Biology Chapter 7

Photosynthesis

The process of converting light energy into chemical energy in plants.

Chloroplasts

Organelles in plant cells where photosynthesis occurs.

Light-dependent reactions

The phase of photosynthesis that requires sunlight to produce ATP and NADPH.

Light-independent reactions

Also known as the Calvin Cycle, this phase does not require light and uses ATP and NADPH to fix carbon.

Thylakoids

Membrane-bound structures within chloroplasts that contain chlorophyll.

Stroma

The fluid-filled space surrounding thylakoids in chloroplasts.

Photolysis

The process of splitting water molecules in light-dependent reactions.

Electron Transport Chain (ETC)

A series of proteins in the thylakoid membrane that transfer electrons and generate ATP.

Chemiosmosis

The process by which ATP is produced using the proton gradient generated in the thylakoid membranes.

ATP Synthase

An enzyme that produces ATP as protons flow through it during chemiosmosis.

Calvin Cycle

The stage of photosynthesis that fixes carbon dioxide into glucose.

Carbon fixation

The process of converting CO2 into organic compounds in the Calvin Cycle.

RuBisCO

An enzyme that catalyzes the first step of carbon fixation.

G3P (Glyceraldehyde 3-phosphate)

The three-carbon compound produced in the Calvin Cycle from PGA.

NADPH

An electron carrier produced in the light-dependent reactions.

Glucose

The primary product of photosynthesis, serving as energy for organisms.

RuBP (Ribulose bisphosphate)

The five-carbon sugar that CO2 combines with during the Calvin Cycle.

C3 Plants

Plants that directly use RuBisCO for photosynthesis; less efficient in warm climates.

C4 Plants

Plants that use PEP carboxylase to fix CO2 more efficiently in hot climates.

CAM Plants

Plants that open stomata at night to conserve water and store CO2 for daylight use.

Oxygen (O2)

A byproduct of water splitting during photosynthesis.

Light intensity

An environmental factor that affects the rate of photosynthesis.

Temperature

An environmental factor that influences the efficiency of photosynthesis.

CO2 concentration

A variable affecting the rate of photosynthesis, where higher levels typically enhance production.

Water availability

A factor that is crucial for the process of photosynthesis and impacts plant health.

Mineral nutrients

Essential elements that support plant growth and photosynthesis.

Proton gradient

A difference in proton concentration used to drive ATP synthesis.

Photosystem II (PSII)

The first photosystem in the electron transport chain that absorbs light and initiates electron transport.

Photosystem I (PSI)

The second photosystem that uses light energy to reduce NADP+ to NADPH.

Cellular respiration

The process by which cells convert glucose into usable energy (ATP), releasing CO2 and water.

Energy cycle

The interconnected processes of photosynthesis and cellular respiration.

Electromagnetic spectrum

The range of all types of electromagnetic radiation.

Visible light

The portion of the electromagnetic spectrum that is visible to the human eye, used in photosynthesis.

Blue light (450 nm)

A wavelength of light that is highly effective in driving photosynthesis.

Red light (680 nm)

Another wavelength effective in photosynthesis, absorbed by chlorophyll.

Infrared light

A type of light used in thermal imaging.

Ultraviolet light

Light that can be used for sterilization or tanning.

X-rays

High-energy radiation used for medical imaging.

Photophosphorylation

The production of ATP from ADP and inorganic phosphate using light energy.

Oxidative phosphorylation

The production of ATP using energy from electron transport chains in respiration.

Final electron acceptor (NADP+)

In light reactions, the molecule that accepts electrons, forming NADPH.

Mitochondria

Organelles that carry out aerobic respiration in cells.

Glucose oxidation

The process of breaking down glucose to release energy during cellular respiration.

Stomata

Small openings on plant leaves that allow for gas exchange.

Proton pumping

The process of moving protons across a membrane to create a gradient.

ATP

A molecule that serves as the main energy carrier in cells.

Lumen

The interior space of a thylakoid.

Aerobic conditions

Conditions that require oxygen for cellular respiration.

Reduction phase (Calvin Cycle)

The stage where ATP and NADPH convert PGA to G3P.

Regeneration phase (Calvin Cycle)

The stage that uses ATP to convert some G3P back to RuBP.

ADP

A molecule that is converted into ATP during energy transfer.

NADP+

The molecule that accepts electrons to become NADPH.

Photosynthesis equation

6CO2 + 6H2O + light → C6H12O6 + 6O2.

Cellular respiration equation

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP.

Energy storage

The process of storing energy in the form of glucose during photosynthesis.

Photosynthesis products

Glucose and oxygen are the main products of the process.