The Light Independent Reactions The Light Independent reactions

The Light Independent Reactions • The Light Independent reactions take place in sunlight. • If ATP and NADPH are provided, they can be carried out without light (dark reactions). • Like the light-dependent reactions they occur in the chloroplast but in the area surrounding the thylakoid membranes called the stroma.

The Light Independent Reactions • The light independent reactions are also called the Calvin Cycle. • This is because the reactions form a cycle and were discovered by Melvin Calvin. • The Calvin cycle reactions use carbon dioxide (CO 2) along with ATP and NADPH, which were formed by the light reactions, to produce PGAL.

The Light Independent Reactions • PGAL (phosphoglyceraldehyde) is a molecule that is used to make glucose and other organic compounds (e. g. , amino acids & lipids). • Glucose is made because it is more stable and can store more energy than either NADPH or ATP. • To summarize, the light independent reactions provide the raw materials that are used to make most of what the cell needs to survive.

Light Reactions light ATP + NADPH + O 2 energy H 2 O + H 2 O sunlight Energy Building Reactions NADPH ATP AP Biology O 2 § produces ATP § produces NADPH § releases O 2 as a waste product

Calvin Cycle CO 2 + ATP + NADPH C 6 H 12 O 6 + ADP + NADP CO 2 ADP NADP Sugar Building Reactions NADPH ATP AP Biology sugars § builds sugars § uses CO 2, ATP & NADPH § recycles ADP & NADP § back to the lightdependent reactions to make more ATP & NADPH

Photosynthesis

The Light Independent Reactions

The Light Independent Reactions

What factors affect photosynthesis? • 1. Temperature: Photosynthetic enzymes function best between 0°C (32°F) and 35°C (95°F). • 2. Light: High light intensity increases the rate of photosynthesis, up to a certain level. • 3. Water: A shortage of water can slow or even stop photosynthesis.

GLYCOLYSIS AND RESPIRATION glucose (sugar) + oxygen C 6 H 12 O 6 + 6 O 2 carbon dioxide + water 6 CO 2 + 6 H 2 O • Energy stored in chemical bonds of glucose can be used when the bonds are broken. • Cells capture the energy of glucose through the processes of glycolysis and respiration.

GLYCOLYSIS • Glycolysis, which means glucose breaking, is the first phase in the break down of glucose. • It is an anaerobic phase because it takes place without oxygen. • It takes place in the cytoplasm of the cell. • It requires two molecules of ATP to start the process.

GLYCOLYSIS • During the process, the 6 -carbon glucose is split into two 3 - carbon PGAL molecules. • The two PGAL molecules are then transformed into two molecules of pyruvic acid. • During the process, 4 molecules of ATP are produced, resulting in a net gain of 2 ATP. • Also, 2 NADH molecules are produced. • NADH is an energy-storing compound.

GLYCOLYSIS Summary: • In glycolysis, glucose is changed by enzymes into different molecules one step at a time through a series of chemical reactions. • The initial glucose molecule is broken down and transformed into the final product, which is two molecules of pyruvic acid.

GLYCOLYSIS