anaerobic respiration Flashcards
glycolysis
first stage of respiration
-6C glucose split by series of ten reactions into 2 molecules of 3C compound pyruvate
pyruvate ions
produced by glycolysis
-can be used in aerobic respiration or anaerobic
where does glycolysis take place
in the cytoplasm of the cell
what type of sugar is glucose
6C
source of glucose for glycolysis
-come directly from blood or produced by breakdown of glycogen stores in muscle and liver cells
first step of glycolysis
used ATP to provide energy to phosphorylate the 6C adding two phosphate groups
what does the phosphorylation do to the 6C
makes sugar more reactive and makes it unable to pass through cell membrane- trapped in cell
step 2 of glycolysis
phosphorylated sugar then split to give two molecules of 3 C
whats is split 6C- 3C also known as
-glycerate 3-phosphate GP
what then happens to GP
-converted by several steps into molecule of pyruvic acid-found in solution of pyruvate ions
step 1 of how ATP produced from glycolysis
-2 hydrogen atoms removed from 3C and taken up by NAS forming reduced NADH
-takes place in cytoplasm
-reduced NADH passes through outer mitochondria membrane into electron transport chain
step 2- how ATP made
-small amount of ATP made directly from energy transfer when 3C sugar converted to pyruvate
-phosphorylation of sugar at beginning of glycolysis reversed when final intermediate compound converted to pyruvate
-phosphate group releases used to convert ADP to ATP
anaerobic respiration in cytoplasm
if lots of oxygen pyruvate will enter mitochondria and used in aerobic reactions of krebs cycle
-if oxygen levels low pyruvate remains in cytoplasm and converted to ethanol in plants or lactate in mammals
-only little ATP prpduced
production place aerobic vs anaerobic
aerobic in mitochondria and anaerobic in cytoplasm
oxidation state aerobic vs anaerobic
aerobic complete oxidation and anaerobic incomplete oxidation
waste products aerobic vs anaerobic
aerobic- water and carbon dioxide
-anaerobic- lactic acid or ethanol and carbon dioxide
net energy aerobic vs anaerobic
-aerobic- 31 ATP
-anaerobic- 2 ATP
why do muscles respire anaerobically
-if you exercise hard or long exercises- muscles dont get enough oxygen to supply their needs
-the products pf glycolysis cannot go to krebs cycle so respire without oxygen
what happens to pyruvate from glycolysis in anaerobic respiration
-another 3C dissociates to form lactate and hydrogen ions
result of anaerobic respiration
only two molecules of ATP are produced per glucose molecule respired
-in contrast- up to 8 ATP molecules are produced in glycolysis when pyruvate can feed into krebs cycle
cause of low yield of ATP in anaerobic respiration
-because some of reduced NAD used to reduce pyruvate to lactate rather than entering electron transport chain
lactate moving out of cells into blood equation
glucose to lactic acid + ATP
-C6H12O6 TO 2C3H6O3
how do muscle tissues become acidic
as levels of lactate and hydrogen ions increase during anaerobic respiration in muscles pH falls and becomes acidic
real reason for muscle tissue becoming acidic
neither lactate ions or fall of pH affect muscle contraction
-movement of lactate and hydrogen ions into blood from muscles lowers pH of blood- affects CNS
-reduced nervous stimulation from CNS reduces muscle contraction
-protective adaptation to give muscles time to recover and return to aerobic to raise pH of blood
what happens when exercise stops
levels of lactate remain high in blood
-lactate= toxic
-must be oxidised back to pyruvate to enter krevs cycle to be respired with oxygen
-takes oxygen to oxidise accumulated lactate
how training helps athletes
-allows the to get more oxygen to muscles faster as better blood supply develops
-helps to tolerate higher levels of lactate before muscles fatigue
what happens with repeated exposure to high lactate levels
-more lactate transporter molecules develop in the mitochondrial membranes resulting in faster processing of lactate to pyruvate when oxygen available
part where plants undergo anaerobic respiration
root cells in waterlogged soils
equation for plants producing yeast
glucose= ethanol + carbon dioxide
-ethanol= C2H5OH + 2CO2
main experimental organism used in work on glycolysis
-yeast rather than plants
-easy to grow
-reproduces rapidly
-no ethical issues
-yeast contains all enzymes of glycolysis
stage 1 of workout out glycolysis
-1897- eduard buchner- discovered extract of yeast that has no cells could still convert glucose to ethanol
-showed that enzymes of glycolysis and fermentation are not with associated with structure of cell
stage 2 of workout out glycolysis
-early 1900- arthur harden and W.J young showed phosphate was needed for pathway to proceed and there were 2 elements of yeast extract needed before fermentation could go ahead
-one was inactivated by heat as it contained enzymes
-other was not affected by heat in same way and contained NAD- ADP- ATP
stage 3 working out glycolysis
-with work of inhibitors allowed some of pathway intermediated to be studied
-Gustav Embden and Otto Meyerhof, received novel prize for work on glycolysis and lactate on muscles
-Jakub Parnas discovering phosphorlysis key
alternative names for glycolysis
-embden- meyerhof pathway and embden- meyerhof- parnas pathway
