Flashcards in Unit 8 Deck (59)
Integration level- flow of key metabolites between different pathways
Integration level- interdependence of different organs and tissues
Tissue and organ level
Major metabolic fuel
What is the storage form of glucose?
Cells that contain _________ can generate glucose and send to the blood stream.
Name some examples
Liver, kidney, and small intestine
Other sources of glucose
TAGs and glucogenic amino acids- used for gluconeogenesis
What carries nutrients to the liver?
______ turn nutrients into fuel
What causes enzymes to increase or decrease?
Changes in diet
Needs of other tissues
What allows for passive diffusion of glucose in and of the blood? Found in hepatocytes
What is the glucose phosphorylating enzyme?
Glucokinase (Hexokinase IV)
What makes glucokinase soo special?
It has a higher Km (10mM) than other kinases (4mM)
When is glucose-6-phosphate not made? Why?
When glucose is low
other tissues need the glucose?
Where is GLUT2 found?
In the liver and pancreas
What are the monosaccarides in the liver that can convert into glucose-6-phosphate?
Fructose, galactose, and mannose
What are the potential fates of glucose-6-phosphate in the liver?
1- It is dephosphorylated by glycogen phosphorylase (yields free glucose to send to other tissues)
2- Makes glycogen with phosphoglucomutase
3- Enter glycolysis to make Acetyl-CoA for FA biosynthesis
4- Enter glycolysis pathway to make acetyl-CoA for ATP generation
5- Enter Pentose phosphate pathway to yield NADPH
Glucose-6-phosphate metabolism generates nucleotides and reductive biosynthesis power in the form of ______ via what pathway?
Pentose phosphate pathway
Potential fates of amino acids in the liver:
1- Biosynthesis of proteins for the liver and other tissues
2- Biosynthesis of hormones and nucleotides
3- Biosynthesis of CAC intermediates or pyruvate for gluconeogenesis
What is pyruvate converted to acetyl CoA?
For liver cell energy and conversion to lipids
Potential fates of fatty acids in the liver:
1- Synthesize liver lipids
2- Oxidize to acetyl-CoA and NADH
3- Convert to phospholipids
4- Convert to TAGs for storage
5- Carried to heart and muscle for oxidation
Fate of Acetyl-CoA in the liver:
1-Sent thorugh CAC and oxidative phosphorylation to make ATP
2- Some is converted into cholesterol, which in turn becomes either bile salts or steroid hormones in the blood
3- Excess Acetyl-CoA is converted to ketone bodies for the brain and heart in carbohydrate restriction and fasting
Free fatty acids in the blood bind to what?
Ketone bodies include: (3)
When are ketone bodies made?
when oxaloacetate pools are insufficient to condense with acetyl-CoA
Why are ketone bodies able to enter the brain?
they do not bind to albumin
Ketone bodies are _____ for energy in place of, or to supplement ____.
% of ketone bodies that supply energy for the brain:
For the heart:
Liver functions: (4)
Provide glucose and ketones for other organs
Process amino acids into urea, etc
Store nutrients (iron, fat soluble vitamins)
Detoxify and solubilize organic compounds via cytochrome P45 system
Adipocyte function: (4)
Carry out glycolysis though oxidative phosphorylation
Convert acetyl-coa into fatty acids
Use FA to make TAGS
Release FA when other tissues need them