cell resp Flashcards
formula for cell reso
C6H12O6 + 6O2—> 6CO2 + 6H20 + energy
three main steps of aerobic cell resp
1) Glycolysis
2) Kreb’s Cycle
3) Electron Transport Chain
which part of equation is oxidized and which part is reduced
glucose is oxidized (loss of hydrogen atom) while oxygen is reduced (gain or hydrogen atom)
- it is a oxidiation-reduction reaction
how mnay atp molecules are resulted from breakdown of one glucose
36-38 ATP
2 ways cells harvest energy from food it takes in
Anaerboic: glucose metabolism in absence of oxygen, produces 2 ATP molecules and either ethanol or lactic acid
2 stages are glycolysis and fermentation
Aeerobic: glucose metabolism with oxygen produces 36 ATP, CO2 and H20
involves glycolysis, pyruvate oxidation, krebs cycle and electron transport
three pathways for energy relase
-aerobic cell resp
- anaerobic cell resp
- fermentation: anaerobic process but not technically classified
first step to cell resp
glycolysis
- without oxygen
- generates a small amount of ATP and pyruvate which is a large amount of chemical energy
- main role is to split glucose (6-carbon) into two molecules of pyruvate
- After energy is added it splits into 2, 3-carbon molecules
- more reactions occur when some ATP is synthesised and NAD+ is reduced to NADH
- amount syntheised is greater then amount used to start the process
- net gain of 2 ATP molecules
-
products of gylcosis
2 ATP, 2 NADH and 2 pyruvate 3 carbon
and occurs in cytoplasm
what does NAD+ do in gylcosis
removes hydrogen electrons from intermediate carbon to form 2 NADH and release 2 Hyrogen ions in cytoplasm
what is the pre krebs cycle
occurs in matrix of mitochonria
- pyruvate loses a carbon in the form of CO2
- other two carbon atoms are bonded to coenzyme A this is called acetyl group
- Another NAD+ is reduced to NADH
- CO2 is released
what are the end products of pre krebs cycle
- 2 NADH
- 2 CO2
- 2 acetyl CoA
what is CoA
coenzyme a
it is like a tow truck
attaches to the 2-carbon compound “acetyl group” and tows it to krebs cycle
main role and final products of krebs cycle
produce even more high energy compounds (NADH and FADH2)
products
3 NADH
1 FADH2
2 CO2 (by product)
1 ATP
how many times does the krebs cycle need to occur
twice per each molecule of glucose
by the end of the krebs cycle what has happened to to all 6-carbons
they have been oxidized and released in the form of CO2
what is FAD/FADH2
electron carries that transfer electrons from glycolysis and krebs cycle of resp to ETC
where is the majority of ATP produced
electron transport chain (speciifcally chemiosmosis )
where is the etc and what does it involve
inner membrane of mitochonria and involves passing of high energy electron (NADH and FADH2) from carrier to carrier
1st step of the ETC
as energy is passed from carrier energy is release in a controlled amount to the intermembrane space
this energy is used to pump hydrogen ions across a membrane from the matrix to the intermembrane space
2nd part of the ETC
- buildup of ions creates a concentration gradeint (high in intermembrane and low concentration in matrix)
- can only diffuse back by channel created by ATP synthase
3rd step to ETC
oxygen is the final electron acceptor, oxygen accepts electron and hydrogen ions creating water
what is chemiosmosis
-couples movement of hyrodgen ions down the concentration gradeint to the synthesis of ATP from ADP and phosphate (reduction of adp)
- H+ ions are not allowed to diffuse back to matrix since membrane is semipermeable
where is ATP synthase found and what does it do
inner membrane
- only place permebale to H+ ions
- as hydrogen flows energy is released by ATP synthase, used to make ATP
what is fermentation and where does it occur
cyoplasm of the cell
- pyruvate is further reduced via oxidation of NADH and NAD+
ethanol fermentation
CO2 is removed from pyruvate creating 2 carbon acetadgehype
- NADPH passes electron and hydrogen to this which creates ethanol
supplies small amounts of energy and regenerates NAD+ returning to glycolysis
lactate fermentation
occurs during strenous exercise
- NADH generated during glycolysis transfers it to H+ to pyruvate
- changes pyruvate to locatic acid
