AP BIOLOGY

Detailed explanation-1: -Chloroplasts contain a system of membrane sacs, the thylakoids, some of which are stacked to form grana (singular, granum), whereas others float freely in the stroma .

Detailed explanation-2: -A stack of thylakoids is known as “Granum". It increases the surface area of the chloroplasts.

Detailed explanation-3: -Grana: 1. The thylakoids of the chloroplast form stacks of disks which are called the grana (singular – granum). 2. One thylakoid stack is called a granum.

Detailed explanation-4: -Thylakoids are interconnected disc-like sacs of the internal membrane system of the chloroplast. They are found suspended in the stroma. Thylakoids are arranged in a stack, which is called grana. The thylakoid membrane contains the photosynthetic pigment chlorophyll, which absorbs the sunlight during photosynthesis.

Detailed explanation-5: -A granum is referred to as a stack of 20-100 thylakoid units. Found in more complex plants. Grana are connected to each other by stromal lamellae. Thylakoid membranes of granum contain photosynthetic pigments and enzymes. A granum is the site for the light reaction of the photosynthesis.