Chapter 4.4 Flashcards
Cellular respiration occurs in three series of reactions called
Glycolysis
Citric Acid Cycle
Electron Transport Chain
Cellular respiration requires
glucose and oxygen
Products of cellular respirationa make
CO2, water, and energy
Glycolysis means
the breaking of glucose
Glycolysis is a
series of ten enzyme-catalyzed reactions that break down the 6-carbon glucose molecule into two 3-carbon pyruvic acid molecules
Glycolysis takes place in
the cytosol
Glycolysis involves how many sets of reactions?
Three
First Step of Glycolysis
Two phosphate groups are added to a glucose molecule, one at each end, in a step called phosphorylation.
How much energy does the first step of glycolysis require?
requires energy from two atps, which are used to “prime” the glucose so that it is activated fro some of the energy-releasing reactions that will happen
Second Step of Glycolysis
The 6-carbon glucose molecule is cleaved into two 3-carbon molecules
Third Step of Glycolysis
The electron carrier NADH is produced, ATP is synthesized, and two 3-carbon pyruvic acid molecules result
During glycolysis, how many ATPs are synthesized directly?
Four
Subtracting the two ATPS used in the priming step gives
a net yield of two ATP’s per molecules of glucose from glycolysis
For cellular respiration to continue..
NADH + H+ must be able to deliver electrons to the ETC, replenishing the cellular supply of NAD+
What acts as the final electron acceptor at the end of the ETC?
Oxygen, which enables the chain to continue processing electrons and recycling NAD+
Under anaerobic conditions, the ETC has
no oxygen and therefore nowhere to unload its electrons. As a result, the ETC can no longer accept new electrons from NADH
Anaerobic - As an alternative, NADH + H+ can
give its electrons and hydrogen back to pyruvic acid in a reaction that forms lactic acid
The buildup of lactic acid evantually
inhibits glycolysis and ATP production declines
Pyruvic acid generated by glycolysis can
continue through the aerobic pathways if enough oxygen is available
The reactions inside aerobic reactions include
the synthesis of
Acetyl Coenzyme A/Acetyl CoA
the Citric Acid Cycle
ETC
How many ATP produced per Glucose molecule in aerobic reactions?
Twenty-Eight ATP molecules per glucose
The aerobic reaction begins with
pyruvic acid produced in glycolysis moving from the cytosol into the mitochondria.
From each pyruvic acid,
enzymes inside the mitochondria remove two hydrogen atoms, a carbon atom, and two oxygen atoms, generating NADH and CO2 leacing a 2-carbon acetic acid
Aerobic Reaction - The Acetic Acid then
combines with a molecule of coenzyme A to form Acetyl Co1.