Transport Mechanisms

Various transport mechanisms facilitate the movement of molecules across cellular membranes, essential for cellular respiration.

Definition: Active transport moves molecules against their concentration gradient using energy from ATP.

Example: The ATP-dependent sodium-potassium pump is an example of active transport.

Highlight: Transport proteins can be classified as uniporters, symporters, or antiporters based on their mechanism of action.

Glycolysis Overview

The first stage of cellular respiration occurs in the cytoplasm, where glucose undergoes a series of enzymatic reactions to produce pyruvate. This process generates a net gain of 2 ATP molecules and 2 NADH.

Definition: Glycolysis is the metabolic pathway that converts glucose into pyruvate through a series of 10 enzyme-catalyzed reactions.

Highlight: The process can be divided into two phases: an energy investment phase (-2 ATP) and an energy yielding phase (+4 ATP).

Example: The conversion of glucose to glucose-6-phosphate requires ATP investment, while the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate generates ATP.

Vocabulary: Substrate-level phosphorylation - the direct transfer of a phosphate group from a phosphorylated compound to ADP to form ATP.