FINAL EXam Flashcards
Anabolism
refers to the metabolic pathways that synthesize complex molecules from simpler ones, using energy
example: making glucose from photosynthesis; proteins from amino acids
- requires energy
catabolism
refers to the metabolic pathways that break down complex molecules to simpler ones, releasing energy
example: cellular respiration(breaking down glucose)
- gives off energy
what is metabolic rate affected by?
Eactivity= altered skeletal muscle activity- exercise needs energy
- food-induced thermogenesis- digestion, absorption and use of stores
How does size effect metabolic rate?
the bigger you get metabolic rate drops since you can store more energy than a smaller animal
- the smaller you get the more energy use per gram less energy efficient
when grouping organisms together what is the overall slope of the graph
0.75 .
what is mass-specific?
resting metabolic rate scale with mass
what certain factors affect muscles and the force/production of movement and how?
- # of muscle cells in the tissue
- length of the muscle
- speed of contraction
- the force generated by any muscle will increase as you increase the:
-# of muscle cells in the tissue
- length of the muscle
The force generated by any muscle will decrease with the speed of contraction
a muscle is a bundle of what?
muscle fibres
during growth what takes place inside the cell?
hundreds of myoblasts fish to form a long, multi-nucleate cell
muscle fibres are filled with bundles of
myofibrils
myofibrils consists of stacks of what?
alternating thick and thin filaments
how are the thick and thin filaments in a myofibril organized?
they are arranged along the length of the myofibril in sarcomeres, which are the functional unit of muscles
under a microscope myofibrils appear what?
striated
what are the thin filaments in a muscle?
- actin: these wrap around each other in a helical manner
- tropomyosin: this is a long, rope-like protein that winds around the actin filament. It acts as a regulatory protein by blocking the binding sites for the myosin (thick filament) on the actin molecules
- troponin : this is a complex of three proteins that attach to tropomyosin. It plays a crucial role in muscle contraction by responding to calcium ions, which results in a change in the position of the tropomyosin, thereby exposing the binding sites for myosin
what are the thick filaments in a muscle?
- myosin
each myosin protein is a dimer of two polypeptides coiled around each other with a globular “head” at one end and a long helical “tail”
- dozens of myosin homodimers are arranged into thick muscle filaments with the head group sticking “out”
Each myosin head domain has?
ATP binding site: this is where ATP binds to the myosin head.
- Actin binding site :This site on the myosin head is where it attaches to the actin filament. When myosin binds to actin, it forms a cross-bridge, allowing the myosin head to pull on the actin filament, which contributes to muscle contraction.
Power Stroke Mechanism: The myosin head undergoes a conformational change after the ATP is hydrolyzed into ADP and phosphate. This change moves the head in a way that pulls the actin filament toward the center of the sarcomere, known as the power stroke. After the power stroke, ADP and phosphate are released from the myosin head, resetting it for a new cycle of muscle contraction.
what is a crossbridge?
the interaction between an actin protein and a myosin head group
what is the key thing when thinking about contraction in the sliding filament theory?
actin filaments do not get shorter
myosin filaments do not get shorter
what get shorter is the length of the sarcomere
- when muscle is fully contracted there is a massive overlap of actin+myosin
what is the sarcoplasmic reticulum?
- surrounds the myofibrils, which are the contractile units made up of sarcomeres
- this is where calcium is stored. When the muscle is relaxed, the SR stores calcium ions lowering the concentration in the cytosol
- when the there is a release of the calcium it is moved into the cytosol. this triggers the interaction of actin and myosin.
- after contraction calcium ions are pumped back into the SR, which helps muscle to relax
explain how muscle contraction is activated?
when a signal is received the motor neurone
1. opens ca- channels through facilatated diffusion
- ca ions then diffuse into the myofibril cytoplasm (cytosol)
what happens when the ca2+ enters the cytosol?
- Ca ions bind troponin on the actin filaments
- this causes tropomyosin to shift, exposing myosin-binding sites on the actin
- myosin+actin can now form a cross-bridge
the force generated during a muscle contraction increases when the number of what?
crossbirdges formed on a sarcomere increase
the force generated by any muscle will decrease with speed of contraction TRUE OR FALSE?
true
( rapid contraction decreases # of cross bridges)
The force generated by any muscle will increase as you increase the number of muscle cells in the tissue?TRUE OR FALSE
TRUE( more muscles = more sarcomeres)
the force generated by any muscle will increase as you increase the length of the muscle tissue true or false?
TRUE
longer the muscle cells= more sarcomeres
how does muscle relaxation take place?
- the facilitated ca2+ channels in the SR close ca can no longer leave the SR
- the ca2+ - ATPase pumps remove the ca from the cytosol
- troponin release Ca, causing tropomyosin to change into its original shape and block the myosin binding site
- unable to bind myosin, the actin filaments slide back, lengthening sarcomere, +relaxing the muscle
what are the different forces acting on a runner?
- Gravity: gravity constantly pulls the runner toward the ground, this is the #1 concern for the runner since the runner has to work against it to lift the body off the ground.
- Thrust : in running, thrust is the action of the leg muscles pushing against the ground
- this force propels the runner forward. This is not gonna generate much drag - Drag : Drag is the force that opposes the runners forward motion through the air
- this increases with the runner’s speed and the density in the air. this is not a big concern - muscle action : this is about how runners use there muscles to move, muscles help to overcome gravity by lifting the body and help fight drag by pushing the body forward.
what is metabolic rate?
amount of energy consumed by an animal in a given period ( measured by heat produced, O2 consumed, Co2 produced)
what is the mass-specific metabolic rate?
energy (volume of oxygen) required to move 1 unit mass of organism
unit: J/g x Km
What is the definition of Cost. of Transport?
energy required to move 1 unit mass of an organism 1 unit distance
Explain the Cot for larger animals compared to smaller animals?
the smaller the animal the greater the Cot cost of transport
- the larger the animal the lower the Cot
- velocity increase the lower the CoT
what are the different forces acting on a swimmer?
Gravity: this is the force that pulls the swimmer down. not important
Thrust: this is the force that swimmers generate by pushing against the water. Thrust propels it forward.
Drag: this is the number one concern, the resistance that the water provides against the forward motion of the swimmer. Drag slows the swimmer down.
Buoyancy: this is the force that acts upward, opposite of gravity. It helps keep the swimmer floating.
What are the two types of drag?
viscous drag: energy to move water over body
solve: scales or smooth skin
but small fish can’t swim fast because of viscous drag
- large, not a problem because muscularture to break the hydrogen bonds and break it with drag
- smaller fish tend to have adaptions which allow them to move rapidly in short Burts, useful to evading predators or catching prey.
Inertial forces: water fills void left behind as body moves
- Pressure drag primary force that affects larger fish, since they leave a larger void
- large fish can cruise at high speeds with less energy per unit of mass once they overcome the initial resistance. Their adaptions favour long- distance travel or fast cruising speeds to chase down prey or migrate
what is the forces that act on fliers?
Gravity: is the force that pulls the flier toward the earth
- all fliers must work against gravity to stay aloft. The strength of gravity dictates how much lift and thrust a flier must generate to rise off the ground and stay in the air BIGGEST RESISTANCE
Thrust: thrust is the force that moves the flier forward through the air
- is crucial for overcoming drag and gaining or maintaining speed. In birds, thirst is generated by flapping the wings
Lift: is the force that moves the flier upward, directly opposing gravity
- lift must be equal to or greater than gravity to ascend or remain upward.
- Thrift is when the wings generate lift to counter gravity
when does flying cost less CoT?
it becomes cheaper to fly the lighter the body weight to wing ratio
what is induced power?
energy required to fight gravity
what is parasite power?
the energy required to fight drag
Explain the general trend that takes place for a MSMR vs velocity?
when there is induced power and the velocity increases Energy required to fight gravity decreases
- when there is parasite power does not fight drag since it is not fighting gravity
- but when you draw a curve with both induced and parasite. There is a general trend where when velocity is low metabolic rate is high since it is fighting gravity, as velocity increases gravity becomes less of an energy since wings generating lift which lowers the curve, but then drag becomes more of an issue and so metabolic rate increases again as drag exponentially increases.
rank costs of transport from running, swimming, flying
1.running first
2.flying more efficient since wings counter gravity
3. most efficient is swimmers
what is homeostasis ?
the regulation of an internal environment in the face of changes in the external environment
what is the negative feedback mechanism ?
a change in a factor under homeostatic control that triggers a response that opposed that change.
eg. human Body, it helps regulate temperature by triggering cooling responses like sweating when body temperatures rise above normal
what makes up the negative feedback mechanism?
there is a stimulus: external (internal) change
sensor: detects the change
integrator: compares the signal to a set point
effector:a physiological or chemical that returns us to the set point
what is the positive feedback mechanism?
- tends to move a system away from its equilibrium making it more unstable.
sensor: this component detects changes in the environment or internal system that deviate from a target state or trigger an event.
for example, in childbirth stretch receptor in the cervix serve as sensors that detect the stretching caused by the baby pushing against the cervix
integrator: receives information from the sensor and processes it to determine an appropriate response. For example the brain acts as a control centre during childbirth by releasing oxytocin in response to the cervical stretching
Effector: carries out the response to enhance the original stimulus. In this case of childbirth, the effector would be the muscles of the uterus, which contract more strongly as a result from the oxytocin stimulation.
what is thermoregulation? what is ambient temperature what is body temperature?
- regulating the internal body temperature
- ambient: the temperature of the environment
- body temperature: of Tb is too low, membrane become to viscous + reaction rates are too slow
- if Tb is too high- membrane= leaky Rx rates stop due to denaturation
what are the three types of survivorship curves? AND WHAT IS SURVIVORSHIP CURVES USED FOR
survivorship curves allow us to predict the number of deaths
TYPE 1: these are the the species that where young have high survivorship
- have low/ few offspring
example. humans or larger mammals
TYPE 2:
- survivorship is independent of the age
- few offspring
- reptiles, birds ext. ectotherms
TYPE 3: these have a low survivorship or mortality
- lots of offspring
example plants and insects and fish
on a life history table what does each stand for?
X ?
nx?
sx?
lx?
mx?
R0?
x= age
nx= number of females at each age (x)
sx= survival rate from one age to the next
Ix= survivorship (fraction of original cohort still alive)
mx- fecundity
R0= net reproductive rate ( avg # female offspring per female in cohort over the cohort’s lifespan)
you find this my multiplying (lx)(mx)
explain the different points on a logistic growth curve from r changes with N .
1. When population size is low what happens to the r max
2. when there are more # of organisms what happens?
3. what happens when you reach carrying capacity
4. when it exceeds carrying capacity
- it is high since there is more room for increase in size it also means r>0
- the value of N increases, the value of r decreases. this means number of individuals being born decrease and number of indivudlas dying increase
- N=K
r=0
number of birth = number of deaths
its steady
- can’t support anymore but can support what we have - r<0
when N>k
- when greater than k, PER CAPITA GROWTH RATE IS LESS THAN ZERO SINCE TOO MANY INDIVIUDALS TO SUPPORT
- POPULATION DECLINE
