Photosynthesis, Cellular Respiration, and Fermentation

Equation for Photosynthesis

6CO₂+6H₂O —> C₆H₁₀O₆+6O₂

Equation for Cellular Respiration

C₆H₁₀O₆+6O₂—>6CO₂+6H₂O

Cellular Respiration Definition

Process in which oxygen and glucose undergo a complex series of chemical reactions inside cells.

Purpose of Cellular Respiration

Produce ATP/energy

Who/what need carry out cellular respiration?

All living things

What do cells do when they need energy?

They break down energy rich compounds

Where does stage one of Cellular Respiration occur?

Cytoplasm

Stage 1 of Cellular Respiration

Glucose is broken down into smaller molecules. Oxygen isn’t involved. Only a small amount of energy is released.

Where does stage 2 of Cellular Respiration occur?

Mitochondria

Stage 2 of Cellular Respiration

Uses oxygen. Smaller molecules produced in stage 1 are broken down even more. Releases a lot of energy that cells use for their activities.

Reactants in cellular respiration

Glucose and oxygen

Where do organisms get the reactants needed for cellular respiration from?

Heterotrophs - get glucose from eating food. Autotrophs - make their own glucose. Air is a source of oxygen

Products of cellular respiration

CO₂ & H₂O

Role of the mitochondria in cellular respiration

Large amounts of energy are produced by chemical reactions that occur in the folds of the mitochondria. The amount of mitochondria depends on how much energy is needed.

Relationship between cellular respiration and photosynthesis?

Opposites - form a cycle. Keep levels of oxygen and carbon dioxide relatively constant in the atmosphere.

What happens to the energy produced through cellular respiration?

Used or lost as heat

Fermentation

Releases energy from food without using oxygen. Less energy is released than in cellular respiration.

When is fermentation useful?

In environments with limited oxygen

Where does alchoholic fermentation take place?

Live yeast cells (unicellular fungi)

What does alchoholice fermentation produce?

Alchohol, CO₂, and small amount of energy

How do bakers utilize alchoholice fermentation?

Carbon dioxide creates gas pockets in bread dough, causing dough to rise.

When does lactic acid fermentation occur?

When the body (muscle cells) use up oxygen faster than it can be replaced

What compound is a product of fermentation in muscles?

Lactic Acid

Lactic Acid

Produced during lactic acid fermentation. Fuels muscles and goes away shortly after workout.

What is photosynthesis?

• Process where cells capture energy in sunlight and use it to make food

Where do all organisms get energy from?

Sunlight - direct or indirect

In which organelle does photosynthesis occur?

Chloroplast

Byproduct of photosynthesis

Oxygen

Stage 1 of Photosynthesis

• Chloroplasts use chlorophyll to absorb sunlight

• Sunlight splits water molecules into hydrogen and oxygen

• Hydrogen combines with other atoms during stage 2

• Oxygen is released through openings on underside of leaf

What is chlorophyll?

Green photosynthetic pigment that traps sunlight

What are sugars useful for?

Building larger molecules

Stage 2 of Photosynthesis - Glucose

• C₆H₁₂O₆

  • Most important: sugar produced in photosynthesis

  • H came from splitting water molecules 

  • CO₂ entered through underside of leaf

Reactants of photosynthesis

Carbon Dioxide and Water

Sunlight isn’t a reactant, but it is a requirement

Products of photosynthesis

Glucose and oxygen

Why are plant cells important?

Natural flood control. Absorb 1/6 of the sun’s energy. Ocean plants produce 85% of the world’s oxygen