module 7 Flashcards
define bioenergetics
study of how nutrients provide energy for an organism
define cellular metabolism
the reactions in cells that allow for life to continue
define catabolic reactions
break down biomolecules
define anabolic reactions
build and produce biomolecules
what helps nutrients and waster to cross cellular membrane
integral proteins
what do integral proteins move across in the cellular membrane
lipid bilayer
define metabolic pathway
series of enzyme-catalyzed reactions that convert material to a usable product
define flux
the amount of time it takes compounds to go from beginning to end of a pathway
what intermediate do both carbs and lipids break down into
acetyl-CoA
what makes up acetyl-CoA
acetyl- 2 carbon group
CoA= coenzyme containing ribose and adenine
Once acetyl-CoA is formed where does it go
CAC cycle to create NADH
Where does NADH go once created
shuttled to ETC to create ATP via oxidative phosphorylation
In common pathway where does conversion of acetyl-CoA happen
mitochondria
Define transporters
molecules- like integral protein- move 1 molecule or type across membrane
what is significant about the membranes of mitochondria
have porous outer membrane and non-porous inner membrane
ATP produced in the inner membrane of mitochondria move to
outer membrane and then to cytosol
In cytosol ATP is used how
broken down to ATP to release energy to perform work
For enzymatic breakdown of ATP what is net change in delta G free energy
negative
what is coupling in enzymatic reactions
named for cellular processes powered by breaking ATP bonds
What is FADH2
molecule that is similar to NADH
it can be shuttled to ETC to create ATP
structure is different from NADH permits it to interact with different proteins
what is glycolysis
10 step enzymatic pathway that break down glucose and other molecules into pyruvate with energy production in form of ATP and NADH
where does glycolysis take place
in cytosol as all molecules are water-soluble
what are the first 5 steps of glycolysis called
prep phase- energy investment
what are the last 5 steps of glycolysis called
payoff phase- energy invested becomes NADH, ATP and 2 pyruvate
what happens in first step of glycolysis
phosphorylation where phosphate group is added to glucose by hexokinase
glucose-> glucose-6-phosphate
ATP->ADP
what is the change of Delta G in step 1 of glycolysis
-16.7 kj/mol
what is step 2 of glycolysis
prepares glucose to be cut in half
glucose-6-phosphate->fructose-6-phosphate
phosphohexose isomerase
what is step 3 of glycolysis
seen with step 2- prepares glucose to be cut in half.
frutose-6-phosphate-> fructose 1,6 phosphate
phospho-fructokinase-1
ATP-ADP
what is seen step 4 of glycolysis
fructuose 1,6 -> fructose 1, 6 bisphosphate
aldose
what is seen in step 5 of glycolysis
fructose 1,6 bisphosphate-> glyceradelhyde 3-phosphate and dihydrogenphosphate
triose phosphate isomerase
DAP is converted to GAP
end of the prep phase
what is seen in step 6 of glycolysis
begins the payoff phase
Glyceraldehyde 3-phosphate-> 1,3, bisphosphoglycerate
glyceraldehyde 3-phosphate dehydrogenase
2 Pi, and 2 NAD+ go in and 2 NADH and 2 H+ come out of the reaction
what is seen in step 7 of glycolysis
(2) 1,3, bisphosphoglycerate-> (2) 3-phosphoglycerate
phosphoglycerate kinase
2ADP->2ATP
what is seen in step 8 of glycolysis
(2) 3-phosphoglycerate-> (2) 2-phosphoglycerate
phosphoglycerate mutase
what is seen in step 9 of glycolysis
(2) 2-phosphoglycerate-> phosphoenolpyruvate
enolase
H20 is released
what is seen in step 10 of glycolysis
phosphoenolpyruvate-> 2 pyruvate
pyruvate kinase
2 ADP-> 2ATP
what is the delta G change for reaction 2
1.7kj/mol
ATP is added to which steps in glycolysis
1 and 3
what is significant about prep phase in glycolysis
glucose gets cut in half
what do the 2 GAP molecules move to and form
move to energy and form ATP and NADH
How much ATP is formed with NADH
2.5
what type of reaction is step 7 in glycolysis
substrate level phosphorylation
not used in mitochondria
outline the glycolysis energy balance
prep phase: -2 ATP, 0 NADH
payoff phase: 4 ATP, 2 NADH
Total: 2 ATP, 2 NADH
define fermentation
process that extracts energy as ATP but does not use oxygen or change the concentration of NAD+ or NADH
define respiration of CAC
aerobic and oxidative catabolism of pyruvate
define cellular respiration
cells take in oxygen to produce carbon dioxide to generate energy
describe the 3 step process of cellular respiration
- ) glucose or other molecule like a FA is oxidized into a 2 carbon acetyl CoA compound.
- ) Acetyl-CoA groups are moved through CAC to create NADH or FADH2 molecules and release CO2
- ) NADH or FADH2 molecules are oxidized in mitochondria to produce ATP- via oxidative phosphorylation
What is PDH
pyruvate dehydrogenase
a supramolecular complex with multiple copies of three different enzymes, named E1, E2, and E3, that catalyzes this multistep reaction
PDH regulates the reaction preventing over production of Acetyl-CoA
how many reactions in CAC and what does it yield
8 steps
yields NADH, FADH2 and GTP
what are 2 other names for CAC
krebs cycle tricarboxylic acid (TCA)
What is the CAC cyle
series of oxidative reactions that conserve the energy of acetyl-CoA through a series of small reaction steps
what is the purpose of CAC cycle
convert the acetyl-CoA to energy molecules that are stored and used when necessary
what is the first step in the CAC cycle
known as building step
acetyl-CoA becomes citrate via citrate synthase enzyme
undergoes a condensation reaction where acetyl group is split from CoA and attached to 4 carbon compound oxaloacetone= citrate
what is the 2nd step in the CAC cycle
citrate converts to isocitrate
-OH move from 1 carbon to the next
starts with dehydration of citrate to cis-aconitate as an intermediate: double bond formed in cis-aconitate permits OH to be easily adjacent carbon
what is 3rd step CAC cycle
isocitrate converted to a-ketoglutarate with production of NADH
1rst energy molecule produced
1rst loss Co2 coming from oxaloacetate
what is 4th step of CAC cyle
regulation step: not equilibrium
a-ketoglutarate converted to succinyl-CoA
similar conversion of pyruvate to acetyl-CoA
a-ketoglutarate attached to CoA-SH from succinyl-CoA and release Co2`
what is 5th step of CAC cycle
result in 4 carbon succinate
succinyl-CoA converted to succinate with loss of CoA-SH and forms GTP
what is GTP needed for in the body
neurological processes
what is the 6th step of the CAC cyle
energy formed as FADH2
oxidation step as FAD removed 2 atom H
conversion succinate to fumerase: equilibirum
what is the delta G for step 6 of CAC cyle
delta G =0
what is the 7th step of CAC cycle
fumerate converted to malate through addition of water across doubled fumerate
fumerase( lyase enzyme) creates the double bond
what is the 8th step of CAC cycle
convert malate through oxidation of OH group to C=O to oxaloacetate- forms NADH
what can oxaloacetate accept at step 8 of CAC
Actyl-CoA which starts cycle all over again
what is the chart for energy molecules and how much ATP produced
ATP/GTP- 4 produced; 4 ATP formed
NADH- 10 produced; 25 ATP formed( 10x2.5)
FADH2- 2 produced; 3 ATP formed( 2x1.5)
Total ATP: 32
what happens during 1rst step of b-oxidation process
FAD oxidizes fatty acetyl-Coa form double bond between a and b carbon: result FADH2
FADH2 donate H and electron to ETC to create ATP
Once H and electrons donated FAD oxidize other molecules
where is ETC located
mitochondria
what happens during 2nd step of b-oxidation process
double bond reaction prepare molecule for addition of H2O to make -OH on B carbon step 2
enzyme used is enol-CoA hydratase( lyase enzyme)
what happens during 3rd step of b-oxidation process
-OH group on B carbon oxidized by NAD to C=O group NADH formed( like FADH2) donate H and electrons to ETC to create atp and replace NAD
what happens during 4th step of b-oxidation
carbon chain fragmented into acetyl-CoA group and fatty aceyl-CoA chain( 12 carbon)
what happens after 4 step beta-oxidation process- similar to after glycolysis
Acetyl-CoA enter CAC cycle in mitochondria
what are the other steps after beta-oxidation
fatty acyl-CoA molecule undergoes more B-oxidation- creates FADH2, NADH and acetyl-Coa
what happens at the end of the process of beta-oxidation
2 acetyl-CoA produced when 4 carbon molecule is split in 2
What is the B-spiral
sequential pathway repeats w/chain 2 carbon shorter each time
how many ATP result from single 14 carbon chain in beta-oxidation and CAC combined
94 ATP
how many rounds of beta-oxidation for a 14 carbon acyl-CoA and creates how many FADH2 and NADH
6 rounds
6 of each FADH2 and NADH
7 acetyl-CoA molecules at the end
what does each acetyl-CoA yield
which cycle
3 NADH
1 FADH2
1 GTP
CAC
what is the yield chart for b-oxidation
NADH- 6 produced; 15 ATP( 6x2.5)
FADH2-6 produced; 9 ATP( 6x1.5)
Define VLCAD
very long chain acyl-coA dehydrogenase
acts on FA chains 12-18 long
Define MCAD
medium chain acyl-CoA acts on chains 4-14 chain long
Define SCAD
short chain Acyl-CoA dehydrogenase act on short chains 4-8 carbon long
what is a mutation that can occur in beta-oxidation pathway
which is most common
on enzyme: hinder or stop FA degradation
most common: MCAD- difficulty processing medium chain triglycerides
what are some signs and symptoms of MCAD mutation
how managed?
vomiting, lethargy, low blood sugar
typically seen in infancy and early childhood
managed primarily with diet and prognosis is good with early detection
state the 8 intermediates and enzymes for CAC
- Acetyl-CoA; citrate synthase
- Citrate; aconitatse
- Isocitrate; isocitrate dehydrogenase
- a-ketoglutarate; a-ketoglutarate dehydrogenase complex
- succinyl-CoA; Succinyl CoA synthase
- Succinate; Succinate dehyratase
- Fumerate; fumerase
- Malate; malate dehydrogenase
A scientist uses the term flux regarding a biochemical pathway. What does flux mean?
Flux is used to describe the rate of which a reaction is performed and completed.
A particular pathway breaks down proteins into amino acids. Is this an anabolic or a catabolic pathway?
Catabolic. This is degradation of a molecule.
The acetyl group is connected to CoA to make Acetyl-CoA. A) What specific atom of CoA connects to the carbon atom on the acetyl group? B) What nucleotide base is part of CoA?
A) Sulfur
B) Adenine
Both carbohydrates and lipids are broken down into Acetyl-CoA for further processing. What pathway does Acetyl-CoA go to next?
Citric Acid Cycle- CAC
What is the “ETC” and what happens there?
Electron transport chain. NADH is converted into ATP at the ETC.
What is the sign (+ or -) of ΔG for the breakdown of ATP to ADP? Why is the sign important?
(-). A negative means spontaneous, or favorable, and is able to power other processes.
What are the two phases of glycolysis? How many reactions in each?
The preparatory phase and payoff phase. Five reactions in each.
How many ATPs are invested in glycolysis?
2
What is the net number of ATP gained from glycolysis?
2 ( 2 invested, 4 produced, 2 yield)
How many reactions of glycolysis have a single arrow “→” in their reaction equation?
3
What is the fate of pyruvate produced in glycolysis?
Under anaerobic conditions, it goes to lactate or sometimes ethanol or other products to regenerate NAD+ for glycolysis. Under aerobic conditions, it proceeds to the citric acid cycle.
For one molecule of glyceraldehyde-3-phosphate, how many ATP or NADH are produced (or required) in the glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate step in glycolysis?
1 NADH produced
In ____(A)_____, phosphate from _____(B)_______ is transferred to ADP and yields ATP.
In ___(C)____, phosphate from ATP is transferred to ____(D)_______ forming ADP .
A) reaction 7
B) 1,3-bisphosphoglycerate
C) Reaction 3
D) Fructose-6-phosphate
How many steps are found in the CAC?
8
How much ATP is produced per NADH molecule after oxidative phosphorylation? Per FADH2?
NADH- 2.5 per molecule. FADH2 – 1.5 per molecule
How many CO2 are lost per each turn of the CAC?
2 molecules of CO2 are lost.
How many of the steps in the CAC are equilibrium reactions?
5
What reaction is catalyzed by the PDH?
pyruvate to acetyl-CoA
The 𝛽-oxidation pathway is the degradation pathway for fatty acids. A. Where, in the cell, does the 𝛽-oxidation pathway occur? B. How many steps are in the 𝛽-oxidation pathway?
A. mitochondria
B. 4 steps
How many FADH2 and NADH molecules are produced per round of 𝛽-oxidation?
1 FADH2 and 1 NADH
Can 𝛽-oxidation occur with odd-numbered fatty acids? Can 𝛽-oxidation occur with fatty chains containing double bonds? Explain your answer in at least three complete sentences.
Yes to both types of chains. The 𝛽-oxidation process occurs with both unsaturated fatty acids (those with double bonds) and fatty acids that have an odd number of carbons. Double bonds and odd-numbered chains each present a structural problem for the standard enzymes of the pathway. So, there are additional steps with enzymes for each type of molecule, but the molecules are degraded with energy recovered.
