Question

(a)Draw a simple diagram and briefly explain how are the s- and p-orbitals arranged in the 1st and 2nd electron shells of an atom?

(b)During autocrine signalling, chemical signals such as hormones released elsewhere from the body travel through blood to cause a response in the target cells. True or

false?

(c) Which of the following two types of drugs would easily penetrate the cell membrane without the aid of a membrane protein: lipid-soluble or water soluble drugs?

Answer 1

a. Electron shells contain subshells like s, p, d and f. Each subshell is composed of orbitals. s subshell contains 1 orbital and p subshell contains 3 orbitals. 1st electron shell contains only s subshell while 2nd electron shell contains s and p orbitals.These orbitals are arranged in the shells in the following way:

b. False; During autocrine signalling a chemical messenger or hormone released by a cell interacts with the autocrine receptors on same cells. If a chemical messenger or hormone secreted by a cell act on distant cell by travelling through blood is called endocrine signalling.

c. Lipid soluble drugs easily penetrate the cell membrane without the aid of a membrane protein. The maximum portion of cell membrane is composed of lipids and thus lipid soluble drugs easily penetrate the membrane.