Chapter 12: Bioenergetics and Regulation of Metabolism Flashcards
____________ measures the overall change in heat of a system during a reaciton.
enthalpy
What is the GIbbs free energy equation?
ΔG = ΔH - TΔS
Spontaneous reactions proceed in the forward direction and have a negative or positive ΔG?
negative
Nonspontaneous reactions have a net gain of energy and have a negative or positive ΔG?
positive
Most of the ATP in a cell is produced by mitochondrial ____ ____________, but some is produced during what other pathways?
ATP synthase; glycolysis (indirectly from GTP) and TCA
ATP is consumed in what two ways?
- hydrolysis
- transfer of phosphate group to another molecule
The ________________ state, also called the absorptive or well-fed state, occurs shortly after eating. This state is marked by greater ________________ (synthesis of biomolecules) and fuel storage.
postprandial; anabolism
What is the opposite of anabolism?
Catabolism (breakdown of molecules for energy)
Nutrients flood in from the gut and make their way via the ____________ ________ ________ to the ____________, where they can be stored or distributed to other body tissues.
hepatic portal vein; liver
________ promotes glycogen synthesis in liver and muscle.
insulin
After glycogen stores are filled, the liver converts excess glucose to ____________ ____________ and ________________.
fatty acids and triacylglycerols
In the fasting state, what occurs?
- glycogenolysis first
- gluconeogenesis at max velocity about 12 hours later
- amino acids and fatty acids released due to decreased insulin and increased epinephrine
During prolonged fasting what occurs?
- increased glucagon
- glycogen stores depleted and gluconeogenesis occurs
- lipolysis occurring, and then eventually ketone bodies formed
____________ is a peptide hormone secreted by the beta-cells of the pancreatic Islets of Langerhans.
insulin
____________ is a peptide hormone secreted by the alpha-cells of the pancreatic Islets of Langerhans
glucagon
What is the primary target of glucagon?
heapatocytes
____________ from the adrenal cortex are responsible for part of the stress response. During fight or flight, ____________ must be rapidly mobilized from the liver in order to fuel actively contracting muscle cells while fatty acids are released from adipocytes.
glucocorticoids; glucose
Glucocorticoids, especially ____________, are secreted with many forms of stress, including exercise, cold, and emotional stress.
cortisol
Cortisol also elevates blood glucose levels and increases glucose availability for nervous tissue through what two mechanisms?
- inhibits glucose uptake in tissues / increases hepatic output of glucose via gluconeogenesis
- enhances activity of glucagon, epinephrine, and ohter catecholamines
Catecholamines are secreted by the ____________ ____________. What are two major examples?
adrenal medulla; epinephrine (adrenaline) and norepinephrine (noradrenalie)
What do catecholamines do?
Increase the activity of the liver and muscle glycogen phosphorylase, which promotes glycogenolysis
What do catecholamines do for the liver?
Increase glucose output by stimulating glycogenolysis
The increase in metabolic rate produced by a dose of ____________ hormone occurs after a latency of several horus but may last for several days, while ____________________ produces a more rapid increase in metabolic rate and has a shorter duration of activity.
thyroxine; triiodothyronine
What are the 2 major roles of the liver?
- maintain a constant level of blood glucose
- synthesize ketones when excess fatty acids are being oxidized
What do adipose tissues do after a meal?
stimulate glucose uptake
What are the major fuels of skeletal muscle?
glucose and fatty acids
What is the primary fuel of muscle contraction during HIIT vs. continuouse moderate intensity?
During HIIT, anaerobic glycolysis. During moderate/high intensity exercises, glucose at first then fatty acids.
Between meals, the brain relies on blood glucose supplied by hepatic ____________ or ____________.
glycogenolysis or gluconeogenesis
During prolonged fasting, the brain will use ________ ________.
ketone bodies
How is the respiratory quotient calculated?
CO2 produced / O2 consumed
________ is secreted by the stomach in response to signals of an impending meal, e.g. sight, sound, taste, and smell.
ghrelin
____________ further increases appetite and is involved in alertness and sleep-wake cycle.
orexin
________ is a hormone secreted by fat cells that decreases appetite by suppressing orexin production.
leptin
How is BMI calculated?
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