PhotosynthesisPhotosynthesis

Chapter 8

What is energy?What is energy?

the ability to do work

Autotrophs and heterotrophsAutotrophs and heterotrophs

Plants and some other types of Plants and some other types of organisms are able to use organisms are able to use light energylight energy from the from the sunsun to produce to produce foodfood..

- - autotroph (producer): organisms such autotroph (producer): organisms such as plants, which use the sun to make as plants, which use the sun to make their own food through photosynthesistheir own food through photosynthesis

- heterotroph (consumer): other - heterotroph (consumer): other organisms, such as animals, that cannot organisms, such as animals, that cannot use the sun’s energy directly and must use the sun’s energy directly and must eat other organisms for foodeat other organisms for food

Autotroph or heterotroph?Autotroph or heterotroph?

Autotroph or heterotroph?Autotroph or heterotroph?

Chemical Energy and ATPChemical Energy and ATP

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

Adenosine triphosphate (ATP)Adenosine triphosphate (ATP)

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

Adenosine diphosphate (ADP)Adenosine diphosphate (ADP)

“Used” ATPcontains:- adenine (N containing compound)- ribose (5 C sugar)- 2 phosphate groups

2

ADP vs. ATPADP vs. ATPCells 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.

ATPATPcells use ATP for cells use ATP for active transportactive transport and and movementmovement

ATP and GlucoseATP and Glucose

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

8-2: Photosynthesis, 8-2: Photosynthesis, An OverviewAn Overview

Photosynthesis vs. chemosynthesisPhotosynthesis 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 EquationThe Photosynthesis Equation reactants products

MEMORIZE THIS!

Light and PigmentsLight and PigmentsPlants 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 PigmentsLight and PigmentsChlorophyll is not the only pigmentCarotenoids: 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 8-3: The Reactions of PhotosynthesisPhotosynthesis

Inside a ChloroplastInside a Chloroplastphotosynthesis takes place inside a chloroplast

Inside a ChloroplastInside a Chloroplastchloroplasts contain thylakoids, a sac-like photosynthetic membranethylakoids 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 ChloroplastInside a Chloroplastphotosynthesis 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 ReactionsLight-Dependent Reactions

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

The Calvin CycleThe Calvin CyclePart 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 timeIn photosynthesis, 6 CO2 molecules are used to produce 1 6–carbon sugar molecule (C6H12O6)

Factors Affecting PhotosynthesisFactors Affecting Photosynthesisavailability of water: too little water will slow or stop photosynthesistemperature: optimum (most photosynthesis occurs) temperatures between 0C and 35Cintensity of light: more light, more photosynthesis

Question 1Question 1

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

Question 2Question 2

One of the principal compounds that living things use to store energy isa. DNA b. ATPc. H2Od. CO2

Question 3Question 3

In addition to light and chlorophyll, photosynthesis requires a. water and oxygenb. water and sugarsc. oxygen and carbon dioxided. water and carbon dioxide

Question 4Question 4

The leaves of a plant appear green because chlorophyll a. reflects blue lightb. absorbs blue lightc. does not absorb green lightd. absorbs green light

Question 5Question 5

The products of photosynthesis are a. sugars and oxygenb. sugars and carbon dioxidec. water and carbon dioxided. hydrogen and oxygen

Question 6Question 6

Which organelle contains chlorophyll? a.

b.

c.

d.

Question 7Question 7

The first process in the light-dependent reactions of photosynthesis is a. light absorptionb. electron transportc. oxygen productiond. ATP formation

Question 8Question 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 9Question 9

The light-independent reactions of photosynthesis are also known as the a. Calvin cycleb. Priestley cyclec. Ingenhousz cycled. van Helmont cycle

Question 10Question 10

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