PBIO Exam 2
Lactase dehydrogenase
-2 pyruvate and 2 NADH from glycolysis -2 NADH ---> 2NAD+ -2 lactate
Products of glycolysis
-2 pyruvate+2ATP+2NADH
Statements that correctly describe monosaccharides.
-A monosaccharide can convert between an α-ring form and a β-ring form. -All monosaccharides except dihydroxyacetone have multiple isomeric forms. -The α- and β-ring forms of a monosaccharide have more chiral carbons compared to the straight form. -
Transfer of phosphated from these intermediates to _____ from ______ (substrate level phosphorylation)
-ADP -ATP
Glycolysis Reactions ATP ----> NAD+ and PI-------> ADP ----->
-ADP -NADH -ATP
The energy released by transfer of electrons is used to convert _______ and ______ to ______
-ADP;Pi -ATP
After the citric acid cycle
-ALL six carbons from glucose (pyruvate) have been released as CO2 -Some ATP has been made (4 total) -Most of the energy originally present in glucose is stored in reduced electron carriers
Passing of electrons from reduced electron carriers to oxygen generates the vast majority of ______ in cells
-ATP
Statements that correctly describe catabolic and anabolic pathways in cells.
-ATP is formed from ADP and Pi by catabolic pathways; anabolic pathways require conversion of ATP to ADP and Pi. -Anabolic pathways require reduced electron carriers, while catabolic pathways generate reduced electron carriers.
In complex III C (cyt C) forms ________ (oxidized form) and ________ (reduced form)
-CoQ -Cyt C red -ener
Hormone from the adrenal glands that ensures adequate supply of energy under conditions of stress
-Epinephrine
In complex II coenzyme Q forms ______ (oxidized form) and _______ (reduced form)
-FAD CoQH2
Which of the following correctly describes regulation of glycogen metabolism by insulin, glucagon, and epinephrine?
-Glucagon, epinephrine, and insulin are important for regulating both glycogen breakdown and glycogen synthesis. -ALL three enzymes are important for regulating BOTH glycogen breakdown and glycogen synthesis. Signaling of a particular hormone will activate one process and inhibit the other. This is important for coordinated regulation of glycogen breakdown and synthesis to ensure that the two processes don't occur at the same time in a cell.
A person is diagnosed with a rare metabolic disease. They are able to digest amylose, but cannot break down amylopectin or glycogen. The most likely explanation for this disease is that they lack an enzyme capable of
-breaking α(1,6) glycosidic bonds. -Both glycogen and amylopectin have branches, while amylose does not. Branches are attached via α(1,6) glycosidic bonds. In all three molecules, α(1,4) glycosidic bonds connect glucose molecules in chains. NONE of the three types of polysaccharides have β(1,4) or β(1,6) glycosidic bonds .
Uncouplers
-allow movement of protons from the intermembrane space to the matrix -do not affect electron transport through the ETC -inhibit formation of ATP by ATP synthase
Is gluconeogenesis catabolic or anabolic
-anabolic -lower free energy molecules to higher free energy molecules -require energy currency -require electrons
GLUT-2
-bidirectional (in/out) -lower affinity for glucose -[glucose]blood = [glucose] in cell -Low BGL=release glucose -High BGL=take in glucose
If protein kinase A (PKA) could NOT be activated in a cell, that would affect regulation of
-both glycogen breakdown and glycogen synthesis. -Protein kinase A (PKA) is activated in response to glucagon and epinephrine signaling. Activation of PKA results in phosphorylation of glycogen phosphorylase AND glycogen synthase, the two main regulatory enzymes of glycogen metabolism. Therefore, this mutation would affect regulation of BOTH processes.
glycogen phosphorylase
-breaks bonds by phosphorolysis -involved in glycogen breakdown -breaks α(1,4) glycosidic bonds
Is glycolysis catabolic or anabolic
-catabolic -higher free energy molecules to lower free energy molecules -form energy currency -strip electrons
ATP (and other energy currency molecules) transfer energy between ___________ and __________ processes
-catabolic, anabolic
2 NADH Transfer of electrons to oxygen to generate more ATP ------> If no oxygen available ---->
-cellular respiration -fermentation
Electron carriers act as coenzymes and are ________by reaction so must be __________
-changed -regenerated -theres a limited supply of electron carriers in cells, so for every reaction that transfers electrons to a carrier there must be a reaction in which the carrier donates the electrons
Glycogen phosphorylase
-enzyme that removes glucose molecules from chain ends -requires a chain at least five glucose units away from branch point -breaks a(1,4) glycosidic bonds by phosphorolysis -product =glucose-1-phosphate
Inhibition of an enzyme
-enzyme will be less active because it cannot bind its substrate as well
Activation of an enzyme
-enzyme will be more active because it can bind its substrate better
_____ that catalyze ________ ______ cannot be shared between opposing pathways (why they are important for regulation)
-enzymes -irreversible reactions
Hormone that ensures adequate supply of energy under conditions of stress
-epinephrine
two different conformations (isomer forms) exist in _______
-equilibrium
Oxygen is the ______ ________ ________
-final electron acceptor -regenerates oxidized electron carriers required for processes to function -when present oxygen also accepts electrons removed during glycolysis
Role of glycogenin in the formation of glycogen molecules
-form glucose primers
Catabolic pathways
-breakdown processes -convert higher free energy molecules to lower free energy molecules -energy released used to form energy currency molecules (e.g. ATP) -strip electrons (often used to obtain more energy currency molecules)
Phosphorolysis
-breaking bond with phosphate group
Glycogen synthesis
-formation of glycogen from glucose (storing excess energy as carbohydrates) 1) transported into cells from blood 2)synthesized using energy currency molecules (and electrons) 3) glucose 4)ATP-->ADP+Pi 5)glycogen
Hexokinase 1-3 has a _____Km and __________ affinity saturated at normal blood glucose concentrations
-low -high -muscle cells phosphorylate glucose under all blood glucose level -store as glycogen or breakdown via glycolysis to generate ATP
Glucagon released under conditions of ________ blood glucose _________ glycogen synthesis
-low -inhibits
Passing electrons from molecules with _________ ______ for electrons to molecules with _________ ________ for electrons releases energy
-low affinity -high affinity
When is glucagon released? What is activated in cells? What happens to the regulatory enzymes
-low blood glucose -protein kinase A (PKA) -phosphorylated
Anabolic
-lower free energy molecules to higher free energy molecules -require electrons -require energy currency
ATP
-main energy currency in cells -adenosine triphosphate
Glucose
-main energy source for brain cells -ONLY energy source for red blood cells -energy can be obtained more rapidly than the energy stored in lipids -some energy can be obtained from glucose in the absence of oxygen
Role of UDP-gluocse pyrophosphorylase in the formation of glycogen molecules
-make substrate
Glycogen synthesis
-make substrate -form glucose primers (short chains to start a molecule) -lengthen chains -add branches
Electron carriers act as coenzymes are required for ______ ________ reactions that involve __________ or ___________ of substrates
-metabolic pathway -oxidation;reduction
Monosaccharides can be ___________-functional group attached to hydroxyl group (s)
-modified
Function of glucose-6-phosphatase (liver only)
-modify glucose molecules for next step
Electron carriers
-molecules that transfer electrons between other molecules
An individual cell has ______ types of hormone receptors (able to respond to specific set of hormones)
-multiple
Energy investment phase of glycolysis
-must "invest" 2 ATP -some ATP converted to ADP to get things started
Glycosidic bonds are ____ by fixed ________ conformations and _______ _______
-named -ring -carbon numbers
Monosaccharides are ________ based on their________ _______ _______ (aldose or ketose)
-named -unique functional group
All cellular pathways have ______ free energy changes overall
-negative
All cellular pathways must have ________ free energy changes overall therefore __________ __________ cannot be ______________ opposites
-negative -opposing pathways -exact
All cellular pathways have overall _______ free energy changes- energy ______ by oxidation of glucose is ________than energy used to form ATP
-negative -released -LESS
Ring formation generates a ____ _____ ______ -this is WHY there are two different ring forms
-new chiral carbon
If a drug was added to a cell that completely inhibited glycogenin, how would that affect glycogen metabolism in the cell?
-new glycogen molecules could not be formed -Glycogenin forms the glucose primers required to start a new glycogen molecule. Metabolism of existing glycogen molecules would not be affected
If glucagon signaling did ______ lead to phosphorylation of _______ ________ glycogen synthesis would ______ be inhibited
-not -glycogen synthase -not
When phosphofructokinase NOT activated glycolysis __________________
-not activated
Transfer of electrons to oxygen ____________ the __________ _____________ ______ required for the processes of cellular respiration and glycolysis to continue
-regenerates -oxidized electron carriers
Liver Compartmentalization
-regulate blood glucose level under normal conditions -provide glucose to other tissues under times of stress
Glycogen metabolism in liver
-regulate blood glucose levels under normal conditions -provide glucose to other tissues under times of stress
Liver ______ blood _______ levels
-regulates -glucose -ability to form glucose important for increasing blood glucose levels when glucose levels are too low
Reduction potential (E)
-relative affinity of a molecule for electrons
Falling blood glucose -Glucagon Activates processes that ______ glucose from storage and ______ glucose in _______
-release -synthesize -liver
In the electron transport chain electron passing reactions ________ energy which is used to form a _________ _______
-release -proton H+ gradient
Function of glycogen phosphorylase enzyme
-release glucose molecules
Glycogen metabolism breakdown steps
-release glucose molecules -remove branches -modify glucose molecules for next step
insulin
-released under conditions of high blood glucose -activates glycogen synthesis -causes a response in liver cells -causes a response in muscle cells
glucagon
-released under conditions of low blood glucose -causes a response in liver cells -activates glycogen breakdown
epinephrine
-released under stressful conditions -causes a response in liver cells -causes a response in muscle cells -activates glycogen breakdown
High concentration ----> Low concentration membrane gradient _______ energy ________ entropy _________ more
-releases -increases entropy -more disordered
passing electrons to oxygen __________ energy-used to ______ ATP
-releases -form
Conversion of molecule A to molecule B is an exergonic reaction. This means that conversion of molecule A to molecule B _______ energy. Therefore, the reaction could be linked to ______________.
-releases; formation of ATP from ADP and Pi -Exergonic reactions convert reactants with higher free energy to products with lower free energy, and therefore release energy. That energy can be used to form ATP from ADP and Pi (an endergonic reaction).
Glycogen breakdown:
-removal of glucose molecules from glycogen (release stored glucose)
Function of debranching enzyme
-remove branches
Debranching enzyme
-removes branches -substrate=branch with four glucose units -removes three glucose units and attaches to existing chain -removes branch point glucose
Low concentration -----> High concentration membrane gradient _________ energy ________ entropy _________ distorted
-requires -decreases -less
Forming ATP from ADP and Pi ______energy energy provided by ____________
-requires -energy releasing reaction/process
Gluconeogenesis ______ _____ energy currency molecules
-requires -six
Pentoses and hexoses primarily exist as _____
-rings
Cellular respiration
-series of processes involved in the complete oxidation of carbons originally from fuel molecules (glucose) -carbons released as carbon dioxide -requires oxygen -involved in oxidation of ALL fuel molecules
Oxidative Phosphorylation
-series of reactions catalyzed by enzymes embedded (stuck) in a selectively permeable membrane
Main sites of energy storage
-skeletal muscle -liver -adipose tissue -play different roles -differ slightly in the metabolic processes that occur in the cells -regulation of certain metabolic pathways is different
A particular type of hormone can have different effects -different molecules inside cell
-skeletal muscle and liver cells have different versions of some enzymes involved in glucose metabolism -epinephrine in skeletal muscle process that breaks down glucose activated -epinephrine in liver cells process that forms glucose activated
_______ amount of hormone can cause a ________ response in a target cell
-small -BIG -interaction of just one hormone molecule with a receptor protein alters the activities of many molecules/enzymes inside a cell (signal gets amplified)
Monosaccharides
-smallest carbohydrates -monomer units
Receptor proteins are ________
-specific -ONLY interact with ONE type of hormone
Adipose tissue Compartmentalization
-storage site of triacylglycerols
Reduced electron carrier also represent _________ ____________
-stored energy
Epinephrine is released during times of ________
-stress
When is epinephrine released? What is activated in cells? What happens to the regulatory enzymes
-stress -protein kinase A (PKA) -phosphorylated
*pyruvate kinase
-substrate level phosphorylation-transfer of phosphate from intermediate to ADP (forms ATP) -irreversible
phosphoglycerate kinase
-substrate level phosphorylation-transfer of phosphate from intermediate to ADP (forms ATP) -reversible
Gluconeogenesis
-synthesis of glucose from non carbohydrate substrates (pyruvate) -production of glucose is important for regulating blood glucose levels -significant amount of ATP required to power muscle cell contractions-do NOT use up ATP making glucose -rely on glycogen stores and glucose transported from liver
anabolic pathways
-synthesis processes -convert lower free energy molecules to higher free energy molecules -energy required supplied by energy currency molecules -require electrons
The modified monosaccharide 1,3-bisphosphoglycerate is generated at one step in the first pathway involved in converting the energy of a glucose into the energy currency ATP (glycolysis). Based on its name, what do you know about the molecule?
-t has two phosphate groups, one attached to carbon 1, and the other attached to carbon 3.
Glycogen metabolism in skeletal muscles
-take in and store glucose -break down glucose to generate the ATP (energy) needed to power muscle cells
Skeletal muscles Compartmentalization
-take in and store glucose -break down glucose to generate the ATP (energy) needed to power muscle cells
Glucose as _ carbons
6
After the citric acid cycle all ___ carbons from glucose have been released as _________
6 CO2
Glycolysis occurs in _____ cells
ALL
Energy released by passing electrons to oxygen is used to form most of the ______ in your cells
ATP
Oxidative phosphorylation generates the vast majority of _______ from all energy storage molecules
ATP
Energy supplied by removal of phosphates from energy currency molecules ________ and _______ results in ______energy molecules
ATP GTP
Cellular respiration generates MUCH more ______ from the energy stored in glucose compared to glycolysis alone (_________ reactions dont generate any)
ATP fermentation
What reaction happens in the energy investment phase of glycolysis?
ATP ----> ADP
Glucose ------>
Glycogen
Breakdown of 32 ATP
Glycolysis 2 ATP citric acid cycle 2 ATP 10 NADH 25 ATP 2 FADH2 3 ATP
GER
Got Electrons=Reduced
__________ proton concentration in the intermembrane space and ________ proton concentration in the mitochondrial matrix
Higher Lower
Reactions of complex _____ do NOT transport protons
II
Although the activity of all enzymes in a pathway is important for controlling how much final product is formed, most metabolic pathways have a few enzymes that act as key regulatory points. These enzymes catalyze irreversible reactions. What's the difference between an irreversible and a reversible reaction?
Irreversiblereactionshavelargenegativefreeenergychanges, and reversible reactions have free energy changes near zero.
What type of enzyme removes phosphates (dephosphorylates enzymes)
Phosphatases
Removal of a phosphate group generates ________ and ________
Pi(free phosphate group) ADP (adenosine diphosphate)
Fermentation
Process that allows cells to extract SOME energy from glucose under conditions of insufficient oxygen-occurs in certain types of cells (bacteria, yeast, muscle)
Based on the conditions under which each of these hormones is released, it is reasonable to predict that F-2,6-BP ____________phosphofurctokinase and _______________ fructose-1,6-bisphosphatase
activates;inhibits
Fourth reaction in glycolysis
aldolase
Maltose/Lactose have aldose therefore
aldoses that CAN open up at the anomeric carbon (aldehyde group becomes availble to donate electrons)
Glucagon produced and released by _______ in pancreas
alpha cells
Insulin produced and released by _______ in pancreas
beta cells
HIGH affinity for electrons=________ reduction potential
bigger
The molecule a-ketoglutarate has a higher affinity for electrons than the molecule succinate. Therefore, a-ketoglutarate has a _________ reduction potential, and transfer of electrons from a-ketoglutarate to succinate would _________ energy
bigger;require
Ability to respond to hormone signaling is related to roles in ________ __________
carbohydrate metabolism
3) In Acetyl-CoA Formation one carbon removed (from3 pyruvate ) is released as ______
carbon dioxide
All processes of _________ ________ require oxygen to occur. Without oxygen all electron carriers would eventually be converted to reduced forms and it would not be possible to regenerate the oxidized forms required for formation of acetyl-CoA and the citric acid cycle
cellular respiration
reversible reactions
free energy changes in cells near zero (small) - relative concentrations of reactants and/or products can be altered to switch whether the forwards or reverse reaction is favorable - shared between opposing pathways
Products of gluconeogenesis
glucose+4ADP+2GDP+6Pi+2NAD+
NAD+ is an _______ ________ _______
oxidized electron carrier
5 carbons
pentose
Third reaction in glycolysis
phosphofructokinase
Electron carriers are molecules that act as shuttles to carry electrons between reactions and processes in cells. When electrons are transferred to an electron carrier it gets __________, and when an electron carrier gives up its electrons, it becomes ______________
reduced; oxidized
Different forms (isozymes) of some enzymes are important for?
regulation of glycolysis that allows epinephrine to cause different responses in liver versus muscle cells
Electron transfer reactions in oxidative phosphorylation ________ the energy needed to convert ADP and Pi to ATP
release
In complex 1 ,III, VI energy released is used to?
transport protons from the matrix to the intermembrane space
Fifth reaction in glycolysis
triosephosphate isomerase
Thermogenin channels allow protons to move through the membrane from higher to lower concentrations _____________ going through ATP synthase-smaller gradient (fewer protons in the intermembrane space = _____ ATP
without less
Insulin is released ________ blood glucose
-high
Glucagon is released ________blood glucose
-low
Transfer of phosphates from ATPs generates ____ energy intermediates with phosphate groups
-low
Oxygen is required to act as the _______ ________ ______ for the electrons removed from glucose
final electron acceptor
Uncouplers will _________ electron flow through the ETC
not affect
P/O ratio
number of ATP generated per pair of electrons transferred from electron carrier to oxygen
Does Cellular respiration require oxygen?
obtaining additional energy from pyruvate requires oxygen
electron transfer reactions and proton transport are part of the same reactions
one cant happen without the other
REDUCED electron carrier
-has electrons -can donate electrons
Statements that correctly describe glucose transporters (GLUTs).
-Glucose must interact with a GLUT to be transported across the membrane of a cell. -GLUTs are present in the membranes of both muscle cells and liver cells. -Glucose transporters are required to allow glucose to move across a cell's membrane. When a glucose molecule interacts with a GLUT, that causes the transporter to change shape and "dumps" the glucose molecule on the other side of the membrane. Both liver and muscle cells have GLUTs, but they have different types of GLUTs with different properties that relate to their roles in the body. Liver cell GLUTs allow glucose both into and out of cells (bidirectional), which allows them to help maintain appropriate blood glucose levels. Muscle cell GLUTs ONLY allow glucose into cells. Muscle cells do NOT play a role in supplying other cells with glucose. Insulin signaling increases the number of GLUTs present in muscle cell membranes, which allows muscle cells to bring in more glucose when excess is available.
Two hormones from the pancreas that regulate blood glucose levels under normal conditions
-Insulin -Glucagon
Statements that correctly explain why metabolic pathways involve series of connected reactions rather than being carried out in a single reaction
-It allows energy released by cellular processes to be captured more effectively. -It allows cells to control cellular processes more effectively. -Using multiple reactions to get from the starting molecules to the final products means that MORE enzymes are necessary (one for each reaction). This provides more points at which the pathway can be controlled. While using multiple reactions allows energy to be captured (and used) more effectively and efficiently, it does NOT change where you start or where you end, and therefore CANNOT increase the amount of energy released (or required).
Meta bolic pathways are cellular processes involved in energy transformation (converting energy between different forms). What are the main energy storage molecules in cells?
-Lipids and Carbohydrates
Metabolic processes are controlled by ______ different mechanisms and signals
-MANY -enzyme activity (molecules & phosphorylation) -enzyme levels -hormones -compartmentalization (organelles/tissues/cells)
In complex I Coenzyme Q (CoQ) forms _________ (oxidized form) and ________ (reduced form)
-NAD+ -CoQH2
In gluconeogenesis electrons provided by reduced electron carrier ________ converted to oxidized from __________
-NADH -NAD+
fructose-1,6-bisphosphatase NOT inhibited gluconeogenesis _________ inhibited
-NOT
Muscle cells ________ play a role in supplying other tissues with glucose
-NOT -use ATP to power cell contractions, NOT to form glucose
GLUT-4
-ONLY into cell -higher affinity for glucose -# of transporters increases in response to insulin signaling -Low BGL=not much in -high BGL=take in LOTS of glucose
______ electron carriers can accept electrons, and transfer of electrons from molecules with less affinity for electrons to molecules with greater affinity for electrons ______ energy.
-Oxidized; releases -Electron carriers are molecules that accept and give up electrons to transport electrons around in cells. The reduced form of an electron carrier has electrons, while the oxidized form can accept electrons. Passing electrons from a molecule that has a low affinity for electrons to another molecule that has a higher affinity for electrons releases energy.
Seventh reaction in glycolysis
-Phosphoglycerate kinase
Formation of glycogen molecules requires the coordinated actions of all of these enzymes
-UDP-glucose pyrophosphorylase (make substrate) -glycogenin (form glucose primers) -glycogen synthase(lengthen chains) -branching enzyme (add branches)
Why does cellular respiration require oxygen
-Ultimate electron acceptor
Target cell
-a cell with receptor proteins that can interact with the hormone
Statements that correctly describe hormones in humans.
-a particular type of hormone can cause different responses different cells -released into the bloodstream -a specific type of hormone can interact with multiple types of hormone receptor proteins
Glycogen synthase only forms __________ glycosidic bonds
-a(1,4)
Glucagon will _______ glycogen breakdown in liver cells, and will ______ glycogen breakdown in muscle cells.
-activate; not affect -Glucagon is produced and released in response to low blood glucose. Activation of glycogen breakdown in liver cells, and subsequent release of glucose into the bloodstream is essential for your body's ability to maintain appropriate blood glucose concentrations. Muscle cells do NOT have receptors for glucagon, and therefore CANNOT respond to glucagon signaling. Muscle cells don't play a role in regulating blood glucose levels, and store/use glucose to generate ATP required for muscle cell functions.
High blood glucose levels ---> insulin signaling---> increased levels of F-2,6-BP phosphofructokinase ____________ glycolysis _____________(rate of glycolysis increases) fructose-1,6-bisphosphatase ____________ gluconeogenesis _____________ (pathway doesnt function)
-activated -activated -inhibited -inhibited
Glucagon signaling leads to phosphorylation of regulatory enzymes. Phosphorylation _________ glycogen breakdown and ________ glycogen synthesis
-activates;inhibits -glucose is released in response to low blood glucose levels -activates processes that increase glucose availability -inhibits processes that use glucose
Role of branching enzyme in the formation of glycogen molecules
-add branches
The two unique functional groups of monosaccharides
-aldose -ketose
Glucose is an _________ and therefore is a __________ _______
-aldose -reducing sugar
Based on the roles of liver and muscle cells in carbohydrate metabolism, it is reasonable to predict that liver cells have receptors for ________ and muscle cells have receptors for _______
-all three hormones -insulin and epinephrine
First reaction in Glycolysis
-hexokinase
Hormones
-chemical messages important for long distance communication -produced and released in response to specific stimuli -travel through the bloodstream -reach ALL cells, but only cause a response in specific cells (target cells) -allow coordinated regulation of metabolic processes in your body -many hormones have different types of receptors on different types of cells
All monosaccharides (except one) have at least one _____ ____ and therefore have multiple ______ ______
-chiral carbon (C-OH) -isomeric forms
Aldolase 4th reaction in glycolysis
-cleavage (splitting) reaction -reversible
4) In Acetyl-CoA Formation two other carbons (from pyruvate) transferred to carrier molecule called_________forming ___________
-coenzyme A (CoA) -acetyl-CoA
Electron carriers act as ________
-coenzymes
Phosphorylation and dephosphorylation alter enzyme activity by causing ___________ (________) ________- that can ________ or _______ an enzyme
-conformational (shape) shape -active or inhibit
Glucose modification breakdown of liver cells
-converted to glucose-6-phosphate -dephosphorylated by glucose-6-phosphatase-ONLY produced in liver cells (NOT muscle cells) -released from cells glucose-1-p ----> glucose-6-p ----(glucose-6-phosphatase)---> glucose---released from cells
Glucose modification breakdown of muscle cells
-converted to glucose-6-phosphate -oxidized (broken down) to generate ATP glucose 1-P --(mutase)--> glucose -6-p ----> glycolysis (first process involved in glucose oxidation)
Glycosidic bond
-covalent bond that attaches one monosaccharide to another
Cellular Respiration:Citric Acid Cycle
-cycle of reactions (last reaction regenerates substrate for first reaction) -two carbons transferred from acetyl-CoA-get released as carbon dioxide -electrons transferred to oxidized electron carriers (forms reduced electron carriers) -enough energy released to form one ATP
The processes of cellular respiration are virtually identical in prokaryotic cells they just occur in the ____ instead of the mitochondria
-cytoplasm
enolase
-dehydration reaction (removes water) -reversible
Insulin signaling leads to ________________ of regulatory enzu,es
-dephosphorylation -protein phosphatase 1 (PP1)
*fructose-1,6-bisphosphatase
-dephosphorylation reaction -irreversible
*glucose-6-phosphatase
-dephosphorylation reaction -irreversible
A particular type of hormone can have different effects -different receptors
-different effects in different types of cells-different receptors -lung and heart muscle cells have different kinds of epinephrine receptors -different molecules inside cell
Energy is transferred __________-___________reaction linked (coupled) to __________ reaction
-directly -endergonic -exergonic
Aldoses, but NOT ketoses, can act as reducing agents (aka reducing sugars) This is because the aldehyde group can ________ electrons to other molecules, which causes the other molecules to become_________
-donate; reduced
Many more ______ are removed from ______by the processes of _________ _______
-electrons -pyruvate -cellular respiration
Gluconeogenesis summary
-electrons provided by reduced electron carrier (NADH) -converted to oxidized from (NAD+) -energy supplied by removal of phosphates from energy currency molecules (ATP and GTP) -results in lower energy molecules (ADP and GDP)
Steps in first pathway involved in converting the energy of a glucose molecule into the energy of ATP
-electrons removed from the carbons originally present in glucose transferred to electron carriers -conversion of glucose (higher free energy) to pyruvate (lower free energy) releases the energy needed to form ATP
Complex III
-electrons transferred from CoQH2 through complex to the mobile electron carrier cytochrome C (Cyt C) -forms CoQ (oxidized form) and Cyt C red (reduced form)
Complex VI of the ETC
-electrons transferred from Cyt C red through complex to oxygen -forms Cyt C (oxidized form) and water (H20) -energy released used to transport protons from the matrix to the intermembrane space
Complex II of the ETC
-electrons transferred from FADH2 though complex to the mobile electron carrier coenzyme Q (CoQ) -forms FAD (oxidized form) and CoQH (reduced form) -Not enough energy released to transport protons
Complex I of the ETC
-electrons transferred from NADH through complex to the mobile electron carrier coenzyme Q (CoQ) -forms NAD+ (oxidized form) and CoQH2 (reduced form) -energy released used to transport protons from the matrix to the intermembrane space
Glycolysis summary
-electrons transferred from carbons originally present in glucose to the oxidized electron carrier NAD+ which forms NADH -conversion of glucose (higher free energy) to pyruvate (lower free energy) coupled to formation of ATP -partial oxidation of glucose carbons -more electrons can be removed from pyruvate IF oxygen is present
After glycolysis most of the ________ from glucose is stored in _________
-energy -pyruvate
After the citric acid cycle MOST of the _______ originally present in glucose is stored in _____ _______ ______
-energy -reduced electron carriers
Ninth reaction in glycolysis
-enolase
Glycogen synthase
-enzyme that catalyzes the addition of glucose units to ends of chains -requires a chain at least four glucose units long -substrate=UDP-glucose -forms a(1,4) glycosidic bonds
Glycogenin
-enzyme that catalyzes the formation of glucose primers -dimer (two identical subunits) -attaches primers to R-group of specific tyrosine -substrate=UDP-glucose
It is reasonable to predict that glucagon signaling activates glucose _______ and glycogen _________.
-formation; breakdown -Glucagon is released in response to low blood glucose levels. In response to glucagon signaling, processes that help increase blood glucose levels are activated. This includes formation of glucose as well as breakdown of glycogen (the storage form of glucose) to release glucose molecules from storage.
Evolutionary change led to glycogen metabolism enzymes with complementary properties that allow glycogen molecules to be _______and ________ _______in cells
-formed -broken down
Branching enzyme
-forms branches -requires a chain at least eleven glucose units long (substrate) -removes seven-glucose unit segment-breaks a(1,4) glycosidic bond -attaches to existing chain via a(1,6) glycosidic bond
Electron transport chain (ETC) consists of
-four enzymes complexes -mobile electron carriers
Hormone released during falling blood glucose
-glucagon
When is protein kinase A (PKA) activated in cells
-glucagon (low blood glucose) -epinephrine (stress) -glycogen synthase=little/no activity glycogen synthesis inhibited -glycogen phosphorylase=high activity glycogen breakdown activated
Glycogen signaling leads to activation of PKA and phosphorylation of regulatory enzymes. What would happen if glycogen synthase could NOT be phosphorylated in response to glucagon signaling
-glucagon signaling would not inhibit glycogen synthesis
fructuse-1,6-biphosphatase inhibited __________________ inhibited
-gluconeogenesis
Substrates of glycolysis
-glucose + 2ADP +2Pi+2NAD+
Falling blood glucose activates
-glucose release -glucose synthesis
von Gierke disease is a rare, inherited disease caused by a mutation that prevents production of functional glucose-6-phosphatase. Which of the following would be observed in an individual with von Gierke disease?
-glucose removed from glycogen by glycogen phosphorylase would not be released from liver cells -Glucose-6-phosphatase is important for release of glucose molecules removed from glycogen by glycogen phosphorylase, which breaks glycosidic bonds via phosphorolysis, producing phosphorylated glucose (specifically glucose-1-phosphate). Glucose-1-phosphate is converted to glucose-6-phosphate by a mutase enzyme, and the phosphate removed by glucose-6-phosphatase. Unphosphorylated glucose can be transported out of liver cells by GLUTs (glucose transporters), but phosphorylated glucose cannot. Muscle cells do NOT produce glucose-6-phosphatase and do NOT transport glucose out of cells. -
Rising blood glucose activates
-glucose uptake -glucose storage -glucose break down
Glycogen synthesis
-glucose----> glycogen -formation of glycogen from glucose -storing excess energy as carbohydrates
Glycogen breakdown
-glycogen ----> glucose -removal of glucose molecules from glycogen -release of stored glucose
Glucagon/epinephrine active ________ and inhibit _________
-glycogen breakdown -glycogen synthesis
breakdown of glycogen molecules (and modification of glucose after removal) require the coordinate actions of all of these enzymes
-glycogen phosphorylase (release glucose molecules) -remove branches (debranching enzyme) -modify glucose molecules for next step (glucose-6-phosphatase liver only)
Two main regulatory enzymes of glycogen metabolism
-glycogen synthase -glycogen phosphorylase
Coordinated regulation of ______________ ______________ and ________________ ______________ ensures that glycogen is not ____________________ ____________ and ____________ ___________ in a cell AND helps maintain appropriate levels of _____________ in your blood
-glycogen synthase -glycogen phosphorylase -simultaneously formed -broken down -glucose
Correctly describe glycogen synthesis
-glycogen synthase can only add glucose units to chains that have more than three glucose units -both glycogenin and glycogen synthase use UDP-glucose as a substrate -all glycogen molecules have protein in the center -branching enzyme both breaks and forms glycosidic bonds
Glycogen metabolism enzymes have specific properties that are essential for allowing glycogen molecules to be formed and broken down in cells. What would happen if branching enzyme removed 7 glucose units from a branch only 10 glucose units long
-glycogen synthase cannot add glucose units -glycogen phosphorylase cannot remove glucose units -debranching enzyme cannot remove branch
Glycogen synthase is ONLY involved in ______ _______, so glycogen breakdown would still be activated
-glycogen synthesis
Insulin activates _________ and inhibits _________
-glycogen synthesis -glycogen breakdown
-Under conditions of high blood glucose, the drug indicated in the question above that prevents dephosphorylation of glycogen synthase will affect regulation of
-glycogen synthesis. -Glycogen synthase is ONLY involved in glycogen synthesis, and NOT in glycogen breakdown.
A drug completely inhibits the function of UDP-glucose pyrophosphorylase. ALL enzymes that would NOT be able to function properly in a person treated with the drug.
-glycogenin -glycogen synthase -UDP-glucose pyrophosphorylase catalyzes the reaction that forms the substrate for glycogen synthesis, UDP glucose. Therefore, treating a person with this drug would prevent formation of UDP-glucose. Glycogenin and glycogen synthase both use UDP-glucose as a substrate, so neither of these enzymes would be able to function normally. The other enzymes do not use UDP-glucose as a substrate (they act on existing glycogen molecules) and therefore would function normally.
First process involved in glucose oxidation
-glycolysis
When phosphofructokinase is activated ______________ activated
-glycolysis
Coordinated regulation of _____________ and ___________ is important for preventing waste of energy AND ensuring sufficient levels of _______ and _________ in cells
-glycolysis -gluconeogenesis -ATP -glucose
Glucokinase has a ______Km and _________ affinity low activity at normal blood glucose conditions _______ blood glucose levels increase activity
-high -low -high -liver cells will not phosphorylate a significant amount of glucose at normal blood glucose levels -at high blood glucose levels glucose gets phosphorylated in liver cells and stored as glycogen
UDP-glucose has a ______ free energy Allows formation of glycosidic bonds between glucose to be favorable
-high -favorable
When is insulin released? What is activated in cells? What happens to the regulatory enzymes
-high blood glucose -PP1 (Protein phosphatase 1) -dephosphorylated
A drug prevents dephosphorylation of glycogen synthase in cells. Will this drug affect regulation of glycogen metabolism under conditions of high blood glucose only, low blood glucose only, or both high and low blood glucose?
-high blood glucose only -Insulin signaling activates protein phosphatase 1 (PP1) in cells, which is why insulin signaling leads to dephosphorylation of carbohydrate metabolism regulatory enzymes (e.g. glycogen synthase). Insulin is produced and released when blood glucose levels are high, and therefore this drug will affect regulation of glycogen metabolism under conditions of high blood glucose. -Low blood glucose triggers the release of glucagon, which causes protein kinase A (PKA) to be activated and thus leads to phosphorylation of regulatory enzymes. Because this drug only affects dephosphorylation of glycogen synthase, regulation of glycogen metabolism will occur normally when blood glucose levels are low.
Insulin is released in response to ____ blood glucose levels; glucagon is released in response to ______ blood glucose levels.
-high; low
Energy investment phase allows formation of molecules (intermediates) with _________ free energy than ATP
-higher
Intermediates with phosphate groups modified to generate molecules with ______free energy than ATP
-higher
Molecules that have bigger reduction potentials have _______ affinities for electrons.
-higher -A bigger reduction potential is related to a higher affinity for electrons.
Passing electrons from molecules with ______ ______ for electrons to molecules with _______ ______ for electrons requires energy
-higher affinity -low affinity
Catabolic
-higher free energy molecules to lower free energy molecules -strip electrons -form energy currency
ATP has a ______ free energy than ADP and Pi. Therefore, formation of ATP from ADP and phosphate (Pi) is an _______ reaction.
-higher; endergonic -The free energy of ATP is higher than the free energy of ADP and phosphate (Pi). Therefore, formation of ATP from ADP and Pi requires energy (endergonic reaction).
Electron transport chain (ETC) inhibitors
-inhibit electron transfer reactions catalyzed by specific enzymes in the ETC -block electron transport through the ETC -inhibit formation of ATP by ATP synthase
ATP synthase inhibitors
-inhibit movement of protons through the channel in ATP synthase -inhibit formation of ATP by ATP synthase -inhibit electron transfer through the ETC -concentration of protons in the intermembrane space gets VERY high
Explain why taking DNP ( an uncoupler) would promote weight loss. Propose ONE side effect of taking this drug
-inhibits ATP formation -dehydration
Hormone released during rising blood glucose
-insulin
Skeletal muscles ______ receptors ________ receptors take in and ________ _______ _______ _______ _____ to generate the ATP (energy) needed to power muscle cells
-insulin -epinephrine -store glucose -break down glucose
Two hormones that regulate blood glucose levels under normal conditions
-insulin -glucagon
Liver _______ receptors _______ receptors ________ receptors regulate _______ ________ _______ under normal conditions ______ _______ to other tissues under times of stress
-insulin -glucagon -epinephrine - blood glucose levels -provide glucose
When is protein phosphatase 1 (PP1) activated in cells
-insulin (high blood glucose) -glycogen synthase=high activity glycogen synthesis activated -glycogen phosphorylase=little/no activity glycogen breakdown inhibited
debranching enzyme
-involved in glycogen breakdown breaks α(1,4) glycosidic bonds forms α(1,4) glycosidic bonds breaks α(1,6) glycosidic bonds
branching enzyme
-involved in glycogen synthesis -breaks α(1,4) glycosidic bonds -forms α(1,6) glycosidic bonds
glycogen synthase
-involved in glycogen synthesis -forms α(1,4) glycosidic bonds
A particular enzyme is a key regulatory enzyme of a metabolic pathway. Therefore, it is reasonable to predict that the enzyme catalyzes a/an _______ reaction.
-irreversible -Irreversible reactions have such favorable free energy changes that it is not possible for cellular conditions to change in a way that would make the reverse reaction favorable. Therefore, irreversible reactions can only occur in only one direction in cells and cannot be shared between opposing pathways. This is why the enzymes that catalyze irreversible reactions are key regulatory enzymes - controlling their activity only affects a pathway in ONE direction.
__________ reactions can ONLY occur in ______ direction in a cell-__________free energy change is too large to overcome under cellular conditions
-irreversible -one -negative
Cori cycle
-lactate transported via the bloodstream to liver cells -conditions in liver (plenty of NAD+) favor conversion of lactate to pyruvate -pyruvate used to form glucose by gluconeogenesis-transported to muscle cells
Role of glycogen synthase in the formation of glycogen molecules
-lengthen chains
Glucose-6-phosphatase is produced in
-liver cells only
Polysaccharides
-longer chains of monosaccharides connected by glycosidic bonds -structure -signaling -energy storage -starch -glycogen
Low blood glucose levels or stress ----> glucagon or epinephrine signaling------> decreased levels of F-2,6BP phosphofructokinase ____________ glycolysis _____________(can be regulated by other signals) fructose-1,6-bisphosphatase gluconeogenesis (can regulated by other signals
-not activated -not activated -not inhibited -not inhibited
Monosaccharides are named based on their unique functional group (aldose or ketose) and ______ __ ____
-number of carbons -numbered from carbonyl end
Glycolysis is the _________ pathways via which _______ (ATP) can be obtained from glucose in the absence of sufficient oxygen
-only -energy
Catabolic processes are _________ processes-________ electrons from molecules
-oxidative; strip
In glycolysis NAD+ is ___________
-oxidized
Since some electrons are removed from the carbons originally present in a glucose mole, these carbons are getting ________ the electron carriers produced by glycolysis are ______
-oxidized -reduced
In glycolysis glucose gets ______ (electrons removed) and produces ___________________________
-oxidized -reduced electron carriers
When a molecule donates electrons, it becomes ________. When a molecule accepts electrons, it gets _________.
-oxidized; reduced -Oxidation refers to loss of electrons, and reduction is gain of electrons.
In cellular respiration the maximum number of electrons possible are removed from the carbons originally present in glucose and ultimately transferred to oxygen. Therefore in cellular respiration the carbons originally from glucose are completely ___________ and oxygen is _______
-oxidized;reduced
Electrons are then transferred by electron carriers within and between complexes to ________ forming ________
-oxygen -water
Without ______ to act as the _______ __________ _________ NADH generated by glycolysis must be converted back to __________ (the oxidized form that can accept electrons) some other way in order for glycolysis to continue
-oxygen -final electron acceptor -NAD+
Energy payoff phase of glycolysis
-payoff of 4 ATP -overall pathway produces ATP and reduced electron carriers
*Phosphofructokinase 3rd reaction in glycolysis
-phosphate transferred from ATP -irreversible
*Hexokinase (multiple isozymes) First reaction in Glycolysis
-phosphate transferred from ATP -irreversible -glucose becomes glucose-6-phosphate
Eighth reaction in glycolysis
-phosphoglycerate mutase
Removal of glucose molecules by phosphorolysis means ___________ _________ is generated _________ using ___________BUT _________ of each glucose molecule in glycogen synthesis _________ TWO ________
-phosphorylated glucose -without -ATP -costs -ATP
Glucagon/epinephrine signaling leads to ___________ of regulatory enzymes
-phosphorylation -protein kinase A (PKA)
Hormone signaling (interaction of hormones with their receptors) often leads to phosphorylation of enzymes import for regulating metabolism. Correctly describe phosphorylation in the context of enzyme regulation
-phosphorylation always changes the shape of an enzyme
glyceraldehyde-3-phosphate dehydrogenase
-phosphorylation and electron transfer -generates reduced electron carrier (NADH) -reversible
Correctly describes glycogen
-primarily stored in muscle and liver cells -branches attached by a(1,6) glycosidic bonds -homoglycan composed of glucose -has a (1,4) glycosidic bonds
Epinephrine
-produced and released in response to stress -stimulates processes in target cells that ready body for actions (increase glucose and lipid availability)
Glycolysis _______ ______ energy currency molecules
-produces -two
Selective permeability
-property of membranes that allows only certain molecules to move through it -most molecules cannot pass directly through membrane-lipid tails make membrane interior hydrophobic and most cell molecules are hydrophilic -movement of molecules through membrane is controlled by proteins in membrane
Glucose transporters (GLUTs)
-proteins embedded (stuck) in cell membranes that transport glucose across the membrane
Unique reactions of gluconeogenesis
-pyruvate carboxylase -phosphoenolpyruvate carboxykinase -fructose-1,6-bisphosphatase -glucose-6-phosphatase
Tenth reaction in glycolysis
-pyruvate kinase
Extra energy can be released as "____________" (heat) but _________ be created
-random energy -CANNOT
OXIDIZED electron carrier
-ready to accept electrons
Glucose-6-phosphate isomerase 2nd reaction in glycolysis
-rearrangement reaction -reversible
phosphoglycerate mutase
-rearrangement reaction -reversible
triosephosphate isomerase 5th reaction in glycolysis
-rearrangment reaction -reversible
A particular type hormone can have different effects-different effects in the same cell (multiple ways)
-receiving different combinations of hormone signals
In glycolysis NADH gets ______
-reduced
The processes that allow you to obtain energy from glucose generate _________ electron carriers that transfer electrons to oxygen. Transfer of these electrons to oxygen ________ energy.
-reduced (have electrons) -releases
Anabolic processes are ______ processes-__________ electrons to occur
-reduced; require
Which of the following explains why, although aldohexoses such as glucose exist primarily as rings, they can still act as reducing sugars?
-the two different ring forms interconvert -When ring-form aldohexoses (or aldopentoses) interconvert between the two types of ring structures (alpha and beta), the ring opens up. In the straight-chain form, the aldehyde group is present and can donate electrons to reduce other molecules (i.e. act as a reducing agent). The aldehyde group is NOT present in the ring structure. Ketoses do NOT act as reducing sugars because they lack an aldehyde group.
Three reactions in glycolysis are irreversible. This means that __________________________
-they generate products with significantly lower free energy than the substrates
Disaccharides
-two monosaccharides connected by a glycosidic bond
*Pyruvate carboxylase
-unique reaction of gluconeogenesis -carboxylation reaction (adds carbon from CO2) -required energy released by conversion of ATP to ADP and Pi -irreversible
*Phosphoenolpyruvate (PEP) carboxykinase
-unique reaction of gluconeogenesis -decarboxylation reaction (removes carbon as CO2) -releases energy needed to transfer phosphate from GTP and generate phosphoenolpyruvate -irreversible
Rising blood glucose -Insulin Activates glucose ______ and processes that _______ glucose and or processes that _______ _____ glucose in the liver/muscle/adipose
-uptake -store -break down
Glycolysis and gluconeogenesis are coordinately regulated in a cell to ensure only ONE of the two pathways functions at a time. If both glycolysis and gluconeogenesis occurred at the same time in a liver cell, the cell would ______ per molecule of glucose broken down and formed
-use four energy currency molecules
Correctly describe metabolic pathways
-using multiple steps (reactions) does not change the total amount of energy released or required by a process -the free energy change of a pathways is equal to the sum of the free energy changes of the individual reactions -reversible reactions can occur in both directions in a cell, but irreversible reactions can only occur in one direction -the overall free energy changes for both catabolic and anabolic processes are favorable (negative)
Three irreversible reactions in Glycolysis
1) hexokinase 3) phosphofructokinase 10) pyruvate kinase
FADH2 P/O ratio
1.5
Glycolysis has _____ reactions
10
2ADP + 2Pi --->
2 ATP
Supplies energy for energy-requiring processes
2 ATP
Products of fermentation
2 lactate lactic acid 2 ethanol + 2CO2 alcoholic fermentation Cannot be used to generate more ATP under conditions of insufficient oxygen
6 glucose carbons ---->
2 pyruvate of 3 carbons each
Substrates of gluconeogenesis
2 pyruvate+4ATP+2GTP+2NADH
How many times does this occur PER molecules of glucose?
2 times per molecule of glucose
NADH P/O ratio
2.5
2NAD+ ---->
2NADH
During fermentation 2 pyruvate can turn into either __________ or _______
2NADH--->2NAD+----> 2 lactate 2CO2 2NADH ---> 2NAD+ ----> 2 ethanol
How many ATP are generated by the complete oxidation of one glucose molecule?
32
glucose + 6O2 ---> 6CO2 + 6 water +
32 ATP
After the citric acid cycle how many ATP have been made
4
All products of oxidation of one molecule of glucose in the presence of oxygen after the citric acid cycle
4 ATP 10 NADH 2 FADH2
Sucrose have ketose therefore
Aldose (so can act as reducing sugar) but cant open up (fixed glycosidic bond) Ketose CANNOT act as a reducing sugar
If thermogenin was produced in a cell would this affect ATP synthesis by oxidative phosphorylation
Allows protons to move through membrane without going through ATP synthase -smaller gradient (fewer protons in the intermembrane space) =less ATP
Two ring formations _____ and _____
Alpha Beta
Most cellular molecules __________ pass directly through cell membranes
CANNOT
Acetyl-CoA
CoA C C CoA carrying two carbons
Different isomeric forms have different properties
Composition and arrangement matter -glucose, fructose, galactose (CG H12 O6)
In complex VI forms ________ oxidized form and ________
Cyt C Water
A protein called thermogenin forms a channel in the inner membrane of mitochondria that allows protons to move freely across the membrane. In which direction will protons move?
Down from high to low concentration
Triacylglycerols---->
Fatty acids
What type of enzyme adds phosphates (phosphorylates enzymes)
Kinase
ADP and Pi have ________ free energy than ATP
LOWER
Gluconeogenesis occurs in ______ cells
Liver
LEO
Lost Electrons= Oxidized
What reaction(s) happen in the energy payoff phase of glycolysis
NAD+ -----> NADH because it gets phosphorylated ADP ----> ATP
2) In Acetyl-CoA Formation some electrons passed to NAD+ (oxidized electron carrier) forms
NADH
In glycolysis additional energy lost in use of electrons carried by _____ (transfer of these electrons to oxygen allows formation of ATP)
NADH
Fermentation does _______ generate any additional ATP
NOT
The ketotriose dihydroxyacetone does _____ have any chiral carbons (or isomeric forms)
NOT
Are the P/O ratios the same for NADH and FADH2?
No fewer protons are contributed to the gradient when electrons are transferred from FADH2 FEWER protons=LESS ATP
Goal of fermentation
Regenerate oxidized electron carriers (NAD+) required to accept the electrons removed from glucose in glycolysis
Forming ATP from ADP and Pi _________ energy. Therefore, cellular processes that __________ energy can form ATP from ADP and Pi
Requires, release Going from lower free energy reactants (ADP and Pi) to higher free energy products (ATP) requires energy. Because forming ATP from ADP and Pi requires energy, that energy needs to come from somewhere (energy cannot be created!).
UDP-glucose pyrophosphorylase forms _______
Substrate UDP-glucose
Maltose and lactose are reducing sugars, but sucrose is not-WHY
Sucrose has a ketose Maltose/Lactose have a aldose Aldoses that
Glycogen synthase and glycogen phosphorylase the main regulatory enzymes of glycogen metabolism, are allosteric enzymes-what does that tell you about these enzymes?
T form=less active R form=more active
How many times does the citric acid cycle occur per glucose?
TWice per molecule of glucose (2 acetyl-CoA are generated from the 2 pyruvate produced per glucose by glycolysis)
Does oxidative phosphorylation occur in prokaryotic cells?
Yes but does not occur in mitochondria -everything happens in cytoplasm
Amylose
a(1,4) glycosidic bonds -glucose
Glycogen
a(1,6) glycosidic bond a(1,4) glycosidic bonds -glucose
Amylopectin
a(1,6) glycosidic bond a(1,4) glycosidic bonds -glucose
NAD+ is required to
accept electrons removed from glucose in glycolysis
O2 _________ ___________ from ALL the reduced electron carriers generated by conversion of acetyl-CoA an and the citric acid cycle and glycolysis
accepts electrons
_______ protons are contributed to the gradient when electrons are transferred from FADH2
fewer
Glucagon and epinephrine signaling ____ levels of F-2,6-BP
decrease
Formation of ATP by ATP synthase is ________from formation of ATP in glycolysis and the citric acid cycle. In oxidative phosphorylation, Pi is added directly to ADP (not substrate level phosphorylation)
different
*Energy gets transferred directly
endergonic reaction linked to exergonic reaction
Electron transport chain (ETC)
enzyme complexes with electron carriers and mobile electron carriers
bifunctional enzyme
enzyme that alters levels of the allosteric effector fructose-2,6-bisphosphate in response to hormone signals
ATP synthase
enzyme that uses energy stored in proton gradient to form ATP from ADP and Pi
Electrons passed from reduced electron carriers to ________ in complexes
enzymes
Isozymes
enzymes that catalyze the same reaction but have different properties
More branches =
faster release of glucose molecules
When phosphate is transferred from ATP in the hexokinase reaction glucose turns into
glucose-6-phosphate
Second reaction in glycolysis
glucose-6-phosphate isomerase
Sixth reaction in glycolysis
glyceraldehyde-3-phosphate dehydrogenase
Glycogen breakdown steps
glycogen ----> glucose ---> oxidized (broken down) to allow formation of ATP ---> released from cells into blood (provides glucose to other cells)
Inside liver cell
glycogen synthesis
Inside skeletal muscle cell
glycogen synthesis or glycolysis (generates ATP)
Energy not converted to ATP is lost as ______
heat
6 carbons
hexose
ATP ----> ADP has a __________ free energy change
high
ATP is formed in oxidative phosphorylation by movement of protons through a channel in ATP synthase. Proton movement is coupled (linked) to phosphorylation of ADP to form ATP. Therefore protons must move through ATP synthase's channels from where theres ________ proton concentration to where the proton concentration is ______
higher;lower
Muscle cell hexokinases (1-3) have a much lower Km for glucose than glucokinase, Therefore muscle cell hexokinase have a ________ affinity for glucose and at the same glucose concentration will be _______ active compared to glucokinase
higher;more
Transfer of a free phosphate group to glyceraldehyde-3-phosphate (G3P) is significantly endergonic. It is linked (coupled) to the transfer of electrons from G3P to NAD+. Therefore NAD+ must have a _________ affinity for electrons than G3P, and transfer of electrons from G3P to NAD+ must __________ energy
higher;release
Insulin signaling ________ levels of F02,6-BP
increase
Epinephrine signaling has different effects on glycolysis in liver versus muscle cells. Based on the conditions under which epinephrine is released, it is reasonable to predict that epinephrine signaling __________ glycolysis in liver cells and _________ glycolysis in muscle cells
inhibits; activates
Hormone signals active MANY _____ or ______ that __________/________ MANY regulatory enzymes
kinases;phosphatases phosphorylate/dephosphorylate
irreversible reactions
large NEGATIVE free energy changes in cells - relative concentrations of reactants and/or products CANNOT be altered to switch whether the forwards or reverse reaction is favorable - NOT shared between opposing pathways - points of control
Glucokinase (hexokinase 5) is active in ________
liver cells
Liver and muscle cells have different roles in the body
liver-regulate blood glucose levels under normal conditions -provide glucose to other tissues under times of stress skeletal muscles-take in and store glucose-break down glucose to generate the ATP (energy) needed to power muscle cells
ADP ----> ATP has a _________ free energy change
low
1) In Acetyl-CoA Formation pyruvate (3 carbon) enter the
mitochondrial matrix
electron carriers
molecules that act as electron shuttles
ATP yield
moles of Pi consumed/moles of oxygen consumed
More chiral carbons=
more isomeric forms
Heteroglycan
multiple types of monosaccharide
Hexokinase 1,2,3 is active in ________________
muscle cells
Liver and muscle cells have different types of GLUTs in their membranes, which have slightly different properties. One type of GLUT only allows glucose to move into cells, the other type allows glucose to move both into and out of cells Thinking about their roles in your body, its reasonable to predict that the type of GLUT found in ______ cell membranes only allows glucose into cells, and the GLUT type in the membranes of ______ cells allows glucose to move both in and out
muscle; liver
Does Fermentation require oxygen?
no or low oxygen
Homoglycan
one type of monosaccharide
In oxidative phosphorylation, electrons are passed from reduced electron carriers (NADH, FADH2) to oxygen, and this allows formation of ATP from ADP and Pi. Therefore transfer of electrons from reduced carriers to oxygen must ________ energy, and oxygen must have a ______ affinity for electrons compared to the reduced electron carriers
release;higher
Conversion of ATP to ADP and Pi _____ energy
releases
Transfer of electrons from molecules with lower affinity to molecules with higher affinity for electrons _________ energy
releases
The proton gradient generated by the ETC is ________ for ________ ___________
required ATP synthesis
Formation of ATP from ADP and Pi ________ energy
requires
Peptide bonds are the ____ between all types of amino acids
same
Fewer branches =
slower release of glucose molecules
LOW affinity for electrons = ______ reduction potential
smaller
Membrane gradients are a form of ______ energy
stored
4 carbons
tetrose