1 The measure of a complete circle, in radians, is 2Ï. 2  A radian is defined as the ratio of the arc length, ââsââ to the length of the radius âârââ. 3  One radian is equal to a little less than 57.3 degrees.
A thylakoid is a membrane-bound compartment inside chloroplasts and cyanobacteria. They are the site of the light-dependent reactions of photosynthesis. Thylakoids consist of a thylakoid membrane surrounding a thylakoid lumen.Chloroplast thylakoids frequently form stacks of disks referred to as grana (singular: granum).n higher plants thylakoids are organized into a granum-stroma membrane assembly. A granum (plural grana) is a stack of thylakoid discs. Chloroplasts can have from 10 to 100 grana.
Stacked into grana, the shape of the thylakoids allow for optimum surface area, maximizing the amount of photosynthesis that can take place. Within the chloroplast the grana resemble stacks of green pancakes, and are not uniform in their height or distribution.