Flashcards in Digestion,TCACycle, OxidativePhosphorylation_Molecules Deck (56):
What is ATP?
Energy currency of the cell
What happens when there is insufficient ATP?
A healthy cell maintains ATP at what level?
5 - 200 times that of ADP
What is a property of ATP that allows it to maintain ATP levels 5 - 200 times that of ADP?
Constantly used and regenerated
What is the half life in cell of ATP?
What does amylase breakdown starch into?
What are the specific brush border enzymes?
What is lactose intolerance caused by?
How does starch get absorbed?
Starch -> Salivary amylase/Pancreatic amylase -> Oligosaccharies, Maltotriose, Maltose -> Brush - Border Hydrolases -> glucose,galactose, fructose -> absorption
How does sucrose & lactose get absorbed?
Sucrose & lactose -> brush-border hydrolyses -> glucose, galactose, fructose -> absorption
What enzymes plays a part in digestion?
1) Salivary amylase
2) Pepsin in stomach
3) Pancreatic Enzymes
4) Brush border Enzyme
5) Bile salts
What does salivary amylase do?
Initial breakdown of starch
What does pepsin in stomach?
Initial breakdown of protein
Name the pancreatic enzymes involved in digestion?
Name the brush border enzymes involved in digestion
What does bile salts do in digestion?
How is protein digested to polypeptides?
Acid denaturation and pepsin hydrolysis in the stomach
What does pancreas do int the duodenum?
Pancreas secretes a range of proteolytic enzymes (proteases) into the dudoenum
What are the proteases that the pancreas secretes into a duodenum?
Name the endopeptidases
Name the exopeptidases
Carboxypeptidases A and B
Name the Brush Border peptidases
What do Brush Border peptidases do?
Hydrolase oligopeptides to AA
What is pepsin generated from?
Generated from inactive pepsinogen in the low pH of stomach
What is trypsin and chymotrypsin secreted from?
Secreted from the pancreas as inactive trypsinogen and chymotrypsinogen
How is activation initiated?
By enterokinase in the small intestine
How does the body prevent tissue breakdown?
Digestive proteases are produced as inactive zymogens
What are examples of pancreatic problems?
2) Pancreatic insufficiency
What is pancreatitis?
Inflammation of pancreas
What happens in pancreatitis?
1) Triggers activation of inactive zymogens, particularly trypsinogen
2) Active trypsin degrades pancreatic tissue
What is pancreatic insufficiency characteristic of?
Cystic Fibrosis, pancreatic ducts blocked
What happens during pancreatic insufficiency?
Patient cannot digest food: failure to thrive
What is the treatment for pancreatic insufficiency?
Pancreatic supplements i.e. pancreatic enzymes in tablet form
What are fats in food emulsified by?
What is ligases secreted from and goes into ?
What does lipase do?
1) Degrade bile emulsified fats
2) Releasing fatty acids
What is the process of digestion of fats?
1) Bile salts emulsify dietary fats in the small intestine, forming mixed micelles
2) Intestinal lipases degrade triacylglycerols
3) Fatty acids and other breakdown products are taken up by the intestinal mucosa
What is ATP generation and the mitochondria?
In oxygen utilising cells (aerobic) the vast majority of ATP is generated in the mitochondria of the cell
What is acetyl group bound to coenzyme A called?
What is a common metabolite of all major food molecules?
Acetyl - CoA
What is Coenzyme A used for?
1) Carrier of acyl groups
2) Forms high energy toaster bond
What is Coenzyme A derived from?
Pantothenic acid (Vitamin B5)
what are the major ATP generating pathways in all aerobic cells?
What is TCA cycle?
Tricarboxylic Acid Cycle (a.k.a Citric Acid cycle)
Where does TCA cycle take place?
Takes place in the mitochondrial matrix
Where does oxidative phosphorylation take place?
Takes place in the inner mitochondrial membrane
ATP is generated in the mitochondria from two sequential processes what are they?
Under aerobic conditions where is pyruvate oxidised?
In the mitochondria
How does pyruvate oxidatively decarboxylate?
It diffuses through the pores in the outer mitochondrial membrane and is transported across the inner mitochondrial membrane into the mitochondrial matrix, where it is oxidatively decarboxylated to acetyl CoA
Pyruvate oxidatively decarboxylation is catalysed by..?
What is TPP (thiamin pyrophosphate) used for?
1) Carrier of pyruvate
2) Carrier of the hydroxyethyl group that is formed by pyruvate decarboxylation
With the exception of lipoic acid, the coenzymes of pyruvate dehydrogenase require what vitamins for synthesis?
1) Pantothenic acid (CoA)
2) Niacin (NAD)
3) Riboflavin (FAD)
4) Thiamin (TPP)
What happens if there is a deficiency of the vitamins?
impair pyruvate dehydrogenase reaction.
For example thiamin deficiency (beriberi) blood levels of pyruvate lactate and alanine are elevated after a carbohydrate rich meal because pyruvate would be either reduced to lactate or transmitted to alanine (when major reaction blocked).
What is special about the TCA cycle?
1) Final common pathways for the oxidation of all major
2) Active in all cells the possess mitochondria
What are the other names of TCA cycle?
Citric Acid Cycle or Kreb's Cycle