Cellular Respiration and Photosynthesis Flashcards

Vocabulary flashcards about cellular respiration and photosynthesis.

Cellular Respiration

The process of breaking down glucose into CO₂ and using the energy to make ATP.

Glycolysis

Splits glucose (6C) into 2 pyruvate (3C), producing 2 ATP and 2 NADH.

Citric Acid Cycle

Pyruvate is converted to Acetyl-CoA, releasing CO₂, and producing NADH, FADH₂, and ATP.

Oxidative Phosphorylation

NADH/FADH₂ donate electrons to the ETC, leading to ATP production. Uses O₂ as the final electron acceptor, creating H₂O.

ATP & NADH

Energy 'money' that is recycled, not made from scratch, during cellular respiration.

Citric Acid Cycle Location and Function

Takes place in the mitochondrial matrix, involving a series of 8 enzyme-driven reactions to break down carbon molecules and release energy.

Substrate-Level Phosphorylation

A way to make ATP directly during the citric acid cycle when an enzyme uses energy from the reaction to build ATP.

Oxidative Phosphorylation

Final step of cellular respiration, converting NADH and FADH₂ into ATP. Requires oxygen.

Electron Transport Chain (ETC)

NADH and FADH₂ donate electrons to a chain of proteins in the membrane, pumping protons and creating potential energy.

Chemiosmosis

H⁺ flows back into the matrix through ATP Synthase, powering the synthesis of ATP from ADP + P.

Oxygen's Role in ETC

Final electron acceptor in the ETC, combining with electrons and H⁺ to form H₂O.

ATP Synthase

A complex enzyme that uses the proton gradient like a waterwheel to generate ATP.

Fermentation

A backup process that kicks in when there’s no oxygen. It occurs in the cytoplasm and lets glycolysis continue by recycling NADH into NAD⁺.

Lactic Acid Fermentation

Happens in muscle cells and causes soreness.

Alcohol Fermentation

Occurs in yeast and produces ethanol and CO₂.

Competitive Inhibitor

Blocks the enzyme’s active site.

Non-competitive Inhibitor

Changes enzyme shape by binding elsewhere.

Photosynthesis

Process where plants use light, CO₂, and water to make glucose and oxygen.

Stroma

Fluid within the chloroplast where sugars are made (Calvin Cycle).

Thylakoids

Contain chlorophyll, where light is absorbed.

Light Reactions

Use light to make ATP and NADPH. Water is split, and oxygen is released. Takes place in thylakoid membrane

Calvin Cycle

Uses ATP and NADPH to turn CO₂ into glucose. Takes place in stroma.

Photosystem II (PSII) and Photosystem I (PSI)

Named by discovery order, both contain chlorophyll, which absorbs light energy is located in the thylakoid membrane.

Photosystem II

PSII electron passed to PSI. Energy is used to pump protons into thylakoid space → creates proton gradient and drives ATP synthesis.

Photosystem I

Re-excites the electron with more light and electron passed to NADP⁺, reducing it to NADPH.

Electron Source for PSII

Replaces lost electrons by splitting H₂O producing O₂ and adds more protons to the gradient.

Cyclic Electron Flow

Only uses PSI. Electrons cycle back into the ETC producing only ATP and no NADPH

Calvin Cycle Goal

The main goal is to make sugars (starting with a 3-carbon sugar, which can become glucose).

Photorespiration

Rubisco sometimes makes a mistake: when O₂ is high and CO₂ is low, rubisco uses O₂ instead of CO₂ which wastes energy and releases CO₂.

C4 Plants

Fix CO₂ in mesophyll cells using a different enzyme and then send that carbon to rubisco in bundle sheath cells, separating CO₂ fixation from rubisco by space.

CAM plants

Fix CO₂ at night and store it and during the day, they release the stored CO₂ to rubisco separating the process by time instead of space.