Term
| Are Ribosomal Proteins enzymes? Do they Catalyze reactions in Protein Synthesis? |
|
Definition
|
|
Term
| Ribosomal proteins associated with small subunit are designated by numbers ____ to ____ (eukaryotes.) |
|
Definition
|
|
Term
| Ribosomal proteins associated with the large subunit are ____ to ____ (eukaryotes.) |
|
Definition
|
|
Term
| Ribosomal proteins are coded by _____ and therefore _______ is needed. |
|
Definition
|
|
Term
| In eukaryotes protein synthesis occurs in the _____ and ribosomal proteins are transported to the ____ for binding to the newly synthesized _____ RNA. |
|
Definition
cytoplasm
nucleolus
ribosomal |
|
|
Term
| Intact small and large subunits (___ & ____) are transported out of the ____ to the ____ for translation. |
|
Definition
rRNA and r-protein
nucleus
cytoplasm |
|
|
Term
| In periods when large amount of protein synthesis is required coordination of _____, ______, _____, and messenger RNA for the ribosomal structural proteins must occur. |
|
Definition
| RNA polymerase I, II, III, |
|
|
Term
| Prokaryotic protein synthesis begins while ______. |
|
Definition
| messenger RNA still being synthesized. |
|
|
Term
| Prokaryotic protein synthesis begins on messenger RNA still being synthesized. This can occur since _______ |
|
Definition
| there is no barrier such as the nucleus to cytoplasm in eukaryotes. |
|
|
Term
| Binding of the mRNA by_____ in prokaryotes protects the mRNA from ______. |
|
Definition
ribosomes
degradation by nucleases. |
|
|
Term
| Eukaryotic protein synthesis occurs in the cytoplasm. This requires the transport of the ________ from the nucleus. |
|
Definition
| large and small ribosomal subunits |
|
|
Term
| ________ all associate with the ribosomal ____ subunit to begin the process of protein synthesis. |
|
Definition
Messenger RNA , initiator tRNA and initiation factors
small |
|
|
Term
| major difference between prokaryotic and eukaryotic mRNA is the fact that prokaryotic mRNAs are ______, which means the mRNA ______. |
|
Definition
polycistronic
codes for more than one protein. |
|
|
Term
| ____ is the most regulated step in protein synthesis. |
|
Definition
| Initiation Step of Protein Synthesis |
|
|
Term
| Protein synthesis is a ____ energy demanding process and control of initiation will control ______. |
|
Definition
|
|
Term
| The ____ ribosomal subunit is where initiation begins in both prokaryotes (___S) and eukaryotes (___S). |
|
Definition
|
|
Term
| The small subunit for both prokaryotes (30S) and eukaryotes (40S) is associated with inititiation factors in a pre-initiation complex; ______ in prokaryotes and _____ eukaryotes |
|
Definition
|
|
Term
| The small subunit will bind the initiator tRNA ____, which is a unique tRNA since it is the only aminoacyl tRNA (one "charged" with an amino acid) that can _____. |
|
Definition
methionine
bind to the P site on the ribosome. |
|
|
Term
|
Definition
| "charged" with an amino acid |
|
|
Term
| Other than the initiator tRNA, all tRNAs bound to the P site contain _____. |
|
Definition
| growing peptides. (not just a single amino acid as with initiator tRNA) |
|
|
Term
| The association of the initiator tRNA with the pre-initiation complex requires another initiation factor, ____ for prokaryotes or ____ for eukaryotes. Both of which bind _____ |
|
Definition
|
|
Term
| Unique to eukaryotes is the requirement for _____ in initiation of protein synthesis, because ____ is required for mRNAs that have a ___ at the 5' end. |
|
Definition
ATP hydrolysis to ADP
Energy
CAP |
|
|
Term
| The 5' mRNA CAP has a compact ____ structure that requires the energy of ATP hydrolysis to be unwound to allow initiation to occur. (Eukaryotes Only) |
|
Definition
|
|
Term
| The ____(unwinding) activity of the mRNA 5' CAP is associated with initiation factors ___________. |
|
Definition
helicase
eIF-4A, 4B and 4F. |
|
|
Term
| When the 40S (Small Subunit Eukaryotes) pre-initiating complex has bound: _________ the 40s ____ complex is formed and can bind to the large ribosomal subunit (50S prokaryotes and 60S eukaryotes). This step requires ______ |
|
Definition
all necessary initiating factors, initiator tRNA and mRNA
initiation
hydrolysis of GTP to GDP by IF2. |
|
|
Term
| The binding of the intiation complex to the large subunit requires _____ by ____. |
|
Definition
| hydrolysis of GTP to GDP by IF2. |
|
|
Term
| Energy comes from hydrolyzing ___ to ____ for charging a tRNA by binding an amino acid. |
|
Definition
|
|
Term
| Energy comes from hydrolyzing ___ to ____ for charging of initiator methionine tRNA. This energy of the attached amino acid and tRNA will be used at ______ bond in the ____ step |
|
Definition
ATP to AMP
peptide
elongation |
|
|
Term
| For both prokaryotes and eukaryotes. associtaion of the small and large subunits requires energy from the hydrolysis of ____ to ____. |
|
Definition
|
|
Term
| Hydrolysis of ___ to ____ for eukaryotes for unwinding the 5' mRNA Cap. |
|
Definition
|
|
Term
| Elongation is a three-step process involving:________ ribosomes, elongation factors (proteins), transfer RNA, messenger RNA and a ribozyme (RNA enzyme) |
|
Definition
| ribosomes, elongation factors (proteins), transfer RNA, messenger RNA and a ribozyme (RNA enzyme) |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| At initiation what is the status of the tRNA biding sites of the Ribosome? |
|
Definition
| Methionine tRNA is in P site, A and E sites are empty at initiation. |
|
|
Term
| Hydrolysis of ____ to ____ by ___ for association of subunits. |
|
Definition
|
|
Term
| GTP to GDP by IF2 for association of subunits Is this just for eukaryotes or both prokaryotes and eukaryotes? |
|
Definition
|
|
Term
| Hydrolysis of ___ to ____ for unwinding CAP on mRNA in eukaryotes catalyzed by _____. |
|
Definition
ATP to ADP
initiation factors eIF-4A, 4B and 4F. |
|
|
Term
| Elongation step 1. P site has initiator met tRNA or a growing peptide chain, E sites is empty at initiation or has a "empty " tRNA (during elongation cycles) and A site will bind incoming aminoacyl tRNA. Energy comes from: ____ |
|
Definition
| Energy: GTP to GDP by EF-Tu/EF-Ts (prokaryotes) and EF-1α/EF-1β (eukaryotes). |
|
|
Term
| Elongation step 2. Status of A, P, E site. |
|
Definition
| P site a growing peptide chain, E sites has a "empty " tRNA and A site has amino acyl tRNA. Peptide bond formation between growing peptide at the P site and the aminoacyl tRNA at the A site. |
|
|
Term
| Peptide bond formation is catalyzed by _____ (__S prokaryotes or ___S eukaryotes ribosomal RNA ), which is called _____. |
|
Definition
ribozyme
23S Pro 28S Eu
Ribozyme named peptidyl transferase. |
|
|
Term
| Elongation step 3. Status of A, P, E site. |
|
Definition
| Elongation step 3. A-site is briefly occupied by growing peptide chain with a conformational change in the ribosome and mRNA moves 3 codons in the 5' direction. A-site is then empty, growing peptide chain at the P site and "empty" tRNA is at E site. |
|
|
Term
| Elongation step 3. energy comes from. |
|
Definition
| GTP to GDP by EF-G (prokaryotes) and EF-2 (eukaryotes) . |
|
|
Term
| Following the initiation step there are always __ tRNA molecules associated with the ribosomes until the final step of termination when the subunits dissociate. |
|
Definition
|
|
Term
| There is cross talk between the _ site and _ site |
|
Definition
|
|
Term
| "proof-reading" mechanism of Protein Synthesis is _____ |
|
Definition
| When the A site is empty and the E site contains a "empty" tRNA molecule the incoming aminoacyl tRNA must bind correctly to the A site resulting in a change in conformation of the ribosomes affecting the E site which results in the ejection of the "empty" tRNA. If an incorrect aminoacyl tRNA comes into the A site, the conformational change does not occur and the aminoacyl tRNA is ejected. |
|
|
Term
| When the A site is empty and the E site _______ |
|
Definition
| contains a "empty" tRNA molecule |
|
|
Term
| When the A site is empty and the E site contains a "empty" tRNA molecule the incoming aminoacyl tRNA must bind correctly to the A site resulting in a change in conformation of the ribosomes affecting the E site which results in the ejection of the "empty" tRNA. |
|
Definition
|
|
Term
| If an incorrect aminoacyl tRNA comes into the A site, what happens? |
|
Definition
| The conformational change that ejects the empty tRNA from the T site does not occur and the aminoacyl tRNA is ejected |
|
|
Term
| Proteins synthesized on ribosomes in the cytoplasm are targeted to _____ based on the amino acid sequence within the protein. |
|
Definition
|
|
Term
| Nuclear proteins contain a sequence of amino acid designated as the ______ sequence, that is one or more short sequences of _______, located at the _____ of the sequence. |
|
Definition
nuclear localization
lysines and arginines (positively charged amino acids)
middle |
|
|
Term
| Mitochondria proteins are directed by a ______ sequence, which is composed of a _______. |
|
Definition
mitochondrial localization
alternating pattern of a few hydrophobic amino acids (such as valine, isoleucine, leucine, methionine) and a few positively charged amino acids (lysine and arginine ). |
|
|
Term
| The mitochondrial localization sequences is located ______ and is recognized by _____. |
|
Definition
At the N Terminus
cytoplasmic molecular chaperone. |
|
|
Term
| lysine and arginine are ____ charged. |
|
Definition
|
|
Term
| Endoplasmic Reticulum (ER) proteins contain a signal sequence at the _____ of the protein consisting of _______. |
|
Definition
| 9 to 12 hydrophobic amino acids. |
|
|
Term
| Endoplasmic Reticulum (ER) proteins contain a signal sequence at the N terminus of the protein consisting of 9 to 12 hydrophobic amino acids, which is recognized by _________ |
|
Definition
| signal recognition particle (SRP). |
|
|
Term
| The proteins destined to be in the ER are transported as ______. |
|
Definition
| nascent proteins still attached to ribosomes in the act of being synthesized |
|
|
Term
| ______ is continuous with the outer nuclear membrane. |
|
Definition
|
|
Term
| Proteins directed to the ER either ____ or _____ |
|
Definition
| reside there or are transported to other organelles such as Golgi, Endosomes and Lysosomes. |
|
|
Term
| ER modifications include: ______ |
|
Definition
| disulfide bonds formation, addition of carbohydrates (glycosylation) and proteolytic cleavages. |
|
|
Term
| Many ER proteins are modified in the ____ and further modified in the ____. |
|
Definition
|
|
Term
| Golgi Apparatus is Usually located near the _____. |
|
Definition
|
|
Term
| The entry side of the Golgi Apparatus for proteins is referred to as the ____ face and the exit side is the ____ face. |
|
Definition
|
|
Term
| Gouty arthritis - caused by ______. |
|
Definition
| accumulation of a breakdown product of purine nucleotide catabolism - uric acid |
|
|
Term
| Location of 50% of the cases of gouty arthritis _____ |
|
Definition
| Metatarsal-phalangeal joint at base of big toe ~50% of cases |
|
|
Term
| Several common ______ drugs target specific steps or enzymes associated with nucleotide synthesis |
|
Definition
|
|
Term
| The sugar is linked to the base by a ______ at the _____ position of the sugar. |
|
Definition
Beta-Glycosidic Linkage
1' |
|
|
Term
| Ribose and Deoxyribose differ by ____ |
|
Definition
| A Hydroxyl group at the 2' position |
|
|
Term
| Ribose and its derivative deoxyribose are products of the _______. |
|
Definition
| pentose phosphate pathway |
|
|
Term
| What has a higher cellular concentration, Ribonucleotides or Deoxyribonucleotides? |
|
Definition
|
|
Term
| ______ cells are primary source of nucleotides in adults |
|
Definition
|
|
Term
| nucleotide synthesis levels are extremely low in _____ cells |
|
Definition
|
|
Term
| Salvage pathway involves the joining of |
|
Definition
| Activated Ribose (PRPP) and a base |
|
|
Term
| The _____ salvage pathways are especially important for energy saving and effects of their absence. |
|
Definition
|
|
Term
| Some tissues (most notably ____ tissue) rely almost exclusively of salvage pathways. |
|
Definition
|
|
Term
| _____ nucleotides assembled on ribose |
|
Definition
|
|
Term
| ____ bases pre-assembled, then attached to ribose |
|
Definition
|
|
Term
| Purines are assembled stepwise on C-_’ of _______ which is first activated to form _______. |
|
Definition
1
ribose-5-phosphate
phosphoribosyl pyrophosphate (PRPP) |
|
|
Term
| Transfer of pyrophosphate from ATP to ribose-5-phosphate is catalyzed by ______. |
|
Definition
|
|
Term
| What is the rate limiting step of nucleotide biosynthesis? |
|
Definition
| PRPP synthetase transferring pyrophosphate group from ATP to ribose-5-phosphate |
|
|
Term
| rate limiting steps of biochemical pathways are important steps for ______. |
|
Definition
| regulation (eg feedback inhibition) |
|
|
Term
| PRPP can be directed towards: ______. |
|
Definition
Pyrimidine Metabolism
Purine Metabolism
Histidine Metabolism |
|
|
Term
| ______ contributes two N to the synthesis of Purines. |
|
Definition
|
|
Term
| ____ contributes almost its entire structure including: _____ to purine synthesis. |
|
Definition
|
|
Term
| Purine rings are assembled from:_______ |
|
Definition
| glycine, glutamine, aspartate, N10-formyl-tetrahydrofolate and CO2 (or bicarbonate). |
|
|
Term
| ______ is the first purine base constructed |
|
Definition
|
|
Term
| Inosinate (IMP) is the first purine base constructed and _______ bases are derived from inosinate. |
|
Definition
|
|
Term
| The purine base in IMP (Inosinate) is named ______. |
|
Definition
|
|
Term
| What enzyme catalyzes the step that commits to purine synthesis? |
|
Definition
| glutamine phosphoribosyl amidotransferase (aka PRPP amidotransferase) |
|
|
Term
| Commitment to purine biosynthesis is catalyzed by glutamine phosphoribosyl amidotransferase (aka PRPP amidotransferase) which takes ______ as a reactant and by adding a ____ from _____, it forms ______. |
|
Definition
PRPP
adds an amine from glutamine by hydrolyzing off pp to the C1' of the ribose and forms phosphoribosylamine |
|
|
Term
| IMP is a branch point between ____ and _____. |
|
Definition
|
|
Term
|
Definition
| Add GTP and Aspartate to IMP to form adenylosuccinate which turns into AMP |
|
|
Term
|
Definition
Add NAD+ to form XMP (Xanthosine Monophosphate)
Then add ATP and Glutamine to XMP to form GMP |
|
|
Term
| _____ is the source of phosphates for formation of di- and triphosphate forms of nucleotides. |
|
Definition
|
|
Term
| Formation of which phophate mono di or tri requires a specific enzyme? |
|
Definition
|
|
Term
| Specific enzymes are required for the formation of each diphosphate, termed _______. |
|
Definition
| nucleotide monophosphate kinases (ex: adenylate kinase, guanylate kinase) |
|
|
Term
| A single enzyme with broad specificity, _______, catalyzes the second reaction of Diphosphate to Triphosphate |
|
Definition
| nucleotide diphosphate kinase |
|
|
Term
| glutamine phosphoribosyl amidotransferase (aka PRPP amidotransferase) is inhibitted by ______ |
|
Definition
|
|
Term
| PRPP synthetase is inhibited by ______. |
|
Definition
|
|
Term
| Conversion of IMP to GMP is inhibited by _____. |
|
Definition
|
|
Term
| Conversion of IMP to AMP is inhibited by _____. |
|
Definition
|
|
Term
| The reciprocal substrate relation whereby ATP is used in the synthesis of GMP and GTP is used in the synthesis of AMP Does what? |
|
Definition
| balances the production of these nucleotides |
|
|
Term
| Salvage pathways allows you to regenerate nucleotides from free bases by attaching them to _____. |
|
Definition
|
|
Term
| _______ catalyzes the recovery of hypoxanthine or guanine. |
|
Definition
| Hypoxanthine-guanine phosphoribosyl transferase (HGPRT) |
|
|
Term
| HGPRT catalyzes the recovery of ____ or _____. |
|
Definition
| hypoxanthine into IMP or guanine into GMP. |
|
|
Term
| How is most adenine is recovered? |
|
Definition
| via inosine (IMP), which is recovered from hypoxanthine by HGPRT |
|
|
Term
| _______ Catalyzes the recovery adenine into AMP. |
|
Definition
| Adenine phosphoribosyltransferase |
|
|
Term
| _______ catalyzes the recovery of uracil |
|
Definition
Pyrimidine phosphoribosyl transferase
DOES NOT RECOVER cytosine |
|
|
Term
| _____ is the end product of purine degradation in humans. |
|
Definition
|
|
Term
| Uric acid is the end product of purine degradation in humans, must be excreted in _____. |
|
Definition
|
|
Term
| Uric acid solubility is dependent on several factors including ____ & _____. |
|
Definition
|
|
Term
| Normal uric acid levels in humans are close to _______. |
|
Definition
| its solubility level (~7mg/dl in plasma and interstitial fluids). |
|
|
Term
Normal Range of Uric Acid:
–
Males: _____ mg/dl
–
Females: _____ mg/dl |
|
Definition
Males: 2-7.5mg/dl
Females: 2-7 mg/dl |
|
|
Term
| Uric acid levels increase with ______ & ______. |
|
Definition
|
|
Term
| Elevations in uric acid levels above its solubility level (hyperuricemia) can lead to _______ or _______. |
|
Definition
| deposition of uric acid crystals in the urine (kidney stones) or of sodium urate in plasma or interstitial fluids (gout). |
|
|
Term
| following hyperuricemia and deposition of uric acid crystals in the urine results in ______ |
|
Definition
|
|
Term
| following hyperuricemia and deposition of sodium urate in the interstitial fluids results in ______. |
|
Definition
|
|
Term
| Gouty arthritis is an inflammatory disease caused by _____ deposition in joints, particularly in the _____ where temperatures are lower |
|
Definition
|
|
Term
| Diagnosis of Hyperuricemia is arrived at by detection of _______ crystals under polarized light microscopy in aspirate from affected joint. |
|
Definition
|
|
Term
| Diagnosis of Hyperuricemia is arrived at by detection of ______ under skin, often on affected joint |
|
Definition
| tophus (deposit of monosodium urate crystals) |
|
|
Term
| Causes of hyperuricemia is basically anything that causes: ________ |
|
Definition
| increases in purine biosynthesis, degradation or decreases uric acid excretion |
|
|
Term
| Metabolic diseases that result in an increased supply of ribose-5-phosphate would lead to ______ |
|
Definition
|
|
Term
| Increased cell _____ would lead to hyperuricemia. |
|
Definition
| cell turnover – presumably because purines from these cells must be degraded (eg cancer patients undergoing chemotherapy) |
|
|
Term
| ______ renal excretion would lead to hyperuricemia. |
|
Definition
|
|
Term
| Genetic causes of hyperuricemia include _____ in PRPP synthase activity |
|
Definition
| increased PRPP synthase activity (normally rate-limiting) |
|
|
Term
| PRPP synthase activity is typically rate-_____ |
|
Definition
|
|
Term
| Genetic causes of hyperuricemia include _____ in HGPRT activity (salvage enzyme) |
|
Definition
|
|
Term
| Partial deficiency of HGPRT activity leads to______ |
|
Definition
|
|
Term
| Complete deficiency of HGPRT leads to _____ |
|
Definition
|
|
Term
| Lesch-Nyhan syndrome is characterized by _______. |
|
Definition
| spasticity, mental retardation, choreoathetosis and self-mutilation. |
|
|
Term
| Although individuals with Lesch-Nyhan syndrome are hyperuricemic, the neurological symptoms are not caused by uric acid but due to the _______. |
|
Definition
| reliance of the brain on the salvage pathway for purine synthesis. |
|
|
Term
| A genetic glucose metabolism disorder, ________, can result in hyperuricemia by leading to ______ |
|
Definition
von Gierke Disease
increased activity of the pentose phosphate pathway (More PRPP) |
|
|
Term
|
Definition
|
|
Term
| 2 classes of Anti-inflammatory drugs for treating hyperuricemia and gout? |
|
Definition
Colchicine
NSAIDs (eg indomethacin, ibuprofen) |
|
|
Term
| 3 Options for the Treatments for hyperuricemia and gout? |
|
Definition
Anti-inflammatory drugs
Uricosuric agents
Inhibition of xanthine oxidase |
|
|
Term
| Uricosuric agents cause _____ |
|
Definition
| increase renal excretion of uric acid |
|
|
Term
| Inhibition of xanthine oxidase is accomplished by what drug? |
|
Definition
|
|
Term
| Inhibition of xanthine oxidase is accomplished by Allopurinol and leads to _______. |
|
Definition
| decreased levels of uric acid and increased levels of hypoxanthine and xanthine, more soluble |
|
|
Term
| Allopurinol-Mechanism of Action? |
|
Definition
| Allopurinol replaces the usual substrate (Hypoxanthine or Xanthine) of Xanthine Oxidase and binds tighthly non covalently to Xanthine Oxidase, thereby inhibiting it from making Uric Acid. |
|
|
Term
| The anti-inflammatory drug for treating hyperuricemia and gout ______ can also cause gastrointestinal side effects |
|
Definition
|
|
Term
| How do you treat acute Gouty Arthritis? |
|
Definition
| NSAIDs unless they have an allergy, then Colchicine. |
|
|
Term
| How do you treat Chronic Gouty Arthritis? |
|
Definition
| Uricosic agent or Allopurinol |
|
|
Term
| ndividuals with chronic gout are generally counseled to alter their diet to avoid ________ foods. |
|
Definition
|
|
Term
| excess purines cannot be ____ and must be ______. |
|
Definition
|
|
Term
| The pyrimidine ring is assembled from: ________ |
|
Definition
| glutamine (as a source of ammonia), aspartate and CO2 (or bicarbonate). |
|
|
Term
| Glutamine is converted to _____ before it is added to pyrimidine ring synthesis. |
|
Definition
|
|
Term
| Carbamoyl phosphate derived from CO2 and Glutamine forms ______ of the pyrimidine ring, while aspartate forms _______ |
|
Definition
|
|
Term
| ____ is the first pyrimidine nucleotide |
|
Definition
|
|
Term
| Hereditary orotic aciduria results from a deficiency of _____ & can be treated by _____ |
|
Definition
deficiency of pyrimidines
oral administration of pyrimidines |
|
|
Term
| The pyrimidine ring is assembled from: ______ |
|
Definition
| glutamine (as a source of ammonia), aspartate and CO2 (or bicarbonate). |
|
|
Term
| The initial step of pyrimidine biosynthesis is the formation of ______. |
|
Definition
| The formation of carbamoyl phosphate from gluatmine and CO2 |
|
|
Term
| The initial pyrimidine ring is combined with PRPP to form _______. |
|
Definition
|
|
Term
| The initial pyrimidine ring is combined with PRPP to form UTP, which can then become _______. |
|
Definition
|
|
Term
| TMP can be converted into ______. |
|
Definition
|
|
Term
| Hereditary orotic aciduria caused by mutations that affect conversion of ________ |
|
Definition
| Orotate into OMP into UMP (The First Pyrimidine Ring, which can be transformed into TMP or CTP) |
|
|
Term
| Hereditary orotic aciduria, condition results from ______ and can be treated with ______. |
|
Definition
| Condition due to deficiency of pyrimidines and can be treated with oral administration of pyrimidines. |
|
|
Term
| Hereditary orotic aciduria presents with ______. |
|
Definition
| Orotic acid (Orotate) crystals (asymptomatic) in urine of newborns. |
|
|
Term
| UMP + ATP ---> UDP + ADP is catalyzed by what enzyme? |
|
Definition
|
|
Term
| UDP + ATP ----> UTP + ADP |
|
Definition
| (nucleotide diphosphate kinase (broad range)) |
|
|
Term
|
Definition
|
|
Term
| CTP is formed by amination of UTP, ____ serves at the source of the amino group. |
|
Definition
|
|
Term
| Formation of deoxynucleotides is catalyzed by ______. |
|
Definition
|
|
Term
| Ribonucleotide reductase activity is highest when? |
|
Definition
| just prior to S-phase in the cell cycle |
|
|
Term
| Ribonucleotide reductase activity is intricately regulated by _____. |
|
Definition
|
|
Term
| Ribonucleotide reductase activity is negatively regulated by _____ |
|
Definition
|
|
Term
| In the process of Ribonucleotide reductase converting the 2' Hydroxyl to a hydrogen, what is oxidized? |
|
Definition
|
|
Term
| Expression of Ribonucleotide Reductase is controlled at the level of the ______. |
|
Definition
| cell cycle (increases prior to DNA synthesis) |
|
|
Term
| Ribonucleotide Reductase Expression increases prior to ____. |
|
Definition
|
|
Term
| _____ levels control the overall activity of Ribonucleotide Reductase |
|
Definition
| dATP, if dATP levels are high, RR activity is decreased |
|
|
Term
| Levels of ______ control substrate selectivity of Ribonucleotide Reductase. |
|
Definition
|
|
Term
| dUMP is formed from dUDP via _____. |
|
Definition
| dUTP (cleaved by dUTPase to form dUMP and PPi) |
|
|
Term
| dUMP can be formed by deamination of _____. |
|
Definition
|
|
Term
| dTMP is formed from ______. |
|
Definition
|
|
Term
| dUMP is converted to dTMP by Thymidylate Synthase and in the process ____ is converted to _____. |
|
Definition
|
|
Term
| Methylene-THF is converted back into DHF by ______, which is the RDS of _____. |
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Definition
DHF Reductase
Thymidylate Synthase |
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Term
| In degradation of pyrimidines is C converted to U or U to C? |
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Definition
| C is converted to U for degradation by deamination |
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Term
| Uracil and Thymine (pyrimidines) in the process of degradation are reduced by ______. |
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Definition
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Term
| Uracil and Thymine (pyrimidines) in the process of degradation are reduced by Dihydropyrimidine DH, a deficiency of this leads to ______. |
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Definition
| Increase in Pyrimidine Levels |
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Term
| In Adenosine deaminase deficiency (ADD) what enzyme is defective? |
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Definition
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Term
| In Familial Orotic aciduria what enzyme is defective? and leads to _____ |
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Definition
Orotate phosphoribosyl-transferase
Accumulation of orotic acid in blood and urine |
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Term
| In Lesch-Nyhan syndrome what enzyme is defective? |
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Definition
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Term
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Definition
| severe combined immunodeficiency |
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Term
| ADA deficiency results in a lack of functional ____ and ___ cells. |
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Definition
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Term
| ADA deficiency is deficiency of _____ |
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Definition
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Term
| ADA (Adenosine Deaminase) deficiency results in immunodeficiency as a result of build up of ________. |
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Definition
| dAMP, dADP and dATP. Inhibition of ribonucleotide reductase by dATP is implicated in the immunodeficiency, thereby blocking DNA synthesis |
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Term
| Why is ADA (Adenosine Deaminase) deficiency results in immunodeficiency as a result of build up of dAMP, dADP and dATP and not AMP, ADP, and ATP? |
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Definition
| The Ribose (AMP ADP ATP) side of degradation can be fed through an alt pathway of AMP to IMP (VIA Adenosine Deaminase) to Hypoxanthine to xanthine to uric acid |
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Term
| flurouracil is a suicide inhibitor of _____ and can be used in cancer treament. |
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Definition
| thymidylate synthase (dUMP to dTMP) |
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Term
| Antifolates are analogs of ______, which block thymidylate synthase by inhibiting _____ activity, leading to a depletion of THF. |
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Definition
dihydrofolate (DHF)
DHF Reductase (takes DHF back to THF for Thymidylate Syntahse to convert dUMP to dTMP) |
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Term
| _____ rings are assembled on a ribose support while _____ rings are synthesized prior to attachment to ribose |
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Definition
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Term
| Deoxynucleotides are synthesized by _____ of ribonucleotides |
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Definition
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Term
| Chromosomes are globally demethylated during ______. |
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Definition
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Term
| Chromosomes are remethylated during ____. |
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Definition
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Term
| Hypermethylated regions of DNA are organized into _____. |
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Definition
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Term
| Hypomethylated regions of DNA are organized into _____. |
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Definition
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Term
| In eukaryotes, only one base (_____) can be modified by methylation. |
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Definition
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Term
| In eukaryotes, only one base (cytosine) can be modified by methylation. This modification always occurs in the context of ____ dinucleotide. |
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Definition
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Term
| In prokaryotes, base methylation does what? |
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Definition
| protects DNA from digestion by restriction enzymes and functions as a kind of primitive immune system. |
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