Answer:
4,3,1,5,2
4. Vesicles full of acetylcholine are stored at the axon terminal.
3. Action potential arrives at the neuromuscular junction.
1. Action potential is propagated in the sarcolemma.
5. Acetylcholine is released into the synaptic cleft.
2. Acetylcholine binds to ligand gated sodium channels.
Explanation:
Nerve impulse is generated from somatic motor neurons and reaches neuromuscular junction. The nerve impulse specifically reaches a region named 'synaptic end bulbs' at axon terminal. These synaptic end bulbs are in turn connected to the motor end plate region of a sarcolemma.
As soon as the nerve impulse reaches neuromuscular junction, it triggers the opening of voltage gated ion channels which in turn facilitate the influx of Ca²⁺ from the extracellular fluid to the inside of neuron where synaptic vesicles containing neurotransmitter acetylcholine are already stored.
The Ca²⁺ causes the exocytosis of synaptic vesicles which fuse with the plasma membrane of motor neuron as a result of which acetylcholine is released in the synaptic cleft.
The acetylcholine further binds with the acetylcholine receptor which is present at the motor end plate of a skeletal muscle fibre. These receptors are ligand gated ion channels.
Binding of acetylcholine with its receptor causes the ion channels to open and cations like Na⁺ enter the muscle fibre so as to make the electric potential inside the muscle positive.
There are many varying characteristics and exceptions to each type of protist.
They have been previously categorized based on what they are not.
They are all eukaryotes composed of one or more cells that contain nuclei.
There are no exceptions to the characteristics of each type of protist.
They are microscopic and therefore too small to study accurately.
Recent studies show that protists have not descended from one common ancestor.
Answer:
A plant’s ability to photosynthesize depends on a variety of factors, including the amount of available sunlight. Plants also go into a protective mode after an environmental crisis, which helps protect the plants’ chloroplasts from damage. During this period, photosynthesis is low. The technique used in this research improved the plants’ ability to recover after a crisis, boosting plant growth and crop yield. This research could ultimately lead to growing crops successfully in different types of environments and in a shorter period of time.
Answer:
DNA stores that info
Explanation:
In eukaryotic cells (ex. plants and animals) the DNA is found in the nucleus of the cell. Structures called ribosomes build proteins (this process is called translation).
The correct answer is option (B) continental drift.
Continental drift is a theory explaining the movement of the earth’s continents over the geological time scale, drifting across the ocean bed. It was proposed by Alfred Wegener in 1912. Similar plants and animal fossils found around the shores of the different continents suggests that these continents were once joined as a single super continent named Pangaea. This Pangaea broke up long ago and the continents moved to their current positions. The ancient fossils of the same species of plants and animals were found on rocks of the same age but on the continents that are now widely separated.
