Tag: biology

blood is the bodily fluid that is responsible to carry nutrients and oxygen to the body cells and transports the metabolic waste materials from these. It contains antibodies, nutrients and oxygen. However, the nature of blood is different in different organisms. In human beings, 55% of blood is plasma which is made up of 92% water and  7% proteins and salts and carry RBC's WBC's and Platelets. The RBC's are without nuclei. In the earthworm the  blood consists of ameboid cells and hemoglobin dissolved in the plasma. Cockroaches lack heamoglobin in their blood. are thus white. Like all amphibians frogs have red blood cells with a distinct nucleus.

Blood Plasma is the liquid portion of the blood. This is composed of water( 90%), ions, energy substrates, nutrients, metabolites,  antibodies, proteins, and lipoproteins. The most numerous cation in blood plasma is Na+, K+, Mg+, and Ca2+. However, Na+ is the main cation and is responsible for the plasma osmolarity.

The bicarbonate buffering system of blood is an important buffer system in the acid-base homeostasis of living things, including humans. As a buffer, it tends to maintain a relatively constant plasma pH and counteract any force that would alter. In this system, carbon dioxide ${CO _{2}}$ combines with water ${H _{2}O}$ to form carbonic acid ${H _{2}CO _{3}}$, which in turn rapidly dissociates to form hydrogen ions ${H^{+}}$ and bicarbonate ${HCO _{3}^{}}$ as shown in the reactions below.
${CO _{2} + H _{2}O \rightleftarrows H _{2}CO _{3} \rightleftarrows HCO _{3}^{-} + H^{+}}$
The carbon dioxide - carbonic acid equilibrium is catalyzed by the enzyme carbonic anhydrase; the carbonic acid - bicarbonate equilibrium is simple proton dissociation/association and needs no catalyst. Any disturbance of the system will be compensated by a shift in the chemical equilibrium.

The main harmful substances in the blood are urea and bicarbonate ions. Urea is the product of excess amino acids. It is transported into blood plasma by the liver and removed by the kidney. This process is called excretion. 

It is mostly water (up to 95% by volume), and contains dissolved proteins (6–8%) (i.e.—serum albumins, globulins, and fibrinogen), glucose, clotting factors, electrolytes (Na⁺, Ca²⁺, Mg²⁺, HCO₃⁻, Cl⁻, etc.), hormones, carbon dioxide (plasma being the main medium for excretory product transportation) and oxygen.

The blood is composed of a faintly yellow transparent fluid known as the plasma and floating in this fluid are numerous cells or corpuscles of different kinds. Thus Blood -Blood cells $=$ Plasma.

The three proteins found in human blood plasma are :
Albumin - which is involved in controlling the osmotic balance.
Globulins - that produce antibodies, and is thus, involved in defence purposes.
Fibrinogens - that helps in clotting of blood.
Thus, the correct answer is option (A).