Molecular Biology Assignment: Electrical and Synaptic Signaling

This assignment delves into the core concepts of molecular biology, focusing on signal transduction mechanisms within neurons. It examines the GPCR pathway, receptor tyrosine kinases (RTKs), and the role of secondary messengers like cAMP. The assignment further explores the generation and maintenance of resting membrane potential, emphasizing the Na+/K+-ATPase pump. It also covers neurotransmitters, their functions, and examples of their inactivation processes within the synaptic cleft. The student's responses provide concise explanations of these key biological processes, supported by relevant references.

Running head: MOLECULAR BIOLOGY
MOLECULAR BIOLOGY
Name of the student:
Name of the university:
Author note

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MOLECULAR BIOLOGY
Question 1:
During the GPCR pathway, trimetric g protein breakdown to two subunits and exhibit
their activity. In this context, FRET can be performed for demonstrating the separation of G from
G subunits. Two proteins such as can be yellow fluorescent protein (YFP) and cyan fluorescent
protein (CFP) can be labeled and attached to the G subunit through genetic engineering. Labeling
with organic fluorescent dyes requires purification, chemical modification, and intracellular
injection of a host protein (Bajar et al. 2016). If trimetric G is present, these two proteins
together will provide emission at 414 nm. During the pathway, if the subunit of G separated then,
these two proteins will also cleaved and give yellow emission at 525nm.
Question 2:
Receptor tyrosine kinases (RTKs) that bind to protein hormones usually exist as dimers
or while binding to ligands. In this context, Ligand binding leads to activation of the kinase
activity of the receptor along with the auto phosphorylation of tyrosine residues in its cytosolic
domain (Wang 2016). Hence, after attachment with the ligand, it initiates a Signal Transduction
Cascade Involving Ras and MAP Kinase.
Question 3:
Secondary messenger is intracellular signaling molecules released by the cell in response
to exposure to extracellular signaling molecules. It is Camp. High levels of Camp inhibit PKA
and low levels inhibit PKA.

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MOLECULAR BIOLOGY
Question 4:
The resting membrane potential is a consequence of different concentrations of Na+ and
K+ ions inside and outside the cell. It is established the Na+/K+-ATPase which transports 2
potassium ions inside and 3 sodium ions outside at the cost of 1 ATP molecule.
Question 5:
Neurotransmitters is transmits signals across a chemical synapse.
 Serotonin: send a signal to the nerve
 Dopamine: send the signal to the brain
 GABA: inhibits nervous system (Ribeiro et al. 2016)
 Glutamate: send a signal to other cells
Question 6:
Two examples of the neurotransmitter inactivation:
 Released into the synaptic cleft
 After attaching to the cell (Bucher and Wightman 2015)

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MOLECULAR BIOLOGY
Reference:
Bajar, B.T., Wang, E.S., Zhang, S., Lin, M.Z. and Chu, J., 2016. A guide to fluorescent protein
FRET pairs. Sensors, 16(9), p.1488.
Bucher, E.S. and Wightman, R.M., 2015. Electrochemical analysis of neurotransmitters. Annual
review of analytical chemistry, 8, pp.239-261.
Ribeiro, J.A., Fernandes, P.M., Pereira, C.M. and Silva, F., 2016. Electrochemical sensors and
biosensors for determination of catecholamine neurotransmitters: a review. Talanta, 160, pp.653-
679.
Wang, Z., 2016. Transactivation of epidermal growth factor receptor by G protein-coupled
receptors: recent progress, challenges and future research. International journal of molecular
sciences, 17(1), p.95.