When a molecule binds to a receptor on a cell surface, it means that a signal has been received by that cell. In this case, the cell that sent the signal is the same cell that is receiving the signal. Autocrine signaling is the term that describes a cell sending a signal to itself ("auto" in this context means self). Exocrine signaling occurs when a substance is secreted through a gland or duct. Endocrine signaling occurs when a substance is secreted into the bloodstream. Paracrine signaling occurs when a cell sends a signal to nearby cells (often to change the behavior or properties of those cells).

Fungal cells have cell walls composed of chitin, a polysaccharide similar in structure to cellulose.

Fungal cells have cell walls composed of chitin, a polysaccharide similar in structure to cellulose.

While the photosynthetic process differs slightly among these organisms, cyanobacteria, algae, and ferns (along with all other plants) all undergo photosynthesis-the process of using sunlight to synthesize food from carbon dioxide and water.

While the photosynthetic process differs slightly among these organisms, cyanobacteria, algae, and ferns (along with all other plants) all undergo photosynthesis-the process of using sunlight to synthesize food from carbon dioxide and water.

Each molecule of glucose produces 2 pyruvate molecules. Each of these pyruvate molecules go through the citric acid cycle and produce 1 ATP each, resulting in 2 ATP total.

Each molecule of glucose produces 2 pyruvate molecules. Each of these pyruvate molecules go through the citric acid cycle and produce 1 ATP each, resulting in 2 ATP total.

Fungal cells have cell walls composed of chitin, a polysaccharide similar in structure to cellulose.

Fungal cells have cell walls composed of chitin, a polysaccharide similar in structure to cellulose.

Fungal cells have cell walls composed of chitin, a polysaccharide similar in structure to cellulose.