Other Carbohydrates Metabolism Flashcards
Why is Cellulose not digested in Human GI Tract?
We lack the enzyme required to break the Beta 1-4Glycosidic bonds in cellulose
Carbohydrates Strucutre
Contain CHO
COntain and ALdehyde group or Keto group
Many Hydroxyls -OH
Carbohydrate function
Used as Fuel by tissues
Used to synthesis cellular polymer like nuclei acids, glycoproteins and glycolipids
Excess Carbs converted to Glycogen
When GLycogen stores full Carbs converted to Triacylglycerols
Locations of carbohydrate metabolism and enzymes present
Mouth - Salivary Amylase
Small Intestine - Pancreatic amylase(breaks a1-4 bonds), isomaltase(a1-6bonds), Lactase, Sucrase
How are the enzymes found in the small intestine
They are transmembrane bound proteins found embedded on the surface of the brush border cells of i the intestinal epithelial cells
How are monosaccharides absorbed from the gut lumen into the blood?
SGLT1 from intestine lumen into Epitehlial cell
ACTIVE TRANSPORT
GLUT2 from epithelial cell into Blood
FACILITATED DIFFUSISON
SGLT1 Stands for
Sodium-Glucose Transporter 1
GLUT GLucose Transporter 5 types:
GLUT1: Adult RBCs,Blood-Brain Barrier, Fetal Tissue
GLUT2: Kidney, liver, S INTESTINE, B CELLS PANCREAS
GLUT3: Nerons, Placenta
GLUT4:INSULIN REGULATED, Adipose Tissue, Striated Muscle
GLUT5: Spermatazoa, intestine
General 4 steps of Carb Catabolism
Stage 1: Break down into basic molecules
Stage 2: Break down intermediates and produce reduced cofactors
Stage 3: Krebs cycle, make some intermediates, reduced coenzymes and energy
Stage 4: OXidative Phosphorylation, Make lots of ATP, and regenerates reducing power
What is LActose Intolerance (BASIC)
Inability to digest Lactose
Due to deficiency in Lactase enzyme
3 Types of Lactase Deficiency causing Lactose Intolerance
Primary Lactase Deficiency
Secondary Lactase Deficiency
Congenital Lactase Deficiency
What Causes Primary Lactase Deficiency
Lack of Lactase Persistence allele in adults
What causes Secondary Lactase Deficiency
Small intestine injury (Where lactase is found)
GASTROENTRITIS
ULCERATIVE COLITIS
CHRON’S DISEASE
COELIAC DISEASE
Usually reversible
What causes Congenital Lactase Deficiency?
Autosomal Recessive Inheritance of defective Lactase gene
Can’t Digest Breast Milk
Symptoms of Lactose Intolerance
Bloating
Diarrhoea
Flatulence
Abdominal pain/cramps
Lactose Intolerancee symptoms explained
Lactose not digested by body
Bacteria in small intestine break it down releasing gases (bloating and pain)
causes water to be pulled into intestines (diarrhoea)
Fructose 2 Key Metabolic Enzymes
Fructokinase
Aldolase
Fructokinase Function
Phosphorylates Fructose to Fructose-1P
Aldolase Function
Converts Fructose-1P to Glyceraldehyde and DHAP (DihydroxyacetoneP)
Fructose Metabolism End Goal
Make Gylceraldehyde-3-P to enter GLYCOLYSIS
What causes Fructose Intolerance?
ALDOLASE DEFICIENT
Fructose Intolerance Consequences
Fructose-1-P accumulates in Liver causing damage and death
Where does Lactose Come from?
Lactose = Glucose and Galactose
Galactose metabolism 2 Key Enzymes
Galactokinase
uridyl transferase
Galactokinase Function
Phosphorylates Galactose to GALACTOSE-1-P
Uridyl Transferase Function in Galactose metabolism
Needed in the process to convert Galactose-1-P into Glucose-1P
What is Galactosaemia?
Inability to utilise Galactose
2 reasons Galactosameia can happen
Deficient in enzymes:
-Galactokinase
-Uridyl Transferase
What happens to galactose in Galactokinase deficiency Galactosaemia:
Galactose accumulates
Enters Galactitiol/ALDOSE REDUCTASE pathway
Which depletes NADPH
Galactokinase deficient Galactosaemia consequences:
NADPH stores depleted from Galactitol pathway
So eye lens strucutre damaged since no NADPH to help prevent inappropriate formation of disulphide bonds between crystallin proteins CAUSING CATARACTS
Galactose and Galactiitol Build up in eye can increase intra-Ocular Pressure which can cause blindness
Symptoms of kinase deficienct Galactosaemia:
Cataracts
Blindness (Increased Intra ocular pressure)
How does Uridyl Transferase Deficient Galactosaemia compare to Galactokinase deficient Galactosaemia?
Galactose and Galactose-1-P accumulate
Worse than kinase deficiency
Uridyl Transferase Deficient Galactosaemia symptoms:
Organ damage/failure: liver, kidney and brain
Cataracts
Blindness
