Photosynthesis and Metabolic Modes

These flashcards cover key concepts from the lecture on photosynthesis, including autotrophs, light reactions, pigments, and the overall process of photosynthesis.

Autotrophs

Organisms that make their own organic molecules from inorganic sources of Carbon (CO2).

Photoautotrophs

Autotrophs that use light energy to make organic molecules (e.g., plants, some algae, some bacteria).

Chemoautotrophs

Autotrophs that use chemical energy to make organic molecules (e.g., some bacteria and archaea).

Heterotrophs

Organisms that consume other organisms or dead organic matter for organic molecules.

Main Metabolic Modes

Refers to the different ways organisms obtain energy and matter for metabolism, including autotrophy and heterotrophy.

Chloroplast

An organelle in plant cells where photosynthesis occurs, mainly in mesophyll cells.

Photosynthesis Equation

Light + 6CO2 + 6H2O → C6H12O6 + 6O2, involves redox reactions and occurs in two stages: Light Reactions and Calvin Cycle.

Light Reactions

The first stage of photosynthesis where light energy is captured and converted into chemical energy.

Calvin Cycle

The second stage of photosynthesis that synthesizes glucose using carbon dioxide and the products of light reactions.

Pigments

Molecules that absorb light energy; in plants, chlorophylls a and b are the predominant pigments.

Photosystems

Complexes in the thylakoid membranes that contain pigments and proteins to harvest light energy.

Chlorophyll

Green pigment in plants that absorbs light energy for photosynthesis; includes a porphyrin ring and hydrocarbon tail.

Cyclic electron flow

A process in photosynthesis where electrons are cycled back to Photosystem I, helping maintain ATP levels.

NADP+ reductase

An enzyme that catalyzes the conversion of NADP+ to NADPH in the light reactions of photosynthesis.

Chemiosmosis

The process of ATP generation in chloroplasts, driven by a proton (H+) gradient across the thylakoid membrane.

ATP Synthase

An enzyme that synthesizes ATP from ADP and inorganic phosphate using the energy from H+ diffusion.

Comparison of Chemiosmosis

Differences in H+ gradient management between mitochondria and chloroplasts, relating to ATP production.

Porphyrin ring

The light-absorbing 'head' of chlorophyll molecules containing a magnesium atom at the center.

Visible Light

The spectrum of light that plants absorb for photosynthesis, ranging from violet to red wavelengths.

Primary Electron Acceptor

The molecule in the photosystems that accepts electrons boosted by light energy from chlorophyll.

P680 and P700

Special chlorophyll molecules in Photosystem II (P680) and Photosystem I (P700), respectively, involved in light absorption and electron transfer.