glycolysis Flashcards
where about in cells does glycolysis take place?
the cytoplasm
what shape of molecule does fructose usually form?
a furganose (5-membered ring)
what is glucose coberted to in glycolysis?
pyruvate
what shape of molecule is glucose usually found as?
hexose (6 membered ring)
what is the first step of glycolysis?
phosphorylation of glucose to glucose -6- phosphate (CONSUMES ATP)
how many steps of glycolysis are there?
nine
what is the second step of glycolysis?
isomeriszation of glucose-6-phosphate to fructose-6-phosphate (i.e. the shape of the molecule is changed but the molecular formula remains the same)
what is the third step of glycolysis?
phosphorylation of fructose-6-phosphate to fructose1.6 biphosphate (consumes ATP) - this forms a symmetrical phosphorylated compound that can easily be split into two
what is the fourth step of glycolysis?
cleavage of fructose-6-phosphate to two molecules of glyceraldehyde 3 phosphate
what is the fifth step of glycolysis?
oxidative phosphorylation: glyceraldehyde-3-P is simultaneously oxidised and phosphorylated into 1,3 biphosphoglycerate by the reduction of NAD to NADH
(NAD+ accepts hydrogen and electrons from glyceraldehyde-3-P)
what does NAD stand for?
nicotinamide adenine dinucleotide
what is the reactive group of NAD?
the nicotinamide group (can accept electrons)
which vitamin provides this nicotinamide part of the NAD?
vitamin B3
what does a lack of vitamin B3 cause?
Pellagra - sensiivity to sunlight, dermatitis, alopecia, glissitis, weakness, ataxia
what is the 6th step of glycolysis?
transfer of a phosphate group to ADP to form ATP. 1,3 biphosphoglycerate becomes 3-phosphoglycerate (2 ATP produced)
what is the seventh step of glycolysis?
3-phosphoglycerate is converted to 2-phosphoglycerate (MOLECULAR REARangemet)
what is the 8th stage of glycolysis?
DEHYDRATION of 2-phosphoglycerate to phosphoenol pyruvate
what is the 9th and last stage of glycolysis?
transfer of phosphate from phosphoenol pyruvate to ADP (PRODUCING 2 MOLECULES OF ATP) and 2 molecules of pyruvate
how is NAD+ regenerated in AEROBIC conditions?
NADH passes the hydrogen and electrons through a system known as the ELECTRON TRANSFER CHAIN which combines therewith oxygen to form water
how is NAD+ regenerated in ANAEROBIC conditions?
by reducing pyruvate to lactate (passing the electrons and hydrogen to pyruvate to make it lactate) (NB MUSCLE ACHES)
which enzyme catalyses the phosphorylation of glucose to glucose-6-phosphate?
hexokinase
which enzyme phosphorylates fructose-6-phophate to fructose-1,6-biphosphate?
phosphofructokinase
which enzyme phosphorylates phosphoenolpyruvate to pyruvate?
pyruvate kinase
what are three conditions that INHIBIT phosphofructokinase?
high ATP
low pH
high citric acid
