Energy transfer in the body Flashcards
1
Q
phosphate bond energy
adenosine triphosphate: energy currency
A
-powers all of the cells energy-requiring processes
-potential energy extracted from food
-
-energy stored in bonds of ATP (as high amount of energy, ATP known as high energy phosphate
-energy is transferred to do work
2
Q
harnessing ATPs potential energy
A
when ATP joins with water and is broken down (hydrolysis) ADP, Pi forms
-outermost phosphate is released
-catalyzed by the enzyme
-energy is released (7.3kcal/mol)
ATP= ADP+Pi +energy
3
Q
cellular respiration
A
the process by which cell transfer energy from food to ATP in a stepwise Eries of reactions
ATP is continually resynthesizes and supplied to the body through different metabolic pathways
4
Q
aerobic metabolism
A
in the presence of, requiring, utilizing oxygen
(longer term energy yield)
5
Q
anaerobic metabolism
A
in the absence of, not requiring, nor utilizing oxygen
(fast producing energy)
6
Q
limited currency
A
cell stored a limited quantity of ATP at all times ( g)
resynthesis depends on rate of use
the ATP levels in cells create sensitivity to ATP/ADP balance
7
Q
if an imbalance is created ( ADP ratio starts to increase) the breakdown of other energy storage compounds such as:
A
fat, glycogen, phosphocreatine are triggered to facilitate ATP resynthtesis
creatine kinase activation
-enzyme to catalyst PCr hydrolysis
8
Q
Energy systems
cells generate ATP through
3 systems
A
ATP-CP system
glycolytic system
oxidative system
9
Q
Anaerobic ATP- creatine phosphate
A
fuels: ATP and creatine phosphate
Fatigue: In 10 sec (max effort)
activity: 10 sec at max (100 m sprint)
rate: allows rapid muscle contraction
enzymes: ATPase, creaitne kinase
location: chemical reaction occur in the cytoplasm
byproducts: none
energy yield: 1 ATP/ precursor fuel
recovery: 3 min
10
Q
creatine phosphate
A
is a high energy phsophate stored in cells (4-6x more ATP)
the breakdown of creatine-phosphate allows an immediate resynthesis of ATP to allow muscle contraction to continue
11
Q
ATP-CP system
A
-fatigue is due to depletion of creatine phosphate
full recovery takes 3 min
half recovery takes 30 seconds
recovery depends on energy (ATP) supplied by aerobic energy system
12
Q
ergogenic aid
A
creatine monohydrate used to enhance recovery
13
Q
anaerobic glycolytic system
lactic acid system - overview
A
Fuels- glycogen or glucose
fatigue- a few minutes (due to lactic acid)
activity- 10 to 30 sec to 2 to 3 min
Rate: fast, but slower than ATP-CP system
enzymes: phosphofructokinase (PFK) and lactate dehydrogenase (LDH)
location; chemical reactions occur in the sarcoplasm
energy yield: 2 ATP/glusoce
recovery: 2 hours
14
Q
glycolytic energy system
A
fatigue is die to lactic acid build-up
acidity inhibits: PFK, clacium binding to troponin, cross-bridge cycling
full recovery: 2 hours
recovery is dependent on an individuals aerobic condition (aerobically trained muscle will remove lactic acid more quickly from the circulation and use it as fuel)
15
Q
glycogen
A
the main storage form of carbohydrate in the body (muscle and liver)
composed of many molecules
must be broken down to glucose molecules before being used as a fuel source to resynathesize
16
Q
glycogenesis (glycogen synthesis)
A
surplus glucose forms glycogen in low cellular activity and/or with depleted glycogen reserves
17
Q
glycogenolysis (glycogen breakdown)
A
glycogen reserve break down (hydrolyzed) to produce glucose in high cellular activity with glucose depletion
18
Q
anaerobic glycolytic system (anaerobic lactic system)
A
rapid glycolysis
-breakdown of glucose produces 2 pyruvate
-complex system
-10 enzymatic reactions
-pyruvate without presence of oxygen converts to lactate (catalyzed by lactate dehydrogenase LDH)
energy yield: 1 mol glucose = 2 mol ATP (net)
19
Q
a series of 10 enzymatically controlled chemical reactions create 2 pyruvate molecules from the anaerobic breakdown of glucose
A
glycolysis
20
Q
lactate or lactic acid
A
lactic acid (pyruvic acid) and lactate (pyruvate) are not exactly the same
-anaerobic glycolysis technically produces (pyruvic acid) lactic acid
terms often used interchangeably bc
-lactic acid quickly dissociated into salt form called lactate
21
Q
effects of lactic acid
A
acidification of muscle inhibits further glycogen breakdown (remembers pH affects rxns)
decreases calcium binding capacity
-impedes muscle contraction
22
Q
both resting and exercise levels of La- depend on the balance b/w production and clearance (removal)
this balance is often termed
A
turnover
pyruvate is converted to lactate when temporarily combine with H from NADH
23
Q
possible ways to dispose of lactate
A
gluconeogenesis in the liver (Cori cycle) replenish glucose levels
utilization by other muscle fibers (lactate shuffle)
utilization in the same muslce fiber where it is produced
24
Q
cori cycle
A
liver can convert some lactate back to glucose
25
glycogenesis
glucose can be converted to glycogen to be stored in liver when oxygen becomes available
26
lactate dehydrogenase
enzymes can exist in different forms
termed "isozymes or isoenzymes"
LDH exists in an muscle form and an Heart form
27
LDH (m) drive
pyruvate to lactate
28
LDH (H) drives
lactate to pyruvate
29
Aerobic energy system (oxidative system)
fuels: glycogen, glucose, fats, proteins
fatigue: occurs in hours (glycogen depletion)
recovery: 24-48 hr
activity: 2-3 minutes or more
rate: slow
location: chemical reactions producing majority of ATP occur in the mitochondria
30
aerobic energy system
enzymes
complex metabolic pathways; many enzymes (pyruvate dehydrogenase, citrate synthase, succinate dehydrogenase ect....)
energy yeild: 36 ATP, 460 ATP (triglyceride)
31
aerobic metabolism
resynthesis of ATP via the breakdown of fuel with the aid of oxygen
most complex of 3 systems
oxidative production of ATP involves multi processes
32
slow glycolysis
occurs in sarcoplasm
33
citric acid cycle (Krebs cycle)
occurs in mitochondria
34
electron transport chain- oxidative phosphorylation
occurs in inner mitochondrial membrane
35
aerobic (slow) glycolysis
glycolysis can be involved in anaerobic (rapid) or aerobic (slow) ATP production
process of glycolysis is the same whether oxygen is present or not
glucose is broken down to pyruvic acid
the difference is in the end product
36
without O2 (________) pyruvate was converted to lactate
rapid glycolysis
37
with oxygen (________) pyruvate is converted to acetyl coenzyme A (acetyl Co A)
slow glycolysis
38
purpose of the citric acid cycle/ Krebs cycle (overview)
degrades pyruvate into smaller components
acetyl CoA acts as an entry point for pyruvate (from carbohydrate) and also fats, protein (fatty acids and amino acids)
produces NADH+H+, FADH2
produces ATP at one step (x2 cycles = 2ATP)
39
citric acid cycle
acetyl Co A enters Citric acid cycle (Krebs)
series of complex reactions resulting in complete oxidation of Acetly Co A
Acetyl CoA splits
carbon combines with remaining oxygen blood to the lungs to be expired
-hydrogen from coenzymes and original CHO substrate is released (carried by NAD and FAD for use in ETC)
produces 2 ATP
40
CAC / Krebs cycle enzymes to know
succinate dehydrogenase (SDH)
citrate synthase (CS)
-two enzymes of the Krebs cycle that are easy to measure
-often used as an indicator of mitochondrial volume
isocitrate dehydrogenase (IDH)
-rate limiting enzyme
41
potential energy for electron transport / respiratory chain
hydrogen from substrate is released from both glycolysis and citric acid cycle
co-enzymes
-NAD and FAD
-accept hydrogen and beomce reduced co-enzyme carriers (temporary storage of energy) to the ETC
-NADH
-FADH2
42
Aerobic metabolism phase 1
pyruvate from glycolysis
43
aerobic metabolism
phase 2
electron transport chain: reduced coenzyme complexes become oxidized
44
ETC: what happens to NADH and FADH
-NADH and FADH donate their H+ along with a pair of electrons to the ETC
-ETC = chain of complexes, where ATP is formed from the transfer of electrons down the chain
oxygen is involved
"oxidative phosphorylation"
45
electron transport chain
-ETC oxidizes NADH and FADH (removes hydrogen)
-hydrogen atoms are split into protons and electrons
-removes electrons from hydrogen
-electrons pass from cytochrome to cytochrome (electron carries) through the chain to the final electron acceptor O2
-oxygen accepts electrons
enzyme: cytochrome oxidase
-hydrogen and oxygen combine to produce water
46
ETC
protons are pumped across inner ________ membrane
mitochondrial
47
ETC
produces an electrical gradient representing stored potential energy
this energy...
this energy drives the coupling mechanism for ATP synthesis
48
synthesizes ATP from ADP+Pi + energy
32 ATP produced
90% of ATP synthesis takes place in respiration chain by oxidative reactions
ETC - oxidative phosphorylation
49
creatine kinase
anaerobic alactic
50
citrate synthase
citric acid cycle
51
phosphofructokinase
anaerobic lactic
52
cytochrome oxidase
ETC
53
pyruvate dehydrogenase
slow glycolysis
54
1 glucose --- 2 pyruvate
releases H to ETC (carried by NDH)
produces 2 ATP (net)
glycolysis review
55
acetyl CoA --- CO2
release H to ETC (carried by NADH and FADH)
produces 2 ATP
citric acid/ Krebs cycle
56
glycolysis and Krebs cycle produce a small amount of _______
main function is to supply hydrogen (and in turn electrons) to 3rd stage of respiration (ETC)
hydrogen carriers NAD and FAD (now NADH and FADH) transport electrons from H to ETC
ATP
review of glycolysis and Krebs cycle
57
oxygens role in energy metabolism
three prerequisites for continual resynthesis of ATP during coupled oxidative phosphorylation
-availability of NADH or FADH
-presence of oxygen
-sufficient concentration of enzymes and mitochondria
58
glucose catabolism
glycolysis= 2 ATP (substrate phosphorylation)
Krebs cycle= 2 ATP (substrate phosphorylation)
ETC= 32 ATP (oxidative phosphorylation)
total= 36 ATP
59
feel continuum
as metabolic systems act on a continuum, so do feel sources
-we don't necessarily use all CHO or all fats at one period of time
60
carbohydrates vs. Fat Oxidation
-the breakdown of carbohydrates or fats in the mitochondria for energy is called oxidation
-during oxidation, oxygen is consumed and carbon dioxide is produced
-the ratio of carbon dioxide produced to oxygen consumed at the cellular level is called the respiratory quotient
61
respiratory Quotient
RQ= carbon dioxide output/ oxygen consumption at cellular level
if RQ = 0.7 then 100% of energy is coming from oxidation of fats
if RQ= 1.0 then 100% of energy is coming from oxidation of carbohydrates
62
higher RQ mean a higher utilization of CHO=
high intensity, shorter duration
63
lower RQ means a higher utilization of fat=
long duration, low intensity
64
respiratory exchange ratio
RER= CO2/O2
carbon dioxide output / oxygen consumption at total body level
can go above 1.0
i.e. RER > 1.1 = max
65
at higher intensity short duration exercise we primarily use muscle glycogen.
what implications does that makes in terms of fuel choice for athletes
carbohydrates
66
at lower intensity long duration exercise we primarily use FFA
what implications does that makes for fat loss programs in terms of exercise percrisption
if you want to shift substrate utilization toward fat you might want to use a lower capacity
67
although, long duration activity uses fats as primary fuel source, glucose/glycogen depletion will be the __________ in performance of long duration events
limiting factor
68
pyruvate formed during glucose metabolism important to maintain Krebs cycle intermediates i.e. decreased levels would slow Kreb's even if metabolizing fatty acids
69
glucose/ glycogen depletion
-prolonged exercise
-repetitive of intense training
-inadequate nutritional intake (high fat/ high protein diet)
-inadequte caloria intake
-diabetes
70
_______ from proteins or fats can produce glucose; however, we till cannot maintain adequate stores without CHO consumption
gluconeogenesis
70
fuels/energy source
carbohydrate (CHO)
fat
protein
71
fuel storage in the body
energy yeild 1g CHO=
energy yeild 1g fat-
replenishing stager of these fuels is dependent on diet
4kcal energy
9kcal energy
72
fuel choice
CHO storage in the body is limited to less than 2000 kcals
fat stores are significantly higher, generally exceeding 70,000kcal
73
CHO fuel source of choice
fat is less accessible for metabolism (much process )
-much be broken down from its complex form
_______________
to its basic form
--------------
*only free fatty acids are used to directly form ATP
triglyceride
glycerol and free fatty acids
74
proteins
not typically used as fuel; but can be if other fuels are depleted or less available (ultramarathon, caloric restriction)
75
fats and protein = aerobic metabolism
sharing common pathways
the first stage is different
CHO=
fats=
proteins=
similar from
glycolysis
beta oxidation
deamination
citric acid cycle and on
76
overview of energy release from macronutrients
carbohydrate oxidation via
glycolysis
glucose broken down produce pyruvate, with oxygen produce acetyl co A
77
overview of energy release from macronutrients
fat oxidation via
beta oxidation
fatty acids broken down to produce acetyl co A
78
overview of energy release from macronutrients
protein oxidation via
deamination
some amino acids broken down to form pyruvate or acetyl Co A
79
fat digestion - liver
after being taken up by the digestive tract triglycerides are packaged in chylomicrons
liver take up chylomicrons , re-packages triglycerides into lipoproteins
80
lipoproteins
triglycerides, cholesterol and proteins
81
high density lipoproteins (HDL)
low triglyceride content
82
low density lipoproteins (LDL)
medium triglyceride content
83
very low density lipoproteins (VLDL)
high triglyceride content
84
fat catabolism
complete oxidation of a triacyglycerol molecule yields about molecules
460 ATP
85
fat catabolism
________- serves as the most plentiful source of potential energy
stored fat
86
fat catabolism
fat becomes the primary energy feul for exercise and recovery when intense, long-duration exercise depletes both _______________________
glucose and muscle glycogen
87
fat catabolism
fat supplies 30-80% of energy for biologic work depending on:
-nutritional status
-level of training
- intensity of physical activity
-duration of physical activity
88
fat catabolism
total fuel reserves from fat in a young healthy adult male
60,000 to 100,000kcal stored in adipocytes
3000kcal stored in intramuscular triacyglycerol
89
fat storage
stored fat is the body's most plentiful source of potential energy, but slow
90
energy release from fat
mobilization
-first step in utilizing fatty acids is
-triglyceride is split into 3 fatty acids and glycerol
HSL- hormone sensitive lipase drive lipolysis
91
glycerol
-a carbon backbone
-can be made from glucose
-can be made into glucose (gluconeogenesis in the liver)
92
fatty acids
long carbon chains
93
saturated fatty acids
carbons are "saturated" with hydrogen atoms
94
unsaturated fatty acids
some of the hydrogen atoms are gone
mostly from plants
95
triglycerides (fats) are broken down trough lipolysis by the HSL enzyme (hormone sensitive lipase) into ___________
fatty acids and glycerol
96
glycerol can indirectly be converted to glucose (in liver) to be used in citric acid cycle (can not be used directly as glycerol)
97
FFA can be oxidized through beta oxidation to produce the end product
_________________
can not generally be used as glycerol
98
_________- enters into the citric acid cycle and so on
acetyl co a
99
beta oxidation
occurs in the mitochondria
fatty acid is broken down by 2 carbons at a time
formation of acetyl coA= 2 carbon molecule
100
one enzyme of beta-oxidation that is often measured = hydroxyacyl dehydrogenase
101
glycerol and fatty acid catabolism summary
triacyglycerol molecule= three fatty acid molecules and one glycerol
fatty acid molecules = 147 ATP x 3 = 441 ATP
glycerol = 19 ATP
102
_________ is the commune entry point for CHO, protein and fat catabolism
pyruvate
103
____________ undergo the process of beta-oxidation
glycerol and fatty acids
104
_______- is driven by the enzyme hormone sensitive lipase
lipolysis
105
beta oxidation occurs in the ________
mitochondria
106
________ is a glycogenic molecule
glycerol
107
protein metabolism "glucose alanine" cycle
purpose: to maintain blood glucose levels
may provide 5-10% of energy needs during prolonged exercise
108
protein as a fuel source
-proteins are digested into amino acids
-useable forms of amino acids can be used either directly in muscle or by conversion to glucose (gluconeogenesis)
-amine group (NH3) must be removed first
109
removal of NH3 broken down to useable amino acid
oxidative deamination
-removal of NH3
-N secreted from the body
-filtered through kidney and eliminated through urine
-increases bodies need for water
-mainly in the liver
-deaminase (enzyme) involved
-convert deaminated amino acids to pyruvate or acetyl coA
-enter citric acid cycle for oxidation
110
proteins as a fuel source
amino acids are
glucogenic
ketogenic
glucogenic (can convert glucose)
-when deaminated will form
pyruvate
oxaloacetate
malate
ketogenic
-when demented will form
acetyl coA (for citric acid cycle)
acetoacetate
111
importance of amino acids during aerobic exercise
replenishment of intermediates of the Krebs cycle
amino acids can be converted to glucose in the liver. this glucose can then go back to the muscle to be used as a fuel source
112
review
3 broad stages for macronutrient use in energy metabolism
1. digestion, absorption and assimilation into useful form
2. degradation into subunits of acetyl coA
3. oxidation of acetyl coA and H20
113
what regulates energy metabolism
overall energy state dictate the direction of the metabolic pathways
rate limiting modulators
-ATP: high ATP to ADP ratio indicate low energy requirement = no need to restore ATP
-ADP= high ADP to ATP ratio indicates high energy requirement = need to restore ATP= increased metabolism of stored nutrients
others:
cyclic AMP
NAD
calcium
pH
114
normal effects
lipolysis is stimulated by
epinephrine
norepinephrine
glucagon
growth hormone
these hormones increase during exercise and augment delivery of FFA to muscle
intracellular mediator
-cAMP activates hormone-sensitive lipase to start breakdown of fat
115
the metabolic hill
-interrelationships among CHO, fat and protein metabolism
-citric acid cycle as the vital link between food energy and chemical energy
-when excess CHO or protein is ingested it is converted to fat
116
117
the metabolic hill
Glucose (CHO) conversion to fat
-lipogenesis (formation of fat)
-citrate diverted to cytosol
-fatty acids are synthesized
118
The metabolic hill
protein conversion to fat
excess amino acids deaminated
convert to pyruvate then to acetyl-coA
fatty acids are synthesized if no energy required
-if energy would be used in the citric acid cycle
119
the metabolic mill
slower rate of energy release from fat
rate of fat oxidation is slower than that for carbohydrate
-carbohydrate oxidation helps maintain fat oxidation rates
-carbohydrate depletion impairs exercise performance
-glucose = neural
-glycogen=muscular fatigue
120
glycogen depletion
-prolonged exercise (marathon type activities)
-intense training
-inadequate total caloric intake
-inadequate CHO intake (low CHO diets)
-diabetes
121
important enzymes for ATP-CR system
ATPase: ATP---- ADP+P+free energy
creatine kinase (CK): PCr-- P+ CR
122
important enzymes for glycolysis
phosphofructokinase (PFK): rate limiting enzyme
lactate dehydrogenase (LDH): pyruvate ----- acetyl CoA
intermediate =
pyruvate dehydrogenase (PDH): pyruvate ---acetyl CoA
123
importnat enzymes CAC/krebs cycyle
citrate synthase (CS): measure mitochondrial volume
succinate dehydrogenase (SDH): measure mitochondrial volume
isocitrate dehydrogenase (IDH): rate limiting enzyme
124
important enzymes ETC
cytochrome oxidase: can be measured to determine capacity of ETC
125
important enzymes lipolysis
HSL: hormone sensitive lipase
126
important enzymes glycogenolysis
phosphorylase
127
important enzymes beta oxidation
hydroxyacyl dehydrogenase (HOAD): rate limiting enzyme
128
important enzymes for deamination
deaminase
129
important enzyme for transmutation
transaminase
130
review glycolysis and CAC/Krebs cycle
-glycolysis and CAC/Krebs each produce a small amount of ATP
-main function is to supply hydrogen (and in turn electrons) to 3rd stage of respiration (ETC)
-hydrogen carriers NADH+ FADH2 (reduced coenzymes of NAD and FAD) transport electrons from H to ETC
131
ETC-OP review
in the ETC hydrogen atoms are split into protons and electrons
the electrons are pumped across the membrane
-providing energy for phosphorylation of ADP to form ATP
-(oxidative phosphorylation)
end products are H2o and ATP
energy yield:32 ATP
132
glycogen depletion
-prolonged exercise (marathon type activities), connective dyes of intense training
-inadequate total caloric intake
-inadequate CHO intake (low CHO diets)
-diabetes
133
fat breakdown review
fats (triglycerides) broken down via lipolysis to glycerol and 3 fatty acids
fatty acids oxidize via to acetyl coA
-enter Krebs cycle and so on
-H released and carried by NADH to
134
protein breakdown review
protein broken down to amino acid
-removal of NH3
deamination (transmission)
-amino acid to pyruvate or acetyl coA, enters Krebs cycle and so on
-H released and carried by NADH to ETC
135
importance of blood glucose
blood glucose levels must remain stable because nerve and brain tissue depend heavily on glucose
glucose (simple CHO) is stored as glycogen (complex CHO) in muscle and liver
136
how do you think insulin hormone changes during exercise
release in the blood stream
decrease in exercise
-promotes uptake and storage of glucose as glycogen in liver and muscle, promotes utilization of glucose by other tissues in the body
promotes uptake of amino acids into muscle (where they are converted to proteins)
promotes uptake of fatty acids into adipose tissue (where they are stored as triglycerides)
-inhibits glucogenogenesis
137
how do you think epinephrine hormone changes during exercise
release in the blood stream
increase in exercise
simulates glycogen breakdown (glycogenolysis)
stimulates the breakdown of triglycerides in adipose tissue
suppresses insulin secretion
stimulates gluconeogenesis
138
how do you think glucagon hormone changes during exercise
release in the blood stream
increase in exercise
stimulates glycogen breakdown in liver (glycogenolysis)
stimulates gluconeogensis
139
how do you think cortisol hormone changes during exercise
release in the blood stream
increase in exercise
stimulates the breakdown of protein to amino acids
stimulates breakdown of fats (TG) from adipose tissue
stimulates gluconeogenesis
140
during exercise
glucose...
-glucose uptake (from the blood) by muscle increases
-to maintain blood glucose levels, glucose must be related by the liver
141
depletion
if muscle uses glucose during exercise and liver releases glucose (which can then be used by the muscle) how does the body prevent the liver from running out of glucose ?
the conversion of metabolites (lactate, glycerol, pyruvate, amino acids) into glucose is called "glucogenesis aka "glycogenesis"
*fatty acids cannot be converted to glucose
142
how does glucose get into the muscle fiber form the blood ?
-glucose transport proteins (GLUT-4)
-migrate from inside the muscle to muscle membrane in reposes to exercise
-once at membrane, allow glucose to travel into muscle
143
if you want to replenish glycogen stores after performing Lon, intense exercise, when is the best time to consume CHO ?
Immediately after
as GLUT-4s will be at the muscle membrane and allow glucose to enter muscle
144
what hormone that allows uptake of glucose into skeletal muscle, is lacking in individual with type I diabetes
insulin
145
what population might have very low GLUT-4 levels in muscles, which may contribute to development of type II diabetes ?
inactive and obese populations
146
hormones involved in glucose metabolism
in resting muscle:
insulin is high after a meal
-packs metabolites (fat, protein, CHO) away into tissue
-insulin release is inhibited/suppressed during exercise
147
147
glycemic index 1-100
low
moderate
high
low<40
moderate 40-60
high > 60-100
glucose = 100
148
glycemic index has considerations for
diabetes
obesity
exercise performance
149
what is the best CHO meal to consume before endurance exercise
white toast
white potatoes
whole wheat spaghetti
lentils
why?
lentils
because they have a very low glycemic index, and they are a complex CHO
because the energy sources will be available in the body throughout exercise
150
what is the CHO meal to consume before endurance exercise WHY?
white bread 69
white potatoes 70
whole wheat spaghetti 42
lentils 29
151
ingestion of high glycemic food- high levels of glucose released into the blood stream
-significant insulin related in response
-large uptake of glucose
-potentially resulting in hypoglycaemia
152
low blood sugar would in turn signal increased breakdown of glycogen and could result in earlier glycogen depletion
153
high GI food should not be eaten within 60 min prior to aerobic exercise
154
Low GI vs. mod GI prior to endurance exercise
-low GI lentil bar vs moderate GI power bar
-ingested prior toe exercise of 75 minutes of cycling
-low GI had significantly higher levels of fat utilized during exercise, thus sparing glycogen
-with high GI, get spike in insulin production which inhibits fatty acid oxidation
155
hormone involved in glucose metabolism
why the redundancy
-epinephrine, glucagon, cortisol
-released during exercise to stimulate gluconeogenesis
why the redundancy?
control of blood glucose levels is so important for survival that several hormones play similar roles so that if one hormone isn't working there is a back up
156
glucagon
stimulates glycogen breakdown in liver (glycogenolysis)
157
epinephrine
stimulates glycogen breakdown in liver (glycogenolysis)
stimulates breakdown of triglycerides in adipose tissue
158
cortisol
stimulates breakdown of triglycerides from adipose (lipolysis)
stimulates breakdown of protein to amino acids
159
which of the following does NOT stimulate gluconeogenesis
a. cortisol
b. epinephrine
c. glucagon
d. insulin
insulin
160
metabolic adaptations to exercise training
ATP production, storage and turnover 1. ATP-pc
see changes in: ATP production, storage and turnover
equal ATP per gram of precursor fuel
increased ATP-PC software
-spring training (increase ATP 100%, PC 40%)
-interval training (increase PC 20%)
decreased depletion at same absolute workload
increased ATP-PC turnover
161
what popular nutritional supplement has been used to speed up the rate of phosphocreatine resynthesis following exercise?
creatine
162
creatine-phosphate + ADP= creatine + ATP
theoretically an increase in creatine would drive the recovery reaction (drive the reaction to the left)
163
why do some studies show that creatine supplementation doe snot improve the rate of creatine-phosphate recovery after exercise?
ATP, energy requiring reaction as well
Reversing ADP but need ATP to do it
164
during recovery, reysnthesis of creatine phosphate depends on ATP supplied by the aerobic energy system
165
if taking nutritional supplements (proteins, amino acids, creatine) to promote muscle mass gain, it is important to ensure they are NOT taken in close proximity of exercise
true or false
FALSE
you should take them in close proximity
166
Metabolic adaptations to exercise training
Carbohydrates
increase muscle and liver glycogen
slower rate of glycogen depletion
less CHO in fuel mixture
increased rate of glycogenolysis (sprint training)
167
metabolism adaptations to exercise training
fat
increased mobilization of FFA from adipose
increased plasma FFA during sub-max exercise
Increased fat storage adjacent to mitochondria within muscles
increased ability to utilize fat
168
carnitine
increased muscle carnitine content transports fatty acids muscle (translocation) thereby increasing fat oxidization (beta oxidation) and reducing muscle glycolysis, and increasing glycogen storage
169
oral ingestion of Carnitine
although oral ingestion has been found to enhance fat metabolism in animals, research has not been able to conclusively find this in humans
170
metabolic adaptations to exercise training
protein
increased ability to utilize leucine
(ketogenic= acetyl coA)
increased capacity to form alanine
(glycogenic = pyruvate)
171
metabolic adaptations to exercise training
enzymes, O2 utilization, lactate
enzyme activity
oxygen utilization
lactate accumualtion
172
metabolic adaptations to training
enzyme activity
1. glycolytic enzymes (anaerobic training)
-increased glycogen phosphorylase activity
- increased PFK activity
-decreased LDH activity
173
metabolic adaptations to training
enzyme activity
2. mitochondrial enzymes (aerobic training)
-increased size and number of mitochondria
-increased activity of most of the enzymes of the Krebs cycle, electron transport and oxidative phosphorylation
174
metabolic adaptations to training
oxygen utilization (aerobic training)
1. maximal oxygen consumption increases
2. sub-maximal oxygen cost decreases
-increased myoglobin concentration
175
metabolic adaptations to training
lactate accumulation (aerobic/anaerobic)
1. decreased La accumulation at sub-maximal workloads
2. increased workload to achieve lactate threshold
3. increased maximal La
176
lactate accumulation
-blood lactate threshold
-lactate production exceeds clearance
-average for untrained = 55% max aerobic capacity
-training increases lactate threshold
177
what type of motor unit would be recruited when workload is easy? what type of motor unit would be recruited when workload becomes hard?
Type I, type II
178
which muscle fiber type would more likely produce lactate
type II
179
how would an increase in mitochondria affect the lactate accumulation? (increases number and size)
It would decrease it
one of the major adaptations of aerobic training
180
effect of aerobic training
-increases the number and size of mitochondria in your muscle fibres
-increases the chance that pyruvate or lactate, formed during glycolysis, will be taken up by mitochondria for oxidation
-decreases the build up of lactic acid
-decreases fatigue
181
which is a better predictor of endurance performance: VO2 max or anaerobic threshold
why?
Anaerobic threshold
Both predict performance
but anaerobic threshold is better predictor
-lactate accumulation, glycogen sparing, delaying the shift to anaerobic sources
-if you are in a along endurance event and you can maintain a longer percentage of VO2 max with out hitting anaerobic threshold, pace would be better without producing lactate
Will not reach anaerobic threshold till later in exercise than someone with not as good anaerobic threshold
182
if you are in charge of scheduling a one-day track and field meet how much tie should you allow between the qualifying heats and the final heat for the 400m run
it would take a couple hours (2-3hr ) for full recovery
183
why should athletes involved in mainly anaerobic sports (hockey, football) also incorporate some aerobic training into their programs
Aerobic system is needed to replenish anaerobic fuel sources
-to also move lactate that has been built up
