glycolysis Flashcards
overall equation of glycolysis
glucose + 2Pi + 2ADP + 2NAD+ –> 2 pyruvate + 2 ATP + 2NADH + 2H+ +2H2O
free energy released
197jk/mol
NAD is
used
ATP is
produced
ATP is the currency of…
free energy in biological system
primary cellular energy carrier through the triphosphate group
ATP
ATP is used in processes such as..
anabolism/biosynthesis mechanical work/movement active molecular transport
hydrolysis of ATP
liberates energy (an immediate donor)
entropy change during hydrolysis of ATP
-7.3 kcal mol-1
2 types of metabolism
anabolic reactions catabolic reactions
anabolic
- biosynthetic and receptive provides: -an energy source -reducing equivalents- source of H+ ions (NADH) -precursor molecules-building blocks
anabolic simple
building up
catabolic
degradative and oxidative provides: -energy -reducing equivalents -precursors
energy balance
for a healthy balance: diet/ anabolic pathways must be balanced with catabolic pathways
what lead to metabolic diseases such as obesity and Type 2 diabetes
an energy imbalance -when more anabolic pathways are occurring than catabolic
energy balance is regulated by
1.diet 2.exercise
how many people are obese in the UK
two in every thee people are overweight or obese -61.9% of women -65.7% of men
obesity predisposes
to diabetes Type 2- through regulatory substances produced by adipose tissue that cause insulin resistance
major components of western diet
-carbs -lipids -protein
fate of each dietary component
-0xidation for energy (catabolism) -storage (until required), then release -conversion- into something more useful
why is catabolism of glucose so important
glucose accounts for more than 80% of dietary carbohydrate catabolism
lactose
galactose and glucose
sucrose
fructose and glucose
aerobic glucose metabolism
pic
anaerobic glucose metabolism
pic
anaerobic glucose metabolism in yeast cells
pic
glycolysis provides
provides rapid energy source for short, intense bouts of exercise e.g. sprinting etc
do both prokaryotes and eukaryotes have glycolysis
yes
glycolysis is
substrate level phosphorylation
how much net ATP is produced
2
how many are overall involved
4
3 states of glycolysis
stage1- investment stage stage2- investment stage continued stage3- energy generation stage
stage 1- investment stage
energy is consumed to convert glucose to two three carbon sugar phosphates (isomers)
stage 2-investment stage continued
oxidation of glyeraldehyde 3 phosphate
stage 3- energy generation stage
each reaction in this phase occurs twice. Steps result in the transfer of phosphate groups to ADP and the reduction of NAD+ -ATP and NADH produced
key reactions of glycolysis
- glucose + ATP –> Glucose-6-phosphate + ADP 2. fructose -6-phosphate + ATP –> fructose 1,6BP + ADP 3. G-3-P +NAD+ + Pi –> 1,3bisphosphoglycerate + NADH + H+
which reactions in glycolysis generate ATP
- 1,3-bisphosphoglycerate –> 3- phosphoglycerate 2. phosphoenolpyruvate –> pyruvate
1,3-bisphosphoglycerate –> 3- phosphoglycerate
generates ATP
phosphoenolpyruvate –> pyruvate
generates ATP
glucose + ATP –> Glucose-6-phosphate + ADP
-catalysed by hexokinase -traps glucose -uses ATP -irreversible reaction
fructose -6-phosphate + ATP –> fructose 1,6BP + ADP
catalysed by phosphofructokinase -irreversible reaction -uses ATP -rate-limiting control point
G-3-P +NAD+ + Pi –> 1,3bisphosphoglycerate + NADH + H+
-catalysed by G-3-P dehydrogenase -reversible reaction -oxidation redcution, NAD+ reduced to NADH
G-3-P +NAD+ + Pi –> 1,3bisphosphoglycerate + NADH + H+
-catalysed by G-3-P dehydrogenase -reversible reaction -oxidation redcution, NAD+ reduced to NADH
how is ADP regenerated
due to the numerous reaction which utilise ATP ATP+ H2O –> ADP + pi
NAD+ is regenerated via either-
- lactose dehydrogenase (anaerobic) 2. oxidative phosphorylation (aerobic)
how is metabolism controlled
enzymes
which enzymes are controlled
-irreversible enzymes -enzymes at the start of a pathway or branch point -rate limiting enzymes e.g. phosphofructokinase
rate limiting enzyme
phosphofructokinase
how are enzymes controlled
-by altering levels of synthesis of key enzymes (slow) -by altering activity of key enzymes (fast)
by altering levels of synthesis of key enzymes
slow
by altering activity of key enzymes
fast
by altering activity of key enzymes
fast
summary
glycolysis breaks down glucose to pyruvate in a there stage process and 2 pyruvate molecules are produced as well as 2ATP and 2NADH
