M2 L10 Flashcards
complete glycolysis pathway
explain the difference between anaerobic and aerobic glycolysis and the situations when one pathway is used instead of the other
anaerobic glycolysis: two mol of ATP per mol of glucose. ATP levels can be maintained for short times in the absence of oxygen. glycolysis can also occur in cells with an abundant supply of oxygen. end result is lactate and 2 ATP
aerobic glycolysis: cells must have mitochondria, end product of glycolysis is pyruvate, its then completely oxidized to CO2 and H2O. it uses citric acid cycle and electron transport chain. ~32 ATP per mol of glucose. 2 ATP, 2 NADH & 2 pyruvate per mole of glucose
use a diagram of the glycolytic pathway to explain where and why ATP is both used and produced
it is used in reaction 1 to make ADP, which is then converted to ATP in reaction 3.
2 ATPs are generated in reaction 7 and again in reaction 10
use a diagram of the glycolytic pathway to identify the irreversible reactions and explain why they are irreversible under physiological conditions
reaction 1,3 are irreversible because they use energy and form ADP from ATP
explain the metabolic importance of the lactate dehydrogenase reaction
this is an emergency energy-yielding pathway in most mammalian tissues, it is an anaerobic fermentation (happens in the lack of oxygen)
which one is reduced and which one is oxidized out of NAD and NADH+
NADH is reduced NAD is oxidized. If [NAD+] goes down, [NADH] goes up and vice versa. 2 NADH/H+ are generated by glyceraldehyde 3-phosphate dehydrogenase and the NAD+ must be regenerated to ensure continuation of glycolysis
explain pyruvate dehydrogenase insufficiency
If the phosphatase is not fully functional or only able to operate at very slow rates, the PDH enzyme will remain phosphorylated, and hence inactive.
explain pyruvate kinase and phosphofructokinase insufficiency and how it causes exercise intolerance
pyruvate kinase insufficiency is caused by odd shaped RBCs, because they are reliant on aerobic glycolysis which is the only source of ATP, muscles don’t get enough energy it can cause exercise intolerance
explain why glucose is an absolute necessity to animals
glucose is metabolized in cells as a source of fuel to make ATP for use in energy requiring cellular processes. All cells without mitochondria can only get energy from glucose, brain uses glucose, can lead to death if not enough
what is substrate level phosphorylation?
The synthesis of ATP from ADP where the phosphate group is provided from the substrate of the coupled reaction.
How do animals obtain energy? What is this energy used for?
All animals are chemotrophs – we get our energy from the breakdown of compounds to simpler molecules (e.g. glucose to CO2 and H2O)
why do cells carry out glycolysis?
To provide energy for cells and to provide metabolic intermediates for other pathways.
