The sodium – potassium pump is involved in establishing the resting membrane potential true or false
ANSWER: TRUE
Answer:
D
Explanation:
When a substance moves from low to high concentration it is moving against its concentration gradient, which requires more energy.
A. It depends on where it is moving, not the substance
OB. This is describing diffusion
OC. Does not require energy, it is passive transport through a semi-permeable membrane
Answer:
As this is DNA replication, this is the unwounding process
Explanation:
In DNA replication, the parent DNA to be replicated is unwound to enable access of the replication machinery (replisome) to this genetic material. The origin of replication will be identified first, which in the prokaryotes is only one, and in the eukaryotes, we have many. This sites are recognized by specific sequences on the genome. after this, melting of the DNA occurs at this origin creating a replication bubble and two replication forks. This allows for the unwinding of the DNA by the enzyme Helicases in the direction of the replication fork. Another enzyme present in this step is also the single strand binding proteins (SSB). These proteins function in the prevention of re-anealing of the unwound DNA strand by attaching themselves to each strands. Another enzyme called the topoisomerases also function here by reducing the torque (twisting) produced upstream of the replication fork as result of DNA unwounding. An example is the gyrase
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.
