Parkinson's disease often involves the degeneration of neurons that produce , which are located in a brain area called the

Parkinson's disease often involves the degeneration of neurons that produce dopamine, which are located in a brain area called the substantia nigra.

Explanation:

Parkinson's disease is a disorder that is characterized by the progressive death of dopaminergic neurons and that leads to motor and cognitive disorders. This neuronal loss is located in the area of union between the brain and the spinal cord, the brainstem, particularly in those neurons that are in a nucleus called substantia nigra and more specifically, in a portion of this nucleus that is called the compact part. Dopamine is an amino acid that, in the brain, acts as a neurotransmitter, that is, it is capable of transporting information from one group of neurons to another through chemical and electrical mechanisms. Dopamine is responsible for transmitting information from the substantia nigra to other areas of the brain that form a connection circuit to each other. As a consequence of the degeneration of the substantia nigra, dopamine levels decrease, appearing the characteristic disorders of the disease, as the deterioration of movement.

you are certainly talking about this picture:

a: is the label of the white square, it is showing the  replication fork, formed by helicase (d) ==> so it is the site of dna separation and replication 

b: is a new dna brand that is following directly the replication fork, so it is continuous ==> built continuously from 5' to 3

c: dna polymerase cannot replicate dna on its own, it needs the of their proteins, and one of them plays the role of a clamp which fixes  the dna with the dna template and increases  the processivity of the enzyme. ==>   stops polymerase from falling off the  template.

d: is the enzyme responsible for forming the replication fork (helicase) ==> unwinds and separates dna into two strands

e: is the delayed strand, it is built  in the opposite sense of the helicase, so dna will be built in fragments ==> built  fragments from 5' to 3 joins

and finally f: is the enzyme that builds  the new dna strand (dna polymerase) ==>   adds nucleotides to make a new dna helix.

credit: gradman555p98x9p

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