Download Aerobic Respiration / Cellular Respiration

Cellular Respiration
Cellular respiration is a process that plants, animals, and other living
things go through to make energy. It is a process that uses glucose
from the food we eat to make usable energy in the form of ATP. There
are two types of cellular respiration available depending on the
organism. Below I will detail each.
Aerobic Respiration / Cellular Respiration
Aerobic respiration is when oxygen is used. Glucose and oxygen diffuse
into the cells and go through a multi-step process to make ATP, carbon
dioxide, and water. The first break down is when the glucose is broken
down into 2 pyruvic acids in a process called glycolysis. When this
happens a net of 2 ATP are made. The pyruvic acids will then enter the
mitochondria with the oxygen to go through the Kreb's Cycle and the
Electron Transport Chain, which will convert (through a series of a lot
of steps) the pyruvates and oxygen into carbon dioxide and water. By
the end of these two processes, 34 additional ATP have been made.
This is why the mitochondria is called the powerhouse!
Anaerobic Respiration / Fermentation
However, not all organisms undergo cellular respiration in this way.
Yeast go through a process of anaerobic respiration (without oxygen)
called alcoholic fermentation. Glycolysis still occurs (where the
glucose is broken down into 2 pyruvic acids and 2 ATP, but then the
pyruvic acids are broken down further by the yeast and alcohol and
carbon dioxide are produced. No additional ATP are formed! A second
type of anaerobic respiration is performed by bacteria cells. This
process is called lactic acid fermentation. Again, the bacteria will
begin with glycolysis, but will then break the pyruvic acids down
further into lactic acid. This is the liquid that you often times see in
your dairy products, like in yogurt or cottage cheese! Animals have the
ability to switch to lactic acid fermentation if their cells run out of
oxygen in order to use the glucose and make ATP, but the process is
not nearly as beneficial because so few ATP are produced.
Above: the first two show results from lactic acid fermentation while the remaining three
show what can be made using alcoholic fermentation