Photosynthesis and Cellular Respiration

Two ways to get food “troph” = food Autotrophs – Auto = self – Autotrophs make their own food Heterotrophs – Hetero = different – Heterotrophs get their food from something else (they have to eat it)

Two ways to get food Autotrophs – Plants Heterotrophs – Animals

Photosynthesis

Water Cycle – remember when water vapor exits a leaf we called it TRANSPIRATION, not evaporation.

Photosynthesis Converts the sun’s energy into chemical energy stored in sugar Takes place in specialized structures inside plant cells called chloroplasts – Chlorophyll is the pigment that absorbs sunlight.

Thylakoid Membrane

Photosynthesis 2 different reactions – Light Reactions Capture light energy for photosynthesis – Calvin Cycle Produces glucose sugar

Light Reaction – Light dependent Reaction (Occurs in the thylakoid membrane of chloroplast) 1.Water splits, O2 is released into atmosphere 2. Electrons from 2 Hydrogen's are captured by chlorophyll, in photosystem ll. 3.Electrons are energized by sunlight 4. Some energy is stored in ATP molecule 5. Electrons are Re-energized By sunlight 6. Spent e- Picked up NADP taxi

Someone interpretation of how energized electrons travel through the Electron Transport Chain.

Can you identify the reactants and the products of light Reaction?

Photosynthesis Reaction 6CO H 2 O + light energy → C 6 H 12 O 6 + 6O 2 Can you circle the reactants and the products just for Light reaction. Was chlorophyll needed in light reaction?

Dark Reaction – also called Light Independent reaction or Calvin Cycle

Dark Reaction (Calvin Cycle) Remember : Calvin is DARK and SWEET

*Where is the Dark Reaction occurring in the Chloroplast? *What reactant does Dark Reaction start with?

Cellular Respiration Cells Breathing

Cellular Respiration Happens in both plant and animal cells Overall Reaction: – C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O

Cellular Respiration Overview Depends on whether or not there is oxygen Aero = oxygen Aerobic Respiration – makes energy Anaerobic Respiration – Fermentation (makes alcohol)

Step 1: Glycolysis The energy that cells make and use is called ATP – Adenosine triphosphate Glycolysis makes 2 molecules of ATP (energy) Glycolysis happens in the cytoplasm of the cell

Step 2: Check for Oxygen If oxygen is present, the cell can make more ATP If no oxygen is present, the cell has to recycle the pieces from glycolysis and makes alcohol.

Step 3 with oxygen: Cellular Respiration Oxygen required=aerobic 2 more sets of reactions which occur the cell’s mitochondria – 1. Kreb’s Cycle – makes 2 ATP Also called the Citric Acid Cycle – 2. Electron Transport Chain – makes ATP

Step 3 without oxygen: Fermentation The cell must recycle the materials from glycolysis. This recycling process is called fermentation. The product of fermentation is alcohol.

Kreb’s Cycle (Citric Acid Cycle)

Energy Tally 36 ATP for aerobic vs. 2 ATP for anaerobic – Glycolysis 2 ATP – Kreb’s 2 ATP – Electron Transport32 ATP 36 ATP Anaerobic organisms can’t be too energetic but are important for global recycling of carbon