Answer and Explanation:
The steps of the sliding filament theory are:
Muscle activation: breakdown of energy (ATP) by myosin.
Before contraction begins, myosin is only associated with a molecule of energy (ATP), which myosin breaks down into its component molecules (ADP + P) causing myosin to change shape.
Muscle contraction: cross-bridge formation
The shape change allows myosin to bind an adjacent actin, creating a cross-bridge.
Recharging: power (pulling) stroke
The cross-bridge formation causes myosin to release ADP+P, change shape, and to pull (slide) actin closer to the center of the myosin molecule.
Relaxaction: cross-bridge detachment
The completion of the pulling stroke further changes the shape of myosin. This allows myosin and ATP to bind, which causes myosin to release actin, destroying the cross-bridge. The cycle is now ready to begin again.
The repeated cycling through these steps generates force (i.e., step 2: cross-bridge formation) and changes in muscle length (i.e., step 3: power stroke), which are necessary to muscle contraction.
Answer:
An association between two organisms in which one benefits and the other derives neither benefit nor harm.
Explanation:
Passive transport DOES NOT need energy(ATP), while active transport does.
Answer:
Trees have to adapt to their environments in order to survive them, from the shape of their leaves to the size of their branches. They also have had to adapt the shape of their crowns to the kind of climate they live in so that they may have better chances at survival.
In warm areas with lots of sunlight for instance, you will see broad cones as the tree takes advantage to get as much sunlight as it can. In colder areas where snow is abundant, trees will be conical in shape so as not to gather too much snow when it falls.
