Tumor-suppressor genes generally encode proteins that in one way or another inhibit cell proliferation. Loss-of-function mutations in one or more of these proliferation inhibitory proteins contribute to the development of many cancers. Prominent among the classes of proteins encoded by tumor-suppressor genes are:

A. Intracellular proteins that regulate or inhibit entry into the cell cycle

B. Receptors or signal transducers for secreted hormones or developmental signals that inhibit cell proliferation

C. Checkpoint pathway proteins that arrest the cell cycle if DNA is damaged

D. Proteins that promote apoptosis

Following genes belongs to the above class-

i. p53

ii. Rb

iii.TGF- β

iv. Caspase 3 and 7

which of the following match is correct?

#Question id: 11207

#Unit 7. System Physiology – Animal

In multiple sclerosis, the myelin sheaths around the axons of the brain and spinal cord are damaged and demyelination results. How does this disease manifest at the level of the action potential?

 I) Action potentials move in the opposite direction on the axon.

 II) Action potentials move more slowly along the axon.

 III) No action potentials are transmitted.

#Question id: 11206

#Unit 7. System Physiology – Animal

Tetrodotoxin blocks voltage-gated sodium channels, and ouabain blocks sodium-potassium pumps. If you added both tetrodotoxin and ouabain to a solution containing neural tissue, what responses would you expect?

#Question id: 11205

#Unit 7. System Physiology – Animal

What would probably happen if a long neuron had one continuous myelin sheath down the length of the axon with no nodes of Ranvier?

#Question id: 11204

#Unit 7. System Physiology – Animal

Why do Na+ ions enter the cell when voltage-gated Na+ channels are opened in neurons?

#Question id: 11203

#Unit 7. System Physiology – Animal

Which of the following statements about action potentials is correct?

#Question id: 11202

#Unit 7. System Physiology – Animal

If you experimentally increase the concentration of K+ inside a cell while maintaining other ion concentrations as they were, what would happen to the cell's membrane potential?