factor II and X
Explanation:Antithrombin inactivates its physiological target enzymes, Thrombin (Factor II), Factor Xa and Factor IXa. ATIII binds to thrombin and then forms the thrombin-anti thrombin complex or TAT complex. This is a major natural pathway of anticoagulation. This binding of thrombin to AT is greatly enhanced in the presence of heparin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 26
Incorrect
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Vitamin K deficiency can be found in which of the following condition?
Your Answer: Jaundice with indirect hyperbilirubinemia
Correct Answer: Cholestatic jaundice
Explanation:Vitamin K1-deficiency may occur by disturbed intestinal uptake (such as would occur in a bile duct obstruction), by therapeutic or accidental intake of a vitamin K1-antagonist such as warfarin, or, very rarely, by nutritional vitamin K1 deficiency.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 27
Incorrect
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Which of the following is a granulocyte?
Your Answer: Monocyte
Correct Answer: Eosinophil
Explanation:Granulocytes are a category of white blood cells characterized by the presence of granules in their cytoplasm. There are three principal types of granulocytes, distinguished by their appearance under Wright’s stain:
- Basophil granulocytes
- Eosinophil granulocytes
- Neutrophil granulocytes
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This question is part of the following fields:
- Haematology
- Medicine
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Question 28
Incorrect
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Choose the most correct answer, what reduces affinity for oxygen in haemoglobin?
Your Answer: Binding with 2,3 bisphosphoglycerate
Correct Answer: All the options are true
Explanation:The strength with which oxygen binds to haemoglobin is affected by several factors. These factors shift or reshape the oxyhaemoglobin dissociation curve. A rightward shift indicates that the haemoglobin under study has a decreased affinity for oxygen. The causes of shift to right can be remembered using the mnemonic, CADET, face Right! for CO2 and CO, Acid (H+), 2,3-DPG, Exercise and Temperature.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 29
Correct
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Which of the following cells will degranulate and release histamine when binding to IgE?
Your Answer: Basophils
Explanation:Basophils have protein receptors on their cell surface that bind IgE, an immunoglobulin involved in microparasite defence and allergy. When activated, basophils degranulate to release histamine, proteoglycans (e.g. heparin and chondroitin), and proteolytic enzymes (e.g. elastase and lysophospholipase).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 30
Correct
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Where is retinol mainly stored?
Your Answer: Liver
Explanation:Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids (most notably beta-carotene). The liver stores a multitude of substances, including glucose (in the form of glycogen), vitamin A (1–2 years’ supply), vitamin D (1–4 months’ supply), vitamin B12 (3–5 years’ supply), vitamin K, iron, and copper.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 31
Correct
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With regards to splenic micro-architecture which is not contained within the red pulp
Your Answer: Malpighian corpuscles
Explanation:Red pulp is responsible for mechanical filtration of red blood cells and is composed of sinusoids, which are filled with blood, splenic cords of reticular fibers and a marginal zone bordering on white pulp. White pulp provides an active immune response through humoral and cell-mediated pathways. Composed of nodules, called Malpighian corpuscles. These are composed of: lymphoid follicles, rich in B-lymphocytes and periarteriolar lymphoid sheaths (PALS), rich in T-lymphocytes.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 32
Correct
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What is the average life span of red blood cells?
Your Answer: 4 months
Explanation:Approximately 2.4 million new erythrocytes are produced per second in human adults. The cells develop in the bone marrow and circulate for about 100–120 days (4 months) in the body before their components are recycled by macrophages.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 33
Incorrect
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The following play a role in regulation of intestinal iron absorption except:
Your Answer: Recent dietary intake of iron
Correct Answer: Urinary iron excretion rate
Explanation:The human body’s rate of iron absorption appears to respond to a variety of interdependent factors, including total iron stores, dietary intake, the extent to which the bone marrow is producing new red blood cells, the concentration of haemoglobin in the blood, and the oxygen content of the blood. Classic examples of genetic iron overload includes hereditary hemochromatosis (HH) and the more severe disease juvenile hemochromatosis (JH).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 34
Correct
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In the clotting mechanism, activation of factor IX can occur through the direct actions of:
Your Answer: Factor VIIa & XIa
Explanation:Factor IX is processed to remove the signal peptide, glycosylated and then cleaved by factor XIa (of the contact pathway) or factor VIIa (of the tissue factor pathway). When activated into factor IXa, in the presence of Ca2+, membrane phospholipids, and a Factor VIII cofactor, it hydrolyses one arginine-isoleucine bond in factor X to form factor Xa. Factor IX is inhibited by antithrombin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 35
Incorrect
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The haemostatic plug formation in response to injured blood vessel wall is stimulated by exposure of which substance to platelets?
Your Answer: von Willebrand factor (vWF)
Correct Answer: Collagen
Explanation:When the endothelium is damaged, the normally isolated, underlying collagen is exposed to circulating platelets, which bind directly to collagen with collagen-specific glycoprotein Ia/IIa surface receptors. This adhesion is strengthened further by von Willebrand factor (vWF), which is released from the endothelium and from platelets.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 36
Incorrect
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Which clotting factor is responsible for stabilization of the fibrin clot by formation of covalent cross-linkages?
Your Answer: Factor VIII
Correct Answer: Factor XIIIa
Explanation:Factor XIII or fibrin stabilizing factor is an enzyme of the blood coagulation system that crosslinks fibrin. Deficiency of this factor (FXIIID) affects clot stability.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 37
Correct
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Which of the following foods do NOT contain high levels of folate?
Your Answer: Yellow vegetables
Explanation:Folate naturally occurs in a wide variety of foods, including vegetables (particularly dark green leafy vegetables), fruits and fruit juices, nuts, beans, peas, dairy products, poultry and meat, eggs, seafood, grains, and some beers. Avocado, beetroot, spinach, liver, yeast, asparagus, and Brussels sprouts are among the foods with the highest levels of folate
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This question is part of the following fields:
- Haematology
- Medicine
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Question 38
Correct
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von Willebrand factor stabilises which clotting factor?
Your Answer: Factor VIII
Explanation:Von Willebrand factor’s primary function is binding to other proteins, in particular factor VIII, and it is important in platelet adhesion to wound sites. It is not an enzyme and, thus, has no catalytic activity. Factor VIII degrades rapidly when not bound to vWF. Factor VIII is released from vWF by the action of thrombin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 39
Correct
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The actions of thrombin result directly in the release of:
Your Answer: Fibrin monomers
Explanation:Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalysing many other coagulation-related reactions.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 40
Correct
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What is the average life span of neutrophils?
Your Answer: 24 hours
Explanation:The average lifespan of inactivated human neutrophils in the circulation has been reported by different approaches to be between 5 and 90 hours.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 41
Incorrect
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The extrinsic coagulation pathway is initiated by activation of which clotting factor?
Your Answer: Factor II
Correct Answer: Factor VII
Explanation:The tissue factor pathway (extrinsic) begins following damage to the blood vessel. FVII leaves the circulation and comes into contact with tissue factor (TF) expressed on tissue-factor-bearing cells (stromal fibroblasts and leukocytes), forming an activated complex (TF-FVIIa).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 42
Correct
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Which enzyme deficiency causes Beriberi?
Your Answer: Thiamine
Explanation:Beriberi refers to a cluster of symptoms caused primarily by thiamine (vitamin B1) deficiency. Symptoms of beriberi include weight loss, emotional disturbances, impaired sensory perception, weakness and pain in the limbs, and periods of irregular heart rate.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 43
Correct
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Which of the following vitamin deficiencies is associated with xerophthalmia?
Your Answer: Vitamin A
Explanation:Xerophthalmia caused by a severe vitamin A deficiency is described by pathologic dryness of the conjunctiva and cornea. The conjunctiva becomes dry, thick and wrinkled. If untreated, it can lead to corneal ulceration and ultimately to blindness as a result of corneal damage.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 44
Incorrect
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Question 45
Incorrect
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Which one of the following is true about bone marrow?
Your Answer: Yellow marrow is mainly fat cells with scanty blood vessels and capillaries
Correct Answer: At birth the bone marrow is entirely red marrow and is converted to yellow marrow with age
Explanation:The two types of bone marrow are red marrow, which consists mainly of hematopoietic tissue, and yellow marrow, which is mainly made up of fat cells. Red blood cells, platelets, and most white blood cells arise in red marrow. Both types of bone marrow contain numerous blood vessels and capillaries. At birth, all bone marrow is red. With age, more and more of it is converted to the yellow type; only around half of adult bone marrow is red.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 46
Correct
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Where is Vitamin B12 mainly stored in the body?
Your Answer: Liver
Explanation:The total amount of vitamin B12 stored in body is about 2–5 mg in adults. Around 50% of this is stored in the liver. Approximately 0.1% of this is lost per day by secretions into the gut, as not all these secretions are reabsorbed.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 47
Correct
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Choose the correct statement regarding the protein C/S system?
Your Answer: The protein C/S complex inactivates factor Va and VIIIa
Explanation:The best characterized function of Protein S is its role in the anti coagulation pathway, where it functions as a cofactor to Protein C in the inactivation of Factors Va and VIIIa.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 48
Incorrect
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Which of the following is a function of Vitamin C?
Your Answer: Iron transport across the enterocytes
Correct Answer: Hydroxylation of proline to hydroxyproline for collagen synthesis
Explanation:Vitamin C acts as an electron donor for eight different enzymes: Three enzymes (prolyl-3-hydroxylase, prolyl-4-hydroxylase, and lysyl hydroxylase) that are required for the hydroxylation of proline and lysine in the synthesis of collagen.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 49
Correct
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Inactive cellular marrow is called
Your Answer: Yellow marrow
Explanation:The two types of bone marrow are red marrow, which consists mainly of hematopoietic tissue, and yellow marrow, which is mainly made up of fat cells.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 50
Correct
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Question 51
Incorrect
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Why is tissue plasminogen activator (tPa) a valuable treatment used in myocardial infarction and stroke?
Your Answer: It stimulates intravascular coagulation
Correct Answer: It forms plasmin from its inactive precursor
Explanation:tPA is a serine protease involved in the breakdown of blood clots. It functions by converting plasminogen, an inactive precursor, into plasmin, an active enzyme. Plasmin then degrades fibrin, the main protein component of blood clots, leading to clot dissolution. This mechanism is particularly valuable in the treatment of myocardial infarction (heart attack) and ischemic stroke, where timely dissolution of the clot can restore blood flow to affected tissues and reduce damage.
Therefore, the correct answer is:
- It forms plasmin from its inactive precursor
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This question is part of the following fields:
- Haematology
- Medicine
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Question 52
Correct
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Vitamin B12 is transported from the enterocytes to the bone marrow by which factor?
Your Answer: Transcobalamin II (TC IIi)
Explanation:B12 must be attached to IF for it to be efficiently absorbed, as receptors on the enterocytes in the terminal ileum of the small bowel only recognize the B12-IF complex. Once the IF/B12 complex is recognized by specialized ileal receptors, it is transported into the portal circulation. The vitamin is then transferred to transcobalamin II (TC-II/B12), which serves as the plasma transporter.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 53
Correct
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Which one of the following is necessary to activate plasminogen to plasmin?
Your Answer: tPA
Explanation:In circulation, plasminogen adopts a closed, activation resistant conformation. Upon binding to clots, or to the cell surface, plasminogen adopts an open form that can be converted into active plasmin by a variety of enzymes, including tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), kallikrein, and factor XII (Hageman factor).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 54
Incorrect
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Bone marrow barrier is important to:
Your Answer: All of the above
Correct Answer: Allow mature red blood cells to pass into circulation
Explanation:The blood vessels of the bone marrow constitute a barrier, inhibiting immature blood cells from leaving the marrow. Only mature blood cells contain the membrane proteins, such as aquaporin and glycophorin, that are required to attach to and pass the blood vessel endothelium.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 55
Correct
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Transport of Iron into enterocytes occurs via which membrane transporter?
Your Answer: Divalent metal transporter 1(dmt1)
Explanation:To be absorbed, dietary iron can be absorbed as part of a protein such as haem protein or iron must be in its ferrous Fe2+ form. A ferric reductase enzyme on the enterocytes’ brush border, duodenal cytochrome B (Dcytb), reduces ferric Fe3+ to Fe2+. A protein called divalent metal transporter 1 (DMT1), which can transport several divalent metals across the plasma membrane, then transports iron across the enterocyte’s cell membrane into the cell.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 56
Correct
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Which of these vitamins is not found in plants?
Your Answer: Vitamin B12
Explanation:No fungi, plants, nor animals (including humans) are capable of producing vitamin B12. Only bacteria and archaea have the enzymes needed for its synthesis. Proved food sources of B12 are animal products (meat, fish, dairy products).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 57
Correct
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Question 58
Correct
-
What is the main function of vitamin E?
Your Answer: It is an antioxidant
Explanation:Vitamin E has many biological functions, the antioxidant function being the best known. Other functions include enzymatic activities, gene expression, and neurological function(s).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 59
Correct
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Which of the following conditions is associated with eosinophilia?
Your Answer: Ascaris
Explanation:Eosinophilia can be idiopathic (primary) or, more commonly, secondary to another disease. In the Western World, allergic or atopic diseases are the most common causes, especially those of the respiratory or integumentary systems. In the developing world, parasites are the most common cause e.g. Ascaris
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This question is part of the following fields:
- Haematology
- Medicine
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Question 60
Incorrect
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Which of the following is a precursor to the tissue macrophage?
Your Answer: Normoblast
Correct Answer: Monocyte
Explanation:Monocytes are a type of white blood cell, or leukocyte. They are the largest type of leukocyte and can differentiate into macrophages or dendritic cells.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 61
Incorrect
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Question 62
Incorrect
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Which of the following factors is directly responsible for the breakdown of fibrinogen to fibrin?
Your Answer: Fibrinogen degradation products (FDPS)
Correct Answer: Thrombin
Explanation:Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the coagulation cascade, the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalysing many other coagulation-related reactions.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 63
Correct
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Synthesis of haem for haemoglobin occurs in the?
Your Answer: Mitochondria of the red blood cells
Explanation:Haemoglobin (Hb) is synthesized in a complex series of steps. The haem part is synthesized in a series of steps in the mitochondria and the cytosol of immature red blood cells, while the globin protein parts are synthesized by ribosomes in the cytosol.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 64
Correct
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In the normal adult, haematopoiesis is present
Your Answer: Axial skeleton and proximal ends of long bones
Explanation:In children, haematopoiesis occurs in the marrow of the long bones such as the femur and tibia. In adults, it occurs mainly in the pelvis, cranium, vertebrae, and sternum.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 65
Correct
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Question 66
Correct
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90% of erythropoietin necessary for haemopoesis is produced by the kidneys, the remainder is formed in the?
Your Answer: Liver
Explanation:Erythropoietin is produced by interstitial fibroblasts in the kidney in close association with peritubular capillary and proximal convoluted tubule. It is also produced in perisinusoidal cells in the liver. While liver production predominates in the fetal and perinatal period, renal production is predominant during adulthood.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 67
Correct
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Which of the following conditions is procoagulant?
Your Answer: Factor V Leiden
Explanation:Factor V Leiden is a genetic mutation of one of the clotting factors in the blood, Factor V. This mutation makes Factor V resistant to inactivation by activated Protein C, which normally helps to regulate clot formation. As a result, individuals with Factor V Leiden are at increased risk of developing abnormal blood clots (thrombophilia), making it a procoagulant condition.
The other conditions listed are associated with bleeding tendencies rather than increased clotting:
- Afibrinogenemia: A rare genetic disorder where there is a complete lack of fibrinogen, leading to bleeding problems.
- Hemophilia: A group of inherited bleeding disorders where blood does not clot properly due to the lack of sufficient blood-clotting proteins (factors VIII or IX).
- Hypothrombinemia: A condition characterized by low levels of prothrombin, leading to increased bleeding.
- Christmas disease (Hemophilia B): A form of hemophilia caused by a deficiency of factor IX, resulting in a bleeding tendency.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 68
Incorrect
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Regarding Iron stores, which of the following contains the highest proportion of total body iron?
Your Answer: Ferritin
Correct Answer: Haemoglobin
Explanation:Most well-nourished people in industrialized countries have 4 to 5 grams of iron in their bodies. Of this, about 2.5 g is contained in the haemoglobin needed to carry oxygen through the blood, and most of the rest (approximately 2 grams in adult men, and somewhat less in women of childbearing age) is contained in ferritin complexes that are present in all cells, but most common in bone marrow, liver, and spleen.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 69
Correct
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Iron absorption occurs primarily in which part of the GIT?
Your Answer: Duodenum
Explanation:Like most mineral nutrients, the majority of the iron absorbed from digested food or supplements is absorbed in the duodenum by enterocytes of the duodenal lining.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 70
Incorrect
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Which vitamin is found in NAD and NADP?
Your Answer: Vitamin B6
Correct Answer: Vitamin B3
Explanation:In organisms, NAD can be synthesized from simple building-blocks (de novo) from the amino acids tryptophan or aspartic acid. In an alternative fashion, more complex components of the coenzymes are taken up from food as the vitamin called niacin (vitamin B3)
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This question is part of the following fields:
- Haematology
- Medicine
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