Term
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Definition
| the rate of metabolite flow |
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Term
| What is the relationship between transcription factors & response elements? |
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Definition
| TRANSCRIPTION FACTORS = nuclear proteins that (when activated) bind specific DNA regions (RESPONSE ELEMENTS) near a gene's promoter & activate or repress the transcription of that gene, leading to increased or decreased synthesis of the encoded protein |
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Term
| What is the difference between a transcriptome & a proteome? |
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Definition
transcriptome = the entire complement of mRNAs present in a given cell type or organ
proteome = the protein complement of a cell type or organ |
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Term
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Definition
| the total ensemble of low molecular weight metabolites |
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Term
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Definition
| processes that serve to maintain homeostasis at the molecular level (to hold some cellular parameter at a steady level over time, even as the flow of metabolites through the pathway changes) |
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Term
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Definition
| a process that leads to a change in the output of a metabolic pathway over time, in response to some outside signal or change in circumstances |
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Term
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Definition
| produces AMP after hydrolysis of ATP produces ADP |
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Term
| AMP-activated protein kinase (AMPK) |
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Definition
| mediator of regulation by AMP; responds to an increase in [AMP] by phosphorylating key proteins & thus regulates their activities |
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Term
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Definition
| the rate at which metabolites flow through the pathway |
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Term
| elasticity coefficient (sigma) |
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Definition
| a parameter which expresses quantitatively the responsiveness of a single enzyme to changes in the concentration of a metabolite or regulator; it is a function of the enzyme's intrinsic kinetic properties |
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Term
| What is the role of gluconeogenesis (primarily in the liver) in mammals? |
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Definition
| to provide glucose for export to other tissues when glycogen stores are exhausted & no other dietary glucose is available |
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Term
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Definition
| different proteins that catalyze the same reaction |
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Term
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Definition
| the predominant hexokinase isozyme of myocytes; has a high affinity for glucose (it is half saturated at about 0.1 mM) |
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Term
| What is the significance of muscle hexokinase I & hexokinase II being allosterically inhibited by their product (glucose 6-phosphate)? |
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Definition
| whenever the cellular concentration of glucose 6-phosphate rises above its normal level, these isozymes are temporarily & reversibly inhibited, bringing the rate of glucose 6-phosphate formation into balance with the rate of its utilization & reestablishing the steady state |
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Term
| What is the predominant hexokinase isozyme of the liver? |
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Definition
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Term
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Definition
| an efficient glucose transporter in hepatocytes that rapidly equilibrates the glucose concentrations in cytosol & blood; allows for the high Km of hexokinase IV to allow its direct regulation by the level of blood glucose |
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Term
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Definition
| the hormone that acts when the blood glucose level decreases by signaling the liver to produce & release more glucose & to stop consuming it for its own needs |
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Term
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Definition
| mediates the rapid hormonal regulation of glycolysis & gluconeogenesis; an allosteric effector for the enzymes PFK-1 & FBPase-1 |
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Term
| ChREBP (carbohydrate response element binding protein) |
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Definition
| a transcription factor important to carbohydrate metabolism; expressed primarily in the liver, adipose tissue, & kidney |
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