UNIT 5: Photosynthesis and Respiration BIG IDEA: Energy is produced and released by making and breaking chemical bonds

Think About It: With your partner, come up with a list of activities that you do that requires energy What gives us energy?

Energy Directly or indirectly , all energy in living things comes from the sun

Obtaining Energy Autotrophs Organisms that are capable of making food (energy) from simple inorganic substances EX: green plants, algae

Two Types of Autotrophs 1. Photoautotrophs: use carbon dioxide and light energy to drive reactions needed to make food

Next type… 2. Chemoautotrophs: utilize inorganic chemicals for the energy to drive food making reactions

Obtaining Energy Heterotrophs Organisms that cannot make their own food (energy) and must depend on other plants or animals as food source (energy) Examples: Humans, dogs, cats

Photosynthesis Process of capturing energy of sunlight and transforming it into chemical energy CO2 + H2O----glucose + O2

Photosynthesis Two stages Light reactions- light energy is converted into chemical energy of two intermediate molecules Calvin cycle-Organic molecules are formed from CO2

Photosynthesis Sunlight, sometimes called white light, is a form of energy that travels in waves Wavelength: the distance between the crest of one wave and the crest of the next wave

Visible Light Spectrum Depends on wavelength Blue: 380 (nm) Green: 500 (nm) Yellow 560 (nm) Light red: 600 (nm) Darker red: 750 (nm)

Photosynthesis Pigments: absorb light EX: a red object absorbs all the visible colors of the spectrum except red which is reflected and gives the object the red color

Types of Photosynthetic Pigments Chlorophylls: absorb red and blue light, appear green Carotenes: absorb blue, appear orange Xanthophylls: appear yellow, may not be used to absorb light

                  The color of an egg yolk is from the xanthophyll carotenoids lutein and zeaxanthin The color of an egg yolk is from the xanthophyll carotenoids lutein and zeaxanthin

CHLOROPLAST Site of Photosynthesis

PARTS OF THE CHLOROPLAST Inner and outer membrane Thylakoids Grana Stroma

Parts of the Chloroplast Thylakoid- Membrane of the thylakoid contains photosynthetic pigments; flattened sacs Site of the light reactions

Parts of the Chloroplast Grana- Stacks of thylakoids Stroma-Region b/t grana Site of the light independent reactions

Photosynthesis Reactions Light Dependent Reactions-energy from light makes the reaction happen Light Independent Reactions- Doesn’t need the energy from light to make the reaction happen but they do need products of the light reaction to proceed.

Steps in Light Dependent

Light Dependent Reactions- In the Chloroplast Pigments in the photosynthetic membranes absorb light (pigments are located in Photosystem I & II When the light hits the chlorophyll in Photosystem II the electrons become excited and jump up.

The electrons are captured by the electron transport chain. We need to replace the electrons that are lost so we steal some from water . This breaks the water molecule apart forming H+ and O

As we transport electrons down the chain we use their energy to produce ATP The electrons now go to Photosystem I and it loses electrons to NADP+ to make it NADPH.

The final products of the light reaction At the end of the light reaction we have made NADPH ATP O2

Reactants used during the light reaction Water Also used sunlight

Light independent reaction ( Calvin Cycle) A. Use CO2 , ATP, NADPH B. Uses products from light reaction (Light is not necessary for this reaction) C. Location stroma

Steps in Light Independent Reaction: 6 CO2 reacts with the sugar, ribulose phophate (RuBP)sugar called phosphoglycerate (PGA) PGA12 phosphoglyceraldehyde (PGAL) NADPH and ATP from light reaction provide energy for this step

Steps in Light Independent Reaction (con’t) PGAL does 2 things: Makes more RuBP to continue cycle (requires 10 PGAL to do this) b. Form 1 glucose (requires 2 PGAL)

Concept Map Section 8-3 Photosynthesis includes Light- dependent reactions Calvin cycle takes place in uses use take place in Thylakoid membranes Stroma NADPH ATP Energy from sunlight to produce of to produce ATP NADPH O2 Chloroplasts High-energy sugars

Figure 8-7 Photosynthesis: An Overview Section 8-3 Light O2 Sugars CO2 Chloroplast Chloroplast NADP+ ADP + P Calvin Cycle Light- Dependent Reactions ATP NADPH

Factors Affecting Photosynthesis Four main types: Light intensity Temperature Water Mineral availability

Cellular Respiration Release of the energy stored in food Occurs in the inside of the cells of both autotrophs and heterotrophs

Adenosine Triphosphate (ATP) Energy released during cellular respiration is stored as ATP Consists of adenine, ribose and three phosphates

How is energy stored in ATP? Energy is stored in the bonds. Once a bond breaks (causing ATP to lose a phosphate group), there is a release of energy.

Release of Energy

Adenosine diphosphate or (ADP) Two phosphate groups, adenine, and ribose Where would the energy be in ADP

Two Types of Cellular Respiration Aerobic Respiration: Occurs in presence of oxygen Occurs in the mitochondria Produces about 36 ATP

Second Type of Cellular Respiration Anaerobic Respiration: Occurs without oxygen Occurs in the cytoplasm Produces 2 ATP

Which type of cellular respiration is more efficient? Aerobic because it produces more ATP (more energy)

Two types of Anaerobic Respiration: 1. Alcoholic Fermentation: yeast produces alcohol 2. Lactic Acid Fermentation: muscles produces lactic acid when they don’t have enough oxygen

What is the equation for cellular respiration? GLUCOSE+ 6O26 CO2 + 6 H2O + Energy (36 ATP)

What is the relationship between photosynthesis and cellular respiration? Opposite reactions Let’s write the two reactions to see