Tag: transportation in living organisms

In a healthy individual, there are two normal heart sounds called lub and dub. Lub is the first heart sound. It is associated with the closure of the tricuspid and bicuspid valves at the beginning of systole. The second heart sound dub is associated with the closure of the semilunar valves at the beginning of diastole.

Human blood passes from the inferior vena cava into the diastolic right atrium of the heart because of a pressure differential between the atrium and the vena cava. This negative pressure gradient is created by atrial diastole and pulls blood to the atrium which is then pumped to the ventricles by contraction.

Due to one complete cardiac cycle, the two atria contract during the first 0.1 seconds, followed by ventricular systole for 0.3 seconds and finally joint diastole for 0.4 seconds. 

Hb contains a protein portion called globin and a pigment portion called haem. The haem portion consists of four atoms of iron, each capable of combining with a molecule of $O _{2}$. Thus, one Hb carries 4 molecules of $O _{2}$.

Nearly 20-25% of $CO _{2}$ is transported by RBCs whereas 70% of it is carried as bicarbonate in plasma. About 7% of $CO _{2}$ is carried in a dissolved state through plasma. About 97% of $O _{2}$ is carried by RBCs in the blood. About 3% of $O _{2}$ Is transported in a dissolved state through the plasma.

Heat Shock is given to bacteria for transformation that alters the membrane fluidity. The increase in temperature creates pores in the bacterial plasma membrane and allow plasmid DNA to enter the bacterial DNA. For the heat shock, the DNA-bacteria mixture is put into a 42C to 37C water bath.