Both starch and glycogen are made up of glucose, however: (a) starch is present in liver and glycogen is present in red blood cells. (b) glycogen is made in animal cells, but starch is made in plant cells. (c) both starch and glycogen are present in animal and plant cells. (d) both starch and glycogen are present in plant cells only.

Starch and glycogen are both complex polysaccharides composed of glucose units linked by glycosidic bonds [1]. However, they serve as energy storage molecules in different kingdoms of life. Starch is the primary storage form of glucose in plants, produced in leaves through photosynthesis and stored in various plant tissues [1][2]. It consists of two components: amylose and amylopectin [1]. In contrast, glycogen is the major storage form of carbohydrate in animals, often referred to as 'animal starch'. It is highly concentrated in the liver and skeletal muscles to maintain glucose homeostasis [3][4]. While both are chemically similar glucose polymers, glycogen is more extensively branched than the amylopectin found in starch. Crucially, glycogen does not exist in plant tissues, and starch is not synthesized by animal cells.

Sources

1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 10: Life Processes in Plants > 10.2.1 Leaves: the ̒ food factories̓of plants > p. 140
2. [2] Science-Class VII . NCERT(Revised ed 2025) > Chapter 10: Life Processes in Plants > FASCINATING FACTS > p. 143
3. [3] https://www.sciencedirect.com/topics/neuroscience/glycogenesis
4. [4] https://www.ncbi.nlm.nih.gov/books/NBK560599/