Term
| Siderblasts: ____'s that have failed heme biosynthesis. |
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Definition
Red blood cells that have failed biosynthesis.
CP p 403 physio |
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Term
ALA dehydratase is a key target for _______ ___________. It is aka: PBG synthase.
What step in heme biosynthesis does it mediate? Where does this reaction take place?
a. Cytosol
b. Mitochondria |
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Definition
ALA dehydratase is a key target for lead poisoning.
It is involved in the second step - where porphobilinogen is formed. It takes place in the cytosol of the cell. |
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Term
| Steps 3 and 4 of heme biosynthesis also take place in the ___________ and link ___(#) porphobilinogens together. This is known as the "ring closure." |
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Definition
Ring closure takes place in the cytosol and links 4 porphobiliogens together, from a linear structure to the structure of the heme molecule.
CP physio pa 404. |
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Term
| Ferrochelatase deposits ___^2+ into the protoporphyrin III molecule, making _______. |
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Definition
Ferrochelatase deposits Fe2+ into the protoporphyrin III molecule, making Heme.
CP page 404 |
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Term
| Heme biosynthesis is very active in the Liver and ______ ____________ _____________. |
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Definition
Bone marrow reticulocytes.
CP page 404 |
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Term
The end product of heme biosynthesis - heme - uses the mechanism of ___________ ___________ to control ALAS in two ways:
1. __________ ____________ conformational change of the enzyme
2. binding of a co-repressor which decreases the rate of mRNA ____________. |
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Definition
Feedback inhibition to control ALAS...
...Allosteric inhibition produces a conformational change in the enzyme.
Binding of the co-repressor decreases the rate of mRNA transcription.... |
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Term
| The first two substrates in the Heme biosynthesis pathway are what? |
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Definition
| Succincyl CoA and Glycine |
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Term
| Porphyria: an inherited ________ ___________ disorder that results from ______ ___________ in the process of heme metabolism. |
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Definition
Autosomal dominant disorder that results from ( enzyme mutations ) in the process of heme metabolism.
CP p 405 |
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Term
A patient labs show an accumulation of ALA enzyme of the heme pathway, and PBG. They also have been having some abdominal pain and psychiatric signs and symptoms. When a urine sample is taken, the color of their urine darkens.
What do they have?
A_________
I___________
Porphyria
What chief inhibitory neurotransmitter does an excess of PBG mimic in the body? |
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Definition
Acute Intermittent Porphyria
PBG is sensitive to light, and darkens...
PBG acts like GABA in the body, when in excess.
CP p 405 |
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Term
| A patient presents with unusual skin damage and scarring that would not properly heal. They also complained of increased light sensitivity and they have very dark urine. What part of the heme metabolic pathway is being adversely affected, and what is this condition called? |
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Definition
The latter part of the heme biosynthesis pathway is defective, and the cause of this is "Congenital erythropoietin Poprhyria."
Page 405 PHysio |
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Term
| What are the three major products of Hemoglobin catabolism? |
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Definition
| Globin Polypeptides, POrphyrin Ring, And IRON = Fe2+ CP p 406 |
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Term
| Heme __________: Is a complex enzyme active in the reticuloendothelial cells of the _______, ____________, And _______ ____________. (Hint: What are the blood producing organs?) |
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Definition
Heme OXYGENASE:
Liver, spleen, and Bone marrow
CP page 406 |
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Term
| Bili__________ gives a bruise its purple color, whereas bili_______ gives a bruise its yellow color. Which one of these is hydrophobic and requires albumin as a carrier? |
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Definition
Biliverdin: Purple color
Bilirubin: Yellow color, requires albumin.
p 407 |
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Term
Bilirubin is converted to two products after being conjugated with ____________ acid....
These products are listed below.
Stercobilinogen
Stercobilin
Which one is used to excrete bilirubin in urine? In feces? |
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Definition
Glucuronic Acid....
Stercobilinogen - urine - no color
Stercobilin - feces - brown |
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Term
UDP glucose dehydrogenase produces this: (The conjugated form of bilirubin:)
______________ _____________ |
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Definition
Diglucaronic Bilirubin
CP p 407 |
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Term
How can serum bilirubin levels be tested?
Citrate Buffer at pH 3 will allow for _________ detection of ____________ bilirubin.
Citrate buffer with detergent will allow for _________ detection of ___-__________ bilirubin. |
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Definition
Citrate buffer allows us to detect DIRECT levels of CONJUGATED bilirubin.
Citrate Buffer and DETERGENT allows us to detect TOTAL levels of NON-CONUGATED bilirubin. |
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Term
What is the name of the condition that occurs when bile fragments are produced during heme degradation? (Hint: Yellowing of the skin)
What are the two types of this condition and which is more severe? |
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Definition
Jaundice:
Hemolytic Jaundice & neonatal (physiologic) jaundice. CP p 409 |
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Term
Neonatal jaundice is corrected with the use of the drug ____________ - which turns on the expression of the deficient enzymes.
Another method is __________ (light exposure) which promotes by converting non-conjugated bilirubin to its soluble form.
If left uncorrected, what is the name of the brain damage that can result? |
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Definition
PHenobarbitol
Phototherapy
Karnicterus: brain damage from excessive amounts of bilirubin. |
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Term
Explain the impact that prehepatic (i.e. hemolytic anemia) would have on levels of conjugated bilirubin and non-conugated bilirubin.
Conjugated:
Non-conjugated: |
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Definition
Hemolytic anemia would result in levels of conjugated bilirubin increasing, and non-conjugated bilirubin severely increasing as the liver is unable to keep up heme metabolism.
CP page 409 |
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Term
An intrahepatic cause that impacts heme metabolism would be:
1. bile duct obstruction
2. Megaloblastic anemia
3. Hepatitis
4. Hemolytic anemia
What happens to :
Levels of Conjugated bilirubin___________
Levels of non-conjugated bilirubin________ |
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Definition
3. Hepatitis.
Conjugated Bilirubin decreases
And Non-conjugated bilirubin increases dramatically.
CP p 409 |
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Term
| What is a potential example of a pathology where conjugated bilirubin would dramatically increase? |
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Definition
Bile duct obstruction
CP page 409 |
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