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Biochem Cluster II

review information about biochem cluster II

QuestionAnswer
enzymes that hydrolyze phosphoesters phosphatases (also, hydrolases and esterases)
steps in pathways that are the targets of regulation (irreversible or reversible) irreversible
insulin stimulates _______ and inhibits _______ glycolysis, gluconeogenesis
glucagon stimulates _______ and inhibits _______ gluconeogenesis, glycolysis
the most complex allosteric control in glycolysis/gluconeogenesis happens at these enzymes phosphofructokinase (glycolysis) and fructose-1,6-bisphosphatase (gluconeogenesis)
The ETC is coupled to the formation of ATP from ADP and Pi in the mitochondria by… a chemiosmotic gradient
The key enzyme in the synthesis of a strand of glycogen is… glycogen synthase
Hydrogen cyanide gas is toxic in large part because it inhibits… the passage of a pair of electrons through one of the proteins complexes of the ETC
Glycolysis INHIBITED by… ATP,NADH
Glycolysis STIMULATED by… AMP
Gluconeogenesis inhibited by… AMP
Gluconeogenesis STIMULATED by… ATP, NADH ??
Though gluconeogenesis is a/an _______ pathway, it still uses _____, not _____ like most anabolic pathways anabolic; NADH, NADPH
The pentose phosphate pathway takes place in…(5) liver, mammary glands, testes, adipose tissue, adrenal cortex
The source of energy for glycogen synthesis UTP (UDP-glucose)
Functions of the pentose phosphate pathway interconvert monosaccharides, secondary route for glucose oxidation-->NADPH, production of pentose sugars (mainly ribose), catabolism of pentoses --> 3/6C sugars for glycolysis
The two parts of the pentose phosphate pathway oxidative (sugars --> NADPH) and non-oxidative (differently sized monosaccharides --> F6P or glyceraldehyde-3-phosphates
ETC is located WITHIN the… INNER mitochondrial membrane
Which way are protons pumped in the mitochondria? Which way do they flow after this concentration gradient is formed? FROM the matrix TO the intermembrane space; THEN back TO the matrix FROM the intermembrane sapce
Name two transmembrane proteins involved in the ETC coenzyme Q and cytochrome C
The most evolutionarily conserved protein cytochrome C!
The only organs where glucose-6-phosphatase exists liver and kidneys
Most common entry point for PPP G6P (glucose-6-phosphate), then ox-decarb to ribulose-5-phosphate --> R5P
Glycogen is stored in the ¬¬______ of liver cells and the ¬¬______ of muscle cells cytoplasm, sarcoplasm
Committed step of glycolysis conversion of G6P to F6P (aldose-ketose isomerization by isomerase)
Glycolysis occurs in the ¬¬¬¬_______ cytoplasm
TCA cycle occurs in the _______ mitochondria (matrix)
Alpha-keto glutarate can be made into ¬¬¬______ glutamic acid
Oxaloacetate (OAA) can be made into this amino acid aspartic acid
Phosphatases in gluconeogenesis break the phosphoesters bonds by a _______ reaction hydrolysis
Possible sources of carbon for gluconeogenesis glucogenic amino acids (MAJOR), lactate from muscle cells, glycerol from triacylglycerols or membrane phospholipids
Glucose units in glycogen are connected at the (?,?) position and branched at the (?,?) position 1,4 and 1,6
Branching of glycogen gives what benefits? (3) increased energy capacity, easier/faster to split bonds, increased solubility
Glucagon and epinephrine STIMULATE _____ ______ and INHIBIT _____ ______ glycogen breakdown, glycogen synthesis
Insulin STIMULATES _____ _____ and INHIBITS _____ _____ glycogen synthesis, glycogen breakdown
Insulin and glucagon are released from what organ? pancreas
Do insulin and glucagon directly bind to cellular enzymes? NO! (they are “second messengers”)
Possible symptoms with problems in LIVER glycogen metabolism increased glycogen concentrations, enlargement of liver (hepatomegaly), abnormally structured glycogen, or low blood glucose levels
Possible symptoms with problems in MUSCLE glycogen metabolism abnormally structured glycogen, inability to maintain long-term, strenuous exercise
Galactosemia is caused by… deficiency of an epimerase enzyme that converted galactose to useable glucose
Treatment of galactosemia is simply… elimination of as much galactose as possible in diet
In gluconeogenesis, pyruvate is shuttled out of mitochondria in the form of… malate
Balanced equation for glycolysis…GO! glucose + 2 ATP + 4 ADP + 4 Pi + 2 NAD+ --> 2 pyruvate + 2 ATP + 2 NADH
Balanced equation for gluconeogenesis…GO! 2 pyruvate + 4 ATP + 2 GTP + 2 NADH --> glucose + 4 ADP + 2 GDP + 2 NAD+ + 6 Pi
Balanced equation for TCA cycle…GO! acetyl CoA + FAD + 3 NAD+ + GDP + Pi --> 3 NADH + FADH2 + GTP + 2 CO2 + CoA
Glycolysis costs __ ATP and generates NET of __ ATP, __ NADH 2, 2, 2
Gluconeogenesis costs __ ATP, __ GTP, and __ NADH, for a total of __ net nucleoside triphosphates used and generates _____ 4, 2, 2, 12 ATP equivalents, a free glucose
TCA produces what forms of energy and how many of each? How much ATP equivalents is that? 1 FADH2, 3 NADH, 1 GTP for a total of 12 ATP equivalents
Fatty acids are activated (attached to ____) in ¬¬the _____ by the enzyme _____. They are now called ____ CoA, cytosol, thiokinase, fatty acyl CoAs
Fatty acyl CoA can cross the _____ but need to be attached to ______ by the enzyme ______ in order to cross the _____ outer mitochondrial membrane, carnitine acyl transferase, inner mitochondrial membrane
Number of acetyl CoA molecules required to produce a molecule of cholesterol 18
Number of ATP gained from β-oxidation of palmitate 131 (35 from just degradation, 96 from acetyl CoA --> TCA cycle
In times of severe stress or untreated diabetes, the liver turns to _____ for energy fatty acid β-oxidation
Excess _____ from ______ is converted into ketone bodies in the liver acetyl CoA, fatty acid β-oxidation
Why does acetyl CoA build up and lead to ketone body synthesis? the molecule oxaloacetate (OAA), which would normally be combined with acetyl CoA in the TCA cycle to produce CO2 and reduced coenzymes-->energy in ETC, is not available because it is being used by gluconeogenesis!!
_____ can spontaneously decarboxylate to form acetone acetoacetate
True or false: Under periods of extended stress, organs such as the heart and skeletal muscle, and to some extent the brain can oxidize ketone bodies for fuel TRUE
Fatty acid synthesis occurs in the ¬¬______ cytosol
The separation of fatty acid synthesis and fatty acid degradation into two different cellular compartments is a form of _________ regulation
Pyruvate can be carboxylated to ______ by the enzyme ______ and decarboxylated to ______ by the enzyme _______ oxaloacetate, pyruvate carboxylase; acetyl CoA, pyruvate dehydrogenase
The committed step of fatty acid synthesis is… the carboxylation (activation) of acetyl CoA to form MALONYL CoA
Major enzyme complex of fatty acid synthesis; has two identical subunits fatty acid synthase
The condensation energy to form the bond that extends the growing fatty acid chain comes from… the release of the recently added terminal carbonyl group of MALONYL CoA as carbon dioxide
The enzyme that forms malonyl CoA from acetyl CoA is called… acetyl CoA carboxylase
Through simple fatty acid synthesis, humans can create (?:?) fatty acids, but with help from the ______ in the cell’s ¬¬_______ ________, it can be extended/unsaturated to (?:?) 16:0, microsomes, endoplasmic reticulum, 18:1
Omega-3 fatty acids are ______ fatty acids abundant in _____ and proven to have ________ benefits essential, fish, cardiovascular
Omega-6 fatty acids are ______ fatty acids, notably precursors for ________ _____, which is the precursor for a group of signaling molecules called ________, which include (4 things) essential, arachidonic acid, eicosanoids; leukotrienes, prostaglandins, prostacyclins, and thromboxanes
Concerning fatty acid synth/deg, insulin stimulates ______ synthesis
Concerning fatty acid synth/deg, glucagon stimulates ______ degradation
Two primary sites for allosteric control of FA synth/deg are (enzymes) ________ acetyl CoA carboxylase, carnitine acyl transferase
Main stimulator of acetyl CoA carboxylase citrate (precursor to acetyl CoA release for FA SYNTHESIS)
Main inhibitor of acetyl CoA carboxylase palmitoyl CoA (activated FA, represents FA BREAKDOWN)
Main inhibitor of carnitine acyl transferase malonyl CoA (committed step of FA SYNTHESIS inhibits a key step in FA BREAKDOWN)
Triglyceride and phospholipid synthesis uses _TP as an energy source C (CTP!)
The point at which triglyceride and phospholipid synthesis pathways diverge is at the formation of _______ phosphatidate (diacylglycerol-3-phosphate; glycerol with 2 FA and a phosphate)
Replacement of the phosphocholine head group in sphingolipids with a MONOSACCHARIDE creates a ______ cerebroside
Replacement of the phosphocholine head group in sphingolipids with an OLIGOSACCHARIDE creates a ______ ganglioside
Statins are _______ ________ of the enzyme ________ ________, which in responsible for the committed step of ________ _________, the formation of ________ from _________ COMPETITIVE inhibitors, HMG-CoA Reductase, cholesterol synthesis; mevalonate, HMG-CoA
HMG-CoA Reductase is regulated by the addition and removal of ________ groups, which is regulated by the two hormones ________ and _________ phosphate; insulin, glucagon
Mevalonate is converted to intermediates called ______ _______, which include _____ and _____, compounds of (?) carbons isoprenoid units; IPPP, DMAPP, 5
5-carbon compounds are polymerized into a (?)-carbon chain called _______, which is converted to ______, the first compound in cholesterol synthesis to have the characteristic ring system 30, squalene, lanosterol
Lanosterol is converted by _______ to _______, which contains (?) carbons microsomes, cholesterol, 27
In all, it takes (?) acetyl CoA units to make a molecule of cholesterol 18
True or false: humans possess a pathway for cholesterol degradation FALSE
___ binds to ___ receptors on the liver and is taken up through _______ _______ LDL, LDL, receptor-mediated endocytosis
In order to increase excretion, cholesterol is oxidized into ____ _____ and ____ ____ by _______ bile salts, bile acids; microsomes
(?)% of cholesterol excreted into the bile duct is eventually reabsorbed because intestinal bacteria unconjugate it in a process called _______ _______ 95, enterohepatic cycling
Fats from the diet are packaged into _______, a type of _______ that eventually end up in the _____ chylomicrons, lipoprotein, liver
The _____ packages endogenously synthesized lipids into _____, a type of _______ that carries lipids to ______ _______ liver, VLDLs, lipoprotein, peripheral tissues
This lipoprotein picks up excess cholesterol and lipids in the blood, transforming from ____ to ____ and eventually to ____, at which point it is taken back up by the _____ HDL, IDL, LDL, liver
The lower a lipoprotein gets in density, the more _____ it contains and the _______ its lipid:protein ratio becomes lipid, higher
Positive risk factors for coronary heart disease (7) men over 45, women over 55, family history, smoking, HTN, HDL below 35 mg/dL, and diabetes
The only accepted NEGATIVE risk factor for coronary heart disease HDL levels over 60 mg/dL
Tay-Sachs disease, common in _______ _____, is attributed to the inability to break off the _________ head group of sphingolipids, which leads to a _____ of lipids in the brain Ashkenazi Jews, oligosaccharide, buildup
Symptoms of Tay-Sachs disease include…(4) enlargement of head, blindness, retardation, early death
Gaucher disease causes a buildup of _________ in ________ glucocerebrosides, organs besides the brain
Krabbe disease causes a buildup of ________ in the _______ and is usually fatal? (T/F) galactocerebrosides, TRUE
The first step in amino acid breakdown is the _______ of the ______ group by enzymes called ________, which require the coenzyme ________ removal, amine, transaminases, pyridoxal 5’-phosphate
The removed amine groups are transferred to an acceptor molecule that is a/an ________ alpha-ketoacid
After the removal of the amine group, the amino acid is now a/an ________, and the receptor molecule is now a/an _________ alpha-ketoacid, amino acid!
The only 2 purely ketogenic amino acids are…? leucine and lysine
OAA can be aminated to form ______ aspartate
The urea cycle converts the toxic by-product _____ into _____, which is very water soluble and can be easily excreted from the body ammonia, urea
(T/F) One can live with a complete block of the urea cycle FALSE
One turn of the urea cycle uses (?) carbon dioxide(s) and (?) amine group(s) 1, 2
Where do the 2 amine groups of urea come from? 1 from amine group of aspartate, 1 from carbamoyl phosphate (made from a free ammonia and a CO2)
Symptoms of hyperammonemia (2) lethargy, developmental impairment
Phenylketonuria is caused by the lack of the enzyme that breaks down __________, causing byproducts called _______ to build up and cause _______ _______ phenylalanine, phenylketones, mental retardation
The inability to metabolize the carbon skeletons of the three branched amino acids _____, ______, and _____, causes a buildup of their ketoacid forms, which causes ______ of the blood and a sweet smell in the urine is called __________ leucine, isoleucine, valine; acidosis, maple syrup urine disease
The inability to degrade tyrosine leads to a non-threatening urine disease called ________, where the urine appears black in color alkaptonuria
The ____ test tests the renal clearance of urea, and abnormal results may be indicative of…(3) BUN, infection, damage, and/or renal carcinoma
Proper kidney functioning can be determined by the ____-to-_______ ratio BUN, creatinine
Very high levels of creatine or its breakdown product, creatinine, could be indicative of… muscle tissue necrosis
Creatinine clearance is a good measurement of the _______ _______ _______ (???) glomerular filtration rate, GFR
The carbon skeletons of amino acids are derived from _________ of the central metabolic pathways, including (3) intermediates, glycolysis, TCA cycle, PPP
The amine group of all amino acids that are synthesized de novo is derived directly or indirectly from the amine group of ______, whose side chain can be further aminated to form _______ glutamate, glutamine
The amine groups from ______ are transferred by enzymes called ________ to _______ to form new amino acids glutamate, transaminases, alpha-ketoacids
Transaminases, notably ____ and _____, are especially abundant in the ______, and their presence in the blood indicates… liver; ALT, AST; cirrhosis, viral infection, or other chronic liver disorders
The amino acid _________ has been somewhat linked to coronary heart disease and is made from _______, which is made from ________ homocysteine, cysteine, methionine
Some other important biomolecules made from amino acids include… serotonin, creatine, sphingosine, porphyrin ring systems, purine/pyrimidines
There are (?) essential amino acids 9
This many amino acids can be synthesized “de novo” 8
This many amino acids are created through “salvage” pathways 3
Purines are synthesized as _________ and attached to a scaffold of ______ nucleotides, ribose-5’-phosphate
Pyrimidines are synthesized as ______ ______ free bases
The first purine (nucleotide) synthesized de novo and its base inosine-5’-monophosphate (IMP), base: hypoxanthine
The first pyrimidine (free base) synthesized de novo orotic acid (orotate)
The first pyrimidine (nucleotide) synthesized de novo uridine-5’-monophosphate (UMP)
IMP can be converted to ___ using GTP or ___ using ATP depending on cell needs AMP, GMP
Purine synthesis uses…(4) glycine, glutamine side chain, aspartate amine group, formyl groups
Pyrimidine synthesis uses…(2) aspartate, carbamoyl phosphate
Patients with orotic aciduria cannot form _____, so it becomes essential to diet; they also have a buildup of ______, which causes (2) uridine-5'-monophosphate, orotic acid; slow, stunted growth, blood cell deficiencies
_____ is converted into all of the pyrimidine nucleotides needed by the cell uridine-5’-monophosphate
Deoxyribonucleotides are converted from the _______ form of _________ by the enzyme ________ _______ DIphosphate, ribonucleotides, ribonucleotide REDUCTase
Although they are not used in DNA, _______ must be produced and reduced to make thymidine deoxyribonucleotides uridine deoxyribonucleotides
The monophosphate form of __________ is the substrate for thymidylate synthase deoxy-uridine-5’-monophosphate
The two DNA synthesis enzymes targeted by anticancer drugs are _______ and ________ ribonucleotide reductase and thymidylate synthase
The anticancer drug hydroxyurea inhibits the enzyme ________ ribonucleotide reductase
The anticancer drugs 5-fluorouracil and Tomudex inhibit the enzyme ________ thymidylate synthase
Nucleotides ingested in the diet are first converted to their _______ form by _______ enzymes. Then, the glycosidic linkages between the base and the monosaccharide are hydrolyzed by __________ enzymes, different ones for purines and pyrimidines nucleoSIDE, phosphatases, phosphorylase
The monosaccharide released during nucleotide breakdown is… ribose-1-phosphate
Pyrimidine bases are broken down in pathways that release very ________ products that easily excreted in the urine water-soluble
The ultimate product of PURINE degradation is ___ ___, notably INSOLUBLE in water uric acid
The hypoxanthine released from AMP/IMP and the guanine from GMP are both converted to ______, which is then oxidized to ____ ____ by the enzyme ______ _______ xanthine, uric acid, xanthine oxidase
If uric acid levels get too high, this is called _________ and could result in crystallized uric acid depositing in joints, especially in the _________, causing a condition known as ______ hyperuricemia, extremities, gout
Gout can progress to _____ _______ if inflammatory reactions are triggered gouty arthritis
Patients with gout are usually treated with _______, a competitive inhibitor of the enzyme _____ _____, preventing the conversion of _______ to uric acid; this is good since _______ is much more easily excreted allopurinol, xanthine oxidase, xanthine, xanthine
Concerning PURINE salvage pathways, ____ can be formed from free adenine and phosphoribosyl pyrophosphate, and ___ and ___ can be formed from free hypoxanthine and guanine AMP; GMP, IMP
Concerning PYRIMIDINE salvage pathways, the action of the ________ enzyme must be reversed by reacting a pyrimidine with _______ to create a nucleoSIDE, then using special nucleoside kinases to create the _________ phosphorylase, ribose-1-phosphate, nucleotide
Children with a deficiency in the _____ enzyme have extremely high uric acid levels and are considered to have a disease known as ________, which causes extreme self-mutilation HGPRT, Lesch-Nyhan syndrome
Created by: ianray42