Bio: Ch6 flashcards

Photosynthesis

The process of changing solar energy into chemical energy that can be used by plants or animals that eat the plants.

Producers

Organisms that carry out photosynthesis and are responsible for most chemical energy sources, fueling most life on Earth.

Stomata

Openings in plant leaves that collect carbon dioxide (CO2).

Mesophyll cells

Cells in plants that contain chloroplasts and are involved in photosynthesis.

Chloroplasts

Organelles surrounded by a double membrane, containing the stroma and thylakoids where photosynthesis occurs.

Stroma

The fluid within the chloroplast where various reactions of photosynthesis occur.

Thylakoids

Membrane systems in chloroplasts that contain the pigment necessary for capturing solar energy.

Grana

Stacks of thylakoids within the chloroplast.

Thylakoid space

The space formed by connected thylakoids.

Light Reactions

The first stage of photosynthesis where solar energy is converted into chemical energy in the form of ATP and NADPH.

ATP Synthase

An enzyme complex that synthesizes ATP using the energy from the flow of hydrogen ions down their concentration gradient.

Calvin Cycle

The series of reactions in photosynthesis that convert CO2 into glucose using ATP and NADPH produced in the light reactions.

Rubisco

The enzyme responsible for fixing carbon dioxide in the Calvin cycle.

G3P

Glyceraldehyde 3-phosphate, a three-carbon intermediate in the Calvin cycle, used to synthesize glucose and other organic molecules.

C3 Photosynthesis

The primary form of photosynthesis where the first product is a three-carbon molecule, with characteristics that give it inefficiencies under hot and dry conditions.

C4 Photosynthesis

An adaptation allowing plants to fix carbon dioxide into a four-carbon molecule to minimize photorespiration in hot and dry conditions.

CAM Photosynthesis

Crassulacean-Acid Metabolism, a method of photosynthesis where CO2 is fixed at night to reduce water loss in arid environments.

Photorespiration

A process that occurs when oxygen competes with carbon dioxide for the active site of rubisco, reducing photosynthetic efficiency.

Visible Light

The portion of the electromagnetic spectrum that is visible to the human eye, ranging from violet to red.

Electromagnetic Spectrum

The range of all types of electromagnetic radiation, including visible light.

Reduction Reaction

A chemical reaction where a molecule gains electrons and hydrogen ions.

Oxidation Reaction

A chemical reaction in which a molecule loses hydrogen ions.

Redox Reaction

A reaction involving the transfer of electrons from one molecule to another, consisting of both reduction and oxidation.

What is the fundamental process of photosynthesis?

Photosynthesis is the process of changing solar energy into chemical energy that can be used by plants or animals that eat the plants.

What role do producers play in the ecosystem in relation to photosynthesis?

Producers are organisms that carry out photosynthesis and are responsible for most chemical energy sources, fueling most life on Earth.

Which organelles are primarily responsible for photosynthesis in plant cells?

Chloroplasts, which contain the stroma and thylakoids, are the organelles where photosynthesis occurs.

What are the two main stages of photosynthesis?

The two main stages are the Light Reactions and the Calvin Cycle.

What is the primary outcome of the Light Reactions in photosynthesis?

The Light Reactions convert solar energy into chemical energy in the form of ATP and NADPH.

What is the main goal of the Calvin Cycle?

The Calvin Cycle converts carbon dioxide (CO_2) into glucose using the ATP and NADPH produced in the Light Reactions.

What is the function of the enzyme Rubisco in the Calvin Cycle?

Rubisco is responsible for fixing carbon dioxide (CO_2) during the initial step of the Calvin Cycle.

What is G3P and what is its significance in photosynthesis?

G3P (Glyceraldehyde 3-phosphate) is a three-carbon intermediate product in the Calvin cycle that is used to synthesize glucose and other organic molecules.

Why have C4 and CAM photosynthesis evolved as adaptations?

C4 and CAM photosynthesis are adaptations that allow plants to minimize photorespiration and reduce water loss, particularly in hot and dry conditions.

What is photorespiration and why is it considered inefficient?

Photorespiration is a process where oxygen competes with carbon dioxide for the active site of the enzyme rubisco, which reduces the efficiency of photosynthesis because it consumes energy without producing sugar.