Answer:
The correct answer is "It prevents spontaneous muscle's contraction".
Explanation:
Muscle contraction is produce by the interaction of actin and myosin filaments. Basically, myosin binds to the active sites of actin, which produces a protein complex (known as actomyosin) that allows that the filaments slide past each other and generate a contraction. When troponin and tropomyosin block the active sites of actin prevents spontaneous muscle's contraction, because a nervous impulse is needed to remove the inhibitors and that myosin starts the contraction.
Answer:
a. substantia nigra
b. substantia nigra (it is repeated)
Explanation:
Parkinson's disease is a neurodegenerative disease that is caused by the death of neurons that release the neurotransmitter dopamine in the <u>substantia nigra</u>, or locus niger, -a region of the brain that regulates brain circuits that give the 'orders' to initiate voluntary movements- .
The lack of this neurotransmitter leads to the occurrence of the main symptoms suffered by patients: decreased movements, muscle stiffness, postural instability and tremor. These failures are generated by the abnormal way in which neurons work in the absence of dopamine through a mechanism that is not known in depth.
It is the second most frequent neurodegenerative disease, after Alzheimer's disease, with a prevalence of 2% in people over 65 years. The characteristic symptoms of stiffness, bradykinesia and tremor are associated with losses of neurons in the substantia nigra and dopamine depletion in the striatum. There are large cytoplasmic inclusions, called Lewy bodies, which are the pathological mark of the disease and appear predominantly in neurons that contain melanin of the nigra substance. Genetic studies in a subgroup of families with Parkinson's disease with autosomal dominant inheritance found a locus on chromosome 4q-21 23 and a mutation in the gene that encodes a synaptic protein, α-synuclein.
Answer:
A decrease in biodiversity causes a decrease in ecosystem stability, because a change to one organism will have a greater impact on the entire ecosystem. With greater biodiversity, the loss of one type of organism could be moderated by the adaptation of other organisms to fill its role.
I'm sorry but can you be a bit more specific on these following observations?
Cast- solid copy
Mold- hollow form
Carbon film- details left after an organism decays
Trace fossil-record of an organisms activity
Petrified fossils- living things turned into rock
