Inborn Metabolism (Exam 1) Flashcards
pancreas
secretes insulin and glucagon in response to changes in blood glucose concentration
brain
transports ions to maintain membrane potential; integrates inputs from body and surroundings; sends signals to other organs
liver
processes fats, carbohydrates, proteins from diet, synthesizes and distributes lipids, ketone bodies, and glucose for other tissues; converts excess nitrogen to urea
portal vein
carries nutrients from intestines to liver
small intestine
absorbs nutrients from the diet, moves them into blood or lymphatic slides.
lymphatic system
carries lipids from intestine to liver
adipose tissue
synthesizes, stores, and mobilizes triacylglycerols
skeletal muscle
uses ATP to do mechanical work
what happens during strenuous exercise?
lactate builds up in the muscle
acidification of the muscle prevents what
continuous strenuous work
where is the lactase transported to?
liver and converted to glucose there
what does the cori cycle recycle?
NAD+ so glycolysis can continue
energy containing nutrients
carbohydrates, fats, proteins
energy depleted end products
CO2, H2O, NH3
cell macromolecules
proteins, polysaccharides, lipids, nucleic acid
precursor molecules
amnio acids, sugars, fatty acids, nitrogenous bases
muscle
ATP produced by glycolysis for rapid contraction
phsyiological significance of the cori cycle
prevents lactic acidosis in muscle under anaerobic conditions
production of ATP during muscle activity
hexokinase is for the
muscle and other tissues
glucose utilization
phosphorylation of glucose commits glucose for use by that cell
glucokinase is for the
liver
glucokinase has a high
Km and a high Vmax for glucose
a large accumulation of what is dangerous? what does it lead to?
ketone bodies
metabolic acidosis
in diabetes,
insulin does not function properly
glucose levels are insufficient for energy needs
fats are broken down to acetyl-CoA
ketogenesis produces ketone bodies
inborn errors of metabolism
disorders in which single gene defects cause clinically significant blocks in metabolic pathways
pathology in metabolic disorders
from accumulation of enzyme substrate behind a metabolic block
deficiency of a reaction product
first treatment strategy for metabolic disorders
enhance the reduced enzyme activity
absence of glucose 6 phosphate
key feature: seizure
pathways affected: glycogen storage
treatment: cornstarch, frequent feeding
muscle glycogen phosphorylase deficiency
key feature: muscle pain on exertion
pathway affected: glycogen storage in muscle
treatment: glucose plus decreased exertion
carnitine/acylcarnitine translocate deficiency
key feature: seizures
pathway affected: mitochondrial import of fatty acids
treatment: carnitine supplementation and feeding tube
mitochondrial HMG-CoA synthase deficiency
key feature: semi comatose, no ketones
pathway affected: synthesizes ketone precursor
treatment: frequent feeding
increase xanthine oxidase activity and ABCG2 deficiency
key feature: pain and swelling in the joints, usually in the big toe and foot
pathway affected: chronic heterogenous disorder of urate metabolism
treatment: allopurinol
PKU (phenylketonuria) patho
deficiency of the liver enzyme phenylalanine hydroxylase
prevents normal metabolization of phenylalanine
phenylalanine
cannot be synthesized by the body and must therefore be consumed in protein rich foods