Biochemistry 2 Flashcards
Define cellular respiration
series of metabolic reactions that convert stored energy in nutrinets into usuable energy for biological proccesses
give some main points of glycolysis
-anaerobic
-short term energy system
-substrate= glucose
-ineffcient-low yield of ATP
Give some main points of the oxidative system
-aerobic
-long-term energy system
-substrate= glucose, fats
-highly efficient-high yield of ATP
list the steps for the metabolism of fatty acids
-lipase
-beta oxidation spiral
-krebs cycle
-ETC
What is the absorptive state ?
in the fed state- following digestion when nutrients are being absorbed into the blood stream
whats the difference between anabolism vs catabolism?
A-storing
C-breaking down
How long does a meal typically take to digest?
4 hours to completly digest and absorb
whats the key hormone in the absorptive state?
insulin
describe the absorptive state at rest
-free glucose used to produce ATP via oxidative pathways
-lipids used for synthesis
-AA for protein synthesis
-excess blood glucose stored as glycogen
What happens to excess FAs and AAs and glucose once glycogen stores are full?
converted and stored as fat- adipose and triglycerides via lipogenesis
Define post absorptive state
in the fasting state-following absorption- when nutrients have been stored and or are being used for biological proccesses in the body
describe the post absorptive state at rest
-glycogenolysis
-lipolysis
-once glycogen stores are depleted alternate substrates can be used to produce glucose-gluconeogenesis
-free glucose used to produce ATP via oxidative pathways
-FA oxidation occurs
What is the key hormone in the post absorptive state?
glucagon
define muscle glyocgen and liver glycogen
MG-on site source of glucose for contracting muscles
LG-systemic control-maintains blood glucose
Describe glycogenesis
-glucose molecules are linked together in long chains forming glycogen
anabolic pathway requiring ATP
absorptive state
influenced by insulin
describe glycogenolysis
-glycogen splitting
-post absorptive state
-in muscles and other cells glucose is trapped inside as glucose-6-phosphate
-in the liver hepatocytes contain the enzyme needed to remove phosphate-releases free glucose
influenced by glucagon,epinephrine,cortisol
Name the other non-CHO sources that create new glucose
lactic acid-by product of anaerobic glycolysis
glycerol from lipolysis or digestion of dietary fats and oils
AA from dietary protein or body protein stores
give a few facts about lipids
-most conc energy source
-energy yield from fat much higher than carbs or protein
-50% fat store
-balance of storage
Describe lipogenesis-absorptive state
multiple pathways where glucose in ingested, FAs and AAs are converted to fat
-influenced by the presence of insulin
describe lipolysis-post absorptive state
-stored triglycerides in adipose are broken down to glycerol and FAs
FAs- used for energy in most cells- B oxidation, krebs, ETC
glycerol-converted to Pyruvic acid for ATP production, or undergo gluconeogenesis
influenced by glucagon, epinephrine, cortisol, thyroid hormones
describe protein catabolism
-surplus proteins are catabolised for energy or converted to fat
-AA are deaminated
-remainder of molecule is ketoacid
Describe ketoacids
-may enter krebs cycle and be fully catabolised for energy
-may be converted to glucose
-may be converted to fat
Describe hormonal control using anabolic hormones
-insulin
-promotes glucose uptake into cells by binding with insulin receptors on the cell surface
- stimulates GLUT-4
-inhibits glycogenolysis
-promotes glucose conversion to triglycerides-lipogenesis
-promotes protein synthesis
What are two key functions of insulin?
promotes glycogenesis and at the same time inhibits glycogenolysis
promotes lipogenesis and protein synthesis
