Body Fluids and Circulation MCQs for NEET — Zoology Questions with Answers

(d) Matured mammalian RBCs do not have cell organelles including nucleus, Golgi bodies mitochondria, ribosomes, centrioles and endoplasmic reticulum. It increases the surface area of RBCs and enables them to contain more haemoglobin. In the absence of cell organelles, the consumption of oxygen is very low and thus anaerobic respiration occurs in RBCs. Mature RBCs cannot replicate and cannot synthesize RNA as they do not possess machinery required (e.g., various enzymes) for replication and RNA synthesis.

The average lifespan of human RBCs is 120 days. The aged RBCs attract autoantibodies after which they are attached by macrophage in liver and spleen. Spleen is also called as 'graveyard of RBCs'. The process of destruction is called haemolysis.

(a) Aactually per 100 ml of blood there is about 15 gm of haemoglobin in adults & an adult has about 5 lit of blood, the total content of haemoglobin is roughly 700 to 900 grams.

(a) Factor II - Prothrombin

(b) Factor III - Thromboplastin

(c) Factor VIII - Antihaemophilic globulin

(d) Factor XII - Hageman factor

(a) The chordae tendineae or heart strings are cords like tendons that connect the papillary muscles to tricuspid valve and the mitral valve in the heart. The chordae tendinae prevents the flaps from being everted upto the right atrium, these cord-like tendons hold in position other flaps, such as bicuspid or mitral valve.

NCERT, P -281, Rh Grouping

NCERT, P -282, Lymph

NCERT, P -282, Circulatory Pathways, Para1

NCERT, P -283, Circulatory Pathways, Para 2.

NCERT, P -283, Circulatory Pathways, Para 2.