MEH 3 - Energy Production Flashcards
What is stage 1 of catabolism?
Breakdown to building blocks
Where/how is stage 1 of catabolism carried out in the body?
- SALIVA contains amylase
- the PANCREAS contains amylase
- SMALL INTESTINE contains disaccharidases
What are the three types of lactase deficiency?
- primary lactase deficiency (absence of lactase persistence allele)
- secondary lactase deficiency (caused by injury to small intestine)
- congenital lactase deficiency (autosomal recessive defect in lactase gene)
What are the symptoms of lactose intolerance?
- bloating/cramps
- flatulence
- diarrhoea
- vomiting
- ‘rumbling’ stomach
How are monosaccharides absorbed into the blood?
- active transport by sodium dependent glucose transporter (SGLT1)
- facilitated diffusion via GLUT2 transport proteins into blood supply
Where are GLUT2 and GLUT4 proteins found?
- GLUT2 - kidney, liver, pancreatic beta cells, small intestine
- GLUT4 - adipose tissue, striated muscle
Which cells have an absolute requirement for glucose as a food?
- red blood cells
- neutrophils
- innermost cells of kidney medulla
- lens of the eye
- brains prefers glucose but can use ketone bodies
What is stage two of catabolism?
- breakdown to metabolic intermediates
- release of reducing power and energy
What are the functions of glycolysis?
- oxidation of glucose
- NADH production
- synthesis of ATP from ADP
- production of C6 and C3 intermediates
Can glycolysis occur anaerobically?
Yes - with the addition of an enzyme (PDH) it is the only pathway that can operate anaerobically.
How much ATP and NADH is produced in glycolysis?
- 2 ATP produced per glucose
- 2 NADH produced per glucose
Which enzyme converts glucose into glucose-6-P?
Hexokinase (or glucokinase in the liver)
Which enzyme converts fructose-6-P into fructose 1,6-bis-P?
Phosphofructokinase-1
Which enzyme converts phosphoenolpyruvate into pyruvate?
Pyruvate kinase
Why is glucose phosphorylated?
It makes glucose negatively charged so it cant pass back through the plasma membrane. It also increases reactivity to permit subsequent steps.