Outline. One finger of each hand is acclimatized to hot or cold water and then dipped into lukewarm water.

Prior knowledge. The general idea of receptors sending impulses to the brain

Advance preparation and materials
A supply of hot and cold water

Apparatus – per group
3 jars or beakers large enough to accommodate a finger
Thermometer

Experiment

(a) Collect three jars or beakers of about the same size. Fill one with cold water (10-15 °C), one with hot water (40-50 °C) and the third with warm water (about 25 °C).

(b) Place the first finger of the left hand in the cold water and the first finger of the right hand in the hot water. Leave both fingers immersed for at least one minute.

(c) After one minute, remove both fingers from the jars and dip them repeatedly but alternately in the warm water for about a second at a time Notice the temperature sensation in each finger.

Discussion

1 What impression did (i) the left finger, (ii) the right finger give about the temperature of the
warm water?

2 Why should there be any difference in the sensory information from the two fingers? How could you modify the experiment to test your suggestion?

3 Does the result mean that the skin of your fingers is incapable of judging whether an object is hot or cold?

4 What does the result suggest about the way in which the skin responds to temperature Read the rest of this entry »

Molecular biology is the science of study of biology at the molecular level.
William Astbury in Nature described molecular biology as:

“… not so much a technique as an approach, an approach from the viewpoint of the so-called basic sciences with the leading idea of searching below the large-scale manifestations of classical biology for the corresponding molecular plan. It is concerned particularly with the forms of biological molecules and ….. is predominantly three-dimensional and structural – which does not mean, however, that it is merely a refinement of morphology – it must at the same time inquire into genesis and function” (W.T. Astbury, Nature 190, 1124. 1961)

Molecular biology has allowed us to uncover the mysteries of the human body, viruses, bacteria and all other life. As such, it has allowed the progress of medicine to advance to such a degree so that we may begin to cure the previously incurable, and to eventually find cures for every disease that afflicts human kind.

Molecular biology depends not only on biology but also chemistry, genetics, and biochemistry. The understanding of the interactions between DNA, RNA, proteins and lipids is vital in understanding how cells work and how diseases affect these interactions. Researchers and scientists are slowly piecing together these interactions and how each biological molecule functions. By understanding this, scientists can then examine disease conditions, and see if the function of any of the molecules has changed. If a molecule or interaction is affected by disease, scientists can then create therapies which target these alterations and repair them. Read the rest of this entry »