Metabolism Flashcards
Metabolism
The chemical processes that occur within a living organism in order to maintain life
Digestion
The process of breaking down food to its smallest components so that it can be absorbed in the intestine
Absorption
The transport of nutrients from the intestine into the blood or lymph system
3 Carb Monosacchrides
Glucose
Fructose
Galactose
3 Carb Disaccharides
Sucrose
Lactose
Maltose
What is a oligosaccharide
3-10 sugar molecules
2 Oligosaccharides
Raffinose
Stachyose
What is a polysaccharide
10 or more sugar molecules
2 Types of carb polysaccharides
Starch
Glycogen
what 5 enzymes are involved in carb metabolism
Salivary Amylase
Pancreatic Amylase
Maltase
Sucrase
Lactase
Where does carb digestion start
Mouth via Salivary Amylase
What does salivary amylase do
Breakdown of polysaccharides to shorten sugar units
Starch breakdown disaccaride and mono
Di: Maltose
Mono: Glucose
Why is chewing important
Increases surface area for salivary amylase to contact with breaking down further
Where does saliva come from? x3
Parotid Glands
Sublingual Glands
Submandibular glands
What occurs to carbs at stomach
Amylase slows due to acidic enviroment
Chyme is expelled into duodennum
What is chyme
The semifluid mass of partly digested food expelled by the stomach into the duodendum
Where does majority of car absorption occur
Duodenum and the Jejunum
What 3 enzymes are used to digest carbs in small intestine
Di to Mono
Lactase
Maltase
Sucrase
Lactase is made of what
Glucose and Galactose
Maltose is made of
2x glucose
Sucrose is made of
Glucose + Frictose
What occurs in carb digestion in small intetsine
Amylase is secreted into pancreatic juice breaches starches into smaller glucose units
Disaccharides and small polysaccharides are digested by specific enzymes located in the brush borders of the intestinal epithelial cells (then into blood)
Enzyme for brush borders of the intestinal epithelial cells for glucose and galactose
Glut 1
Enzyme for brush borders of the intestinal epithelial cells for fructose
Glut 5
Enzyme from epithelial cell into blood
Glut 2
What stimulates glucose uptake from food
Insulin (high blood sugar)
What stimulates glucagon from stores (glycogen breakdown)
Glucagon
What is glycogenolysis
Breakdown of glycogen to glucose by low blood sugar/glucagon
What is the alpha cells of the pancreas produce
Glucagon
What do the beta cells of the pancreas produce
Insulin
What is the hyperinsulinemic-euglycemic clamp
Gold standard method for measuring insulin sensitivity
-When glucose inflow is matched to insulin uptake from tissue so that blood glucose becomes stable
What is insulin sensitivity
How much of an increase in tissue blood glucose uptake occurs for a given concentration of blood insulin
What does insulin sensitivity increased mean
Rate of blood glucose removal from blood is increased at a given blood insulin concentration
What does decreased insulin sensitivity mean
Rate of glucose removal from blood is decreased at a given blood insulin concentrtion
How does a hyperinsulinemic-euglycemic clamp work
1)Infuse insulin to elevate blood insulin concentration
2)Infuse glucose to increase blood glucose concentration
When glucose inflow is matched to insulin uptake from tissue so that blood glucose becomes stable
Where the clamp happens tells us insulin sensitivity, greater tissue uptake per concentration insulin
What does the clamp tell us
When glucose inflow is matched to insulin uptake from tissue so that blood glucose becomes stable
Where the clamp happens tells us insulin sensitivity, greater tissue uptake per concentration insulin
Insulin clamp curve higher means
Higher insulin sensitivity
Type 1 Diabetes
Insulin deficiency as pancreatic beta cells are unable to produce insulin
Type 2 Diabetes
Insulin level is insufficient to compensate for insulin resistance resulting in hyperglycaemia
Pre-diabetes fasting glucose of HbA1C o what levels
6.0%-6.4%
What is glycated hemoglobin
Glucose in the bloodstream can bind to the protein Hb
What does gkycated heme tell us
Diagnosis of diabtes
-Average plasma glucose over previous 2-3 months (higher percentage = decrease inckusin resiatnce = higher blood glucose)
Healthy HbA1C
5.5%-5.7%
Diabetic HbA1C
greater the 6.5%
What enzyme is used to bring glucose into muscle cell from blood
glut 4
Glucose is used by skelteal muscle how
Undergo Glycoysis to form pyruvate
-to make ATP by TCA
Where is the ETC and TCA cycle occur in the cell
Mito
What is the structure of the mito
Outer Mito Mem
Intermembrane space
Innermito (etc) (CRISTAE)
Matirc
Subsarolecmmal mito fractions do what
Active Transport
Intermyofibrillar mito fractions do what
Contractile
Cristae (therefore ETC) increase with what
Exercise training (more atp)
What is important about the TCA cycle
Pyruvate is used to create NADH and FADH2
What are NADH and FADH2 used for?
Electron carriers and electron donars for etc
What complexs in ETC create gradient
1,3,4
What does complex 1 do
NADH + H+ gradient
What does complex 2
FADH2
Wjay complex involves oxygen that the H+ will come back to in rte membtane from intermembtane space
Complex 4
Explain gradient in ETC
H+ from matrix into intermembrane
Oxygen brings back in ATP synthase
What occurs to undigested carbs
Celluose (fibre of the form diet carb)
-Celluolose is resistant to digestive enzymes and is either
1)Excreted in feces
2)Fermented bt bacteria in large intestine
What pushes undigested carbs to colon
Peristaltic movemets
Peptide bonds break via what
Hydrolysis
Peptide bonds form via what
Condensation
The peptide bond of a protein is formed between what
Carboxyl group and amino group
What are the 5 enzymes involved in protien/aa metabolism
Pepsin
Trypsin
Chymotrypsin
Carnpxypeptidase
Elastase
Where does the chemical digestion of protein start
Stomach
What secretes HCL
Parietal cells in the stomach
What secretes Pepsinogen
Chief Cells in the Stomach
What is the role of Gastrin
Secreted by the stomach to increase HCL and pepsnogen instomach
What is pepsinogen
Inactive form of pepso activated by HCL (decreasing pH)
What does pepsin do
Converts proteins into smaller polypeptides
What free indvidual amino acids x3
Pancreatic Proteases
Brush Border Enzymes
Peptidases
ALL BEFORE SMALL INTESTINE
What hydrolysis peptide bonds (breaks down)
Pancreatic Proteases
What are the 4 Pancreatic Proteases
- Trypsin
2.Chymotrypsin - Carboxypeptidase
- Elastase
What is the central hub for AA metabolism
Liver
Where does most absorption of AA occur
Small Intestine
From Small Intestine where do AA go
Blood then to hepatic portal vein to liver
What are the 3 things that occur to AA in liver
1)Protein Synthesis
2)Transamination
3)Oxidation
What are transamination reactions
Transfer of the amino group from one amino acid to va keto acid via amino transferase enzymes
Why may transamination reaction be important
Produce pyruate for energy
What impacts circulating AA levels
First-pass splanchnic extraction
What is First-pass splanchnic extraction
The uptake and utilization of AA by the GI tract and liver to support protein turnover and metabolic processes
MOST IMPORTANT TO LIFE
What percentage of total AA are available in system circulation ?
55%
What percentage of total AA are absorbed into skeletal muscle?
20%
What percentage of total AA are used for MPS?
11%
Where is branched-chain AA metabolism primarily initiated?
Skeletal Muscle
What are the 3 branched chained AA
Isoleucine
Leucine
Valine
What enzymes bring in BCAA into muscle cell x2
LAT-1- LEUCINE
SNAT-2
What two enzymes metabolize BCAA once inside cell?
BCAT- Transanimation
BCKD - Oxidative Decarboxylation
BCAT is used for what
Transanimation
BCKD is used for what
Oxidative Decarboxylation
T or F BCAA bypass metabolism in splenic tissues
TRUE
What is a deamination reaction
Amino group is removed from the aa producing Ammonia.
Ammonia is a toxic by-product which needs to undergo conversion to ammonium before urea cycle
Glutamate dehydrogenase does what
deamination reaction enzyme
Why may a deamination reaction be imprortant
Alpha-ketogluterate for TCS
Prior to urea cycle ammonia turns into what
Ammonium
What are two ways BCAA metabolism impacts metabolic pathways
Transanimation produces pyruvate
Deanimation produces alpha-ketogluterate
which are byproducts for TCA cycle
ENERGY
Where does the urea cycle take place
Liver
Processes nitrogenous products and houses urea cycle
Then urea is excreted in the kidneys
How is the large intestine a side of AA metabolism
Remnant undugested and unabsorbed components of dietary proteins travel to large intestine where they are metabolized by microbacteria or digested by remaining proteases or peptidases
2 Key enzymes in fatty acid metabolism
Lingual Lipase
Pancreatic Lipase
Short chain FA
C4-C6
Med Chain FA
C8-C10
Long Chain FA
C12-C14
Where does fat digestion begin
Mouth
What is the role of lingual lipase?
Enzyme splits triglycerides into fatty acids and glycerol in mouth
Lingual Lipase is in saliva
What occurs in the stomach for digestions of Fat
Lipase continues to breakdown triglyerides in stomach but slows
What contributes to digestion of fat in duodenum?
Chym enters bile salys and pancreatic lipase are secreted into duodenum
Bile salts emusify large lipid dropelts into small ones
Pancreatic lipase breaks down into
FA
Diacylgkyceros
monoacylgkycerons
Micelles transport fatty acid to villi where contents of tehe micelle enter epithelial cell
What 2 enzymes are used in duodenmum for fat
Bile Salts
Pancreatic Lipase
What are miscelles
Circular/disk shaped structures comorised of compounds like phospholipids and fatty acids
Carry FA to eputhelial cells
What happens to short and med chained fatty acids in ep cells
go into blood
Bind to albumin
Transported to liver
What happens to long chained fatty acids in ep cells
Re-esterfied to triglycerides which combine with cholesterol and phosopholipids to produce chylormicrons
What are chylomicrons used for/ where are they circulated
It allows the transport of long-chain FS in plasma but is absorbed by the lymph system prior to transport in the circulatory system
What happens to chylomicrons when they arrive at skeletal muscle
Lipoprotein lipase (LPL) breaks down triglcerides into free fatty acids and glycerol
Transported into cell through transporters on membrane FABPpm and CD36
Fat Skeletal Muscle transporters x2
FABPpm and CD36
T or F only long chained FA need transprorters into skeletal muscle
True
What is beta-oxidation
Reduction of a long chained FA to produce acetyl-coa for energy in TCA
What is the rate limiting steo in long chain fatty acid oxidation
CPT1
Carnitine transferase
Explain Beta Oxidation
Long chain fatty acid is converted to fatty acyl-coa(Palmitolyl-CoA)
Cartnitine is added to palmitoyl coa by CPTI to allow palmitoyl coa to go through membrane
CPII removes cartitine and palmitoyl-coa/acetyl-coa can be used to produce acetyl-coa
Once thru membrane bet-oxudation does what
Generate acetyl-coa by removing 2 carbons from fatty acid chain
Also generates FADH2 and NADH
