Lecture 9 Flashcards
• (blank) of ATP
– Phosphocreatine (PCr) breakdown
– Degradation of glucose and glycogen (glycolysis)
– Oxidative formation of ATP (oxidative phosphorylation)
• (blank) pathways
– Do not involve O2
– PCr breakdown and glycolysis
• (blank) pathways
– Require O2
– Oxidative phosphorylation
• Krebs cycle and electron transport chain
formation
anaerobic
aerobic
3 substrates of ATP production?
carbohydrates, fatty acids and amino acids
(blank) system=ATP-PCR system, glycolysis
(blank) system= krebs cycle, electron transport chain
The (blank) of each of these systems is to meet the cellular
demand for ATP.
anaerobic
aerobic
goal
ATP-PCr System
• Anaerobic, substrate-level metabolism
• Free ATP: provides (blank) energy lasting < 2 sec
• IMPORTANTLY: (blank) = creatine phosphate
• Phosphocreatine (PCr) exists in concentrations 5-6x
higher in resting muscle than free ATP
• Duration: 3 to 15 s
• Because ATP stores are very limited, this pathway is used
to (blank) ATP
immediate
phosphocreatine
reassemble
PCr System • Primary fuel source for (blank) very intense exercise • 10 - 15 seconds • Weight lifting • Sprinting
(blank) gets added to PCR + ADP to form ATP + CR
short
creatine kinase
Carbohydrate
• All carbohydrate converted to glucose
– (blank) kcal/g; ~2,500 kcal stored in body
– (blank) ATP substrate for muscles, brain
– Extra glucose stored as (blank) in liver, muscles
• Glycogen converted back to glucose when needed to make
more ATP (glycogenolysis)
• Glycogen stores limited (2,500 kcal), must rely on dietary
carbohydrate to replenish
4
primary
glycogen
Fat
• Efficient substrate, efficient storage
– 9.4 kcal/g
– +70,000 kcal stored in body
• Energy substrate for (blank), less intense exercise
– High net ATP yield but slow ATP production
– Must be broken down into free fatty acids (FFAs) and (blank)
– Only (blank) are used to make ATP
• Glycerol will be converted to G-3-P for glycolysis
prolonged
glycerol
FFA’s
Protein
• Energy substrate during starvation
– 4.1 kcal/g
– Must be converted into (blank) (gluconeogenesis)
• Can also convert into (blank) (lipogenesis)
– For energy storage
– For cellular energy substrate
gluconeogenesis
FFA’s
Glycolysis
• Process of breaking down glucose or glycogen (carbohydrate) to form ATP without using (blank)
• Glycogen stored in (blank) (also stored in liver)
• Glucose must be transported into muscle from (blank)
oxygen
muscle
blood
Glucose is transported into the cell by (blank)
GLUT4
Important (blank) of Glycolysis
Hexokinase
Glycogen Phosphorylase
Phosphofructokinase
enzymes
Fates of Pyruvate
• (blank) Fate:
– Lactate (Lactic Acid) via
Lactate Dehydrogenase
• (blank) Fate:
– Acetyl CoA via Pyruvate
Dehydrogenase
anaerobic
aerobic
Activating an Enzyme • Some enzymes are present in both an active and inactive form – When inactive activity ~ 0 • (blank) enzyme increases activity
activating
Glycolysis summary:
• 2 ATP from glucose • 3 ATP from glycogen • 2 NADH + H+ • 2 Pyruvate • 2 Acetyl CoA – When PDH is active – Enters into (blank) metabolism where large amounts of ATP are produce
aerobic
Glycolytic System • Anaerobic • Breakdown of glucose via (blank) • ATP yield: 2 to 3 mol ATP/1 mol substrate • Duration: 15 s to 2 min
• Uses glucose or glycogen as its substrate
– Must convert to glucose-6-phosphate
– Costs (blank) ATP for glucose, 0 ATP for glycogen
• Pathway starts with glucose-6-phosphate, ends with
(blank) acid
– 10 to 12 enzymatic reactions total
– All steps occur in (blank)
– ATP yield: 2 ATP for glucose, 3 ATP for glycogen
glycogenesis
1
pyruvic
cytoplasm
Glycolytic System
• Cons
– (blank) ATP yield, inefficient use of substrate
– Lack of O2 converts pyruvic acid to lactic acid
– Lactic acid impairs (blank), muscle contraction
• Pros
– Allows muscles to contract when (blank) limited
– Permits shorter-term, higher-intensity exercise than
oxidative metabolism can sustain
low
gylcolysis
02
Glycolytic System • Phosphofructokinase (PFK) – Rate-(blank) enzyme ATP ( ADP) PFK activity ATP PFK activity – Also regulated by products of (blank) • Glycolysis = ~2 min maximal exercise • Need another pathway for longer durations
limiting
krebs cycle
Oxidative System • Aerobic • ATP yield: depends on substrate – 32 to 33 ATP/1 glucose – 100+ ATP/1 FFA • Duration: steady supply for hours • Most (blank) of three bioenergetic systems • Occurs in the (blank), not cytoplasm
complex
mitochondria
Oxidation of Carbohydrate
• Stage 1: (blank)
• Stage 2: (blank)
• Stage 3: (blank)
glycolysis
krebs cycle
electron transport chain
The oxidative system
• ATP-PCr and glycolytic systems cannot generate enough (blank) to sustain prolonged
exercise.
• The (blank) system is the final system for cellular ATP production.
– Slow operating system which can utilize CHO, fat or protein for energy supply.
– By far the most complex of the three systems.
– Uses oxygen for cellular energy
• CELLULAR RESPIRATION
– Used during long-term exercise conditions.
ATP
oxidative
phosphorylation, oxidation, reduction
are the 3 coupled reactions of (blank)
oxidative phosphorylation
Oxidation of CHO
• Involves three processes:
– 1. aerobic glycolysis
– 2. Kreb’s Cycle ((blank) cycle or TCA)
– 3. Electron Transport System coupled with (blank)
• Glycolysis is the same process only that (blank) being present determines whether the fate will be pyruvate or lactate.
• The 2-3 moles of ATP (glucose-glycogen, respectively) and pyruvate
– pyruvate is converted into a compound called acetyl coenzyme A or acetyl CoA
– Acetyl CoA enters the TCA and is oxidized.
citric acid
oxidative phosphorylation
O2
Coenzymes
• Assist enzymes by accepting/donating (blank) and electrons
• Required for reaction to proceed
• NAD+ - nicatinamide adenine dinucleotide
• FAD - flavin adenine dinucleotide
• Also CoA (different and used in the TCA cycle)
hydrogen
Pyruvate must be transported into the mitochondria via transport protein- pyruvate (blank) (Active transport)
translocase
Glycolysis can occur with or without O2
– ATP yield (blank) anaerobic glycolysis
– Same general steps as anaerobic glycolysis but, in the presence of oxygen,
• Pyruvic acid acetyl-CoA, enters Krebs cycle
same as
Three factors govern the (blank) through the cycle:
– Substrate availability
– Inhibition by accumulating products
– Allosteric feedback inhibition of early steps
• Product accumulation inhibits all three of these
steps.
rate of flux
- Krebs Cycle
- Tricarboxylic Acid Cycle
- Citric Acid Cycle
What is the difference between these?
nothing, they are different names for the same thing
Important (blank) for TCA cycle – Citrate Synthase – Isocitrate Dehydrogenase – α-Ketogluterate Dehydrogenase – Pyruvate Dehydrogenase
enzymes
Coenzymes • Oxidation = (blank) of electrons • Reduction = (blank) of electrons • Reduced NAD+ = NADH + H+ • Reduced FAD = FADH2 • Electrons carried by reduced forms of these molecules have a high energy potential • REMEMBER: LEO the lion says GER
loss
gain
Electron Transport Chain
• Uses energy from NADH + H+ and FADH2 to pump (blank) ions across the inner mitochondrial membrane
• Hydrogen ion concentration gradient then provides energy to produce (ATP)
hydrogen
ATP
Oxidation of Carbohydrate:
Electron Transport Chain
H+, electrons carried to (blank) via NADH, FADH molecules
• H+, electrons travel down the chain
– H+ combines with O2 (neutralized, forms H2O)
– Electrons + O2 help form ATP
– 2.5 ATP per NADH
– 1.5 ATP per FADH
electron transport chain
Mitochondrial Metabolism
(blank)- most abundant inner membrane proteins
– responsible for transport of adenine nucleotides across and
importing ADP for ox. Phos. and exporting ATP to cytosol
ANT
Electron Transport Chain • Complex I – NADH (blank) • Accepts 2 electrons from NADH + H+ – NADH +H+ is oxidized – LEO the Lion says GER • Pumps Hydrogen ions across membrane
dehydrogenase
Importance of Oxygen
• Electron Transport Chain can only carry one set of
(blank) at a time
• If Oxygen is not present to accept electrons electron
transport chain stops
No Oxygen No Aerobic ATP
electrons
Electron Transport Chain
• (blank) ion gradient
• More hydrogen ions pumped by NADH than FADH2
• As electrons are transported hydrogen ions are pumped
across membrane
• Energy from this gradient is used to produce ATP
hydrogen
The Electron Transport Chain
• Site of (blank) phosphorylation
– The process accounting for high ATP yield
• Series of integral membrane proteins in the inner mitochondrial membrane capable
of oxidation/reduction
• ATP is synthesized during the transfer of electrons from NADH
and FADH2 to molecular oxygen
oxidative
Calculation of ATP Yield
The yield of ATP /NADH oxidized via the ETC is (blank)
The yield of ATP /FADH2 oxidized via the ETC is (blank)
- 5
1. 5
Glucose + O2 is broken down into CO2 + H2O + energy used to form (blank) ATPs
– 2 ATP are formed during glycolysis
– 2 ATP are formed by phosphorylation during Krebs cycle
– electron transfers in transport chain generate 28 ATPs from one glucose molecule
• Points to remember
– ATP must be transported out of (blank) in exchange for ADP
(ANT protein)
• uses up some of proton motive force
– Oxygen is required or you can only produce 2 measly ATP
32
mitochondria
