Systems to cells Flashcards
How much ATP does every human body have?
100-250g
How much ATP does an individual need?
50-75kg (body weight)
How much ATP is reformed everyday?
1000x
Where is energy stored in ATP and how is it released ?
the last phosphate group of ATP, released by hydrolysis of the high energy gamma phosphate bond
Why is glucose a great storage molecule?
It can be complexly oxidised and stored as glycogen
Where is glucose converted to glycogen at?
liver
What is the main stages in ATP production from glucose?
- glycolysis - glucose become pyruvate releasing 2ATP// 2. pyruvate is converted inti Acetyl-CoA in aerobic conditions // 3. Krebs cycle produces 6NADH and 2FADH and 2ATP // FADH and NADH produce 2 ATP EACH
Give examples of some biosynthetic reactions
production of amino acid/ lipid membrane/ RNA/ nucelotides…
In anaerobic conditions what is produced by glycolysis?
lactate
What is glucose stored at when in excess?
triglycerides(in adipose tissue) and glycogen
What happens when glucose levels are low?
Muscles become exporters of glucose and fatty acids
What happens when blood sugar is hight
?
INSULIN is released// glucose is then uptake from the blood, glycogen is produced (converted in the liver) and triglycerides are formed (stored in adipose tissue)
What occurs at low blood sugar?
GLUCAGON is released, glycogen break down occurs, increasing glucose levels
What releases insulin and glucagon?
insulin = pancreatic beta-cells // glucagon = pancreatic alpha-cells
What is gluconeogenesis ?
metabolic pathway generating glucose form pyruvate /lactate (non-carbohydrate substrates)
What stimulates gluconeogenic ?
insulin
What inhibits gluconeogenic ?
glucagon
Where is glycogen stored in cells?
close to mitochondria allowing it to be easily accessed for energy conversion in muscle fibbers
What is the fed state? What does it do?
high blood glucose levels , triggers release of insulin
What is the fasted state? what does it do?
low blood glucose levels , triggers release of glucagon
Describe the enzyme pathway of converting glucose to glycogen.
hexokinase-> phosphoglucomutase-> glycogen synthase
Describe the enzyme pathway of converting glycogen to glucose.
Glycogen phosphorylase-> phosphoglucomutase -> glucose - 6- phosphate
What is the intermediate in the conversion of glucose to glycogen ?
glucose 6 phosphate
What does hexokinase do?
Adds a phosphate to carbon 6 of glucose allowing it to later become glycogen
What is the role of phosphoglucomutases?
changes the position of phosphate group from carbon 6 to carbon 1 or vies versa
What is the regulated reciprocal in the enzyme pathway converting glucose to glycogen ?
glycogen phosphorylase and glycogen synthase// different enzyme is used for different directions of the reaction
What enzymes are involved in phosphorylation?
kinase - adds phosphate to either serine/threonine residual or tyrosine residual /// phosphatase removes phosphate
What mechanisms regulate enzymes
1.change in activity/ 2. change in location/ 3. change in rate of biosynthesis
What changes occur during : prenylation/ ubiquitination/ glyconanation?
adding lipid group/ protein group/ carbohydrate group
Explain the process of phosphorylation.
Addition of a phosphate from an ATP using kinase, salt bridge forms between -ve phosphate and positive aguine and lysine residuals changing the shape
What is the impact of insulin on glucose 1-phsophate?
Switches on glycogen synthase which converts glucose 1 phosphate into glycogen
What is the impact of glucagon on glycogen?
Glucagon switches on glycogen phosphorylase which in turn converts glycogen to glucose 1 phosphate
What is the effect of insulin on protein phosphate 1? What does this result in?
Protein phosphate 1 turns on glycogen synthase and turns off glycogen phosphorylase- PROMOTING CONVERSION TO GLUCOSE
What is the effect of glucagon on protein kinase A? And what does this result in?
protein kinase turns glycogen synthase off and glycogen phosphorylase on- PROMOTING CONVERSION TO GLYCOGEN
What are insulin and glucagon?
polypeptide hormones which are released from the pancreas and bind to specific receptors on muscles/ fat and liver cells
What is meant by irreversible and reversible steps?
irreversible steps - require different enzymes for different directions of reaction// reversible steps use the same enzyme for both direction of reaction