Chapter 7 - Cellular Respiration

Autotroph

an organism that can make organic molecules (food nutrients)

Photoautotrophs

an organism that can make food nutrients by harvesting the energy from the sun

Chemoautotrophs

an organism that can make food nutrients through the reaction of inorganic molecules

Heterotrophs

an organism that does not have the ability to produce its own food
must ingest or absorb organic molecules

Summary of Cellular Respiration

C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O + energy (heat or ATP)

Oxidation

the process in a chemical reaction when an atom or molecule loses an electron

Cellular Respiration (where it occurs)

-occurs in the cytoplasm and mitochondria of plant and animal cells (eukaryotic cells)
-occurs in the cytoplasm and at the cell membrane in bacteria (prokaryotic cells)

Cellular Respiration

the process in which the energy stored in a glucose molecule is released by oxidation. Hydrogen atoms are lost by glucose and gained by oxygen

4 Steps of Cellular Respiration

1. Glycolysis
2. Pyruvate Oxidation
3. Krebs Cycle [Citric Acid Cycle]
4. Electron Transport Chain & Oxidative Phosphorylation

Glycolysis

-occurs in the cytoplasm
-makes four ATP [net 2]
-produces 2 pyruvate molecules and NADH's [electron carriers]
-is a sequence of ten enzyme-catalyzed reactions
-the 6-carbon sugar glucose is broken into two 3-carbon pyruvate molecules

Pyruvate Oxidation

[can only occur if there is enough oxygen]
-occurs in the mitochondria
-no ATP is produced
-In the matrix, pyruvate is converted to (oxidized) 2 Acetyl CoA and NADH is produced
-carbon dioxide is also produced

Krebs Cycle

-occurs in the mitochondria
-2 ATP are produced
-carbon dioxide, NADH, and FADH2 are produced
At the end of the Krebs Cycle, glucose is entirely consumed (all 6 carbons are in the form of CO2) and there was a transformation of energy from the glucose into

Electron Transport Chain

-occurs in the inner membrane of the mitochondria
-about 32 ATP are produced
-H2O is also produced
-NADH and FADH2 produced from steps 1-3 are the source of electrons in step 4
-the energy of the electrons are used to make ATP
-At the end of the ETC, elec

Fermentation

when there is not enough oxygen is available, glycolysis is followed by fermentation
cells regenerate NAD+ to be used in glycolysis to produce some ATP

Metabolism

the process (reactions) by which all living things assimilate energy and use it to grow
breakdown of molecules to produce energy
joining small molecules to build larger ones