Refer to the Graph Below

question 181

Multiple Choice

Refer to the graph below. The graph shows data for the amount of connexin protein present in cells of the right ventricle and cells of the left ventricle isolated from patients who experienced heart failure due to arrhythmia.The quantities are expressed as percentage of the amount of connexin protein present in controls, determined using heart cells from individuals without heart failure.Which hypothesis is supported by these data?

• A) Low numbers of gap junctions result in reduction of coordinated transmission of ions between adjacent heart cells.
• B) Gap junctions lose their specificity of particle transmission as the result of heart disease.
• C) Hundreds of gap junctions per heart cell, covering up to 25 percent of the cell surface area, are needed for healthy cardiac function.
• D) Mutations in connexin proteins can lead to reduced ability of gap junctions to facilitate rapid transmission of ions and small molecules between cells.
• E) The composition of a single gap junction includes six subunits of the protein connexin, which can be reduced to fewer than six in disease states.

---

Definitions:

Agonist

A chemical or drug that binds to receptors in the brain and activates them, thereby producing a biological response.

Euphoria

A feeling of great happiness or well-being, which can be induced by various factors including success, love, or certain drugs.

Parkinson's Disease

A progressive neurological disorder that affects movement, causing symptoms such as tremors, rigidity, and bradykinesia (slowness of movement).

Dopamine

A neurotransmitter in the brain associated with pleasure, movement, and motivation.