Answer:
Neurotransmitters are endogenous chemicals that are released by axon terminals of neurons into the synaptic junctions and act locally to control nerve cell functions.
•Imbalance of neurotransmitters such as serotonin,norepinephrine and dopamine have been linked with depression.
•Abnormal levels of neurotransmitter glutamate leads to changes in the level of Dopamine which can cause transition into psychosis.Dopamine has been implicated as possible cause of schizophrenia.
•Several transmitters are involved in analgesia system (pain suppression),especially involved are enkephalin and serotonin. When Serotonin are released and this causes local cord neurons ti secrete enkephalin,which is believed to cause both presynaptic and postsynaptic inhibition of pain fibres.
•Parkinson's disease also known as paralysis agitans results from widespread destruction of that portion of substantia nigra that sends dopamine-secreting nerve fibres to caudate nucleus and putamen this leads to decrease in dopamine.
•Acetylcholine is responsible brain arousal and muscle contraction.
Answer:
The ability of sequences within the leader mRNA to pair with one another and form stem-lopp structures
Explanation:
A form of feedback regulation controls the trp operon by regulating transcription termination, a mechanism referred to as Attenuation.
-In the presence of high concentrations of tryptophan, RNA polymerase ceases transcription shortly after initiation in a region called the leader sequence.
-If the concentration of tryptophan is low, transcription does not terminate until the entire operon is transcribed. The mechanism of attenuation links alternative RNA secondary structures to transcription termination.
-Immediately after transcription, RNA from the leader region folds into one of two alternative secondary structures.
-One of these structures is a transcription termination signal that stops RNA polymerase from continuing to the end of the operon.
-The alternative structure does not contain a transcription termination signal and allows transcription of a single mRNA that encodes all the structural genes.
-The decision as to which of the two alternative RNA structures formed is regulated by the concentration of tryptophan.
Answer:
A. solar energy in the rays of sunlight
Explanation:
photons in the sunlight rays will excite the electrons in the water molecule and hence will provide the energy for calvin cycle.
Bioaccumulation refers to the accumulation of a toxic chemical in the tissue of a particular organism.
Biomagnification refers to the increased concentration of a toxic chemical the higher an animal is on the food chain.
