Lecture 9 Flashcards by Adam Lapier

• (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

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3 substrates of ATP production?

carbohydrates, fatty acids and amino acids

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(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

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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

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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

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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

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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

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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

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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

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Glucose is transported into the cell by (blank)

GLUT4

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Important (blank) of Glycolysis

Hexokinase
Glycogen Phosphorylase
Phosphofructokinase

enzymes

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Fates of Pyruvate

• (blank) Fate:
– Lactate (Lactic Acid) via
Lactate Dehydrogenase

• (blank) Fate:
– Acetyl CoA via Pyruvate
Dehydrogenase

anaerobic

aerobic

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Activating an Enzyme
• Some enzymes are present in both an active and 
inactive form
– When inactive activity ~ 0
• (blank) enzyme increases activity

activating

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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

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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

pyruvic

cytoplasm

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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

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

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)

2. 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