Question

All of the following are true regarding a neurotransmitters Except:

a) they can generate a postsynaptic potential

b) they may be taken up through the membrane of the postsynaptic cell

c) they may diffuse away from the synapse

d) they may be degraded by an enzyme in the postsynaptic cell’s membrane

e) they may open a chloride ligand gated channel

2) Testosterone, estradiol (estrogen) and cortisol are all made from

a) eicosanoids

b) thromboxane

c) chains of amino acids

d) triglycerides

e) cholesterol

Answer 1

1.Answer: B.

They (Neurotransmitters) are not taken up into the post-synaptic cell.As the action potential of the presynaptic neuron reaches in the axon terminal of the pre-synaptic neuron,the vesicles containing the neurotransmitter molecules move towards the cell membrane and fuse with it to release into the synaptic cleft and bind to the receptors of the post-synaptic neuron.This interaction makes the Ligand gated Cl- channels to open and influx of the ions into the cell.

Eventually, the neurotransmitters are cleared away from the synaptic cleft either by a diffusion or re-uptake into the presynaptic neuron.This neurotransmitter can be recycled and re-used.In some cases enzymes break down the neurotransmitter inside the synaptic cleft. Then the component parts of the neurotransmitter can be passed to the presynaptic neuron for the further synthesize of the neurotransmitter.

2.Answer E.

Testosterone, cortisol and oestrogen are steroid hormones(A class of chemical compounds).

• Testosterone is produced from the Leydig cells of testis(Male reproductive organ)
• Oestrogen is produced by the ovaries(Female reproductive organ) & from placenta (During pregnancy)
• Cortisol is produced from the adrenal cortex.

All steroid hormones are derived from the Cholesterol.

Cholesterol is precursor molecule of 5 main types of steroid hormones ;

1. Progesterone
2. Glucocorticoids (e.g.. Cortisol)
3. Mineralocorticoids
4. Androgens
5. Oestrogen