Cellular Respiration – GlycolysisCoy Stoker
Axia College
Cellular Respiration - Glycolysis1
Cellular Respiration – Glycolysis
Stages of Glycolysis:
Step 1: ATP “Spent”
Step 2: Split
Step 3: NAD+ / Phosphate
Step 4: ATP Produced
Cellular Respiration - Glycolysis2
Glycolysis is only one segment of cellular respiration (Pruitt, Underwood, 2005). Glycolysis is the most primitive of the types of cellular respiration. Glycolysis does not required oxygen so it is called anaerobic. There are four major steps in glycolysis. The process begins with a molecule of glucose. The glucose molecule is exposed to 2 ATP molecules which results in the glucose molecule picking up two phosphates. The result of this reaction is fructose diphosphate and two ADP molecules. Then fructose diphosphate is split into 2 glyceraldehyde phosphate (Respiration, n.d.). Then a free floating phosphate is added to each molecule of glyceraldehyde phosphate and NAD+ picks up a particle of hydrogen from each molecule of glyceraldehyde phosphate. The result of both of these reactions are 2 3-diphosphoglycerate . Finally both molecules of 3-diphosphoglycerate are exposed to 2 ADP a piece which result in 4 ATP. The net result of glycolysis is 2 ATP and 2 NADH.
Cellular Respiration - Glycolysis3
ATP “Spent”
Cellular Respiration - Glycolysis4
ATP
ATP
ADP
ADP
One phosphate from ATP added leaving ADP
One phosphate from ATP added leaving ADP
Fructose D
iphosphate
6 Carbon Glucose
Fructose Diphosphate
Before After2 ATP Spent Split
Next
Glucose P
hosphate
During the first step in glycolysis there is actually a loss of two ATP. A phosphate is taken from both ATP in order to make the resulting fructose diphosphate more reactive. This step also releases two ADP into the cellular plasma which will be used later.
Cellular Respiration - Glycolysis5
Cellular Respiration - Glycolysis6
Split
Fructose Diphosphate
SplitSplit
Glyceraldehyde P
hosphateG
lyceraldehyde P
hosphate
Glyceraldehyde Phosphate
NAD+/Phosphate
Before After NextSplit
The second step is simply splitting fructose diphosphate which makes 2 glyceraldehyde phosphate. By doing this glycolysis is able to double the amount of ATP produced.
Cellular Respiration - Glycolysis7
Cellular Respiration - Glycolysis8
NAD+/ Phosphate
Glyceraldehyde P
hosphateG
lyceraldehyde P
hosphate
NAD+ NADH
NAD+ NADH
Phosphate
Phosphate 3-D
iphosphoglycerate3-D
iphosphoglycerateGlyceraldehyde
Phosphate
3-Diphosphoglyce
rate
4 ATPs Produced
Before After Next-H/+Ph
The third step entails harvesting a hydrogen molecule from each glyceraldehyde phosphate and adding it to NAD+ making NADH, which is used later on in cellular respiration. Also a free floating phosphate is added to glyceraldehyde phosphate to make 2 3-diphosphoglycerate.
Cellular Respiration - Glycolysis9
Cellular Respiration - Glycolysis10
ATP Produced
3-Diphosphoglyce
ratePyruvate
3-Diphosphoglycerate
3-Diphosphoglycerate
ADP ATP
ATPADP
Glyceraldehyde P
hosphateG
lyceraldehyde P
hosphate
ADP ATP
ATPADP
Pyruvat
eP
yruvate
ADPs steal four phosphates making four ATPs
Before After
The third step entails harvesting a hydrogen molecule from each glyceraldehyde phosphate and adding it to NAD+ making NADH, which is used later on in cellular respiration. Also a free floating phosphate is added to glyceraldehyde phosphate to make 2 3-diphosphoglycerate.
Cellular Respiration - Glycolysis11
ReferencesRespiration. (n.d.) Retrieved January 16, 2007, from BioInquiries Website:
http://higheredbcs.wiley.com/legacy/college/pruitt/0471473219/bioinquiries/ch10/bioinquiry_section_10_3.html
Pruitt, P.L., Underwood, L.S. (2005). BioInquiry: Making Connections in Biology. Danvers, MA: Wiley.
Cellular Respiration - Glycolysis12
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