Topic 5 Notes

Photosynthesis

The conversion of light energy to chemical energy, primarily in plants.

Autotrophs

Organisms that produce their own food from simple substances in their surroundings.

Heterotrophs

Organisms that cannot make their own food and depend on other organisms for nutrition.

Cyanobacteria

Early prokaryotes capable of photosynthesis that oxygenated the atmosphere of early Earth.

Chloroplast

Organelle in plant cells where photosynthesis occurs, containing chlorophyll and other components.

Stomata

Pores in leaves that allow carbon dioxide (CO2) in and oxygen (O2) out during photosynthesis.

Chlorophyll

Green pigment found in the thylakoid membranes of chloroplasts, essential for photosynthesis.

Light Reactions

The first stage of photosynthesis that converts solar energy into chemical energy (ATP and NADPH).

Calvin Cycle

The cyclic series of reactions in photosynthesis that uses ATP and NADPH to convert CO2 into sugar (G3P).

Photorespiration

A wasteful process occurring when rubisco binds to O2 instead of CO2, reducing photosynthetic efficiency.

ATP (Adenosine Triphosphate)

The primary energy carrier in cells, used in cellular processes.

Light-Dependent Reactions

Part of photosynthesis that requires light to produce ATP and NADPH.

Light-Independent Reactions

Also known as the Calvin Cycle, it does not require light to produce glucose.

Photosystems

Protein and pigment complexes that capture light energy during photosynthesis.

Rubisco

The enzyme that catalyzes the first step of the Calvin Cycle, fixing carbon dioxide.

Thylakoid

Membrane-bound structures in chloroplasts where the light-dependent reactions occur.

Granum

A stack of thylakoids in the chloroplast, site of photosynthesis.

Chloroplast DNA

The genetic material found in chloroplasts, distinct from nuclear DNA.

Fermentation

A metabolic process that converts sugar to acids, gases, or alcohol in absence of oxygen.

Glycolysis

The first stage of cellular respiration that breaks down glucose into pyruvate.

Electron Transport Chain

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

Oxygen Production

Generated as a byproduct of photosynthesis from the splitting of water molecules.

Carotenoids

Accessory pigments that assist in photosynthesis and provide colors to plants.

Mesophyll

The inner tissue of a leaf where most photosynthesis occurs, containing chloroplasts.

Pyruvate

The end product of glycolysis which enters the Krebs cycle in aerobic respiration.

Glucose

A simple sugar that is a key product of photosynthesis, used for energy.

Photophosphorylation

The process of generating ATP from ADP and inorganic phosphate during photosynthesis.

Stroma

The fluid-filled space in chloroplasts where the Calvin Cycle takes place.

Carbon Fixation

The process of converting inorganic CO2 into organic molecules within photosynthesis.

Domain Bacteria

A large group of prokaryotic microorganisms, including photosynthetic cyanobacteria.