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NEET Questions / Zoology / Structural Organisation In Animals
A scientist is studying the effects of a novel neurotoxin on isolated neurons. The toxin selectively inhibits the anterograde axonal transport of vesicles containing neuropeptides. Which of the following processes would be MOST directly affected?
Myelination of the axon
Retrograde transport of growth factors
Synaptic transmission involving neuropeptides
Sodium-potassium pump activity
Which specific characteristic distinguishes the Nodes of Ranvier from the rest of the myelinated axon in terms of ion channel distribution?
High density of voltage-gated potassium channels
High density of voltage-gated sodium channels
Absence of ion channels
Presence of ligand-gated chloride channels
A patient presents with impaired coordination and balance. MRI reveals lesions specifically affecting the cerebellar Purkinje cells. Disruption of which neurotransmitter system is MOST likely contributing to the observed symptoms?
Cholinergic
Dopaminergic
GABAergic
Glutamatergic
A researcher is investigating the role of astrocytes in regulating synaptic transmission. Which of the following is NOT a function typically attributed to astrocytes in this context?
Recycling of neurotransmitters
Regulation of extracellular ion concentrations
Direct release of neurotransmitters into the synaptic cleft
Maintenance of the blood-brain barrier
Mutations in the gene encoding for connexin proteins can lead to various neurological disorders. Which aspect of neural function would be MOST directly affected by abnormal connexin function?
Axonal transport of neurotransmitters
Synthesis of myelin sheath components
Electrical coupling between adjacent neurons
Reuptake of neurotransmitters from the synaptic cleft
In cockroaches, the blood vascular system is described as open type. This implies:
Blood does not flow in well-defined blood vessels and bathes the tissues directly.
Blood flows in well-defined blood vessels and exchanges materials through capillaries.
Blood flows in a closed circulatory system with a four-chambered heart.
Blood flows in a closed circulatory system with a three-chambered heart.
Which specific structure in the cockroach's digestive system is responsible for storing food and initiating enzymatic digestion?
Gizzard
Malpighian tubules
Crop
Hepatic caeca
Cockroaches exhibit uricotelism. This means their primary nitrogenous waste product is:
Ammonia
Urea
Uric Acid
Amino acids
The primary function of the collateral glands in a male cockroach is:
Produce sperm
Store sperm
Form the outermost layer of the spermatophore
Nourish the developing sperm
The development of a cockroach is described as 'paurometabolous'. This term signifies:
Complete metamorphosis with distinct larval, pupal, and adult stages.
Gradual metamorphosis with nymph stages resembling the adult.
Direct development without any larval stage.
Development with a parasitic larval stage.
