Free Circulation MCQs with Answers
695 Circulation MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The circulatory system covers the chambers, valves and conducting pathway of the human heart, along with the cardiac cycle and control of heartbeat. It compares arteries, veins and capillaries by structure and function, and explains how the lymphatic system returns tissue fluid, transports absorbed fats and supports immunity.
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Read the Circulation notesFree MDCAT chapter notes with key terms695 questions · page 14 of 35
- A. Stomata
- B. Lenticels
- C. Cuticle
- D. Intercellular spaces
Explanation: Stomata are closed during the night hours. Cuticular transpiration, which involves water loss through the plant's cuticle (a waxy layer…
Correct answer: Cuticle- A. Relaxation
- B. Contraction
- C. Division
- D. Movement
Explanation: Vasodilation is the widening of your blood vessels. It happens when smooth muscles found in the walls of arteries or large veins relax…
Correct answer: Relaxation- A. Lymphocytes
- B. Agranulocytes
- C. Monocytes
- D. All of above
Explanation: Lymphocytes are mature, infection-fighting cells that develop from lymphoblasts, a type of blood stem cell in the bone marrow.
Correct answer: Lymphocytes- A. Antigen
- B. Antitoxins
- C. Antibodies
- D. All of above
Explanation: Antibodies in the antiserum bind the infectious agent or antigen. The immune system then recognizes foreign agents bound to antibodies and…
Correct answer: Antibodies- A. Active transport
- B. Passive transport
- C. Diffusion
- D. Both Options B and C are correct
Explanation: Passive transport is a type of transport where no energy is consumed (as opposed to active transport) and diffusion is a type of passive…
Correct answer: Both Options B and C are correct- A. Higher solute concentration to lower solute concentration
- B. Lower solvent concentration to higher solvent concentration
- C. Lower solute concentration to higher solute concentration
- D. All of these
Explanation: In osmosis, water moves from areas of low concentration of solute to areas of high concentration of solute.
Correct answer: Lower solute concentration to higher solute concentration- A. Reticulocytes
- B. Erythrocytes
- C. Basophilic erythroblasts
- D. None of these options are correct
Explanation: Hemoglobin (Hb) is synthesized in a complex series of steps. The heme part is synthesized in a series of steps in the mitochondria and the…
Correct answer: Reticulocytes- A. Antibody
- B. Antigen
- C. Anti A-antigen
- D. Anti O-antigen
Explanation: ABO blood group system is the classification of human blood based on the inherited properties of red blood cells (erythrocytes) as…
Correct answer: Antigen- A. Destroy small particles by phagocytosis
- B. Release heparin to prevent blood clotting
- C. Transport oxygen
- D. Inactivate inflammation producing substances
Explanation: Basophils have a variety of functions, including mediating inflammatory and allergic responses as they contain histamine, in addition to…
Correct answer: Release heparin to prevent blood clotting- A. Vacuolar pathway
- B. Apoplastic pathway
- C. Symplast Pathway
- D. Mineral absorption Pathway
Explanation: The symplast pathway, involves movement of water from one cell to the other by plasmodesmata, hence water moves from cytoplasm of one cell…
Correct answer: Symplast Pathway- A. Ascent of sap
- B. Plasmolysis
- C. Deplasmolysis
- D. Guttation
Explanation: "The explanation for this question will be added soon!".
Correct answer: Ascent of sap- A. Sager
- B. Sayre
- C. Mohl
- D. Drebs
Explanation: The starch-sugar hypothesis is one hypothesis that explains the opening and closing of stomata. It was proposed by German botanist H. Mohl.
Correct answer: Mohl- A. Photosynthesis
- B. Transpiration
- C. Reproduction
- D. Respiration
Explanation: Transpiration is the process of the release of water vapor from aerial parts, such as leaves, stems, and flowers.
Correct answer: Transpiration- A. Lymph capillary
- B. Lymph vessel
- C. Lymph trunk
- D. Lymph node
Explanation: Lymphocytes are important cells of the immune system. Most lymphocytes reside within lymph organs (lymph nodes, thymus, spleen, bone…
Correct answer: Lymph node- A. Water potential
- B. Cohesion tension
- C. Root pressure
- D. Imbibition
Explanation: There are many theories explaining the ascent of sap, including: 1. Cohesion-Tension Theory: The theory states that transpiration pull or…
Correct answer: Cohesion tension- A. T-lymphocytes
- B. B lymphocytes
- C. Neutrophils
- D. Macrophages
Explanation: Cell-mediated immunity is an immune response that does not involve antibodies.
Correct answer: T-lymphocytes277. In immunoglobulins / antibodies, Two light chains and two heavy chains are linked to each other by:
- A. Covalent bonds
- B. Hydrogen bonds
- C. Ionic bonds
- D. Disulphide bonds
Explanation: Each antibody is made up of two short light (L) peptide chains and two long heavy (H) peptide chains (H2L2) joined to each other by…
Correct answer: Disulphide bonds- A. Eosinophils
- B. Neutrophils
- C. Basophils
- D. Platelets
Explanation: Platelets are irregularly shaped, have no nucleus, and typically measure only 2-3 micrometers in diameter.
Correct answer: Platelets- A. Bundle of His
- B. Atrioventricular node
- C. Atrioventricular bundles of fibers
- D. Sinoatrial node
Explanation: Electrical impulses from the heart muscle cause your heart to beat (contract).
Correct answer: Sinoatrial node- A. Atria relax and ventricles contract
- B. Atria contract and ventricle also contract
- C. Atria and ventricles are relaxed
- D. Ventricles remain relax while atria contract
Explanation: During atrial systole following events occur: • AV valves open • SL valves close • Muscles of atria contract and pump blood to ventricles…
Correct answer: Ventricles remain relax while atria contract