Photosynthesis pt 1

These flashcards cover key concepts related to photosynthesis, including processes, structures, and terminology.

What is photosynthesis?

The biological process by which plants, algae, and some bacteria convert light energy into chemical energy (glucose) using carbon dioxide (CO2) and water (H2O).

What is the overall chemical equation for photosynthesis?

6CO2 + 6H2O + \text{light energy} \rightarrow C6H{12}O6 + 6O2

Explain the role of ATP (Adenosine Triphosphate) in cellular processes.

ATP is the primary energy currency of the cell. It stores and transfers energy to power various cellular activities, including muscle contraction, nerve impulse transmission, and the synthesis of molecules. In photosynthesis, it is generated during the light reactions.

Where does photosynthesis primarily occur in plant cells?

Photosynthesis primarily takes place in chloroplasts, which are specialized organelles located mainly in the mesophyll cells of leaves.

What are the key internal structures of a chloroplast?

1. Outer and Inner Membranes: Enclose the organelle.
2. Stroma: The fluid-filled space within the inner membrane.
3. Thylakoids: Sac-like membranous compartments suspended in the stroma.
4. Grana (singular: Granum): Stacks of thylakoids where chlorophyll is concentrated.

What are thylakoids and what is their function in photosynthesis?

Thylakoids are membrane-bound compartments located inside chloroplasts. They contain chlorophyll and other pigments, and are the primary sites where the light-dependent reactions of photosynthesis occur, capturing light energy.

What is the stroma of a chloroplast and what process occurs there?

The stroma is the fluid-filled space that surrounds the thylakoids within the inner chloroplast membrane. This is where the Calvin cycle (light-independent reactions) takes place, converting carbon dioxide into glucose.

How does the electromagnetic spectrum relate to photosynthesis?

Photosynthesis utilizes a specific range of the electromagnetic spectrum, primarily visible light (wavelengths between 400 and 700 nm). Different photosynthetic pigments absorb different wavelengths of this light to drive the light reactions.

What is chlorophyll and its primary role in photosynthesis?

Chlorophyll is a green pigment found in the thylakoid membranes of chloroplasts. Its primary role is to absorb light energy, particularly in the blue and red regions of the visible spectrum, which powers the initial steps of photosynthesis.

What are carotenoids and their function in photosynthesis?

Carotenoids are accessory pigments responsible for yellow, orange, and red colors in plants. They broaden the range of light wavelengths absorbed for photosynthesis and also protect chlorophyll from potential photodamage.

Describe the Calvin Cycle (light-independent reactions) of photosynthesis.

The Calvin Cycle is a series of biochemical reactions occurring in the stroma of chloroplasts. It uses the ATP and NADPH produced during the light reactions to convert (fix) atmospheric carbon dioxide (CO_2) into glucose (sugars). This cycle does not directly require light.

What is the role of NADPH (Nicotinamide Adenine Dinucleotide Phosphate) in the Calvin cycle?

NADPH is an electron carrier molecule that acts as a reducing agent in the Calvin cycle. It provides the high-energy electrons (reducing power) necessary to reduce carbon dioxide (CO_2) into glucose. NADPH is produced during the light reactions.

What are the Light Reactions (light-dependent reactions) of photosynthesis?

The Light Reactions are the first stage of photosynthesis, occurring in the thylakoid membranes. Light energy is captured by pigments, leading to the splitting of water (H2O) (photolysis), the release of oxygen (O2), and the production of ATP and NADPH.

From where does the oxygen released during photosynthesis originate?

Oxygen (O2) is a by-product of the light-dependent reactions of photosynthesis. It originates directly from the splitting of water molecules (H2O) during a process called photolysis, and is then released into the atmosphere.