Question

What structures are found in the cytoplasm, near the plasma membrane, at the axonal end of neuron: a) Voltage sensitive Na^+ channels b) Neurotransmitter Receptors c) Secretory vesicles d) mitochondria e) nucleus What protein is found (evenly distributed) along the entire length of the cell's plasma membrane: a) Voltage sensitive Na^+ channels b) Neurotransmitter Receptors c) Secretory vesicles d) nucleus e) mitochondria Proteins found exclusively at the dendritic end of the neuron: a) Voltage sensitive Na^+ channels b) Neurotransmitter Receptors c) Secretory vesicles d) nucleus e) mitochondria What lipid is the major component of the plasma membrane: a) long chain fatty acyls b) steroids c) phospholipids d) aminolipids Selective permeability allows all biological membranes to be freely permeable to: a) CO_2, O_2, H_2 O b) Na^+, Cl, H_2 O c) glycerol and small nonpolar monomers d) all polymers What is the name when the signal molecule that travels from the producer cell to the target cell through the circulatory system (in the bloods stream): a) autocrine b) paracrine c) endocrine d) exocrine What is the name when signal molecules that are made by producer cells that are adjacent to target cell (cells are physically close to each other), and the signal molecules travel through (diffuses) the extracellular fluid that both producer and target cells share: a) autocrine b) paracrine c) endocrine d) exocrine e) duocrine

Answer 1

9. Since plasma membrane is principally constitued of units of a single glycerol molecule, two fatty acid tails and a phosphate linkage and since this unit is called as phospholipids, the option (c) is correct for this question.

10. Molecules small enough to squeeze through the gaps in the cell membrane, can pass through it. CO₂ , O₂ and H₂O are small molecules, so option (a) is correct. Similarly, it allows Na⁺ , Cl^-to pass through as well. Therefore, option (b) applies as well. This applies to the option (c) as well. However, not all polymers can pass through the cell membrane, so one can rule out option (d).

11. By definition, Endocrine signalling involves the signal molecules targeting distant molecules/cells and are channelled through the bloodstream. So the answer for this question is option (c).

12. Paracrine signalling, by definition, targets nearby cells and the signal molecule passes through the extracellular fluid between producer cell and target cell. Thus, the answer for this question is option (b)