Cellular Respiration Flashcards
Describe the process of cellular respiration in general terms.
Cellular respiration is the breakdown of nutrients with the accompanying synthesis of ATP. It is the process by which chemical energy found in organic nutrients is converted to energy useable by living cells.
Describe the roles of ATP, NAD, and FAD in energy metabolism in the cell.
NAD and FAD participate in electron transfer reactions called reduction-oxidation reactions or redox reactions. Reduction is a gain of electrons and oxidation is a loss of electrons. If electrons are passed from one molecule to another, the molecule losing electrons is oxidized while the one accepting the electrons is being reduced.
Describe the process of glycolysis.
The breakdown of glucose molecules to release energy occurs in three stages:
(i) glycolysis; (ii) the formation of acetyl coenzyme A; (iii) the Krebs cycle
During glycolysis, energy from the glucose molecule is also captured in the form of high-energy electrons that are transferred to NAD+, reducing NAD+ to NADH+H+. During glycolysis, 2 molecules of NADH are generated. The energy available in the NADH will be used to generate ATP during a process called electron transport, which will be discussed in detail later.
Describe the formation of acetyl coenzyme A from pyruvic acid.
The C02 molecules are released as waste products and each acetic acid molecule reacts with a coenzyme called coenzyme A to form acetyl coenzyme A (acetyl CoA). During the formation of acetyl CoA, one molecule of NADH+H+ is produced from each pyruvic acid molecule.
Explain the role of the Krebs cycle in cellular respiration.
The reactions of the Krebs cycle occur in the matrix of the mitochondrion and do not require oxygen.
During the oxidation/reduction reactions of the Krebs cycle, released energy is captured by the direct production of some ATP, as well as by the production of both NADH+H+ and FADH2.
The net effect of the Krebs cycle is that for the 2 acetyl CoA molecules produced from the breakdown of a single glucose molecule, there is a production of 4 CO2, 6 (NADH+H+), 2 FADH2, and 2 ATP molecules.
Describe the role of the electron transport chain in cellular respiration.
