Dayna Denver & Alex Marconi Chloroplasts Dayna Denver & Alex Marconi

What is a Chloroplast? Chloroplasts are only found in plant cells. They are double bound plastids involved in food production for plants and algae. They have very similar function to mitochondria in the animal cell. Produce food and energy for the plant by using a process called photosynthesis

Photosynthesis Chloroplasts catalyze the process of turning light energy into food for the plant, specifically a sugar molecule. It is the opposite reaction of cellular respiration. It uses carbon dioxide and water to produce sugar and oxygen. 6 CO2 + 6 H2O C6H12O6 + 6 O2

Two Parts to Photosynthesis Energy (Sunlight and Water) Light is absorbed through the chloroplast and reacts with chlorophyll (the green pigment in plants) and water. The sunlight excites Hydrogen electrons in water which move down an electron transport chain and are picked up by NADP reducing it to NADPH ATP is produced by the movement of Hydrogen ions passing through an enzyme in the chloroplast membrane. This reaction occurs in the thylakoid and grana inside of chloroplasts, and are all connected by the stroma. Food Production (Carbon and Stored Energy) The plant uses stored NAPDH and ATP to produce sugars. The carbon in carbon dioxide reacts with the ATP to form starches by a process known as the Calvin Cycle. This product is what we know as glucose. In both of these processes oxygen is separated and expelled from the plant.

Photosynthesis Stages 1 & 2

Interesting Plant Adaptations Chloroplast sandwiches? Brewer’s Saltbush Modified photosynthesis Stores CO2 during the day to use later, avoiding major water loss in dry environments

Fun Facts Chloroplasts have their own set of DNA aside from the rest of the cell. Chloroplasts can become other types of organelles such as chromoplasts. Chloroplasts are part of the plant’s immune system. Simple organisms such as algae may only contain a couple chloroplasts per cell. Larger organisms may contain hundreds in one cell. Chloroplasts can sometimes move within a cell to get a better position for sunlight.

Literature Cited Alberts B, Johnson A, Lewis J, et al. “Chloroplasts and Photosynthesis”, Molecular Biology of the Cell, 4th Ed. New York: Garland Science; 2002. Shannon, Cindy. “Cell Structure and Function”, Biology 4 Lecture Notes. Day & Nite; 2016. (9, 22)