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149 Cards in this Set

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What are the 3 options for glucose-6-phospate to be converted into?
glycogen, pyruvate, ribose-5-phsophate
once in the cell, glucose is converted into glucose-6-phosphate. What is good about this as far as metabolism is concerned?
glucose cannot leave the cell, and therefore will be metabolized.
What is the main anabolic purpose of the pentose phosphate pathway?
generation of NADPH for biosynthesis.
What are the two catabolic functions of the pentose phosphate pathway?
generation of pentose for nucleotides and the degradation of pentoses from the diet
What is the net reaction of the pentose phosphate pathway?
(3 glucose-6-P) + (6 NADP+) + (3 H2O) ---> (6 NADPH) + (6H+) + 3 (CO2) + (2 Fructose-6-P) + (Glyceraldehyde-3-P)
How many NADPH result (net) from the pentose phosphate pathway?
6
What are the two phases of the pentose phosphate pathway?
oxidative and non-oxidative
What does NADPH stand for?
Nicotinamide Adenine Dinucleotide Phosphate
What is the regulatory step of the pentose phosphate pathway?
glucose-6-phosphate (alcohol) ---> 6-phosphoglucono-lactone (carboxyilc acid) [oxidation]
Which enzyme regulate the regulatory step of the pentose phosphate pathway?
glucose-6-P dehydrogenase
glucose-6-phosphate dehydrogenase requires --- to function.
NADP+
In the second oxidative reaction in the pentose phosphate pathway, the enzyme 6-phophoglucono-lactonase requires ---.
water (H2O ---> H+)
What is the second oxidation reaction in the pentose phosphate pathway?
6-phophoglucono-lactone --> 6-phosphogluconate
What happens in the third oxidatiive reaction of the pentose phosphate pathway?
6-phosphogluconate ---> ribulose-5-P (CO2 lost)
The third oxidative reaction of the pentose phosphate pathway requires which enzyme?
phophogluconate dehydrogenase
phosphogluconate dehydrogenase (pentose pathway) requires which molecule?
NADP+
The third oxidative reaction in the pentose pathway is a decarboxylation reaction that releases ----, and is therefore ---.
CO2, irreversable
The oxidative reactions in the pentose phosphate pathway yield --- NADPH per glucose.
2
In the non-oxidative reactions of the pentose phosphate pathway, there are 3 reactions. 2 of them are ---- reactions and 1 is a --- reaction.
transketolate, transaldolase
What does a transketolase do?
transfers a carboxy group- forms glyceraldehyde-3-P, a product of the pentose pathway
What does transketolase require for function?
TPP (Vitamin B1, a cofactor)
What does a transaldolase do?
moves blocks of carbon between molecules. Prepares molecule in pentose pathway for second transketolase reaction to form fructose-6-phospate, a product of the pentose pathway.
Ribose-5-phosphate is a metabolite of the pentose phosphate pathway. It also is used in --- biosynthesis.
nucleotide
Fructose-6-P and Glyceraldehyde-3-P are a result of the non-oxidation reactions of the pentose phosphate pathway. Where else are they used?
Glycolysis and TCA cycle
Essentially, the pentose phosphate pathway converts glucose into 3 things for biological funciton. What are they?
DNA, NADPH, and intermediate for the citric acid cycle to for ATP
What is the rate limiting step of the pentose phosphate pathway?
G-6-P dehydrogenase reaction
The rate of the pentose pathway is controlled by the availability o the substrate, ----.
NADP+ (needed for reducing power to NADPH)
Reactive oxygen species have a strong effect on ---, causing mutations.
DNA
Since mitochondria lack DNA repair, they are very susceptible to mutations due to ---.
reactive oxygen species
Which enzyme is used in defense of superoxide species?
superoxide dismutase
What is a superoxide?
O2-
What is a peroxide?
H2O2
What is a hydroxyl free radical?
H2O + .OH
What are three enzymes used in defense against peroxides?
peroxidase, catalase, glutathione
Glutathione functions as an ---
antioxidant
GHS refers to reduced gluthathione, a tripeptide of the amino acids ---, ---, and ---. This functions as an antioxidant.
glycine, glutamate, and cystine
Someone with G-6-P dehydrogenase defficiency confers resistance to --- because there is too much oxidative stress on the transmititng parasite for it to survive.
malaria
Acetyl-CoA is a precursor to --- acids.
fatty
Fatty acids are made from the breakdown of excess ---.
glucose
Fatty acids are formed from repetitive ---- reactions.
condensation
The synthesis of fatty acids requires --- and --- as an energy sources.
ATP, NADPH
In animals, where does NADPH production (the pentose phosphate pathway) take place?
cytosol
In animals, where does fatty acid synthesis take place?
cytosol
In animals, where does acetyl CoA production take place?
mitochondria
In animals, acetyle CoA is produced in the mitochondria and is then exported to the cytosol where is can then be converted into a ----.
fatty acid
In animals, fatty acids are oxidized in the ---.
mitochondria
In plants, NADPH is produced in the ---.
chloroplast
In plants, fatty acid synthesis occurs in the ---.
chloroplast
In plants, fatty acid oxidation occurs in the ---.
peroxisome.
In plants, acetyl CoA is produced in the peroxisome, and is then exported to the chloroplast where it is made into a ---.
fatty acid
phospholipid synthesis occurs in the ---.
endoplasmic reticulum
What is the rate limiting (or committed) step in fatty acid synthesis?
acetyl CoA ---> malonyl CoA (once it's malonyl CoA, it can't become anything other than a fatty acid)
What stimulates the synthesis of malonyl CoA from Acetyl CoA?
citrate
What inhibits the synthesis of malonyl-CoA from Acetyl CoA?
Palitoyl-CoA (the product of the entire pathway)
What is the product of the pathway to build fatty acids?
palmitoyl coA
In the conversion of Acetyl CoA to Malonyl CoA, --- is used as an energy source.
ATP
The acyl carrier protein (ACP) can react with acetyl-CoA or Malonyl-CoA to form 2 seperate ---.
trans-aclases
The fatty acid synthase complex has -- enzyme activities.
7
What is the end product of fatty acid synthesis?
palmitate (16C)
Where is pamitate transported to once it is formed?
endoplasmic reticulum
Fatty acid chains are elongated by adding -- carbons at a time.
2
With each condesation reaction, a fatty acid chain grow by two carbons and also a molecule of --- is released.
CO2
Linoleate and alpha linoleate are --- fatty acids.
essential
The fatty acid synthase in plants and bacteria has seven activities in --- polypeptides.
7 seperate
The fatty acid synthase in yeast has seven activities in --- polypeptides.
2 separate
The fatty acid synthase in vertebrates has seven activities in -- polypeptide.
1 large
Additional sources of NADPH include reactions that occur in the ---, ----, and --- in animals.
liver, mammary gland, adipose tissue
In order to export acetate from within the the mitochondrial matrix into the cytosol, acetyl-CoA must be converted into --- and then transported through the membrane through a specific protein.
citrate
The mitochondrial matrix is impermiable to ----.
acetyl-CoA
--- triggers the activation of citrate lyase, which causes citrate to from Acetyl-CoA (beginning of FA synthesis)
insulin
---- and ----- inhibit acetyl-CoA carboxylase, which causes acetyl-CoA to be converted into Malonyl-CoA (committed step of fatty acid synthesis pathway). These are present in the body during fasting. Palmitoyl-CoA also inhibits this (since it's the final product of FA synthesis)
glucagon, epinephrine (adreniline)
Malonyl-CoA inhibits fatty acyl-carnitine, which induces ----.
beta oxidation
citrate induced the formation of malonyl coA from ---.
acetyl CoA
What are the two regulators for fatty acid synthesis?
citrate and palmitate
What is the regulator of fatty acid breakdown?
insulin
What type of ACP does fatty acid synthesis require?
malonyl
which type of ACP does fatty acid breakdown require?
acetyl-CoAa
What is the energy source for fatty acid synthesis?
NADPH
Which two oxidizing agents are required in the breakdown of fatty acids?
NAD+ and FAD
Where does fatty acid synthesis occur?
cytoplasm
Where does fatty acid breakdown occur?
mitochondria
What is the basic reaction of fatty acid synthesis in terms of carbon?
3C + 2C ---> 4C +1C
What is the basic reaction of fatty acid breakdown in terms of carbon?
4C ---> 2C + 2C
Which organ synthesizes sphingolipids?
brain
Gangliosides are important molecules in the ---.
brain
Excess Acetyl-CoA in the mitochondria often undergo ----.
ketogenesis
What are three conditions that promote ketogenesis?
fasting, diabetes, and a high fat diet
What are the three "ketone bodies"?
acetoacetate, beta-hydroxybutyrate, and acetone
acetoacetate and beta-hydroxybutryate are produced in the liver and act as back up fuel for the generation of ATP when the body doesn't have enough ---.
glucose.
ketone bodies are produced in the liver, used by the ---, ----, and ----. They are formed during conditions of excess Acetyl-CoA and low OAA in the TCA.
heart, kidney, brain
60 percent of glucose in the body is used by the --.
brain
cholesterol is formed from ---.
acetyl CoA
synthesis of cholesterol takes place in the ---. (organelle/region)
cytoplasm
The major sites of cholesterol synthesis are the ---, ---, ----, and ---.
liver, intestine, adrenal cortex, and gonads
All of the carbons in Cholesterol come from ---.
Acetate
Pyruvate can be converted into Acetyl CoA and then if it doesn't go the the TCA, can either be converted into ---- or malonyl CoA in order to build fatty acids.
cholesterol
All cell types are able to synthesize cholesterol, however the major sites include the liver and small intestine. If they cannot provide adequate supply, then ---- synthesis is activated in other cells.
DE NOVO (made from recycled parts)
What is the committed step of cholesterol synthesis?
HMG-CoA to Mevalonate (required HMG-CoA reductase and 2NADPH)
What do Statins do? (drug)
block cholesterol in order to lower choloesterol by compettively inhibiting HMG-CoA reductase (limiting step in cholesterol synthesis)
Where are the 2 NADPH used in the committed step of cholesterol synthesis made?
pentose pathway
In cholesterol synthesis, mevalonate is activated to form ----, which have an active tail and head.
isoprenes
In cholesterol synthesis, isoprenes are condensed to form a 15C ---
chain
The two 15C chains formed in cholesterol synthesis are then ---- head to head to form a 30C chain.
condensed
The pathway to synthesize cholesterol requires A LOT of --- and ----.
NADPH and ATP
The final touches of cholesterol synthesis requires this gas in order to get on the endoplasmic reticulum.
oxygen
Since cholesterol is toxic to cells in high numbers, it is converted into --- for storage.
cholesterol ester
HMG-CoA Reductase is regulated in the endoplasmic reticulum by controlling the transcription of the gene by controlling the gene's ---- region.
promoter
what do SREBP and SCAP control?
The transcription of HMG-CoA Reductase
Glucagon inhibits/promotes HMG-CoA reductase.
inhibits
Insulin inhibits/promotes HMG-CoA reductase.
promotes
Cholesterol can be made into ----, -----, or -----.
steriod hormones, bile acids, or vitamin D
What are the three things that regulated HMG-CoA Reductase?
gene transcription, inhibition, and a short half-life
What do lipoproteins do?
transport lipids in the blood
What do chylomycrons do?
Lipoproteins that transport lipids in the blood to tissues.
Triglycerides and cholesterold are packaged and transported from the liver to adipose tissue by ---.
VLDL
After delivering its contents to the tissues, VLDL is converted first to --- and then into ---, which is taken up by the liver and peripheral tissue cells.
IDL, LDL
what is the major carrier of cholesterol in human plasma?
LDL
Excess cholesterol from tissues is carried back to the liver by ---.
HDL
LDL carries bad cholesterol and HDL carries --- cholesterol.
good
Where is VLDL made?
Liver
Chylomicrons ---> VLDL ----> ? ---> LDL ----> HDL (largest to smallest, least dense to most dense)
IDL
Plasma lipoprotein is in a sphere shape. It has a greasy inside full of triacylglycerols and cholesterol esters, and a polar outsides made of free ---.
cholesterol
cholesterol is amphipathic/non polar.
amphipathic
cholesterol ester is amphipathic/non polar.
non polar
The LDL receptor is a transmembrane receptor with -- different function domains.
5
The LDL receptor performs ------- to bring particles into the cell.
receptor-mediated endocytosis
Endosomes fuse to liposomes that then digest lipoprotein for cell activation at the ----.
LDL receptor
The LDL receptor engulfs larger -- particles and pulls them into the cell.
fat
Bioacids are made from cholesterol in the liver and are then repackaged into ----.
chylomicrons
After reverse cholesterol transport occurs and HDL transports excess cholesterol back to the liver, this excess cholesterol is sometimes --- as bile acids and cholesterol.
excreted
Lipoprotein lipases reside in capillaries waiting for chylomicrons so that they can break them down into ---- for adipose and muscle tissues.
free fatty acids
VDL can be converted into --- or fatty acids.
IDL
IDL can be converted into ---, fatty acids, or be taken back to the liver.
LDL
LDL can be converted into --- or be taken back to the liver.
fatty acids
In familial hypercholesterolemia, the liver cannot take up --- or --- from the blood due to a defective receptor, and therefore the individual suffers from high levels of plasma cholesterol.
IDL or LDL
What does cholestyramina do to treat high cholesterol levels?
enhances reverse cholesterol transport
Statins (such as lipitor) decrease --- levels.
LDL
The phospholipid cascade leads to the generation of DAG and IP3, which are intracellular second ---.
messengers
Diacylglycerol (DAG) is an endogenous activator of ----.
protien kinase C
Inositol triphosphate (IP3) causes a release of a 3rd messengers, ----, from intracellular stores.
Ca2+
Steroid hormones produces most of their effects by inducing the ---- of tissue-specifc genes.
transcription
What is the term for the 20 carbon unsaturated fatty acids derived from arachidonic acid which make up a class of hormone-like biomodulator substances?
eicosanoids
IP3 is formed from the receptor-triggered hydrolysis of ---. (with PLC as a catalyst)
PIP2
In the phopholipid cascade, a hormone binds to its receptor, causing the release of GTP. GTP then binds to PLC, which cleaves PIP2 into IP3. IP3 then binds to a receptor on the Ca2+ channel, which causes Ca2+ to move into the cytoplasm. This actives -----, and causes a biological repsonse.
phosphokinase C
What does IP3 do in the phopholipid cascade?
binds to Ca2+ channel on the ER, which causes Ca2+ to build up in the cell
steroid hormones are all made from --- by removing its side chains and converting it into progesterone.
cholesterol
RU 486 is an antagonist for which hormone?
progesterone (found the in the placenta); also a precursor to many other hormones
steroid hormone receptors are proteins which are not on the cell surface, but rather found --- the cell.
within
What is the zinc binding motif?
zinc binds to DNA and activates a receptor for steroid hormones