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18 Cards in this Set
- Front
- Back
which bonds are involved in glycogen (2)
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a-1,4 : polymer
a-1,6 : branches |
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2 storage locations of glycogen
when are each broken down - for which cells |
LIVER: between meals to maintain BLOOD glucose & brain
MUSCLE: in physical ACTIVITY, energy via GLYCOLYSIS & TCA (not available for blood) |
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2 sources of blood glucose and what times of the day are each important
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GLYCOGENOLYSIS BETWEEN meals
GLUCOENOGENESIS NIGHT |
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how is glucose added to a growing glycogen polymer
- central protein - how may glucose molecules can it attach - enzyme |
glycogen PRIMER covalently attached to GLYCOGENIN - central catalytic protein
adds up to 4 glucose molecules to itself GLYCOGEN SYNTHASE |
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what needs to happen to glucose contained within cells to be used in metabolic pathways (glycogenisis), why
- what enzyme important in doing this - product |
glucose trapped as glucose-6-phosphate...phosphorylated by PHOSPHOGLUCOMUTASE ↔ glucose-1-phosphate
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after phosphorlyation of glucose-6-phosphate by PHOSPHOGLUCOMUTASE → glucose-1-phosphate (in the cell)...
- what role does UTP play in preparing glucose-1-phosphate for glycogen synthesis |
UTP ACTIVATES glucose-1-phosphate to UDP-glucose
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which form of glucose is added to the growing glycogen strand (attached to glycogenin) by GLYCOGEN SYNTHASE
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activated UDP-glucose
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glycogen synthase can add UDP-glucose to growing glycogen polymer...
- which bonds does it introduce - what can't it do |
a-1,4-glycosidic (polymer) bonds
cannot introduce branches (a-1,6) |
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which is the rate-limiting enzyme in glycogen synthesis
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glycogen synthase
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since glycogen synthase cannot introduce new a-1,6-glycosidic branches, which enzyme does this
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TRANSGLYCOSYLASE: branching enzyme for glycogen, adds a-1,6-glycosidic bonds (approx every 10 residues)
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which enzyme releases glucose from glycogen, what is the reaction for this:
- substrates - enzyme - product |
GLYCOGEN PHOSPHORYLASE
[glucose]n + Pi (phosphate) → glucose-1-phosphate + [glucose]n-1 |
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what's the rate-limiting enzyme in glycogenolysis
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GLYCOGEN PHOSPHORYLASE
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when glucose-1-phosphate is released by GLYCOGEN PHOSPHORYLASE from glycogen (glucogenolysis), it isn't available for the cell...
- which enzyme changes this molecule to an available form for the cell glycolysis - what is the product |
PHOSPHOGLUCOMUTASE;
glucose-1-phosphate ↔ glucose-6-phosphate |
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in the LIVER, what process/ reaction is used to release glucose from glucose-6-phosphate for the blood
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de-phosphorylation --> for RBCs & brain
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in MUSCLE, what process/reaction is used to release glucose energy from glucose-6-phosphate for physical ACTIVITY
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GLYCOLYSIS --> TCA
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how does free glucose move between cells (i.e. which transport mechanism)
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glucose TRANSPORT molecules- FACILITATED DIFFUSION (e.g. GLUT2)
....glucose ONLYreleased from LIVER cells via de-phosphorylation (muscle uses glucose-6-phosphate in glycolysis, i.e. glucose not "free") |
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which 2 hormones influence glucogenensis...
- which enzyme do they regulate |
INSULIN: +++stimulates glycogen synthase+++
GLUCAGON: ---inhibits glycogen synthase --- |
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which 4 hormones influence glucogenolysis...
- which hormone do they regulate |
glycogen phosphorylase- rate limiting enzyme in glycogenolysis:
INSULIN ---inhibits --- GLUCAGON, ADRENALINE & CORTISOL +++stimulate+++ |