Photosynthesis Chapter 8

What is energy? the ability to do work

Autotrophs and heterotrophs Plants and some other types of organisms are able to use light energy from the sun to produce food. - autotroph (producer): organisms such as plants, which use the sun to make their own food through photosynthesis - heterotroph (consumer): other organisms, such as animals, that cannot use the sun’s energy directly and must eat other organisms for food

Autotroph or heterotroph?

Autotroph or heterotroph?

Chemical Energy and ATP Energy comes in many forms, including light, heat, and electricity Energy can also be stored in chemical compounds!

Adenosine triphosphate (ATP) ATP is the chemical compound that living things use to store up energy made up of: - adenine (N containing compound) - ribose (5 C sugar) - 3 phosphate groups

Adenosine diphosphate (ADP) “Used” ATP contains: - adenine (N containing compound) - ribose (5 C sugar) - 2 phosphate groups 2

ADP vs. ATP Cells release the energy in ATP by removing a phosphate group and turning it into ADP. Cells can “re-charge” the ADP molecules by reconnecting the phosphate group through respiration.

ATP cells use ATP for active transport and movement

ATP and Glucose Cells must get energy from Carbohydrates to recharge the ATP a single molecule of glucose (sugar) stores more that 90X the chemical energy of one ATP!

8-2: Photosynthesis, An Overview

Photosynthesis vs. chemosynthesis photosynthesis: plants use the energy of sunlight to convert water and carbon dioxide into oxygen and high energy carbohydrates such as sugars and starches chemosynthesis: a similar process to photosynthesis, but it uses heat and sulfur compounds instead of sunlight. Found in some bacteria, especially deep in the ocean near volcanic vents.

The Photosynthesis Equation reactants products MEMORIZE THIS!

Light and Pigments Plants use a pigment called chlorophyll to trap the light. This is what gives them their green color. pigments: light absorbing molecules found in plants that gather the sun’s energy

Light and Pigments Chlorophyll is not the only pigment Carotenoids: plants also contain red, yellow, and orange pigments that absorb other wavelengths of light. We see these pigments in fall leaves

8-3: The Reactions of Photosynthesis

Inside a Chloroplast photosynthesis takes place inside a chloroplast

Inside a Chloroplast chloroplasts contain thylakoids, a sac-like photosynthetic membrane thylakoids contain pigments & proteins to capture the energy in sunlight thylakoids are arranged in stacks called grana (singular: granum) the gel-like matrix that surrounds the grana is called the stroma

Inside a Chloroplast photosynthesis is divided into two stages: 1. light-dependent: reaction that requires light. It releases Oxygen into the air. 2. Calvin Cycle: Does not require light. It creates the carbohydrates molecules

Light-Dependent Reactions Part One of Photosynthesis: light dependent reactions use light to produce O2 gas and create a small amount of ATP

The Calvin Cycle Part Two of Photosynthesis is the Calvin Cycle. It does not require light. Plants use the energy from the ATP made in the light reactions to build sugars that can be stored for a long time In photosynthesis, 6 CO2 molecules are used to produce 1 6–carbon sugar molecule (C6H12O6)

Factors Affecting Photosynthesis availability of water: too little water will slow or stop photosynthesis temperature: optimum (most photosynthesis occurs) temperatures between 0C and 35C intensity of light: more light, more photosynthesis

Question 1 Which of the following are autotrophs? a. impalas b. plants c. leopards d. mushrooms

Question 2 One of the principal compounds that living things use to store energy is a. DNA b. ATP c. H2O d. CO2

Question 3 In addition to light and chlorophyll, photosynthesis requires a. water and oxygen b. water and sugars c. oxygen and carbon dioxide d. water and carbon dioxide

Question 4 The leaves of a plant appear green because chlorophyll a. reflects blue light b. absorbs blue light c. does not absorb green light d. absorbs green light

Question 5 The products of photosynthesis are a. sugars and oxygen b. sugars and carbon dioxide c. water and carbon dioxide d. hydrogen and oxygen

Question 6 Which organelle contains chlorophyll? a. b. c. d.

Question 7 The first process in the light-dependent reactions of photosynthesis is a. light absorption b. electron transport c. oxygen production d. ATP formation

Question 8 Which substance from the light-dependent reactions of photosynthesis is a source of energy for the Calvin cycle? a. ADP b. ATP c. H2O d. pyruvic acid

Question 9 The light-independent reactions of photosynthesis are also known as the a. Calvin cycle b. Priestley cycle c. Ingenhousz cycle d. van Helmont cycle

Question 10 Which equation best summarizes the process of photosynthesis? a. b. c. d.