carbohydrates and lipid metabolism Flashcards
defined as the entire chemical reactions network of the body. Another name often used is intermediary metabolism. Most of the chemical reactions in the body are enzyme catalyzed. The intermediates, substrates or products of these enzyme catalyzed reactions are called as metabolites.
Metabolism
a. is the major fuel for all types of cells in the body. Its oxidation produces energy
-is used for the formation of glycogen, pentoses, lactose and mucopolysaccharides _ center of energy consumption
Glucose
g. Deficiency or absence of enzymes of glycogen metabolism causes
glycogen storage diseases
i. Dietary galactose and fructose are converted to
glucose
Deficiency of enzymes of galactose and fructose metabolism causes
galactosemia and fructosemia
a metabolic disease due to defective glucose metabolism
diabetes mellitus
- Degradation of glucose to two molecules of pyruvate or lactate by sequence of enzyme catalyzed reactions constitutes the process of
- a catabolic pathway
-provides energy to cells
GLYCOLYSIS
- If glucose is degraded to pyruvate then it is called
-occurs in the presence of oxygen
aerobic glycolysis
- If glucose is degraded to lactate then it is
- the absence of oxygen
anaerobic glycolysis
Enzymes of glycolysis are present in the
cytosol of most of the cells
Glucose enters cells by
facilitated transport
Glucose enters liver cells by
facilitated diffusion
- Deficiency of enzymes of erythrocyte glycolysis (pyruvate kinase) causes
hemolytic anemia
- Deficiency of muscle phosphofructokinase causes
decreased muscular performance and fatigue.
is the end product of glycolysis in malarial parasite. LDH of parasite is different from human enzyme. Unlike human LDH parasite enzyme is not subjected to inhibition by substrate pyruvate
Lactate
In brain tumors, lactate production is
10 times more
- Cyclic arrangement of sequence of reactions that convert acetyl-CoA to two molecules of CO2 is called as
citric acid cycle.
Citric Acid Cycle is also called as
Tricarboxylic acid (TCA) cycle or Krebs cycle
Enzymes of citric acid cycle are present in
mitochondrial matrix.
intermediates of TCA cycle are used for the synthesis of (a) Fatty acids, Cholesterol (b) Amino acids (c) Porphyrins (d) Glucose.
: In the liver
- In some liver diseases, like hepatitis and cirrhosis
amphibolic role of citric acid cycle is affected.
excess glucose is stored as
glycogen.
is the Synthesis of Glycogen from Glucose
Glycogenesis
In the muscle, about how many grams of glycogen
245 gms
amt of glycogen in the liver is about
72gms
2 hormones the pancreas release that regulates blood glucose
insulin and glucagon
maintain body glucose balance or body blood glucose level
pancreas
is the process by which one molecule of glucose converted into 2 molecules of pyruvate
glycolysis
is unable to mobilize fat rapidly
Skeletal muscle
increase glycogenolysis in muscle and decrease glycogenesis
- Epinephrine and norepinephrine
increases glycogenolysis and decreases glycogenesis in liver.
glucagon
causes breakdown of glycogen in skeletal muscle to maintain fuel supply for muscle contraction
- Epinephrine
causes inactivation of enzymes of glycogenolysis and activation of glycogen forming enzymes. As a result, glycogenesis occurs in liver and muscle.
Insulin
A 70 kg individual may have lipid store of about
15 kg
It occurs in premature infants and in newborns. It is due to inadequate formation or loss in urine due to renal leakage
Carnitine deficiency
Deficiency of CAT-I in the liver leads to impaired fatty acid oxidation. As a result, hypoketonemia and hypoglycemia develops.
Hepatic carnitine acyl transferase deficiency
Due to deficiency of CAT-II fatty acid oxidation is impaired in muscle. Muscle weakness and myoglobinuria are the main symptoms.
Muscle carnitine acyl transferase-II deficiency
- Synthesis of ketone bodies is
ketogenesis
- Degradation of ketone bodies is called
ketolysis
uses ketone bodies for energy production.
Heart, kidney cortex, brain and to some extent skeletal muscle
prefer to use ketone bodies rather than glucose
- Heart and kidney cortex
During prolonged starvation, brain derives most of energy from
ketone bodies
is unable to use ketone bodies due to lack of enzymes
- Liver
Normal blood ketone bodies level is
1mg/100ml
Hyper ketonemia and ketonuria give rise to
Ketosis
Ketone body formation is impaired in some disease like carnitine deficiency and hepatic CAT-I deficiency
Hypoketonemia
- It occurs in the liver, adipose tissue and intestine of non-ruminants.
- Triglycerides synthesized in liver and intestines are transported to other tissues where as in adipose tissue triglycerides are stored.
Triglyceride biosynthesis
. Carbohydrate or starchy diets produce ______ whereas diets rich are peanut oil or corn oil produce _____
hard fat, soft fat
- Extensive accumulation of lipid in the liver leads to condition known as
fatty liver
is the major site of alcohol metabolism
Liver
Alcohol consumption aggravates
gout and porphyrias
- Bile also contains come free cholesterol. Na+, K+ tauro and glycocholate, Na+, K+ tauro and glycochenodeoxy cholate are called as
bile salts.
- About 99% of bile acids secreted into intestine returns to liver through portal circulation. This is known as
enterohepatic circulation (from intestine to liver and back)
Lysosome degrades cellular glycogen for how many percent?
1-3% of cellular glycogen
2 types of metabolism
Catabolism and anabolism
The intermediates, substrates or products of these enzymes catalyze reactions are called
Metabolites
Brain consumes about _ _grams of glucose per day
100
Building blocks of protein
Amino acids
