Answer:
b) opening calcium pores in the membrane
Explanation:
The opening of calcium ions channels facilitates the migration of vesicles containing neurotransmitters in the pre-synaptic neurons to the tip of the post-synaptic membrane. at the <u>neuromuscular junction </u>These neurotransmitters can either be <u>cholinergic or non-chorlinergic.</u> <u>At the tip of the pre-synaptic membranes the vesicles empty their neurotransmitter contents into the synapse.</u>
The neurotransmitters, diffuse through the neuromuscular junction to bind with the receptors on the <u>post-synaptic membrane on the post-synaptic neuron.</u> This stimulates opening of<u> ligand gated sodium ions,</u> and sodium ions diffuse into the post-synaptic neuronal membrane, to cause <u>depolarization</u>. if the stimulus is up to the threshold levels it generate action potential.
Therefore , more calcium ions channels opening produces; more diffusion of neurotransmitters;leading to opening of more sodium channels for depolarization; and IPSP or EPSP generation.
Answer:
According to the sliding-filament model of contraction, the muscle contraction occur due to the myosin heads propel the actin myofilaments toward the center of the sarcomere. This pulls the Z disks closer together, shortening sarcomere and the entire muscle
Explanation:
In the muscle fiber there are two proteins that facilitate the process of contraction, myosin and actin. Myosin is thicker and more abundant than actin, and its interaction is responsible for the process of muscle contraction.
Both molecules, myosin and actin, form bonds -called cross bridges- where the myosin heads produce the mobilization of actin towards the center of the sarcomere. Z discs are associated with actin myofibrils, so they come close, and promote the shortening of the sarcomere.
This process requires the action of calcium ions, which depolarize the muscle cell and consume energy in the form of ATP.
It should be noted that the myosin and actin molecules do not change their length, but their action causes the muscle fibers to shorten during contraction.
Learn more:
Types of muscle contraction brainly.com/question/7117064
Lions are usually bigger.
Answer:
The repeating subunits of DNA are ribonucleotides whereas in RNA they are deoxyribonucleotides.
Explanation:
Ribonucleotides are repeating subunit of RNA while the deoxy-ribonucleotides are repeating subunits of DNA. That why RNA full form represent the ribonucleic acid and DNA represent deoxyribonucleic acid.
Actually the word "deoxy" means one oxygen is removed or less in DNA. The DNA lacks the one oxygen atom of hydroxyl group at carbon number two of ribose sugar. While RNA have the hydroxyl group at carbon number two of hydrogen atom.
The removal of one hydrogen atom in DNA make it more stable than RNA because DNA is made specifically to store genetic information and needed to be strong. The oxygen atom in RNA makes it vulnerable for attack by other biological molecules.
The tropical rain-forest. It has much diversity and many different species. I believe there are 15 million types of animals and plants just alone in tropical rain forests.
