BIOL373 - UNIT 7 - METABOLISM AND ENERGY BALANCE EXAM
QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS
GRADED A++
Define metabolism, and translate it
set of life-sustaining chemical transformations within the cells of living organisms
Whether transformations of energy substrates (carbs, fats, proteins) are biased toward
anabolism or catabolism
Compare anabolism and catabolism
Anabolism --> storage (build bigger molecules)
Catabolism --> breakdown (into smaller molecules)
What are the 2 forms of regulation of metabolism? Which is primary? What do
they do?
1. endocrine (primary!) --> products of endocrine pancreas (insulin/glucagon ratio)
2. neural --> regulation of food intake (autonomic innervation of pancreas)
What are the three possible uses for ingested biomolecules?
1. fuel --> metabolized to provide energy (ATP)
2. build --> synthesis reactions for growth and maintenance of tissue
3. store --> as glycogen (liver, skeletal muscles) or fat
Metabolism is divided into what two states? What do they mean?
,1. fed / absorptive state --> anabolic --> products of digestion being absorbed and used
for synthesis
2. fasted / postabsorptive state --> catabolic --> body taps into stores
What are the 3 nutrient pools available for immediate use? Where are they found?
1. glucose
2. free fatty acids
3. amino acids
found mostly circulating in plasma
What controls direction of metabolism? How does it differ between the two
states?
Enzymatic control!
In fed-state: enzyme activity for glycogen synthesis increases! enzyme activity for
glycogen breakdown are inhibited (net glycogen synthesis)
In fasted state: opposite (net glucose synthesis)
Compare influence of insulin and glucagon on metabolism state
Insulin --> fed-state (glycogen synthesis)
Glucagon --> fasted-state (glucose synthesis)
What is the goal of the fasted state metabolism? Why is this important?
, maintain plasma glucose levels
Important because brain is acutely dependent on glucose (can also use ketones!)
Compare glycogen export in liver vs muscle
liver --> glycogen can be broken down and exported as free glucose
muscle --. can NOT be exported as free glucose
How is glycogen exported in the muscle?
Either: used in muscle
OR
Exported as: pyruvate or lactate (liver does gluconeogenesis)
How are fats exported?
triglycerides in adipose tissue are exported as glycerol (liver does gluconeogenesis) OR
exported as fatty acids (beta-oxidation)
What does the liver do with fatty acids?
Can produce ketone bodies from fatty acids (ketogenesis)
How are proteins exported?
broken down into amino acids,
Either: used in muscle
OR exported to liver (gluconeogenesis)
When does ketogenesis occur? What are the dangers?
When lipolysis is faster than usage of acetyl CoA --> ketogenesis
ketone bodies are acidic! can send you into metabolic acidosis
QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS
GRADED A++
Define metabolism, and translate it
set of life-sustaining chemical transformations within the cells of living organisms
Whether transformations of energy substrates (carbs, fats, proteins) are biased toward
anabolism or catabolism
Compare anabolism and catabolism
Anabolism --> storage (build bigger molecules)
Catabolism --> breakdown (into smaller molecules)
What are the 2 forms of regulation of metabolism? Which is primary? What do
they do?
1. endocrine (primary!) --> products of endocrine pancreas (insulin/glucagon ratio)
2. neural --> regulation of food intake (autonomic innervation of pancreas)
What are the three possible uses for ingested biomolecules?
1. fuel --> metabolized to provide energy (ATP)
2. build --> synthesis reactions for growth and maintenance of tissue
3. store --> as glycogen (liver, skeletal muscles) or fat
Metabolism is divided into what two states? What do they mean?
,1. fed / absorptive state --> anabolic --> products of digestion being absorbed and used
for synthesis
2. fasted / postabsorptive state --> catabolic --> body taps into stores
What are the 3 nutrient pools available for immediate use? Where are they found?
1. glucose
2. free fatty acids
3. amino acids
found mostly circulating in plasma
What controls direction of metabolism? How does it differ between the two
states?
Enzymatic control!
In fed-state: enzyme activity for glycogen synthesis increases! enzyme activity for
glycogen breakdown are inhibited (net glycogen synthesis)
In fasted state: opposite (net glucose synthesis)
Compare influence of insulin and glucagon on metabolism state
Insulin --> fed-state (glycogen synthesis)
Glucagon --> fasted-state (glucose synthesis)
What is the goal of the fasted state metabolism? Why is this important?
, maintain plasma glucose levels
Important because brain is acutely dependent on glucose (can also use ketones!)
Compare glycogen export in liver vs muscle
liver --> glycogen can be broken down and exported as free glucose
muscle --. can NOT be exported as free glucose
How is glycogen exported in the muscle?
Either: used in muscle
OR
Exported as: pyruvate or lactate (liver does gluconeogenesis)
How are fats exported?
triglycerides in adipose tissue are exported as glycerol (liver does gluconeogenesis) OR
exported as fatty acids (beta-oxidation)
What does the liver do with fatty acids?
Can produce ketone bodies from fatty acids (ketogenesis)
How are proteins exported?
broken down into amino acids,
Either: used in muscle
OR exported to liver (gluconeogenesis)
When does ketogenesis occur? What are the dangers?
When lipolysis is faster than usage of acetyl CoA --> ketogenesis
ketone bodies are acidic! can send you into metabolic acidosis
