Photosynthesis Biology I Chapter 6

Do Now List 5 things that you have eaten in the past 24 hours. Crash Course-Energy

Do Now In 2 lines, explain how ATP adds and removes phosphate groups, include the name of the processes.

Energy Heterotroph-organisms that consume other organisms for their food. Autotroph-organisms that make their own food.

ATP-Adenosine Triphosphate-primarily used as an energy source in living organisms. “Gas" that powers a cell's "engine." ATP molecules store cellular energy. When phosphate groups are removed and molecules of ADP are formed, energy is released. This energy can be used to perform cellular work.

Photosynthesis-the process whereby plants capture energy and make complex molecules. Photosynthesis releases oxygen & sugar. Cellular respiration releases carbon dioxide and water. The sun is considered the ultimate source of energy for life on Earth because either photosynthetic organisms or organisms that have eaten them provide energy for all other organisms on Earth.

Light Energy When light strikes an object, the light may be reflected, transmitted or absorbed. Chlorophyll is green because it reflects green wavelengths of light. Why do the cells of plant roots generally lack chloroplasts?

Do Now In 2 lines, explain the difference between an autotroph and a heterotroph.

Chloroplasts Chloroplast-organelle that is the site of photosynthesis and contains the green pigment chlorophyll Stacks of thylakoids, called grana, are suspended in the stroma of chloroplasts. Thylakoid-System of membranes inside the chloroplast; are arranged in sacs. Grana-stacks inside inner membrane. Stroma-solution surrounding the grana.

Phases of Photosynthesis Photosynthesis Song During the light reactions, plants use the sun’s energy and water to produce energy for the Calvin Cycle, and release oxygen as a waste product. Occurs in the thylakoids. During photosynthesis, the series of reactions that create the complex carbohydrates needed for energy and growth is called the light reactions. The second stage of photosynthesis, in which glucose is manufactured, is called the Calvin Cycle. Occurs in the stroma.

O2 H2O CO2 Light NADP+ ADP LIGHT REACTIONS (in thylakoids) CALVIN Chloroplast Light NADP+ ADP + P LIGHT REACTIONS (in thylakoids) CALVIN CYCLE (in stroma) ATP Electrons NADPH Figure 7.5 O2 Glucose

Steps of Photosynthesis Photosystems I & II, the primary electron receptors, and the electron transport chains are embedded in the membrane of the thylakoids.

Steps of Photosynthesis The electrons from photosystem II are transferred to photosystem I, and the electrons are replaced by the splitting of water molecules.

Steps of Photosynthesis At the end of the electron transport chain, electrons combine with NADP+ and H+ to form NADPH.

Steps of Photosynthesis This reaction occurs in the stroma, the solution in which the thylakoids are located inside the chloroplast.

Chemiosmosis Occurs in the thylakoid membrane and converts captured light energy into chemical energy Chemiosmosis in the thylakoid membrane results in the synthesis of ATP. Light Cycle Light Reaction and Chemiosmosis

Do Now Cells obtain energy by either capturing light energy through photosynthesis or by breaking down carbohydrates through cellular respiration. In both photosynthesis and cellular respiration, the energy is ultimately derived from the Sun in a A. highly efficient process which involves no loss of heat to the environment. B. one-way process. C. reversible process. D. pathway that involves taking in heat from the environment at each step.

Do Now During photosynthesis, plants take in light energy from the Sun, carbon dioxide from the air, and water through their roots to produce A. proteins and nitrogen. B. sugar and nitrogen. C. sugar and oxygen. D. proteins and oxygen.

Transition Products of the light reactions of photosynthesis that provide energy for the Calvin cycle are ATP and NADPH. Transition

Calvin Cycle Calvin Cycle-The series of reactions that create the complex carbohydrates needed for energy and growth. Carbon Fixation-The carbon atoms from CO2 in the atmosphere are bonded, or “fixed” into organic compounds. Occurs within the stroma of the chloroplast

Calvin Cycle Overview Carbohydrates, Proteins, & Lipids are produced from the products of the Calvin cycle. Calvin Cycle Overview Calvin Cycle

Do Now What are the two phases of photosynthesis?

Alternative Pathways Stomata-small pores that allow plants to lose water; allows gas exchange between the environment and the inside of leaves Open during the day; closed at night. C3 plants fix carbon exclusively through the Calvin Cycle. C4 plants fix carbon even when stomata are closed; have an enzyme that can fix CO2 into a 4-carbon sugar. C3 and C4 plants have their stomata open during the day and CAM plants have their stomata open only at night.

Photosynthesis Overview The source of oxygen produced during photosynthesis is water. The major atmospheric byproduct of photosynthesis is oxygen. The source of glucose produced during photosynthesis is carbon dioxide.

Factors that Affect Photosynthesis Light Intensity Photosynthesis increases as light intensity increases. Carbon Dioxide Levels Increasing levels of CO2 increase photosynthesis. Temperature Crash Course-Photosynthesis Virtual Photosynthesis Lab

Do Now During photosynthesis, plants capture light energy from the Sun to break weak bonds in reactants, such as carbon dioxide and water, and form carbon-containing molecules, such as glucose. The carbon-containing molecules can then be used A. to produce inorganic compounds, such as sulfuric acid. B. to synthesize essential amino acids. C. to assemble larger molecules, such as DNA, proteins, and fats. D. all of these

Do Now Write the chemical formula for photosynthesis. 6 H2O + 6 CO2 + Sun  C6H12O6 + 6 O2