Biology- Calvin Cycle and 2.24

Calvin Cycle
2.24 Chemosynthesis

Multiple Choice

Which of the following is the correct equation for PHOTOSYNTHESIS?

• 6CO₂ + 6H₂O --> 6O₂ + C₆H₁₂O₆
• 6CO₂ + C₆H₁₂O₆ + 6H₂O --> O₂ 
• 6O₂ + 6H₂O --> 6CO₂ + C₆H₁₂O₆
• C₆H₁₂O₆ + 6O₂ ---> 6H₂O + 6CO₂ 

Multiple Choice

The two main stages of photosynthesis are the...

• light reactions and respiration
• dark reactions and the Calvin cycle 
• light reactions and the Calvin cycle
• dark reactions and fermentation

What You Will Learn

• The three major steps of the Calvin Cycle

• The role of carbon fixation, reduction, and regeneration in photosynthesis

• How ATP and NADPH are used to create glucose

Overview of the Calvin Cycle

• Occurs in the stroma of the chloroplast

• Uses ATP and NADPH from the light reactions

• Converts CO₂ into glucose through a series of chemical reactions

Multiple Choice

Where do the dark reactions or Calvin Cycle take place? 

• thylakoid membrane
• lumen
• stroma

Step 1- Carbon Fixation

• Carbon dioxide (CO₂) is attached to RuBP (a 5-carbon molecule) by the enzyme rubisco.

• This forms an unstable 6-carbon molecule, which splits into two 3-carbon molecules.

Step 2- Reduction

• ATP and NADPH are used to convert the 3-carbon molecules into G3P (Glyceraldehyde-3-phosphate).

• G3P can be used to form glucose.

• This is the stage where chemical energy is stored in glucose.

Multiple Choice

What molecules created in the light dependent reactions supply the energy to run the Calvin cycle?

• ATP & NADPH
• ADP & NADH
• chlorophyll & ATP 
• carotenoids & chlorophyll

Multiple Choice

What happens to NADPH and ATP after they are used in the Calvin Cycle?

• they recycle back to the light reactions
• they are used to make G3P

Step 3- Regeneration

• Some G3P is used to regenerate RuBP, allowing the cycle to continue.

• ATP is required to regenerate RuBP from G3P.

Summary

• Step 1: Carbon Fixation - CO₂ is fixed to RuBP.

• Step 2: Reduction - ATP and NADPH convert molecules to G3P.

• Step 3: Regeneration - RuBP is regenerated for the cycle to continue.

Multiple Choice

What is the name of the simple sugar that is produced in photosynthesis?

• Sucrose
• Dextrose
• Glucose
• Lactose

What You Will Learn

• The process of chemosynthesis

• How different organisms perform chemosynthesis

Living in Extreme Environments

• Organisms like the Pompeii worm survive at temperatures over 175°F.

• These organisms rely on bacteria that thrive in extreme conditions.

What is Chemosynthesis?

• Chemosynthesis uses chemical energy instead of light to make food.

• Autotrophs like bacteria use this process deep in the ocean.

• Converts CO₂ and inorganic compounds into organic matter using chemical reactions.

Multiple Choice

What is the source of energy for chemosynthesis

• Light energy
• Chemical energy
• Kinetic energy

Chemosynthesis Formula

• Example reaction:

  CO₂ + O₂ + 4H₂S → CH₂O + 4S + 3H₂O

• In this process, hydrogen sulfide is oxidized to produce carbohydrates.

Multiple Choice

What is chemosynthesis?

• Where bacteria use light energy to make glucose.
• Where plants use light energy to make glucose
• Where bacteria use chemical reactions to make glucose

Chemosynthetic Organisms

• Extremophiles live in places like deep-ocean black smokers.

• They use compounds like hydrogen sulfide for energy.

• Organisms like tubeworms rely on symbiotic bacteria to produce food.

Summary

• Chemosynthesis is the process where organisms use chemical energy instead of light to produce food.

• Found in extreme environments, it supports life where photosynthesis is impossible.