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85 Cards in this Set

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  • Back
What are the sugar constituents of Sucrose?
Fructose and Glucose
What are the sugar constituents of Starch?
Glucose polymer
What are the sugar constituents of Lactose?
Glucose and Galactose
What are the sugar constituents of Maltose?
Glucose and Glucose
What are the sugar constituents of Amylose?
Amylose is a linear poly-maltose consisting of Glucose in 1-4 linkage
What bond does ∂-amylase hydrolyze?
1-4 linkage between glucose units of starches.
What inhibits ∂-amylase in the stomach?
HCl
What prevents the denaturing of ∂-amylase, due to stomach acid?
Bicarbonate
Where is ∂-amylase actively hydrolyzing starch?
Mouth and intestines
What is a glycosidase?
An enzyme that hydrolyzes bonds between sugars.
What is an endonuclease?
It is an enzyme that hydrolyzes internal bonds of a complex, e.g., ∂-amylase.
Will ∂-amylase hydrolyze isomaltose (an isomer of maltose)?
No, since isomaltose has a 1-6 linkage. It requires isomaltase
What is the name of the branch of glucose polymer that is connected by a ∂, 1-6 linage?
Amylopectin
What type of bond holds the fructose and glucose together in sucrose?
Alpha 1-2, linkage
What type of bond holds the galactose and glucose together in lactose?
ß, 1-4 linkage
What is the function of the sucrase-isomaltase complex? And where is it found?
It metabolizes sucrose and isomaltose and is found in membrane of the gut.
What is the function of glucoamylase?
It hydrolyzes ∂, 1-4 linkage between glucose-glucose in maltose.
What is the function of lactase?
It hydrolyzes ß, 1-4 linkage between galactose-glucose in lactose.
Why does the lack of lactase (ß-glycosidase) cause diarrhea?
If the enzyme that breaks up lactose is present on the brush border of the intestines then the galactose and glucose are absorbed, if not bacteria breaks it and you get more molecules in the gut… thus water flows out of the cell and into the gut.
What are the products resulting in the gut in the absence of lactase?
Galactose, glucose, CO2, CH4, H2
What is the conclusive measurement of lactase deficiency?
H2 content of exhalation… produced by microbial flora.
How long do the symptoms of lactase deficiency present after consuming milk?
45-60 minutes
What is a channel protein?
A protein that makes a hole in the membrane and facilitate the flow of molecules down their concentration gradient.
What is gated channel?
A protein channel that can be opened or closed in response to metabolic signals.
What is involved in facilitative diffusion?
Stuctrural change in the protein in response to substrate specificity.
What type of curve represents simple diffusion?
Linear
In facilitated diffusion, what type of kinetics is observed?
Saturation kinetics (hyperbolic curve), which will show increases in diffusion as concentration increases, then tapper off, then stop increasing as the protein reaches it V-max.
In a hyperbolic cure (facilitated diffusion), where do you find the Km?
x-int of the _ v-max.
Which has higher affinity, low or high Km?
Low
b. Intestines, Liver, kidney, pancreas
a. Glut 1
b. What effect will this have?
a. Glut 1
b. What effect will this have?
a. Glut 2
What can the body do to modulate the V-max?
Make more transporters
Can V-max and Km be modulated?
Yes
What relevance does the Na+/K+-ATPase have to glucose transport in the intestines, from the gut into the cells? (hint:coupled transport)
a. 3 Na+ out of the cell (against its gradient and building up in the cell) and eventually will flow into the bloodstream
Detail how cholera causes diarrhea.
a. Cholera bacterium releases an endotoxin that catalyzes a ADP-ribosylation rxn.
What is CFTR?
Cystic fibrosis transmembrane regulator protein
What is the treatment of cholera?
Water, sodium and glucose… taking advantage of the Na/K cotransport system.
b. In normal function, what inhibited constitutive synthesis?
a. It binds the adenylate cyclase, then cAMP is produced.
With respect to chlorine channels, what is the sequence of events after cAMP is produced?
a. PKA is activated
What does a high Vmax indicate?
The enzyme works fast.
What are the sugar constituents of Sucrose?
Fructose and Glucose
What are the sugar constituents of Starch?
Glucose polymer
What are the sugar constituents of Lactose?
Glucose and Galactose
What are the sugar constituents of Maltose?
Glucose and Glucose
What are the sugar constituents of Amylose?
Amylose is a linear poly-maltose consisting of Glucose in 1-4 linkage
What bond does ∂-amylase hydrolyze?
1-4 linkage between glucose units of starches.
What inhibits ∂-amylase in the stomach?
HCl
What prevents the denaturing of ∂-amylase, due to stomach acid?
Bicarbonate
Where is ∂-amylase actively hydrolyzing starch?
Mouth and intestines
What is a glycosidase?
An enzyme that hydrolyzes bonds between sugars.
What is an endonuclease?
It is an enzyme that hydrolyzes internal bonds of a complex, e.g., ∂-amylase.
Will ∂-amylase hydrolyze isomaltose (an isomer of maltose)?
No, since isomaltose has a 1-6 linkage. It requires isomaltase
What is the name of the branch of glucose polymer that is connected by a ∂, 1-6 linage?
Amylopectin
What type of bond holds the fructose and glucose together in sucrose?
Alpha 1-2, linkage
What type of bond holds the galactose and glucose together in lactose?
ß, 1-4 linkage
What is the function of the sucrase-isomaltase complex? And where is it found?
It metabolizes sucrose and isomaltose and is found in membrane of the gut.
What is the function of glucoamylase?
It hydrolyzes ∂, 1-4 linkage between glucose-glucose in maltose.
What is the function of lactase?
It hydrolyzes ß, 1-4 linkage between galactose-glucose in lactose.
Why does the lack of lactase (ß-glycosidase) cause diarrhea?
If the enzyme that breaks up lactose is present on the brush border of the intestines then the galactose and glucose are absorbed, if not bacteria breaks it and you get more molecules in the gut… thus water flows out of the cell and into the gut.
What are the products resulting in the gut in the absence of lactase?
Galactose, glucose, CO2, CH4, H2
What is the conclusive measurement of lactase deficiency?
H2 content of exhalation… produced by microbial flora.
How long do the symptoms of lactase deficiency present after consuming milk?
45-60 minutes
What is a channel protein?
A protein that makes a hole in the membrane and facilitate the flow of molecules down their concentration gradient.
What is gated channel?
A protein channel that can be opened or closed in response to metabolic signals.
What is involved in facilitative diffusion?
Stuctrural change in the protein in response to substrate specificity.
What type of curve represents simple diffusion?
Linear
In facilitated diffusion, what type of kinetics is observed?
Saturation kinetics (hyperbolic curve), which will show increases in diffusion as concentration increases, then tapper off, then stop increasing as the protein reaches it V-max.
In a hyperbolic cure (facilitated diffusion), where do you find the Km?
x-int of the _ v-max.
Which has higher affinity, low or high Km?
Low
b. Intestines, Liver, kidney, pancreas
a. Glut 1
a. Which Glut has higher affinity and lower capacity? And what effect will this have?
a. Glut 1… b. Glucose will cross the barrier whenever it is near.
a. Which Glut has lower affinity and higher capacity? And what effect will this have?
a. Glut 2… b. Glucose will only be taken up when [glucose] are high.
What can the body do to modulate the V-max?
Make more transporters
Can V-max and Km be modulated?
Yes
What relevance does the Na+/K+-ATPase have to glucose transport in the intestines, from the gut into the cells? (hint:coupled transport)
a. 3 Na+ out of the cell (against its gradient and building up in the cell) and eventually will flow into the bloodstream… b) 2 K+ out of the cell… c) glucose follows sodium out of the cell and into the bloodstream… d) this drives the flow of sodium and glucose into the cell from the gut.
Detail how cholera causes diarrhea.
a. Cholera bacterium releases an endotoxin that catalyzes a ADP-ribosylation rxn… b) A-subunit binds to adenylate cyclase… c)Adenylate cyclase will constitutively produce cAMP… d) cAMP activates PKA… e) PKA stimulate Chloride transport out of the cell… water follows into the gut… via the CFTR.
What is CFTR?
Cystic fibrosis transmembrane regulator protein
What is the treatment of cholera?
Water, sodium and glucose… taking advantage of the Na/K cotransport system.
a. What role does G-protein play in regular signal for the CFTR? And b) In normal function, what inhibited constitutive synthesis?
a. It binds the adenylate cyclase, then cAMP is produced… b) GTPase hydrolyzes “it”
With respect to chlorine channels, what is the sequence of events after cAMP is produced?
a) PKA is activated… b) PKA stimulate chlorine channel transport, via the CFTR, into the luman
What does a high Vmax indicate?
The enzyme works fast.
What are the three ways glucose levels can be regulated?
a) Blood levels of nutrients (read by cells)… b) Hormones… c) Neuronal
What is the normal homeostatic concentration of glucose in the blood?
80-100 mg/dL (~5 mM)
Which four tissues rely on the glycolysis?
a) lens… b) RBC… c) Kidney Medulla… d) Brain