Term
- __ is a highly branched homopolymer of glucose present in all tissues
- most of the glucose residues in glycogen are linked by __ bonds, about every 10 residues there is a __ branch |
|
Definition
- glycogen
- alpha 1,4 glycosidic bonds; alpha 1,6 glycosidic branch |
|
|
Term
- the largest stores of glycogen are in the __ and __
- __ breaks down glycogen and releases __ to the blood to provide energy for the brain and red blood cells
- __ glycogen stores are mobilized to provide energy for __ |
|
Definition
- liver; muscle
- liver; glucose
- muscle; muscle contraction |
|
|
Term
glycogen degradation consists of three steps:
1. release of __
2. remodeling of __
3. conversion of __ into __ |
|
Definition
1. glucose 1 phosphate
2. glycogen substrate
3. glucose 1 phosphate; glucose 6 phosphate |
|
|
Term
glucose 6 phosphate has three fates
1. __
2. __
3. conversion to __ for release into __ |
|
Definition
1. glycolysis
2. pentose phosphate pathway
3. free glucose; blood stream |
|
|
Term
- __ degrades glycogen from the __ of the glycogen molecule
- the __ catalyzes a phosphorolysis that yields __
- __ is converted into __ by __ |
|
Definition
- glycogen phosphorylase; nonreducing ends
- phosphorylase; glucose 1 phosphate
- glucose 1 phosphate; glucose 6 phosphate; phosphoglucomutase |
|
|
Term
-a __ and __ remodel glycogen for complete degradation
- __ shifts a block of three glycosyl residues from one outer branch to the other
- __ then cleaves the alpha 1,6 bond at the branch point, releasing a __ |
|
Definition
- transferase; alpha 1-6 glucosidase
- transferase
- alpha 1,6 glucosidase; free glucose |
|
|
Term
| __ forms glucose 6-phosphate from glucose 1-phosphate with the use of a __. |
|
Definition
| phosphogucomutase; glucose 1,6 bisphosphate intermediate |
|
|
Term
- __ generates free glucose from glucose 6 phosphate in liver
- the __ is released into the blood for use by other tissues such as the brain and red blood cells
- __ is absent in most other tissues |
|
Definition
- glucose 6 phosphatase
- free glucose
- glucose 6 phosphatase |
|
|
Term
- phosphorylase exists in two forms; a less active __ form that is converted to a more active __ form by __
- the a form is __
- both the __ and __ form display __
- in the b form, the __ state is favored, while in the a form the __ state is favored |
|
Definition
- b; a; phosphorylation
- phosphorylated
- a; b form; R <> T equilibrium
- T state; R state
- T; R |
|
|
Term
-In muscle, the default form of the phosphorylase is the __ in the __.
- When energy is needed, as signaled by an increase in the concentration of AMP, the phosphorylase binds AMP, which stabilizes the __.
- the __ state of the phosphorylase is stabilized by __ and __ |
|
Definition
- b form; t state
- R state
- t; atp; glucose 6 phosphate |
|
|
Term
-A key role of the liver is to maintain adequate blood levels of __.
-As a result, the default state of liver phosphorylase is the __ in the __.
-In essence, liver phosphorylase is prepared to __ unless signaled otherwise.
- glucose is a __ of liver phosphorylase, facilitating the transition from the __ to the __ |
|
Definition
- glucose
- a form; R state
- generate blood glucose
- negative regulator; R; T |
|
|
Term
- heart disease results from a deficiency in the liver isozyme of __
- glycogen accumulates in the liver and __ results, both manifestations of the inability to mobilize glycogen |
|
Definition
- glycogen phosphorylase
- hypoglycemia |
|
|
Term
- __ is released during exercise and stimulates glycogen breakdown mainly in __
- __ is secreted in response to low blood sugar levels and stimulates __ in the __ |
|
Definition
- epinephrine (adrenaline); muscle
- glucagon; glycogen breakdown; liver |
|
|
Term
| __ transmit the signal for initiation of glycogen breakdown |
|
Definition
|
|
Term
- glycogen breakdown is turned off by several mechanisms:
1. intrinsic __ activity of __ converts bound __ to __
2. __ converts cyclic __ to __
3. __ inactivates both __ and __ by dephosphorylation |
|
Definition
1. GTPase; G proteins; GTP; GDP
2. phosphodiesterase; ATP; AMP
3. protein phosphatase 1; phosphorylase kinase; glycogen phosphorylase; |
|
|
Term
- the onset of fatigue coincides with the depletion of __
- however it is not clear whether __ is an actual cause of fatigue |
|
Definition
- glycogen reserves
- glycogen depletion |
|
|
Term
- glycogen degradation yields __
- __ is the monomer that is used to extend the glycogen chain in synthesis |
|
Definition
- glucose 1 phosphate
- udp glucose |
|
|
Term
- __ is the glucose donor in glycogen synthesis
- __ is synthesized by __
- this reaction is subsequently rendered __ by hydrolysis of pyrophosphate |
|
Definition
- udp glucose
- udp glucose; udp glucose pyrophosphorylase
- irreversible |
|
|
Term
| - activated glycosyl unit of __ is attached to glycogen by __ catalyzed by __ |
|
Definition
| - udp glucose; alpha 1,4 glycosidic bond; glycogen synthase |
|
|
Term
- glycogen synthase requires an __ as primer
- the primer is synthesized by __, which generates an oligosaccharide of glucose residues __ long
- __ then extends this primer |
|
Definition
- oligosaccharide of glucose residues
- glycogenin; eight molecules
- glycogen synthase |
|
|
Term
- glycogen synthase can only synthesize __ linkages
- A branch is created by breaking an __ linkage and taking a block of about __ glucose residues and synthesizing an __ linkage by the branching enzyme.
- branching of glycogen increases its __ and the rate of its _ and __ |
|
Definition
-alpha 1,4
- alpha 1,4; seven; alpha 1,6
- solubility; synthesis; degradation |
|
|
Term
- glycogen synthase is usually inactive when in the __ form, and is usually active when in the __ form
- __ has the opposite effects on the activities of glycogen synthase and glycogen phosphorylase |
|
Definition
- phosphorylated b form; unphosphorylated a form
- opposite |
|
|
Term
- only __ molecules of atp are required to incorporate dietary glucose into glycogen
- the complete oxidation of glucose derived from glycogen yields __ |
|
Definition
|
|
Term
- Glycogen synthesis is inhibited by the same __ and __ that stimulate glycogen breakdown.
-__ stimulates glycogen breakdown by phosphorylating and activating __ and inhibits glycogen synthesis by inactivating __ by phosphorylation.
-__ also phosphorylates and inhibits glycogen synthase. |
|
Definition
- glucagon; epinephrine signaling pathways
- protein kinase A; phosphorylase kinase; glycogen synthase
- glycogen synthase kinase |
|
|
Term
-__ shifts glycogen metabolism from the degradation mode to the synthesis mode.
-__ removes phosphoryl groups from __, converting it into the more active __, thereby stimulating __.
-PP1 also removes phosphoryl groups from __ and __, thus __ |
|
Definition
- protein phosphatase 1 (PP1)
- PP1; glycogen synthase b; a form; glycogen synthesis
- phosphorylase kinase; glycogen phosphorylase; inhibiting glycogen degradation |
|
|
Term
-__ consists of a catalytic subunit and two regulatory subunits.
-A key regulatory subunit is the __ that binds glycogen and the PP1, localizing the enzyme with its substrates.
-In muscle, phosphorylation of __ leads to dissociation of __ from glycogen and a __ in the enzyme’s activity.
-A second regulatory subunit, when phosphorylated, binds to and further inhibits __. |
|
Definition
- PP1
- G subunit (G1 in liver and Gm in muscle)
- Gm; PP1; decrease
- PP1 |
|
|
Term
| __ stimulates glycogen synthesis by inactivating __ |
|
Definition
| insulin; glycogen synthase kinase |
|
|
Term
| glucagon,epinephrine: stimulates __; inhibits __ |
|
Definition
| glycogen degradation; glycogen synthesis |
|
|
Term
| insulin stimulates __, and inhibits __ |
|
Definition
| glycogen synthesis; glycogen degradation |
|
|
Term
| glucagon: __ state; __ blood glucose levels; __ |
|
Definition
| starved or fasting; low; hypoglycemia |
|
|
Term
| insulin: __ state; __ blood glucose levels; __ |
|
Definition
|
|
Term
| __ metabolism in the liver regulates the blood glucose level |
|
Definition
|
|
Term
-Diabetes is characterized by the presence of __ and underutilization of the fuel.
-Excess glucose is excreted in the __.
-In type 1 diabetes, __
-In type 2 diabetes, __ |
|
Definition
- excess glucose
- urine
- insulin is not produced
- insulin is produced but the insulin signaling pathway is not responsive |
|
|
Term
- __ - massive enlargement of the liver and hypoglycemia due to the lack of glucose 6-phosphatase from the liver.
-Mutations in the gene encoding the __ also cause von Gierke disease |
|
Definition
- von gierke disease (type I)
- glucose 6 phosphate transporter |
|
|
Term
-__ – structure of liver and muscle glycogen abnormal and glycogen amount increased due to lack of debranching enzyme.
-__ results from defective muscle glycogen phosphorylase.
-__ occur when patients with McArdle exercise |
|
Definition
- cori disease (type III)
- mcardle disease (type IV)
- painful cramps |
|
|
Term
| __, a key product of the pentose phosphate pathway, is the source of biosynthetic reducing power in all organisms. |
|
Definition
|
|
Term
Pentose phosphate pathway consist of two phases:
1. oxidative generation of NADPH
- formula:
2. non-oxidative interconversion of sugars
- __ takes place in the __ |
|
Definition
- glucose 6 phosphate + 2NADP+ + h2o > ribulose 5 phosphate + 2NADPH + 2H+ + CO2
- pentose phosphate pathway; cytoplasm |
|
|
Term
Two Molecules of __ Are Generated in the Conversion of __ into __
- __ converts glucose 6-phosphate into __ and reduces __ to __.
- lactonase converts __ into __
-A second NADPH is generated when __ is converted into __ and __. |
|
Definition
NADPH; glucose 6 phosphate; ribulose 5 phosphate
- glucose 6 phosphate dehydrogenase; 6 phosphoglucono delta lactone; NADP+; NADPH
- phophoglucono delta lactone; 6 phosphogluconate
- 6 phosphogluconate; 5 phosphate; CO2 |
|
|
Term
The Pentose Phosphate Pathway and Glycolysis Are Linked by __ and __
-Ribulose 5-phosphate, generated by the oxidative phase, is isomerized into __ by __. |
|
Definition
- transketolase; transaldolase
- ribose 5 phosphate; phosphopentose isomerase |
|
|
Term
the pentose phosphate pathway and glycolysis are linked by __ and __
- the non-oxidative phase consists of 3 reactions:
- the net result of these reactions is the conversion of __ into __ and __ |
|
Definition
- transketolase; transaldolase
- C5 + C5 (transketolase)> C3 + C7 (transaldolase) > C6 + C4 (transketolase)> C6 + C3
- three pentoses; two hexoses; one triose |
|
|
Term
| the first reaction consists of __ and __ catalyzed by transketolase into __ and __ |
|
Definition
| xylulose 5 phosphate; ribose 5 phosphate; glyceraldehyde 3 phosphate; sedoheptulose 7 phosphate |
|
|
Term
| xylulose 5 phosphate is formed form it epimer __ by __ |
|
Definition
| ribulose 5 phosphate; phosphopentose epimerase |
|
|
Term
| __ and __ are catalyzed by transaldolase into __ and __ |
|
Definition
| glyceraldehyde 3 phosphate; sedoheptulose 7 phosphate; fructose 6 phosphate; erythrose 4 phosphate |
|
|
Term
| transketolase converts __ and __ into __ and __ |
|
Definition
| erythrose 4 phosphate; xylulose 5 phosphate; fructose 6 phosphate; glyceraldehyde 3 phosphate |
|
|
Term
| The sum of the reactions catalyzed by the epimerase, transketolase, and transaldolase shows the conversion of 3 five-carbon sugars into components of the __ and __ pathways. |
|
Definition
| glycolytic; gluconeogenic |
|
|
Term
The Rate of the Pentose Phosphate Pathway Is Controlled by the Level of __
-The first reaction of the pentose phosphate pathway, the dehydrogenation of __ by __, is the __ step of the pathway.
-The most important regulatory factor is the concentration of __ |
|
Definition
NADP+
- glucose 6 phosphate; glucose 6 phosphate dehydrogenase; rate limiting
- NADP+ |
|
|
Term
The pentose phosphate pathway can operate in four distinct modes that result from various combinations of the oxidative phase, the nonoxidative phase, glycolysis, and gluconeogenesis.
1.__ needs exceed the needs for __.
2.The __ and __ needs are balanced.
3.More __ is needed than __
4. __ and __ are both required. |
|
Definition
1. ribose 5 phosphate; nadph
2. nadh; ribose 5 phosphate
3. nadph; ribose 5 phosphate
4. nadph; atp |
|
|
Term
mode 1. ribose 5 phosphate needs exceed the needs for nadph
-__ phase of pentose phosphate pathways converts __ and __ into __ |
|
Definition
| - non-oxidative; 2 fructose 6 phosphate; 1 glyceraldehyde 3 phosphate; 3 ribose 5 phosphate |
|
|
Term
Mode 2. The NADH and ribose 5-phosphate needs are balanced.
-__ phase of pentose phosphate pathways converts __ to __ and __ |
|
Definition
| - oxidative; glucose 6 phosphate; 2 nadph; 1 ribose 5 phosphate |
|
|
Term
Mode 3. More NADPH is needed than ribose 5-phosphate.
1. Oxidative phase forms __ and __
2. Non-oxidative phase converts __ to __ and __
3. Gluconeongenesis converts __ and __ to __. |
|
Definition
1. 2 nadph; 1 ribose 5 phosphate
2. ribose 5 phosphate; fructose 6 phosphate; glyceraldehyde 3 phosphate
3. fructose 6 phosphate; glyceraldehyde 3 phosphate; glucose 6 phosphate |
|
|
Term
Mode 4. NADPH and ATP are both required.
1. Oxidative phase forms __ and __
2. Non-oxidative phase converts __ to __ and __
3. Glycolysis converts __ and __ to __.
- __ can be oxidized to generate __ |
|
Definition
1. 2 nadph; 1 ribose 5 phosphate
2. ribose 5 phosphate; fructose 6 phosphate; glyceraldehyde 3 phosphate
3. fructose 6 phosphate; glyceraldehyde 3 phosphate; pyruvate
- pyruvate; atp |
|
|
Term
-__ helps to prevent damage by reactive oxygen species (ROS).
-__ generated by the pentose phosphate pathway is required to maintain adequate levels of reduced glutathione.
-__ is converted into reduced glutathione by NADPH. |
|
Definition
- glutathione (GSH)
- NADPH
- oxidized glutathione (GSSG) |
|
|
Term
| If __ activity is compromised, adequate amounts of NADPH cannot be generated to maintain GSH levels |
|
Definition
| glucose 6 phosphate dehydrogenase |
|
|
Term
-__ is used to eliminate peroxides, which are reactive oxygen species (ROS).
-Glutathione is also required to maintain the normal structure of __.
-In the absence of glutathione, __ occur among hemoglobin molecules, forming aggregates called __.
-Heinz bodies can cause the red blood cells to __. |
|
Definition
- glutathione
- hemoglobin
- sulfhydryl bonds; heinz bodies
- lyse |
|
|
Term
| Glucose 6-phosphate dehydrogenase deficiency protects against __ by depriving the parasites of __ that they require for growth. |
|
Definition
|
|
Term
-Synthesis: __ are crucial components of cell membranes – separate synthesis pathways for fatty acids, cholesterol, eicosanoids and sphingolipids
-Breakdown: __ and __ are the major forms of stored energy in vertebrates
-__ can supply ATP for a short time only
-Sustained work is fueled by breakdown of __ |
|
Definition
- lipids
- glycogen; triacylglycerol
- glycogen
- triacylglycerols |
|
|
Term
-More energy stored and extracted from __ (unlimited storage) than from __ (limited storage in mammals)
-Fatty acids in triacylglycerols are more __ than amino acids or monosaccharides |
|
Definition
- fatty acids; carbohydrates
- reduced |
|
|
Term
-Fatty acids are stored in adipose tissue as __ in which fatty acids are linked to __ with __ linkages.
-Adipose tissue is located throughout the body, with __ (below the skin) and __ (around the internal organs) deposits being most prominent. |
|
Definition
- triacylglycerols; glycerol; ester linkages
- subcutaneous; visceral |
|
|
Term
how are triacylglycerols in adipose tissue used as energy?
-First Step: Degradation of TAG to release __ and __ into the blood for transport to energy-requiring tissues.
-Triacylglycerols are stored in adipocytes as a __.
- __ stimulate lipid breakdown |
|
Definition
- fatty acids; glycerol
- lipid droplet
- hormones (epi and glucagon) |
|
|
Term
-Hormones bind __
-__ activated – increase in __ stimulates __
-__ phosphorylates hormone-sensitive __ and __, which is associated with the lipid droplet
- __ is activated and initiates the breakdown of lipids. |
|
Definition
-7tm receptors
- adenylate cyclase; cAMP; protein kinase A
- protein kinase a; lipase; perilipin
- adipocyte triacylglyceride lipase (ATGL) |
|
|
Term
| Lipolysis generates __ and __. The __ acids are used as fuel by many tissues. The liver processes glycerol by either the __ or the __ pathway, depending on its metabolic circumstances. |
|
Definition
| fatty acid; glycerol; fatty acids; glycolytic; gluconeogenic |
|
|
Term
catabolism of fatty acids for energy
-Fatty acids are degraded in __ units from the carboxyl terminus
-__ is produced and enters the citric acid cycle, gluconeogenesis or pathways leading to other biomolecules (e.g., amino acids)
-Energy is captured as __ or __
-Three stages for process in eukaryotes:
-- __ of fatty acids in the cytosol
-- __ into the mitochondria (or peroxisomes)
-- __ to two-carbon fragments (as acetyl CoA) in the mitochondrial matrix |
|
Definition
- two carbon acetate
- acetyl coa
- nadh fadh2
-
-- activation
-- transport
-- degradation |
|
|
Term
-Activation: Conversion of __ to __ sets the stage for further catabolism
-__: different synthetase isoforms that operate on different chain lengths
- Takes place on __
-Like many other biosynthetic reactions, this is made irreversible by the __ of inorganic pyrophosphate |
|
Definition
- fatty acids; CoA derivatives
- eukaryotes
- outer mitochondrial membrane
- hydrolysis |
|
|
Term
| The __ transfers long-chain fatty acyl CoA into the matrix of the mitochondria |
|
Definition
|
|
Term
| beta oxidation: degradation of __ to __ produces __, __, and __ |
|
Definition
| fatty acids; acetate; fadh2; nadh; acetyl CoA |
|
|
Term
| __ from fatty acid oxidation |
|
Definition
|
|
Term
net yield of atp per stearate oxidized to 18 co2:
- 9 acetyle coa (cac) = __
- 8 fadh2 = __
- 8 nadh = __
- atp to activate= __
- net yield = __
- once glucose molecules yields __ |
|
Definition
- 90 atp
- 12 atp
- 20 atp
- -2 atp
- 122atp
- 32 atp |
|
|
Term
-For monounsaturated fatty acids, an __ is needed, as the intermediate cis-Δ3-enoyl CoA cannot be processed by acyl CoA dehydrogenase.
-Polyunsaturated fatty acids with even numbers of double bonds need an __ and a __ for degradation |
|
Definition
- isomerase
- isomerase; reductase |
|
|
Term
-β-Oxidation of fatty acids with odd numbers of carbons generates __ in the last thiolysis reaction.
-__, a biotin enzyme, adds a carbon to __ to form __
-__, a citric acid cycle component, is subsequently formed from __ by __, a vitamin B12 requiring enzyme. |
|
Definition
- propionyl coa
- propionyl carboxylase; propionyl coa; methylmalonyl coa
- succinyl coa; methylmalonyl coa; methylmalonyl coa mutase |
|
|
Term
-Excess acetyl CoA from fat catabolism in liver can be converted to __, made of __ and __
-__ are transported in the blood to other tissues for use as fuel
-The components of ketone bodies are __ |
|
Definition
- ketone bodies; acetoacetate; beta hydroxybutyrate
- ketone bodies
- water soluble lipids |
|
|
Term
-Ketone bodies are synthesized in the __ of __
-During __, these are the principal fuel for brain, skeletal muscle, etc |
|
Definition
- mitochondria; liver cells
- starvation |
|
|
Term
-__ provide fuel to tissues like the heart and kidney, where __ is used in preference to glucose
-But..ketone bodies are moderately strong __, and excess production can lead to __.
-Overproduction of ketones can occur in untreated __. Lack of insulin shifts energy production to fats, eve though glucose is present in the bloodstream. |
|
Definition
- ketone bodies; acetoacetate
- acids; acidosis
- diabetes |
|
|
Term
-Most of our need for fats and lipids are met by __, but under some conditions fatty acid synthesis will occur mainly in __ and __
-__ occurs by repetitive addition of two-carbon units to the end of a hydrocarbon chain
-Addition reaction occurs while the chain is covalently attached to the coenzyme __
-When glucose is plentiful, a large amount of __ is produced by __ and can be used for __
-Fatty acid synthesis in all species occurs in the __ |
|
Definition
- diet; liver cells; adipocytes
- fatty acid synthesis
- acyl carrier proteins
- acetyl coa; glycolysis; fatty acid synthesis
- cytosol |
|
|
Term
-High concentrations of __ in the mitochondria inhibits __, increases synthesis of __
-__ and __ are used to form __ – which is then transported to the __
-__ in the cytosol signals an energy rich state – inhibits __, which controls glycolysis |
|
Definition
- acetyl coa; pyruvate dehydrogenase; oaa
- oaa; acetyl coa; citrate; cytosol
- citrate; phosphofructokinase |
|
|
Term
-Fatty acid synthesis requires reducing power in the form of __, as well as energy from __.
-__ generated during conversion of __ to __ (1 NADPH per oxaloacetate/acetyl coA)
-Additional __ comes from __ |
|
Definition
- nadph; atp
- nadph; cytosolic oxaloacetate; pyruvate
- nadph; pentose phosphate pathway |
|
|
Term
Acetyl CoA needed to make __, the main substrate for FA biosynthesis
-__ catalyzes the rate-limiting step for FA synthesis |
|
Definition
- malonyl coa
- acetyl coa carboxylase |
|
|
Term
-__, a complex of enzymes in E. coli, catalyzes fatty acid synthesis
-Fatty acid synthesis occurs on the __, a polypeptide linked to CoA. Intermediates are linked to the __ of the CoA attached to ACP.
-__ attach acyl carrier protein (ACP) |
|
Definition
- fatty acid synthetase
- acyl carrier protein; sulfhydryl group
- transacylases |
|
|
Term
-__ = ACPs
-ACPs are expressed in an inactive, __ form, and the __ moiety is attached post-translationally to a __ residue in ACP
-Fatty acids as well as malonyl and acetyl subunits are covalently attached to __ of __ using an energy-rich, __ linkage |
|
Definition
- acyl carrier proteins
- apo; phosphopantetheine; ser
- thiol; phosphopantetheine; thioester |
|
|
Term
Final stage of initiation is reaction of __ and __ to form __ – the building block for elongation
-Formation of __ from two acetyl ACP molecules is energetically unfavorable, in contrast to the energetically favorable reaction above |
|
Definition
malonyl acp; acetyl acp; acetoacetyl acp
- acetoacetyl acp |
|
|
Term
| __ consumed to prepare for malonyl ACP addition |
|
Definition
|
|
Term
Elongation proceeds by addition of two carbons from __
-__ is released
-Chain length always increased in units of __
-End product is __ or __ carbon fatty acids – longer chain lengths cannot be made by this pathway |
|
Definition
malonyl acp
- co2
- two
- 16; 18 |
|
|
Term
| last step is release from __ |
|
Definition
|
|
Term
| The fatty acid synthase in animals carries out the same reactions as the enzymes in ___, but the mammalian synthase is composed of one large polypeptide chain |
|
Definition
|
|
Term
-Tumors require large amounts of __ to produce precursors for membrane synthesis.
-__ retard tumor growth.
-Mice treated with fatty acid synthase inhibitors also showed dramatic __, suggesting that such drugs may be used to treat __.
-__, when attached to ACP or CoA, is a substrate in fatty acid synthesis and degradation, and is a ketone body as well.
-An isomer of this key biochemical, __ is a potent, illegal drug (GHB) |
|
Definition
- fatty acid synthase
- fatty acid synthase inhibitors
- weight loss; obesity
- beta hydroxybutyric acid
- y hydroxybutyric acid |
|
|
Term
-__ reactions are different in bacteria and eukaryotes – __ perform these reactions
-__: double bonds added to growing chain when it reaches 10 carbons
-__: cannot introduce double bonds during fatty acid synthesis. Utilize desaturases that work after synthesis is complete.
-Mammals lack a __ that works after C9, must get key lipids from __ (e.g. linoleate. D12. Needed for eicosanoid synthesis.) |
|
Definition
- desaturation; desaturases
- prokaryotes
- eukaryotes
- desaturase; diet |
|
|
Term
-Fatty acids longer than 16 or 18 are made by extending __ or __
-__ catalyze these extension reactions |
|
Definition
- palmitoyl CoA; stearoyl CoA
- elongases |
|
|
Term
-___: Key Regulator of Fatty Acid Synthesis
-Carboxylase is inhibited when phosphorylated by __. Inhibition due to phosphorylation is reversed by __.
-AMPK is activated by __, inhibited by __,so it is essentially a fuel gauge |
|
Definition
- acetyl CoA carboxylase
- AMP-dependent kinase (AMPK); protein phosphatase 2A
- amp; atp |
|
|
Term
-__ actives carboxylase by facilitating the formation of active polymers of the carboxylase. __ can partially reverse inhibition due to phosphorylation.
-___, the end-product of fatty acid synthase, inhibits carboxylase by causing depolymerization of the enzyme. |
|
Definition
- citrate; citrate
- palmitoyl CoA |
|
|
Term
-__ and __ inhibit carboxylase by enhancing AMPK activity.
-__ stimulates the dephosphorylation and activation of carboxylase.
-The enzymes of fatty acid synthesis are regulated by __ control. If adequate fats are not present in the diet, the synthesis of enzymes required for fatty acid synthesis is enhanced. |
|
Definition
- glucagon; epinephrine
- insulin
- adaptive |
|
|
Term
-__ alters energy metabolism in the liver
-Excess __ consumption can cause liver damage and cannot be excreted, so we must metabolize it. One pathway for ethanol processing consists of two steps and leads to excess production of __
-Excess NADH inhibits __ and enhances __ production, which may result in __.
-Excess NADH inhibits __ and stimulates __, leading to the accumulation of fats in the liver. |
|
Definition
- ethanol
- ethanol; nadh
- gluconeogenesis; lactate; lactic acidosis
- fatty acid degradation; fatty acid synthesis |
|
|
Term
-Liver converst some of the acetate generated into acetyl CoA, but this cannot be processed by the citric acid cycle because of the paucity of __.
-The build-up of acetyl CoA can lead to __ secretion by the liver, which exacerbates the __ caused by __ accumulation.
-If __ cannot be processed, __ accumulates. previous is very reactive and modifies reactive groups of proteins, causing a loss of protein function.
-As protein damage accumulates, __ function can fail. |
|
Definition
- acetyl coa; nad+
- ketone body acidosis; lactate
- acetate; acetaldehyde
- liver |
|
|
Term
Look at energy used to make stearate versus energy gained from its oxidation:
-Anabolism (synthesis) requires __ ATP
-Catabolism (oxidation) provides __ ATP
-Efficiency is __, a figure consistent with the gluconeogenesis and glycolysis/CA cycle for glucose |
|
Definition
- 201 atp
- 120 atp
- 60% 120/201 |
|
|
Term
-__ – built from fatty acids or from their breakdown products
We will focus on:
-__ – storage
form of fatty acids
-__ –
phospholipids and sphingolipids
-__ – membrane component and precursor to steroid hormones |
|
Definition
- lipids
- triacylglycerols
- membrane lipids
- cholesterol |
|
|
Term
-__: Precursor of storage lipids and many membrane lipids
-Phosphatidate also called __ |
|
Definition
- phosphatide
- diacylglycerol 3 phosphate |
|
|
Term
-Phosphatidate is formed by the addition of __ to __
-__ is then synthesized in two steps:
-TAG synthesis promoted by __. This occurs primarily in the __, then TAGs are transported to muscle (fuel) or adipose tissue (storage) |
|
Definition
- two fatty acids; glycerol 3 phosphate
- triacylglycerol
- triacylglycerol synthetase complex; liver |
|
|
Term
-Phospholipid synthesis = __ + __ (remember __ is formed from phosphatidate!)
-Requires __ of one of the reactants to provide the needed energy
-For some phospholipids, the __ gets activated (e.g. phosphatidylethanoliamine synthesis) |
|
Definition
- diacylglycerol + alcohol (diacylglycerol)
- activation
- alcohol |
|
|
Term
-For some phospholipids, diacylglycerol is activated by forming __
-__ then reacts with an __ to form a __. |
|
Definition
- cdp diacylglycerol
- cdp diacylglycerol; alcohol; phospholipid |
|
|
Term
-__: membrane lipids found in all eukaryotic cells, highest levels in central nervous system
-Have a sphingosine backbone instead of a glycerol backbone – this is converted into __
-The terminal hydroxyl group of ceramide is substituted to form other __ |
|
Definition
- sphingolipids
- ceramide
- ceramide; sphingolipids |
|
|
Term
| __: Dipalmitoyl phosphatidylcholine is found in the extracellular fluid in lungs. This phospholipid, in conjunction with other biomolecules, prevents lung collapse after exhaling. Failure to synthesize sufficient dipalmitoyl phosphatidylcholine (often seen in premature infants) results in collapse of the lung upon exhalation, a pathology called respiratory distress syndrome. |
|
Definition
| respiratory distress syndrome |
|
|
Term
___: inability to degrade a particular ganglioside due to the lack of β-N-acetylhexosaminidase.
Tay-Sachs disease results in death by age 3. |
|
Definition
|
|
Term
-__ helps to regulate lipid metabolism. Different lipids are synthesized depending on whether the phosphatase is active or inactive.
-Loss of __ activity in mice results in loss of body fat and the development of insulin resistance. Excess __ activity results in obesity. |
|
Definition
- phosphatidic acid phosphatase
- phosphatase; phosphatase |
|
|
Term
-Most cholesterol is synthesized in the __ and __
-Cholesterol biosynthesis is regulated by __ and __ cholesterol levels
-All 27 carbon atoms of cholesterol are derived from __
-__ catalyzes the first committed step and is the key point of regulation for cholesterol synthesis |
|
Definition
- liver; intestine
- hormones; serum
- acetyle CoA
-HMG CoA reductase |
|
|
Term
| - ___ – competitive inhibitors of HMG-CoA reductase |
|
Definition
|
|
Term
Three regulatory mechanisms for ___ – covalent modification, repression of transcription, regulation of translation and control of degradation – make this one of the most highly regulated enzymes known
1.The rate of synthesis of HMG CoA reductase is controlled by __
2. The rate of translation of the reductase mRNA is controlled by metabolites of __ and dietary __.
3.Increases in __ concentration result in the proteolytic degradation of the reductase.
4.Phosphorylation of the reductase by ___ inactivates the enzyme. |
|
Definition
HMG CoA reductase
1. srebp
2. mevalonate; dietary cholesterol
3. cholesterol
4. amp dependent kinase |
|
|
Term
-___, ___ and __ are insoluble in water and cannot be transported in the blood stream as free molecules
-These lipids assemble with phospholipids and apoproteins (apolipoproteins) to form spherical particles called __ with:
--__: Triacylglycerols, cholesteryl esters
--__: cholesterol, phospholipids, apolipoproteins
-___ are the largest lipoproteins, delivering triacylglyerols and cholesterol from the intestine to the tissues |
|
Definition
- triacylglycerols, cholesterol, cholesterol esters
- lipoproteins
-- hydrophobic cores
-- hydrophilic surfaces
- chylomicrons |
|
|
Term
various lipoproteins carry __
-Classified according to relative densities and types of lipids
-__ are denser than lipids – the higher density lipoproteins have more protein
-___- 98% lipid
-Cholesterol is carried primarily by __. High levels of __ increase risk of heart disease
-High levels of __ decrease risk of heart disease |
|
Definition
lipids
-
- proteins
- vldl's
- ldl; ldl
- hdl |
|
|
Term
__ transport cholesterol and triacylglycerols throughout the body
- __ carries cholesterol to peripheral tissues
- __ returns cholesterol to liver |
|
Definition
|
|
Term
At the periphiral tissues, cholesterol enters the cell by receptor-mediated endocytosis:
1.__ binds to the __ on the cell surface.
2.The receptor-__ is internalized, a process called __.
3. The LDL is hydrolyzed in __ while the LDL receptor is returned to the cell surface to bind another LDL particle. |
|
Definition
1. ldl: ldl receptor
2. ldl complex; endocytosis
3. lysosomes |
|
|
Term
- ldl receptor defects lead to __ and __
-Excess LDL becomes oxidized, ingested by macrophages, forming __, which become trapped in blood vessels and contribute to the
development of cardiovascular
disease |
|
Definition
- hypercholesterolemia; atherosclerosis
- foam cells |
|
|
Term
how do you treat high blood cholesterol
- goal is to increase the number of __ to remove cholesterol
- synthesis of ldl receptors is regulated by __; so you need to __ and __
1. block de novo cholesterol synthesis by inhibition of __ by __
2. also need to block uptake of __ |
|
Definition
- ldl receptors
- intracellular cholesterol levels; decrease cholesterol; precursors of cholesterol
1. hmg-coa reductase; statins
2. dietary cholesterol |
|
|
Term
-__ = cholesterol derivatives that promote absorption of dietary cholesterol
- absorption of __(above) from the intestine can be blocked by ingesting a __ that binds to them |
|
Definition
- bile salts
- bile salts; resin |
|
|
Term
| __ is a precursor of steroid hormones and other products |
|
Definition
|
|
Term
__ are crucial signal molecules
- all five major classes of steroid hormones are derived from __
- all steroid hormones bind to and activate receptor proteins that then regulate expression of target __ |
|
Definition
steroid hormones
- cholesterol
- genes |
|
|
Term
- __ is derived from cholesterol by the energy of sunlight
- __: regulation of calcium and phosphate metabolism
- __: active form of vitamin d formed from cholesterol |
|
Definition
-vitamin d
- vitamin d
- calcitriol |
|
|
Term
-Deficiency of vitamin D leads to inadequate calcification of cartilage and bone, a pathological condition called __.
-Lack of sunlight, dietary vitamin D important for rickets development: “children’s disease of the English”
I-n adults, vitamin D deficiency results in __, a condition characterized by soft and weak bones.
-Foods are now supplemented with vitamin D |
|
Definition
- rickets
-
- osteomalacia
- |
|
|
Term
-__ obtained from degradation of endogenous or dietary proteins can be used for biosynthesis of new proteins
-__ also serve as precursors in a variety of other metabolic pathways
-__ stability in cells varies widely |
|
Definition
- amino acids
- amino acids
- protein |
|
|
Term
-Amino acids are first used to build new __. Those not needed for this are catabolized to make use of their nitrogen and carbon skeletons
-Amino acid degradation primarily occurs in the __
-First step is often removal of the a-amino group to generate __
-Next, the __ are altered for entry into central pathways of carbon metabolism |
|
Definition
- proteins
- liver
- ammonia
- carbon chains |
|
|
Term
- __ is the first step in amino acid degradation
- some amino acids can be directly deaminated, removal of __ from most amino acids involves two steps:
1. __ transfer amino groups from an amino acid to __ to generate __
2. __, a mitochondrial enzyme, releases __ in the oxidative deamination of __ |
|
Definition
- nitrogen removal
- ammonium
1. aminotransferases; alpha gluterate; glutamate
2. glutamate dehydrogenase; nh4+; glutamate |
|
|
Term
- __ transport nitrogen to the liver
- the __ carries out most amino acid degradation, but it cannot deaminate __
- muscles used __ as fuels. the __ from these amino acids is transported to the liver by the __ |
|
Definition
- peripheral tissues
- liver; branched chain amino acids
- branched chain amino acids; nitrogen; glucose-alanine cycle |
|
|
Term
| - nitrogen can also be transported as __ formed from __ by __ |
|
Definition
| - glutamine; glutamate; glutamine synthetase |
|
|
Term
-In aquatic organisms, __ diffuses directly across cell membranes and is diluted by the surrounding water
-Most terrestrial vertebrates including mammals convert waste ammonia to __. Urea is produced in the __ and carried in the blood to the kidneys, where it is excreted as urine. |
|
Definition
|
|
Term
-Urea is synthesized in the liver in a process called the __
--Urea production is stimulated by the amino acid __ in proportions greater than the amount of it present (suggesting a catalytic role)
--Liver of organisms excreting urea possesses high levels of enzyme, __ (suggesting that arginine has a role in urea synthesis)
Source of nitrogen in urea: __ and __ |
|
Definition
- urea cycle
-- ornithine
-- arginase
- aspartate; NH4+ |
|
|
Term
urea cycle: carbamoyl phosphate
- carbamoyl phospate sythetase (CPS I)
--__, activated by phosphorylation, reacts with __
-- intermediate __ undergoes phosphorylation to give __
- note that __ are consumed
- mammalian cps I required for the regulatory molecules __, available only if free amino acids are present |
|
Definition
-- bicarbonate; ammonia
- carbamic acid; caramoyl phosphate
- two ATP
- N-acetylglutamate |
|
|
Term
carbamoyl phosphate synthetase
- present in all species
-- used in the synthesis of __ and the amino acid __
- mammals have two types
-- type I in __ is used in the __
-- type II in __ uses __ rather than ammonia and is involved in __ synthesis |
|
Definition
-- pyrimidines; arginine
-- liver; urea cycle
-- cytosol; glutamine; pyrimidine |
|
|
Term
urea cycle
1. transfer of __ group to __ from __
2. addition of __
3. elimination leading to __ and __
4.Arginine cleaved by arginase (in the cytosol) into urea, which is excreted, and __, which is transported into the mitochondria. |
|
Definition
1. carbamoyl group; ornithine; carbamoyl phosphate (mitochondrial matrix)
2. aspartate (cytosol)
3. arg; fumarate (cytosol)
4. arginine; arginase; urea; ornithine |
|
|
Term
| fumarate can be converted into __ by the __ and then into __ by the __ |
|
Definition
| oxaloacetate; citric acid cycle; glucose; gluconeogenic pathway |
|
|
Term
urea cycle control
- the urea cycle is generally controlled by substrate availability; more __ means higher rate of urea formation |
|
Definition
|
|
Term
Fasting
-During fasting, liver maintains __ level
-Amino acids become major source for __ production via __, increase in __ excretion
-As __ become major source of energy, __ excretion drops |
|
Definition
- blood glucose
- glucose; gluconeogenesis; nitrogen
- ketone bodies; nitrogen |
|
|
Term
-Defects in any of the urea cycle enzymes result in elevated levels of __
in the blood, which causes nervous system malfunction and can be lethal.
-__ damage caused by excessive alcohol consumption can be fatal in part because the liver is unable to synthesize __ and consequently __ appears in the blood. |
|
Definition
- nh4+
- liver; urea; nh4+ |
|
|
Term
-The carbon skeletons from amino acid breakdown transform into seven major metabolic intermediates:
-Amino acids that are __ are degraded to pyruvate, a-ketoglutarate, succinyl CoA, fumarate and oxaloacetate. They can directly supply the pathway of __
-Amino acids that are __ provide acetyl CoA or acetoacetyl CoA, found in the formation of __ and __ bodies
-Some amino acids are both __ and __ |
|
Definition
- pyruvate, acetyl CoA, acetoacetyl CoA, a-ketoglutarate, succinyl CoA, fumarate and oxaloacetate.
- glucogenic; gluconeogenesis
- ketogenic; fatty acids; ketone bodies
- glucogenic; ketogenic |
|
|
Term
-__: solely ketogenic
-__: both ketogenic and glucogenic
-__: glucogenic |
|
Definition
- l,k
- TIFWY
- other amino acids |
|
|
Term
breakdown of arginine, a __ amino acid
- __ is converted to a citric acid intermediate |
|
Definition
|
|
Term
breakdown of lysine, a __ amino acid
- __, a building block for lipid synthesis |
|
Definition
|
|
Term
- inborn error of __ can disrupt amino acid degradation
-- many human metabolic diseases involve single gene defects in __ pathways |
|
Definition
metabolism
- amino acid breakdown |
|
|
Term
-Phenylalanine and tyrosine are degraded by __ to __ and __
-In 1902, Archibald Garrod studied patients with black urine (__). He realized that the disease was transmitted as a single recessive Mendelian trait that produces a defect in the enzyme that degrades __
-Garrod realized that the urine turned black because __ is oxidized and polymerizes to produce black compounds |
|
Definition
- oxygenases; acetoacetate; fumarate
- (alcaptonuria); homogentisate
- homogentisate |
|
|
Term
phenylketonuria- a defect in __ formation from ___
- caused primarily by a lack or low level of __
- __ accumulates in all body fluids because it cannot be metabolized to __
- accumulation causes __. a diet low in __ can prevent disease |
|
Definition
tyrosine; phenylalanine
- phenylalanine hydroxylase
- phenylalanine; tyrosine
- mental retardation; phenylalanine |
|
|
Term
| defects in catabolism of __ - maple syrup urine disease |
|
Definition
| branched chain amino acids |
|
|
Term
maple syrup urine disease
-The first step in the pathway for catabolism of branched-chain amino acids is transamination to yield an __, which is then oxidatively, decarboxylated to yield a __
-In maple syrup disease, the oxidative decarboxylation reaction is defective. __ accumulate in the blood and urine.
-The disease usually leads to mental and physical retardation and early death. Dietary control is difficult, as it requires a diet low in __,__, and __ starting early in life. This is a rare recessive genetic disease. |
|
Definition
- alpha keto acid; coa derivative
- alpha keto acids
- valine, isoleucine, leucine |
|
|
Term
-__ is needed for amino acids, nucleotides
-Atmospheric N2 makes up 80% of our atmosphere but is virtually unusable by most forms of life
-The __ is extremely strong (940 kJ mol-1) and resistant to chemical attack
-Industrial processing of nitrogen for fertilizer requires mixing N2 with H2 gas over an iron catalyst at 500 degrees C at 300 atm pressure! |
|
Definition
|
|
Term
-Nitrogen fixation: a few bacteria and archaea possess __ which can reduce N2 to __ under conditions compatible with life.
-Nitrogen is then recycled in nature through the __
-__ is the only way organisms have access to the huge pool of atmospheric N2 |
|
Definition
- nitrogenase; ammonia
- nitrogen cycle
- nitrogen fixation |
|
|
Term
- nitrogenase converts __ to __
-__ bacteria that live in root nodules of leguminous plants have nitrogenase
-Some free-living soil and aquatic bacteria also possess nitrogenase
-About 10^11 kg of N2 per year is fixed by these organisms |
|
Definition
|
|
Term
-__: Complex enzyme with iron-protein clusters and iron/molybdenum protein clusters that manage a series of electron transfers
-Overall process converts __ to two __ at the expense of considerable __
-In __, NH3 acquires a proton to form NH4+
-__ is required not to power the reaction, but to make the exergonic reaction __ feasible. |
|
Definition
- nitrogenase
- n2; nh3; atp
- aqueous solution
- atp; kinetically |
|
|
Term
The nitrogenase complex consists of two components:
1.The __ provides high-energy electrons, in the form of __, for reducing power.
2. The __ uses the electrons to reduce N2 to NH3. |
|
Definition
1. reductase; ferredoxin
2. nitrogenase |
|
|
Term
- both the reductase and the nitrogenase are examples of __
- the reductase transfers __ from a donor such as ferrodoxin to nitrogenase |
|
Definition
- iron sulfur proteins
- electrons |
|
|
Term
-The __ of nitrogenase, an iron-sulfur rich part, accepts electrons, and then passes then to the redox center of the enzyme, called the __
-The __ contains __. This is the site of nitrogen fixation. |
|
Definition
- p cluster; MoFe cofactor
- MoFe cofactor; molybdenum |
|
|
Term
-Atmospheric nitrogen can also be converted to NO3 by __
-Soil bacteria and plants make use of __ and __ to synthesize ammonia |
|
Definition
- lightening
- nitrate reductase; nitrite reductase |
|
|
Term
-Ammonia is incorporated into amino acids through __ and __
-In microorganisms, reductive amination is an efficient mechanism for capturing ammonia. __ and __ serve as “nitrogen carriers”
-In mammals, nitrogen is acquired through __; __ serves only a catabolic role |
|
Definition
- glutamate; glutamine
- glutamate; glutamine
- diet; glutamate dehydrogenase |
|
|
Term
| The carbon skeletons for amino acid synthesis are provided by __ of the glycolytic pathway, the citric acid cycle, and the pentose phosphate pathway |
|
Definition
|
|
Term
-Most bacteria and plants (not mammals) synthesize all 20 common amino acids
-Nonessential amino acids for mammals are usually derived from intermediates of __ or __
-__ are those whose carbon skeleton cannot be synthesized and which therefore must come from our diet
-The essential amino acids are:
- __ is essential for growth, but not essential for adults |
|
Definition
-
- glycolysis; citric acid cycle
- essential amino acids
- leucine; isoleucine; valine; lysine; methionine; thronine; histidine, phenylalanine;
- arginine |
|
|
Term
-In general the synthesis of the essential amino acids requires __ than the non-essential amino acids
-Note that __ can be synthesized in one step from __ |
|
Definition
- greater energy investment
- tyrosine; phenylalanine |
|
|
Term
| The amino acids which require the most energy to synthesize are also the ones with the __ – so the pathways that have been lost are the ones with the most steps! |
|
Definition
| longest synthesis pathways |
|
|
Term
transamination reactions
-Transfer of an amino group from an __ to an __
- |
|
Definition
| - alpha amino acid; alpha keto acid |
|
|
Term
| Transamination reactions are catalyzed by __. These enzymes require the coenzyme __, which is derived from __. |
|
Definition
| - transaminases (aminotransferses); pyridoxal phosphate; pyridoxine (vitamin B6) |
|
|
Term
- __,__ and __ are formed from 3 phosphoglycerate
-The glycolytic intermediate __ is the precursor for __. this, in turn, is metabolized to __ and __.
- the synthesis of __ requires the cofactor __, a carrier of one carbon units |
|
Definition
- serine, cysteine, glycine
- 3 phosphoglycerate; serine; cysteine glyceine
- glycine; tetrahydrofolate |
|
|
Term
-__, derived from folic acid, is essential for synthesis of many amino acids and nucleotides
-Mammals cannot synthesize this, and must get it from __
-Tetrahydrofolate is especially important for the embryonic development of the __. Insufficient amounts can lead to spina bifida or anencephaly |
|
Definition
- tetrahydrogolate
- diet
- nervous system |
|
|
Term
-__ is the major donor of methyl groups for amino acid synthesis
-SAM is synthesized from __ and __ in an unusual reaction in which the triphosphate of ATP is cleaved to __ and __. |
|
Definition
- s-adenosylmethionine (sam)
- methionine; atp; pyrophosphate; phosphate |
|
|
Term
-After donation of a methyl group by S-adenosylmethionine, the resulting S-adenosylhomocysteine is cleaved to yield __ and __.
-__ is regenerated from __ by the methylcobalamin-dependent enzyme __, which catalyzes the transfer of a carbon from N5-methyltetrahydrofolate. |
|
Definition
- adenosine; homocysteine
- methionine; homocysteine; methionine synthase |
|
|
Term
| The use of S-adenosylmethionine and its regeneration constitute the activated __ |
|
Definition
|
|
Term
-Individuals with high blood levels of __ are at greater risk for cardiovascular disease.
-The most common cause of increased blood homocysteine is a lack of __ activity, the enzyme that converts homocysteine into cysteine.
-__ appears to damage cells lining blood vessels, increase growth of vascular smooth muscle, and impair vasorelaxation |
|
Definition
- homocysteine
- cystathionine synthase
- homocysteine |
|
|
Term
-__ is a common means of regulating metabolic pathways
-In feedback inhibition, the final product in a pathway inhibits the enzyme catalyzing the committed step.
-The committed step in serine synthesis is catalyzed by 3-phosphoglycerate dehydrogenase, which is inhibited by __. |
|
Definition
- feedback inhibition
-
- serine |
|
|
Term
Regulation of branched pathways is more complicated as the concentration of two products must be considered. Mechanisms for this include:
-__: If two pathways have an initial common step, one pathway is inhibited by its own product and stimulated by the product of the other pathway.
-__: The committed step is catalyzed by two or more enzymes with differing regulatory properties. Three distinct aspartate kinases control the synthesis of threonine, methionine, and lysine in E. coli.
-__: A common step for several pathways is partly inhibited independently by each of the various end products. This type of regulation is illustrated by glutamine synthetase, which is inhibited by a host of biochemicals. |
|
Definition
- feedback inhibition and activation
- enzyme multiplicity
- cumulative feedback inhibition |
|
|
Term
| __ kills plants by inhibiting synthesis of aromatic amino acids |
|
Definition
|
|
Term
- nucleotides are __ because they can be synthesized in the body
- nucleotides consists of __, __, __ |
|
Definition
- non-essential
- base; pentose (sugar); phosphate |
|
|
Term
- bases include __ and __
-- __ included in dna and rna
- __: differences between ribose and deoxyribose
-- __ found in dna and __ found in rna |
|
Definition
- purines(ag); pyrimidines(CT)
- both
- sugar
-- deoxyribose; ribose |
|
|
Term
- __ + __ = nucleoside
- nucleoside + __ = ___ |
|
Definition
- base + sugar
- phosphate; nucleotide |
|
|
Term
- __ is an activated ribose
- __ comes from the pentose phosphate pathway |
|
Definition
- prpp
- ribose 5 phosphate |
|
|
Term
there are two synthesis pathways for both purine and pyrimidine nucleotides
1. __: from bits and parts
2. __: recycle from pre-existing nucleotides |
|
Definition
|
|
Term
- de novo synthesis: the pyrimidine ring is synthesized from __, __, and __
-- steps include the __, and activation with __ occurs after base formation |
|
Definition
- bicarbonate; aspartate; glutamine (or ammonium ion)
-- comitted step; prpp |
|
|
Term
De Novo Synthesis
- __: this is the point of no return
-- occurs __ in the biosynthetic pathway
-- often regulated by __ |
|
Definition
- committed step
-- early
-- final product (feedback inhibition) |
|
|
Term
The pyrimidine ring is assembled and then attached to a __
- pyrimidines are synthesized from __, __, and __, with __ often serving as the nitrogen donor |
|
Definition
ribose sugar
- bicarbonate; aspartate; ammonia; glutamine |
|
|
Term
-__ is the first pyrimidine ring formed. __ is a byproduct of glycolysis. Decaboxylation of orotidylate by __ converts orotidylate to __.
- from hear on uridylate > __ > __ > __ > __ |
|
Definition
orotidylate; ribose 5 phosphate; oritidylate decarboxylase; uridylate
- ump>udp>utp>ctp |
|
|
Term
-__ convert nucleotide monophosphates into nucleotide triphosphates
-- for instance ump kinase forms __
from __
- __ have broad specificity and catalyze the interconversion of di and triphosphate |
|
Definition
-kinases
--udp; ump
- nucleoside diphosphate kinases |
|
|
Term
-__ is formed from utp by the replacement of a carbonyl group with an amino group
-- __ provides the amino group |
|
Definition
|
|
Term
| dUMP produces __, this reaction is catalyzed by __ |
|
Definition
| dTMP; thymidylate synthase |
|
|
Term
__ is a disease associated with defects in pyrimidine synthesis
-- loss of functional __ |
|
Definition
orotic aciduria
-- ump synthetase |
|
|
Term
| pyrimidine rings can by fully __ to soluble structures |
|
Definition
|
|
Term
purine nucleotide synthesis
- this involves the following amino acids: |
|
Definition
| - aspartate; glycine; and glutamine |
|
|
Term
| - __ is the donor of the ribose onto which purine nucleotides are assembled |
|
Definition
|
|
Term
| key steps in purine nucleotide biosynthesis are regulated by __ |
|
Definition
|
|
Term
| know the pathways for amp and gmp biosynthesis |
|
Definition
|
|
Term
salvage pathway for purine nucleotides (similar for pyrimidines)
-This pathway is very important in some organs that lack enzymes required for De-novo synthesis pathway so they depend on an exogenous source of purines.
-Brain has low level of __
-Erythrocytes and Leukocytes (bone marrow) can not synthesize __ (first product of the committed pathway). |
|
Definition
-
- prpp glutamyl amidotransferase
- 5 phosphoribosylamine |
|
|
Term
salvage pathway for purine nucleotides
- __ adds prpp to bases to form nucleotides
- know the salvage pathways for purine nucleotides (slide 39 of 62) |
|
Definition
| - phosphoribosyltransferases (PRT) |
|
|
Term
-__ – accumulation of guanine/hypoxanthine due to absence of HGPRT.
-It is __
- high presence of __ and __
-overproduction of __ |
|
Definition
- lesch nyhan syndrome
- x linked (affects males only)
- guanine; hypoxanthine
- uric acid |
|
|
Term
| the major pathways of purine nucleotide catabolism lead to __ |
|
Definition
|
|
Term
SCID (severe combined immuno-deficiency)
-Genetic defect in the gene that codes for __
leading to excess __.
First disease to be cured with __ |
|
Definition
- amp deaminase; dATP
-gene therapy (injection with purified AMP deaminase). |
|
|
Term
| know the pathways of purine nucleotide catabolis (slide 43 and 45 of 62) |
|
Definition
|
|
Term
| end product of purine nucleotide degradation is __ |
|
Definition
|
|
Term
____
-Inborn errors leading to overproduction of Uric Acid
--Overactive de novo synthesis pathway
-Leads to deposits of Uric Acid in the joints
-Causes acute arthritic joint inflammation |
|
Definition
|
|
Term
Diseases attributed to breakdown of purine metabolism
-__ – accumulation of guanine/hypoxanthine due to absence of HGPRT
-__ – excess dATP due to defect in AMP deaminase
-__ – excess uric acid due to failure of xanthine oxidase |
|
Definition
- lesch nyhan syndrome
- scid
- gout |
|
|
Term
|
Definition
|
|
Term
| __ are synthesized from ribonucleoside diphosphates catalyzed by __ |
|
Definition
| deoxyribonucleotides; ribonucleotide reductase |
|
|
Term
| In the process of catalysis, sulfhydryls in the reductase become __. For catalysis to continue, the reduced sulfhydryls must be __. |
|
Definition
|
|
Term
| The immediate source of electrons for the reduction of the reductase is __. __ catalyzes electron flow from NADPH to thioredoxin and ultimately to the ribonucleotide reductase to regenerate the active enzyme. |
|
Definition
| thioredoxin; theoredoxin reductase |
|
|
Term
| Deoxyuridine diphosphate (dUDP) is converted into __. __ adds a methyl group to dUMP to form __ in a reaction that requires N5, N10-methylenetetrahydrofolate. |
|
Definition
| dUMP; thymidylate synthase; thymidylate |
|
|
Term
| Dihydrofolate reductase regenerates __ from __ |
|
Definition
| tetrahydrofolate; dihydrofolate |
|
|
Term
| __ and __ are choice targets in cancer chemotherapy because the generation of large quantities of precursors for DNA synthesis is required for rapidly dividing cancer cells. |
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Definition
| thymidylate synthase; dihydrofolate reductase |
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Term
| __ plays a crucial role in development of the the fetus. Insufficient __ uptake during pregnancy can result in neural-tube defects, such as spina bifida |
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Definition
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Term
-dna and rna are both __
- __ are essential for information transfer in cells |
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Definition
-nucleic acids
-nucleic acids |
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Term
components of dna
-Nucleic acids are long, linear polymers constructed from __ types of monomers.
-Each monomer consists of a __, __, and a __ |
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Definition
- four
- sugar; phosphate; base |
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Term
- dna and rna differ in the __ component and one of the __
-- rna contains the sugar __ while dna contains __
- give the four nitrogenous bases for dna:
- give the four nitrogenous bases for rna: |
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Definition
- sugar; bases
-- ribose; deoxyribose
- adenine guanine, thymine, cytosine
- adenine, guanine, uracil, cytosine |
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Term
rna
- __ sugar
- __ groups makes RNA very unstable
- __ stranded
- bases are __ |
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Definition
- ribose
- oh
- single
- gcau |
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Term
dna
- __ sugar
- very __
- __ stranded
- bases are __ |
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Definition
- deoxyribose
- stable
- double
- gcat |
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Term
dna
-1o (primary) Structure:
-2o Structure:
-3o Structure:
-4o Structure: |
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Definition
-Linear array of nucleotides
-double helix
-Super-coiling, stem-loop formation
-Packaging into chromatin |
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Term
| The primary structure of DNA is the sequence itself - the order of __ in the deoxyribonucleic acid polymer (based on the bases) |
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Definition
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Term
dna secondary structure
-DNA is __ stranded with __ strands
-__ helix
-Three different helical forms __, __, and __ |
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Definition
- double; antiparallel
- right hand double
- a, b, and z dna |
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Term
structural properties of dna
-DNA consists of two nucleotide strands called __
-Strands run in opposite directions called __
-Strands are held together by __ between bases
-__ always binds with __ and __ always binds with __
-The sides of the ladder are a __, while the “rungs” of the ladder are the __ |
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Definition
- double helix
- antiparallel
- hydrogen bonds
- a;t;c;g
- sugar phosphate backbone; bases |
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Term
dna
- the helices are __ to each other
- each base forms __ with a base of the opposite strand
- the 2 strands wrap around each other to form a __ |
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Definition
- antiparallel
- hydrogen bonds
- double helix |
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Term
features of dna double helix
-Plane of bases are nearly __ to that of the axis
-The distance from one bp to the next (rise) is __
-It takes __ to make one complete turn
-Thus the distance for a full turn (twist) is __.
-There are two grooves: __ and __ |
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Definition
- perpendicular
- 0.33nm
- 10.4bp
- ~3.4nm
- major; minor |
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Term
dsDNA has 2 grooves: major and minor
- allow functional groups are exposed to __
- involved in __ interactions |
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Definition
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Term
three types of dna
1. a-dna
- __ handed
- __ and __
- distance per turn is __
- __ per turn
2. B-DNA
- __ handed
- is __ and __than a dna
- distance for turn is __
- __ per turn
3. z-dna
- __ handed
- is __ and __
- distance per turn is __
- __ per turn |
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Definition
1
- right
- short; broad
- 2.3 nm
- 11bp
2
- right
- longer; thinner
- 3.4nm
- 10.4bp
3
- left
- longest and thinnest
- 3.8 nm
- 12 bp |
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Term
Factor stabilizing DNA double helix
-__ – burying hydrophobic purine and pyrimidine rings in interior
-Stacking interactions – __ interactions between stacked bases.
-__ between bases
-__ – Electrostatic repulsions of negatively charged phosphate groups are minimized by interaction with cations (e.g. Mg2+) |
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Definition
- hydrophobic interactions
- van der waals
- hydrogen bonding
- charge-charge interactions |
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Term
-dna is denatured by __ or __
-- __ rich regions denature first |
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Definition
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Term
DNA sequence determines melting point
-Melting temperature related to G:C and A:T content.
-__ of G:C pair require higher temperatures to denature than__ of A:T pair |
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Definition
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Term
-__ refer to the DNA structure in which double-stranded DNA twists around each other.
- aka ___ |
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Definition
-supercoils
- coiling of coiling |
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Term
| the same dsDNA molecule can have different __ |
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Definition
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