Exam II Flashcards
anaerobic ATP synthesis
glycolysis
aerobic ATP synthesis
Kreb’s cycle
per molecule of glucose, each Kreb’s cycle yields:
8 NADH
2 FADH2
2 ATP
concentrations of citrate synthase (CS) and malate dehydrogenase (MDH) are indicative of what?
enzyme concentrations can indicate a tissue’s ability to synthesize ATP
redox balance in e- transport chain
ratio of reduced/oxidized NAD+/ NADH & FAD+/FADH2
role of metabolic water in e- transport chain
keeps the cycle going by passing e-
NADH produces ____ ATP from ATP synthase
~2.5
FADH2 produces _____ ATP from ATP synthase
~2 ATP
coupling
-links e- transport to oxidative phosphorylation
coupling is loose, which means ATP production is usually around 30 as opposed to a theoretical 38
-coupling is considered “tight” when the P/O ratio is high
uncoupling protein #1 (UCP1)
- maintains redox balance
- some animals use this to produce heat
-provides a path for protons to diffuse from the intermembrane space to the mitochondrial matrix without ATP synthesis
normoxic
normal O2 concentration
hypoxic
below 10% O2 concentration
anoxic
0% O2 concentration
LDH isozyme in pyruvate—> lactate
LDHm
LDH isozyme in lactate–> pyruvate
LDHh
beta oxidation
lipid metabolism
gluconeogenesis
pyruvate—> glucose
expensive, uses ~6 ATP
Glyconeogenesis
pyruvate—> glycogen
excess lactate is transferred to
the heart and/or the liver (Cori cycle)
muscle fiber (cell) types vary in
metabolism
slow oxidative muscles (SO)
-red/slow twitch
-300 ATP/sec
-aerobic metabolism
-lots of myoglobin, mitochondria, and capillaries
-small diameter
-slow to fatigue, low power
fast glycolytic muscles (FG)
-white/fast-twitch
-600 ATP/sec
-anaerobic
-lots of power output
-less myoglobin, mitochondria, and capillaries
-quicker to fatigue
fast oxidative glycolytic muscles (FOG)
-intermediate between FG+SO
-600 ATP/sec
the power of muscles is dependent on
enzymes in myosin heads
muscle contraction
Ca++ binds to troponin
muscle relaxation
Ca++ ATPase pumps release Ca++
typical locomotion muscles are composed of
90% myofibrils
10% sarcoplasmic reticulum, mitochondria, and glycogen
composition of rattlesnake shaker muscles
30% myofibrils
26% sarcoplasmic reticulum
17% glycogen
26% mitochondria
-they can contract ~90 times/sec
synchronus flight muscles in insects
neural input and muscle action potentials are evoked with each muscle contraction
asynchronous flight muscles in insects
-the muscle contracts more than once per nerve impulse
-very sensitive to stretching and can be activated with no action potential
-demands more mitochondria but are very efficient
synchronus muscle mechanism
- elevator muscles pull wings up
- depressor muscles pull wings down
asynchronous muscle mechanism
- Vertical muscles pull on the roof of the thorax, causing the wings to rise. The thorax widens and lengthens, and stretches the longitudinal muscles.
- Longitudinal muscles pull on the anterior and posterior ends of the thorax, causing the wings to lower. The thorax narrows and shortens, and stretches the vertical muscles.
O2 deficit
difference between theoretical O2 demand and actual O2 uptake
excess post-exercise O2 consumption (EPOC)
-the difference between theoretical O2 demand and actual O2 uptake at the end
-not well understood why it occurs, independent of LDH
-can be described as “heavy breathing” after exercise
pay-as-you-go-phase
making ATP as you use it as O2 supply levels out
in order for muscle contraction to occur, ____ must bind to ____
Ca++, troponin (TN)
ATP synthase
permeable to protons and that couples the motive energy of the diffusing protons to the synthesis of ATP from ADP
P/O ratio
-the number of ATP molecules formed per atom of oxygen reduced to water
-electrons that pass the entire length of the electron transport chain from NADH to oxygen
a cell is in redox balance for NAD if……
it can convert NADH back to NAD as fast as NAD is being converted to NADH
anaerobic glycolysis
the entire sequence of reactions that converts glucose to lactic acid
steady-state mechanism
-the cell remains essentially constant in its levels of ATP and of the precursors and by-products of ATP production
-maintains homeostasis
-theoretically free of intrinsic limitations
*usually aerobic ATP production
-resting state, such as sitting and reading
non-steady state mechanism
-depletes supplies, accumulates products, or otherwise alters the conditions of its own operation at rates fast enough that the mechanism is self-limiting/self-terminating
-cannot persist for a long duration of time
*usually anaerobic ATP production
-active, such as running a race
steady-state criterion (4)
- produces ATP as fast as it is used
- uses raw materials no faster than they are replenished
- chemical by-products are voided as fast as they are made
- does not cause other changes in cell function that progress to the point of disrupting cell function
role of phosphagens in ATP production
synthesized by use of high energy phosphate bonds taken from ATP and later donate phosphate bonds to ADP to form ATP
what is the most abundant phosphagen in invertebrates?
arginine phosphate
what is the most abundant phosphagen in vertebrates?
creatine phosphate, high concentration in resting muscle
muscle cells often have enhanced O2 stores because…
they contain myoglobin, which bind to O2 molecules in high concentrations
muscle fatigue
exercise-induced reduction in a muscle’s ability to generate peak forces and maintain power output
what is necessary for muscles that yield a high speed (hypothetically)?
- fast myosin
- weak troponin
- lots of SR + pumps
- lots of mitochondria
- lots of capillaries: O2 to mitochondria +glycogen
maximal exercise
a given individual in a particular state of training is capable of a certain maximal rate of O2 consumption
submaximal exercise
exercise that requires less than the maximum rate of O2 consumption
supramaximal exercise
exercise that requires more than an individual’s maximum rate of O2 consumption
supramaximal exercise transition phase
-demands ATP at a greater rate than can ever be supplied by steady-state aerobic catabolism
-the pay-as-you-go phase is never reached
-anaerobic glycolysis must continue to be tapped for ATP as long as the exercise continues; this causes increasing O2 deficit and lactic acid buildup
light submaximal exercise transition phase
-transition phases occur at the start and end
-no lactate produced
-replenish O2 and phosphagen stores
heavy submaximal exercise transition phase
lactate accumulates at the start and is metabolized at the end (EPOC)
with increasing duration of exercise, ATP production shifts from _____ to ______
anaerobic to aerobic
composition of fish muscle
-SO muscle makes up ~10% or less of the total trunk muscle; never exceeds 25%
-SO muscle is used for slow, steady cruising
-the majority of the trunk is made up of FG-like fibers
-FG fibers are used for bursts of high-speed swimming and is prone to fatigue
O. princeps
high altitude, CO
O. collaris
low altitude, AK
O. hyperborea
sea level, Russia
physiological differences in the lungs of the high altitude pikas
high altitude had bigger lungs+ more capillaries, but diffusion capacity remained unchanged
hematocrit
percent volume of whole blood
high altitude pikas hematocrit
-expressed less RBC and lower hemoglobin (Hb) concentration
-this hematocrit value makes the blood less viscous
-suggests that low Hb concentration is advantageous for high-altitude species
HOAD role in cellular respiration
enzyme that aids in the aerobic breakdown of fats
citrate synthase (CS) role in cellular respiration
-an increase in CS activity is considered to be an indication of an increase in mitochondrial size/density
-CS activity provides a measure of relative overall oxidative capacity
results of CS activity in O. princeps
-CS activity in the diaphragm of O. princeps was significantly higher than O. collaris
-CS activity in skeletal muscle showed little correlation with altitude
results of HOAD activity in O. princeps
-HOAD activity in the cardiac + diaphragm tissue of O. princeps was significantly greater than O. collaris
-HOAD activity in skeletal muscle showed little correlation with altitude
results of LDH activity in O. princeps
-total LDH activity showed a positive correlation to altitude in all tissues examined
-cardiac LDHm activity for O. princeps was significantly lower than other pika species
-in heart muscle, O. princeps had LDHh activity that was nearly 2.5x greater
-high-altitude adapted pikas had diaphragm tissue values that were greater in both LDHm and LDHh activity
-LDHh activity in skeletal muscle was up to 3.8x greater in O. princeps
by increasing CS activity/mitochondrial density in tissues with high oxidative demands, high-altitude pikas maintain…..
maintain aerobic metabolism at a sufficient level without a reliance on glycolytic means of ATP synthesis in tissues critical for O2 transport
metabolic depression
a regulated reduction in the ATP needs of the animal to levels below the needs ordinarily associated with rest in a way that does not present an immediate threat to life
to make ATP during anoxia, animals must turn to….
anaerobic catabolic pathways
when vertebrates turn to anaerobic catabolism, they almost universally produce…
lactic acid, which is never excreted
how do some species, such as turtles, survive in anoxic conditions?
-individuals will induce brain tissue depression, essentially resulting in induced comatose
-turn on anaerobic pathways to supply ATP needs; ATP demand decreases significantly
-the body produces a LOT of lactate; transported to the shell/bones and is neutralized through a buffer
metabolic depression in sea monkeys suggests that
-they enter a sustained state of profound metabolic depression when denied O2
- being exposed to ammonia suggests that metabolic depression is dependent on a low pH
O2 regulation
-maintenance of a steady rate of O2 consumption regardless of the level of O2 in the environment
-often involves active responses, such as an increase in breathing rate as the O2 level in the water/air declines
O2 conformity
the rate of O2 consumption starts to fall as the environmental O2 level falls
O2 regulation/conformity in redline darters (fast-moving streams)
-O2 levels tend to be higher because turbulence creates greater aeration
-lowering the concentration of O2 to 40-50% of the fully aerated levels causes a sharp depression of O2 uptake and deaths
O2 regulation/conformity in slack-water darter (slow-moving streams)
-O2 concentration may only be one-third as high as in fully aerated water
-these fish exhibit a much broader range of O2 regulation
-lowering the concentration of O2 to 40-50% of the fully aerated levels do not affect the O2 uptake
Humans and O2 conformity
-when people are asked to work hard enough that they take in O2 at their peak rate, their maximum rate of O2 consumption becomes a smaller and smaller fraction of their rate at sea level as altitude increases
-the cost of any particular form of physical exertion remains the same regardless of altitude
mechanism of anaerobiosis in goldfish and crucian carp
lactate (3c)—>pyruvate (3c) –> acetyl aldehyde (2c)—> EtOH (2c)
role of ADH in anaerobiosis
enzyme that converts acetyl aldehyde to ethanol
what purpose does the conversion of lactate to EtOH serve for anaerobiosis in fish?
-it does not increase ATP yield
-its principal advantage is believed to be that it makes the excretion of the carbon chains produced by anaerobic glycolysis possible
-ethanol is lost across the gills into the water that the fish inhabit
how does the presence of glycogen stores play a role in metabolic depression for fish?
-glycogen stores provide fuel for making ATP that keeps the brain functional in cold environments
-fish exhibit less metabolic depression than turtles, requiring an increased demand for anaerobic ATP synthesis
succinate fermentation
-under anaerobic conditions, the reductive branch of the TCA cycle is used, producing NAD+ and succinate
-easy to store
-faster to redox than producing lactate
-common in invertebrates, not possible in vertebrates
ambulatory locomotion
-slow-moving, moves spine side to side
-legs positions towards the side of the body, feet face outwards
-lots of energy is used to push up and swing arms
-ex: salamander, crocodile
cursorial locomotion
-running
-legs are underneath the body, toes point forward
-much more efficient
shoulder girdle in relation to sprawled posture (primitive reptile)
-brings a medially directed force toward the shoulder girdle, conferring on medial elements a major role in resisting these forces
-shoulder girdle is much wider
shoulder girdle in relation to limbs situated underneath the belly (placental mammal)
-as the limbs are situated more under the body, these forces are directed less toward the midline and more in a vertical direction
-the position of the limbs might account for loss of some pectoral elements (shoulder girdle is not as wide)
primitive reptile pelvic girdle force distribution
when the limbs are sprawled, propulsive forces are transferred more vertically through the sacrum
placental mammal pelvic girdle force distribution
orientation of the pelvic girdle changes so that the forward thrust of the hindlimbs is brought more into alignment with the line of travel and transferred to the vertebral column
faster, more efficient runners have ____ digits
-less
-results in smaller, firmer contact points
equation for speed
speed (m/sec)= stride length (m/stride) * turnover rate (strides/sec)
plantigrade
-heels, palms, MC, MT are all flat on the ground; most ancestral
-greater dexterity, bears and raccoons
digitigrade
-stands on toes
-longer lever arm, less surface area
-less dexterity, dogs, cats, etc
unguligrade
-stands on the tip of phalanges with hoofs
-very fast and efficient, horses
graviportal
-adaptation in order to bear a significant amount of weight
-slow moving
-elephants
maximum speed
-maximum movement of the lever arm
-muscles should be attached closer to the point of origin/rotation
muscle attachment further away from the joint results in
strong and slow movement
muscle attachment closer to the joint results in
weaker and fast movement
cost of locomotion
-small animals are slower than larger animals due to stride length
-O2 consumption is expensive for small animals regardless of if they are running at an incline/decline
what is the more efficient gait?
-running is more efficient than walking
-if you are efficient, the speed does not matter
cost of transport (COT)
-measure of energy used to move a unit of mass a certain distance
-lowest COT=more efficient
-at some point, the cost is virtually very similar, such as the difference between walking and trotting
COT is greater in _____ animals
smaller
ricochetal locomotion
2 footed hopping
saltatorial locomotion
4 footed hopping
drag
increasing resistance as the speed/velocity increases
how does extensive vertebral spinal flexion affect stride in cheetahs?
-increases stride length and speed
-not very efficient because it is energetically expensive
why do horses maintain a relatively flat vertebral column, how does it affect stride?
-the horse uses its speed for more sustained locomotion
-because they do not flex their spine, this makes their strides more energetically efficient
in order to stay aloft for the longest possible time, a bird should fly at the speed at which the ______ is minimal
metabolic rate
to cover the greatest distance, a bird should fly at the speed at which the __________ is minimal
cost of transport
metabolic rate
energy cost per unit of time
maximum rate of oxygen consumption
-a key property for the study of aerobic activity
-determines the peak rate at which the animal can synthesize ATP by aerobic catabolism; how intensely an animal can exercise in a pay-as-you-go-mode
-used to determine the strenuousness of all aerobic physical activity
ricochetal locomotion in tammar wallabies
-VO2 consumption remains the same despite their speed increasing
-their O2 consumption remains aerobic
-their tendons and muscles behave like a spring, so not a lot of energy is required
-it is more efficient for a wallaby to hop at full speed
minimum COT
-an allometric function of body weight for animals that engage in each primary mode of locomotion
-species that engage in a particular primary mode of locomotion tend to exhibit a regular relation between minimum COT and body size
fossorial locomotion
-digging
-further muscle attachment to the point of rotation
-short, thick bones
volant locomotion
-flying
-more costly energetically, but lower COT
glissant locomotion
gliding
Bernoulli principle
when air/liquid is moving faster, there is less pressure
airfoils (wings)
-increasing the angle will create more lift
-some sort of power is necessary: flapping, jumping
why is volant locomotion graphed as a U shape?
-starts with lots of flapping and then becomes more efficient as speed increases
-as speed increases, drag will increase
-to cover the greatest distance, a bird should fly at the at which COT is minimal
natatorial locomotion
-swimming
-one of the easiest forms of locomotion
-increased body weight will decrease COT
surface swimmers vs. underwater swimmers
-surface swimmers tend to expend more energy to cover distance
-underwater swimmers (besides fish) generally expend more energy to cover distance
fusiform
tapered at both ends, very hydrodynamic
root effect
decrease in Hg affinity for O2 in an acidic environment
O2 tension
O2 is not bound to Hg
swim bladder counter-current system
O2 lock, ensures gas doesn’t escape the swim bladder
migratory line (20 J/m*kg)
the minimum efficiency for migration
temperature
intensity of random molecular motion
heat
energy that something possesses because of random molecular motion
heat transfer
energy moves from high molecular motion–> low molecular motion
conduction
-transfer of heat through non-mobile objects
-usually in solids
equation for conduction (rate of heat transfer per unit SA)
K= T1-T2/d
Bergmann’s “Rule”
as you move further from the equator, endotherms of the same species will get larger
Allen’s “Rule”
animals in warmer environments have larger appendages than those in cold environments
convection
transfer of heat through mobile mediums
H convection equation
H convection= hc (Ts-Ta)
convection coefficient (hc) derivation
sqrt (V)/ sqrt (D)
-where v=wind speed and D= diameter
how does fur/feathers disrupt convection?
-warm air gets trapped in the follicles and circulates
-motionless/slow-moving air insulates very well
-as the air circulates, this increases the Ta, which therefore increases the Ts
evaporation
-breaking water molecules into water vapor
-pulls apart hydrogen bonds
-energetically expensive, takes ~500 calories
thermal radiation
a black object will absorb more thermal radiation and become warmer
Gloger’s “Rule”
animals from humid areas are darker and animal from arid environments are lighter
why do male phaniopepla birds have black feathers despite living in the desert?
-the black feathers absorb a majority of the heat
-allow for greater convection and airflow
active evaporative cooling
water evaporates from the surfaces of the body
shivering
-unsynchronized contraction and relaxation of skeletal-muscle motor units in high-frequency rhythms, mediated by motor neurons of the somatic nervous system
-when a muscle shivers, the conversion of ATP bond energy to heat becomes the primary function of contraction
-energetically expensive
non-shivering thermogenesis
-very common in placental mammals
-brown adipose tissue (BAT)
brown adipose tissue
-receive a rich supply of blood vessels
-well innervated by the sympathetic nervous system
-rich in mitochondria
-releases norepinephrine—> increasing the oxidation of stored lipids
UCP1 in BAT
-suspends the ordinary controls on the rate of aerobic catabolism, permitting unbridled rates of lipid oxidation
-causes the chemical-bond energy of oxidized lipid molecules to be released immediately as heat
