5 - Lecture 5: CARBOHYDRATE METABOLISM: Gluconeogenesis,...

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

View Full Document Right Arrow Icon
Lecture 5: CARBOHYDRATE METABOLISM: Gluconeogenesis, Glycogenolysis, and Glycogen Synthesis January 19, 2011
Background image of page 1

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

View Full DocumentRight Arrow Icon
Basics ! Gluco neo genesis : the creation/synthesis of new glucose ! Glycogeno lysis: the breakdown of glycogen ! Glyco genesis: the creation/synthesis of glycogen
Background image of page 2
Glycogenin Glycogen
Background image of page 3

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

View Full DocumentRight Arrow Icon
Major Concepts 1. Gluconeogenesis, the synthesis of NEW glucose (from non-carbohydrate precursors) occurs only in liver (and to a minor extent in kidney) 2. Glycolysis and gluconeogenesis are tightly and reciprocally regulated.
Background image of page 4
Major Concepts 3. Glycogen metabolism occurs in animals largely in liver and muscle cells 1. Liver can export its glucose, but muscle CANNOT 4. Metabolic regulation is one of the most remarkable features of a living cell
Background image of page 5

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

View Full DocumentRight Arrow Icon
Liver Gluco neo genesis
Background image of page 6
Gluconeogenesis ! Pathway responsible for the synthesis of glucose from non-carbohydrate precursors ! Essential in mammals because there are some cell types that use glucose as their sole or primary fuel source ( e.g., brain, erythrocytes, renal medullary cells) l OBLIGATORY USERS z ! Occurs only in liver (and kidney to lesser extent) – Why? ! Gluconeogenesis needed because liver has only enough glucose (glycogen) to fuel the brain for about 12h. Even after a few hrs fasting, important.
Background image of page 7

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

View Full DocumentRight Arrow Icon
three irreversible steps of glycolysis must be bypassed 3. 2. 1. It ` s glycolysis in reverse, except that ! Gluconeogenesis Glycolysis Fig. 23-7
Background image of page 8
! G o : Standard free energy change: At temp of 298K; pressure at 1 atm (101.3kPa); and all solutes at 1M. ! G ` o : As above, but at pH 7 and in 55.5M water
Background image of page 9

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

View Full DocumentRight Arrow Icon
Shifting Glycolysis into Reverse ! DETOUR Fig. 23-2 * This step occurs in the mitochondrion
Background image of page 10
Step 2 of the Pyruvate Kinase b Detour ` N.B., Energy Cost ! DETOUR Fig. 23-2
Background image of page 11

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

View Full DocumentRight Arrow Icon
Mitochondria provide PEP precursors Recall: PEP has a lot of b pep ` !
Background image of page 12
Note the ATP and GTP demand: It ` s a costly process!
Background image of page 13

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

View Full DocumentRight Arrow Icon
Leucine Lysine
Background image of page 14
! Insulin ! Pink: situation when there are high circulating levels of glucose GLYCOGEN METABOLISM For those of you who didn ` t have breakfast this morning – this is what is happening in your livers right now " ! Blue: situation when there are low circulating levels of glucose ! Insulin High blood glucose
Background image of page 15

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

View Full DocumentRight Arrow Icon
Glycogeno lysis: the breakdown of glycogen Glycogen: polymer of glucose Liver: up to 10% of the weight Muscle: up to 1-2% of the weight Whole body level: more in muscle Beta particle: 55,000 glu molecules Alpha rosette: 20-40 beta particles in a cluster EM micrograph of glycogen from rat skeletal muscle.
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.

Page1 / 58

5 - Lecture 5: CARBOHYDRATE METABOLISM: Gluconeogenesis,...

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