Integration of Metabolism Flashcards
What is impotant about glucose 6 phosphate, pyruvate and acetyl CoA?
They serve as metabolic junction points.
Glucose-6-phosphate can be converted into what three molecules?
Glycogen
Pyruvate
Ribos-5P
Pyruvate can be converted into what four molecules?
acetyl CoA, lactate, alanine and oxaloacetate
Acetyl CoA can be converted into what three molecules?
carbon dioxide, fatty acids and ketone bodies
In the liver, lipid and amino acid breakdown is stimulated by what?
glucocorticoids.
It is distributed as ketone bodies in the bloodstream
Ketone bodies are used in what type of tissues
All tissues
They are used for ATP production
In the liver, what two processes are stimulated by glucocoricoids and glucagon/epinephrine?
gluconeogenesis and glycogenolysis
In adipose tissue, triglyceride breakdown is stimulated by what molecules?
glucocorticoids
In skeletal muscle, what breaks down protein?
cathepsins
In skeletal muscle, protein beakdown is used for what two mechanisms?
gluconeogenesis and ketone body production
In skeletal muscle, glycogen breakdown and glycolysis are stimulated by what molecules?
glucagon and epinephrine
In skeletal muscle, what is made from glycogen breakdown and glycolysis?
lactic acid
In skeletal muscle, glycogen breakdown and glycolysis allow for the glycogen breakdown and glycolysis. What is produced?
lactic acid
What is considered the “number one metabolic player” in the body?
The liver
Why does the liver have such a quick response to dietary conditions?
Becasue of its rapid turnover of its enzymes.
What organ proesses most of the incoming nutrients?
the liver
What metabolic pathway does the liver depend on for its own energy needs?
beta oxidation of fatty acids.
After absorption, where do amino acids directly go to?
the liver through the portan vein
What does the liver use amino acids for?
proteins
gluconeogenesis
biosynthesis of nitrogen containing molecules
fuel
True or false: the liver normally fuels the body by releasing its fat stores during fasting
false
What type of tissue stores triglycerides and releases fatty acids and glycerol?
adipose tissue
What causes the released of fatty acids and glycerol from fatty acid tissue?
glucagon and epinephrine
What protein assists in transporting fatty acids in the blood?
albumin
Brown fat has a high level of what substance?
thermogenin.
It is metabolically activated by cold exposure
What enzymes convert triglycerides into fatty acids and glycerol?
cAMP-activated lipases
What system is used for short-term energy?
phosphagen system
What energy system is used for short-term energy?
anaerobic glycolysis
What energy system is used for long term energy?
oxidative system
Once ATP is exhausted, it is replenished by what enzyme?
phosphocreatine
How long does phosphocreatine last?
approximately ten seconds
The muscle and the liver are both involved in what process?
The cori cycle.
It allows for the regeneration of glucose from lactate.
The liver gonverts lactate into glucose, which is then sent to the muscle and converted into glycogen.
The brain is dependent on blood glucose at ___ to maintain ion gradients.
4.5 mM
How much of the total oxygen consumed does the brain use?
20%
After several days of low glucose intake, what does the brain use as fuel?
keton bodies
Does cardiac muscle use aerobic or anaerobic mechanisms to attain fuel?
aerobic only
What pathway is inhibited by the action of insulin?
gluconeogenesis
As glucose uptake increases, the activity of what transporter is increased?
glucose transporter
As glucose uptake increaes, the activity of what enzyme also increases?
glucokinase
As glycogen synthesis increases, the activity of what enzyme increases?
glycogen synthase
As glycogen breakdown DEcreases, the activity of what enzyme DEcreases?
glycogen phosphorylase
As glycolysis increases, the activity of what enzyme increases?
PFK-1
As fatty acid synthesis increases, the activity of what enzyme increases?
acetyl-CoA carboxylase
As TAG sysnthesis increases, the activity of what enzyme increases?
lipoprotein lipase
What is the only organ capable of carring out all of the reactions of the major biochmeical pathways?
The liver
What pathway is inhibited by the action of insulin?
gluconeogenesis
what type of receptor is the insulin receptor?
receptor tyrosine kinase
As glucose uptake increases, the activity of what enzym also increases?
GLUT4 (muscle, adipose)
Glucokinase (liver)
As glycogen synthesis increases, the activity of what enzyme also increases?
glycogen synthase
As glycogen breakdown decreases, the activity of what enzyme also decreases?
glycogen phosphorylase
As glycolysis acitivty increases, the acitivity ofo what enzyme also increases?
PFK-1
As fatty acid synthesis increases, the activity of what enzyme also increases?
Acetyl-CoA carboxylase
As TAG synthesis increases, the acitivity of what enzyme also increases?
lipoprotein lipase
Insuling binding triggers auto-phosophorylation at what amino acid?
tyrosine
An increase in the fight or flight response causes what to happen to glucose?
it is more readily broken down
As the fight or flight response increases, how is glucagon secretion affected?
it increases
The glucagon receptor acts through what type of proteins?
G proteins.
During a well-fed state, what hormone is active in the liver?
insulin
During a well-fed state, What hormone is present in adipose?
insulin
In the well-fed state, what are some processes that occur in the liver?
cholesterol synthesis, triglyceride synthesis, fatty acid synthesis, gluconeogenesis
In the well-fed state, what are some processes that are active in adipose tissue?
cholesterol synthesis, fatty acid synthesis, triglyceride synthesis, glycolysis, pentose shunt
In the fasting state, what are some processes that occur in the liver?
ketone body synthesis, fatty acid oxidation, gluconeogenesis, glycogenolysis
In the fasting state, what hormone is present in the liver?
glucagon or epinephrine
In the fasting state, what hormone is present in adipose tissue?
glucagon
In the fasting state, what are some processes that take place in adipose tissue?
triglyceride breakdown, fatty acid oxidation
In the fasting state, what are some processes that take place in the muscle?
ketone body utilization, fatty acid oxidation
At high energy, there are ___ levels of ATP and NADH and ___ levels of NAD+.
high, low
When there is high energy, what molecule is favored?
DHAP; it is converted to G3P (Fat)
What is the cellular energy sensor?
AMP-activated protein kinase
When ATP is ____, AMPK is inactivated
high
When ATP is ___, AMPK is allosterically activated.
Low
The ____ between ATP and AMP for binding to the AMPK allosteric sites determines the activity of AMPK.
competition
True or false: AMPK activates glucose uptake and glycolysis
True
True or false: AMPK inhibits insulin secretion
True
What is leptin?
a molecule that is released from fat and signals the hypothalamus that an organism is full.
What does caloric restriction result in?
lower blood glucose levels
declines in glycogen and fat stores
enhanced response to insulin
lower body temperature
What is the effect of deleting the SIR2 gene?
it abolishes the ability of caloric restriction to lengthen life in yeast and roundworms
