Carbohydrate Metabolism 9/18/16 German Flashcards
What is metabolism?
The enzyme catalyzed reactions that transform organic molecules in cells
What are the two parts of Metabolism?
- Catabolism
- Anabolism
What type of metabolism is: energy requiring synthesis of more complex products?
Anabolism
What type of metabolism is: Energy Yielding degradation of complex precursors?
Catabolism
What are four organs that regulate metabolic pathways?
- Pancreas
- Liver
- Muscle
- Adipose Tissue
What is the cell in the pancreas that helps regulate metabolic pathways?
Islet cells
What is the metabolic function of the pancreas?
Release insulin, glucagon, and numerous hormones
What is the cell in the liver that helps regulate metabolic pathways?
Hepatocyte
What is the metabolic function of the liver?
Maintain metabolic homeostasis
How does the liver maintain metabolic homeostasis?
- Normalize blood glucose
- Store glycogen
- Synthesizing and degrading molecules
What are the main molecules that the liver synthesizes and degrades?
- Glycogen
- Glucose
- Fatty Acids
- nucleic acids
- proteins
- ketone bodies
What are the muscle cells that help regulate metabolic pathways?
-Skeletal
-Smooth
-Cardiac
(all of the above myocytes)
What is the metabolic function of muscle?
Utilizes glucose, fatty acids, Amino acids to fuel muscular activity
What cell in adipose tissue helps regulate metabolic pathways?
Adipocyte
What is the metabolic function of adipose tissue?
Store
What are the five key regulators in the metabolic pathways?
- Insulin
- Glucagon
- Epinephrine
- Glucose
- ATP/AMP
What are four reasons why glucose is a central metabolic component?
- Source of ATP
- Energy storage
- Molecular precursor
- Structural backbone
T/F the muscle and adipose tissues are the ones that regulate metabolic homeostasis?
False
-They are the recipients, Panceas and liver regulate
What are the four major pathways of carbohydrate metabolism?
- Respiration
- Storage
- Regenerative
- Synthetic
Which major pathway forms ATP?
Respiration
Which major pathway forms glycogen, glucose?
Storage
Which major pathway forms glucose?
Regenerative
Which major pathway forms nucleic acids, lipids, and amino acids?
synthetic
Is glycolysis a catabolic or anabolic pathway?
Catabolic
Is the citric acid cycle catabolic or anabolic?
Catabolic
Is the oxidative phosphorylation pathway catabolic or anabolic?
catabolic
Is glycogenolysis catabolic or anabolic?
Catabolic
Is glycogenesis catabolic or anabolic?
Anabolic
Is gluconeogenesis catabolic or anabolic?
Anabolic
What is the function of amylases?
Break down complex starch’s
What is glycogen?
chains of glucose molecules that are branched
Where do you primarily find glycogen stores?
- Muscle
- Liver
How much of the liver weight does glycogen form?
10%
How much of the muscle weight does glycogen form?
2%
What does glycogenesis do?
Converts glucose to glycogen
In glycogenesis the first step is going from glucose to what molecule?
Glucose 6-phosphate
In glycogenesis what enzyme is responsible for going from glucose to glucose 6-phosphate?
Hexokinase
In glycogenesis the second step is going from glucose 6-phosphate to what molecule?
Glucose 1-phosphate
In glycogenesis what enzyme is responsible for going from glucose 6-phosphate to glucose-1 phosphate?
Phosphoglucomutase
In glycogenesis the third step is going from glucose 1-phosphate to what molecule?
Uracil diphosphate-glucose
In glycogenesis what enzyme is responsible for going from glucose 1-phosphate to uracil diphosphate-glucose?
UDP-glucose pyrophosphorylase
In glycogenesis the fourth step is going from Uracil diphosphate-glucose to what molecule?
glycogen chain
In glycogenesis what enzyme is responsible for going from Uracil diphosphate-glucose to the glycogen chain?
Glycogen synthase
In glycogenesis what makes glycogen synthase such an important enzyme?
It is the enzyme responsible for the point of regulation
In the fifth step of glycogenesis you go from the glycogen chain to what?
Glycogen particle
In glycogenesis what enzyme is responsible for going from the glycogen chain to the glycogen particle?
Glycogen Branching Enzyme
How many steps and molecules are there in glycogenesis?
Five steps
Six molecues
What does putting a phosphate on glucose do?
It keeps glucose in that cell
What can lead to glycogenesis?
To much glucose
What does glycogenolysis do?
Creates glucose from glycogen
How do you get from glycogen to Glucose 1-phosphate molecules in glycogenolysis?
Glycogen Phosphorylase
How do you get from Glucose 1-phosphate to glucose 6-phosphate in glycogenolysis?
Phosphoglucomutase
In glycogenolysis how do you get from glucose 6-phosphate to free glucose?
Glucose 6-phosphatase
What is unique about glucose 6-phosphatase?
It is only found in the ER of the liver
In glycogenolysis what molecule do you go to from glycogen?
Glucose 1-phosphate
In glycogenolysis what molecule do you go to from glucose 1-phosphate?
Glucose 6-phosphate
In glycogenolysis what molecule do you go to from glucose 6-phosphate?
Free glucose
What can lead to glycogenolysis?
Low blood sugar
When Glycogen synthase is phosphorylated does it lead to activity or inactivity?
Inactivity
What enzyme is responsible for phosphorylating Glycogen Synthase?
Glycogen Synthase Kinase 3
What three things lead to an upregulation of glycogen synthase activity?
- Insulin
- Glucose 6-phosphate
- Glucose
What leads to a down regulation of glycogen synthase activity?
Glucagon
Epinephrine
Why is Glycogen phosphorylase important?
It removers glucose 1-phosphate from glycogen
Is phosphorylase a or phosphorylase b the active form of glycogen phosphorylase?
phosphorylase a
Is phosphorylase a phosphorylated?
Yes
Is phosphorylase b phosphorylated?
No
What is responsible for the up regulation of glycogen phosphorylase?
- Glucagon
- Epinephrine
What pathway does insulin signaling activate?
Glycogenesis
What are there important things in glycogenesis that insulin activates?
- GLUT transporters
- Hexokinase
- Glycogen Synthase
What pathway do epinephrine and glucagon activate?
Glycogenolysis
What are the two Glycogen Phosphorylase Allosteric form?
- b (less active)
- a (more active)
What are two allosteric modulators in glycogenolysis and glycogenesis?
- Glucose
- Insulin
What signaling pathway does glucagon use?
GPCR pathway
What metabolic pathway occurs primarily in the liver?
Gluconeogenesis
What does Gluconeogenesis do?
Synthesizes glucose
What metabolic pathway is lactate or pyruvate converted to glucose in?
Gluconeogenesis
What is the first step of the Cori Cycle?
Glycogen goes to lactate while releasing 1 ATP in the muscle
What is the second step of the cori cycle?
Lactate goes to blood lactate and is transfered as lactate to the liver
What is the third step of the Cori Cycle?
Lactate is converted to glucose by using 1 ATP in the liver
What is the fourth step of the Cori Cycle?
Glucose goes as blood glucose to the muscle
What are the input costs of gluconeogenesis?
- 4 ATP
- 2 GTP
- 2 NADH + H