Bio 108 - Chapter 5 Exam 2 Study Guide

Process of photosynthesis

photosynthesis captures light energy from the sun and converts it to chemical energy stored in sugars and other organic molecules.

equation for photosynthesis

water + carbon dioxide + light energy  →  glucose + oxygen 

6H₂O +    6CO₂     + light energy  →  C₆H₁₂O₆ +  6O₂

Where does water enter the plant?

through the roots

Where does carbon dioxide enter the plant?

through pores in the leaf called stomata

Where does photosynthesis occur?

chloroplasts

Structure of chloroplast

Outer membrane = outside layer

Inner membrane = inside layer

Stroma = fluid → Calvin cycle (makes sugar)

Thylakoid membrane = contains chlorophyll → Light reactions

Grana = stacks of thylakoids

Chlorophyll molecules are embedded in the

inner thylakoid membrane

The primary function of plant pigments is

to absorb solar energy

leaves are green because

chlorophyll molecules absorb violet-blue and red light but reflect or transmit green-yellow light

Light Reactions

• Location: Thylakoid membrane

• Requires: Sunlight + H₂O

• Produces: ATP, NADPH, and O₂

• Purpose: Captures sunlight and converts it into chemical energy (ATP and NADPH).

Calvin Cycle (Light-Independent)

• Location: Stroma

• Requires: CO₂, ATP, and NADPH

• Produces: G3P (used to make glucose)

• Purpose: Uses the energy stored in ATP and NADPH to build sugar

List the processes of the light dependent reactions

Chlorophyll absorbs solar energy and ejects an electron, which is passed down an electron transport chain, and water is split, releasing O₂.

Be able to list the requirements for the light dependent reactions 

  H₂O, ADP, and NADP⁺

List the products of the light reactions

O₂ and the energy-storing compounds ATP and NADH.

List the requirements for the Calvin cycle reactions

ATP, NADPH, CO₂, a five-carbon sugar called RuBP, and the enzyme rubisco.

carbon dioxide is ______ during the Calvin cycle

fixed

The product of the Calvin cycle is

glyceraldehyde-3-phosphate (G3P) - can be used to make glucose.

Photosynthesis is the process

that stores energy in the form of glucose and that cellular respiration is the process that releases energy from glucose.

C3 Photosynthesis

• Most common type

• Less efficient in hot, dry climates

• Examples: wheat, rice

C4 Photosynthesis

• Adapted for hot, dry climates

• More efficient because it conserves water

• Examples: corn and sugar cane 🌽