Lecture_4 - Lecture 4: Glycolysis II 2 ATPs formed in...

Info iconThis preview shows pages 1–17. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 4: Glycolysis II
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 ATPs formed in conversion of glucose to pyruvate Glucose + 2 P i + 2 ADP + 2 NAD + 2 pyruvate + 2 ATP + 2 NADH + 2H + + 2 H 2 O Net reaction Energy released in anaerobic conversion of glucose to pyruvate -96 kJ/mol (-23 kcal/mol) The conversion of glucose to pyruvate cannot keep proceeding because redox balance has not been maintained
Background image of page 2
Redox must be maintained Glyceraldehyde 3-phosphate dehydrogenase generates ATP but at the expense of NAD + Limited amounts of NAD + in the cell NAD + derived from vitamin niacin (dietary requirement in humans) NAD + must be regenerated for glycolysis to proceed
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Re-dox balance steps generation and consumption of NADH Ethanol or lactate
Background image of page 4
3 fates of pyruvate Ethanol Lactate Carbon dioxide No oxygen, fermentation Oxygen Citric acid cycle Electron transport chain
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
Ethanol from pyruvate Yeast and other microorganisms Step 1: decarboxylation of pyruvate Catalyzed by pyruvate decarboxylase Requires coenzyme thiamine pyrophosphate Derived from vitamin thiamine (B1) Step 2: reduction of acetaldehyde to ethanol by NADH Catayzed by alcohol dehydrogenase Regenerates NAD +
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Alcoholic fermentation Glucose + 2 P i + 2 ADP + 2 H + 2 ethanol + 2 CO 2 + 2 ATP + 2 H 2 O No net oxidation-reduction in the conversion of glucose into ethanol (NADH generated and then consumed)
Background image of page 8
oxidation reduction No net oxidation-reduction
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Lactate from pyruvate Occurs in a variety of microorganisms (lactic acid fermentation ) and in higher organisms when oxygen is limiting (muscle in intense exercise) Pyruvate is reduced by NADH to form lactate Catalyzed by lactate dehydrogenase
Background image of page 10
Lactic acid fermentation Glucose + 2 P i + 2 ADP 2 lactate + 2 ATP + 2 H 2 O No net oxidation-reduction
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
CO 2 from pyruvate Oxidative decarboxylation of pyruvate to acetyl coenzyme A (acetyl CoA) Entry point to Citric acid cycle and the electron transport chain Much more energy is extracted from glucose Formed inside mitochondria Aerobic reaction Catalyzed by pyruvate dehydrogenase • NADH transfers its electrons to O 2 in electron transport chain Pyruvate + NAD + + CoA acetyl CoA + CO 2 + NADH
Background image of page 12
Obligate anaerobe – cannot survive in the presence of oxygen Why are the pathways that do not yield much energy used so often?
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Fructose and galactose (monosaccharides other than glucose) No catabolic pathways for metabolizing fructose and galactose Can be funneled into glycolytic pathway By converting them to a metabolite of glucose
Background image of page 14
Entry points in glycolysis for galactose and fructose
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Fructose – 2 pathways Fructose 1-phosphate pathway
Background image of page 16
Image of page 17
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/11/2009 for the course BIOS 342 taught by Professor Tanda during the Spring '09 term at Ohio University- Athens.

Page1 / 44

Lecture_4 - Lecture 4: Glycolysis II 2 ATPs formed in...

This preview shows document pages 1 - 17. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online