Busy. Please wait.

show password
Forgot Password?

Don't have an account?  Sign up 

Username is available taken
show password


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.

By signing up, I agree to StudyStack's Terms of Service and Privacy Policy.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.

Remove ads
Don't know
remaining cards
To flip the current card, click it or press the Spacebar key.  To move the current card to one of the three colored boxes, click on the box.  You may also press the UP ARROW key to move the card to the "Know" box, the DOWN ARROW key to move the card to the "Don't know" box, or the RIGHT ARROW key to move the card to the Remaining box.  You may also click on the card displayed in any of the three boxes to bring that card back to the center.

Pass complete!

"Know" box contains:
Time elapsed:
restart all cards

Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Fun I Exam 2 C

Nucleotide Synthesis and Degradation & DNA

Purine degradation: significant activity occurs in the _____ digestive tract **because all natural foods that we consume have nucleotides in them
Nucleotides are first converted to nucleoSIDES by intracellular ____ Nucleosides are then degraded by _____ These products are converted to XANTHINE by ____ and ____ nucleotidases (under strict regulation to ensure substrates (often intermediates) are not depleted below critical levels Purine nucleoside phosphorylase (PNP) Guanine deaminase & xanthine oxidase
Purine degradation: inosine ---> hypoxanthine Purine nucleoside phosphorylase (PNP)
Purine degradation: hypoxanthine (or PNP product) ---> uric acid xanthine oxidase **target enzyme for gout treatment to prevent production of uric acid
Purine degradation: AMP ---> ? ---> ? ---> ?... AMP ---> IMP ---> Inosine OR AMP ---> Adenosine ---> Inosine **can be deaminased and dephosphorylased in either order Inosine ---> Hypoxanthine ---> uric acid
How many enzymes from IMP --> AMP? How many enzymes from AMP --> IMP? IMP --> AMP = two enzymes (when making nucleotides AMP --> IMP = one enzyme (when breaking down nucleotides)
Oxidizes hypoxanthine to uric acid in liver, intestines (and milk) xanthine oxidase
Humans and other primates excrete ____ in the urine but most N goes out as ____ Birds, reptiles and insects excrete ____ as their major N excretory compound Uric acid Urea (MOST for humans and primates) Uric acid (MOST for birds, reptiles)
Gout occurs from ____ Drug treatment? accumulation of uric acid crystals in extremities (joint of big toe is particularly susceptible. --urate crystals may appear in kidney stones and obstruct urinary tract allopurinol, inhibits Xanthine Oxidase from making uric acid from hypoxanthine
Gout can be exacerbated by ____ purine rich foods
Purine-Nucleotide cycle exhibits anaplerosis by _____ In what tissue is this process particularly important? releases FUMARATE for TCA cycle Contraction of SKELETAL MUSCLE: as AMP builds up, it is converted IMP then back to AMP with release of fumarate which provides more substrate for TCA cycle and stimulates oxidative metabolism for more energy
Lesch-Nyhan Syndrom results from a complete deficiency in ____ Presentation? HGPRT (so can't salvage purines from production and excretion of uric acid); severe hyperuricemia -severe, crippling arthritis due to accumulation of uric acid -retardation -self-mutilation/aggression
HGPRT (hypoxanthine-guanine phosphoribosyltransferase) = ? HGPRT salvages purine at the stage of hypoxanthine (immediately before it would be converted to Uric acid and excreted) adds ribose onto hypoxanthine (using alpha-PRPP) and converts to IMP or GMP
SCID is a group of related disorders involving _______ 30% of SCID patients lack the enzyme ______. In the absence of this enzyme, deoxyadenosine is not deaminated to ______ as normal diminished immune response adenosine deaminase deoxyinosine
Created by: erinlwilliams