Photosynthesis and Photosynthesis and Cellular RespirationCellular 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

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.

Photosynthesis Reaction

6CO2 + 6 H2O + light

energy → C6H12O6 + 6O2

The food plants make is called glucose (sugar)

Photosynthesis

2 different reactions– Light Reactions

Capture light energy for photosynthesis

– Calvin Cycle Produces glucose

sugar

Cellular Respiration

Cells Breathing

Cellular Respiration

Happens in both plant and animal cells

Overall Reaction:– C6H12O6 + 6O2 → 6CO2 + 6H2O

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 32-34 ATP

Kreb’s Cycle (Citric Acid Cycle)

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.

Energy Tally

36 ATP for aerobic vs. 2 ATP for anaerobic

– Glycolysis 2 ATP

– Kreb’s 2 ATP

– Electron Transport 32 ATP 36 ATP

Anaerobic organisms can’t be too energetic but are important for global recycling of carbon