Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

[EX Q]: Context: Human erythrocyte spectrin is an antiparallel heterodimer comprised of a 280 kDa alpha subunit and a 246 kDa beta subunit which further associates into tetramers in the red cell membrane cytoskeleton. Lateral association of the flexible rodlike monomers involves a multiple-step process that is initiated by a high affinity association near the actin-binding end of the molecule (dimer nucleation site). In this study, recombinant alpha and beta proteins comprising two or four "spectrin type" motifs with and without adjacent, terminal nonhomologous domains were evaluated for their relative contributions to dimer initiation, and the thermodynamic properties of these heterodimer complexes were measured. Sedimentation equilibrium studies showed that in the absence of the heterologous subunit, individual recombinant proteins formed weak homodimers (K(d) > 0.3 mM). When 2-motif (alpha20-21 and beta1-2) and 4-motif (alpha18-21 and beta1-4) recombinants lacking the terminal nonhomologous domains were paired with the complementary protein, high affinity heterodimers were formed in sedimentation equilibrium analysis. Both the alpha20-21/beta1-2 complex and the alpha20-21EF/betaABD1-2 complex showed stoichiometric binding with similar binding affinities (K(d) approximately 10 nM) using isothermal titration calorimetry. The alpha20-21/beta1-2 complex showed an enthalpy of -10 kcal/mol, while the alpha20-21EF/betaABD1-2 complex showed an enthalpy of -13 kcal/mol. Pull-down assays using alpha spectrin GST fusion proteins showed strong associations between all heterodimer complexes in physiological buffer, but all heterodimer complexes were destabilized by the presence of Triton X-100 and other detergents. Complexes lacking the nonhomologous domains were destabilized to a greater extent than complexes that included the nonhomologous domains. The detergent effect appears to be responsible for the apparent essential role of the nonhomologous domains in prior reports. Taken together, our results indicate that the terminal nonhomologous domains do not contribute to dimer initiation nor are they required for formation of high affinity spectrin heterodimers in physiological buffers. 
 Question: Alpha-spectrin and beta-spectrin subunits form parallel or antiparallel heterodimers?
[EX A]: antiparallel

[EX Q]: Context: The film opens with narration over a silhouette of Hill House at night. The narrator, Dr. John Markway (Richard Johnson) tells us, "An evil old house, the kind some people call haunted is like an undiscovered country waiting to be explored. Hill House had stood for 90 years and might stand for 90 more. Silence lay steadily against the wood and stone of Hill House. Whatever walked there walked alone." Title and credits follow, then narration continues, "Scandal, murder, insanity, suicide: The history of Hill House was ideal. It had everything I wanted..." The house was built in New England by a man named Hugh Crain for his wife and young daughter. A horse and carriage accident took the life of the first Mrs. Crain (an uncredited Pamela Buckley) before she even saw the house. Hugh Crain (an uncredited Howard Lang) and young daughter, Abigail (an uncredited Janet Mansell) said a few words over the body, but Hugh was left an embittered man. Crain married again, and the second Mrs. Crain (an uncredited Freda Knorr) also died, falling down the main staircase. Hugh Crain left Abigail with a nurse (an uncredited Susan Richards) and went to England where he died in a drowning accident. Abigail kept the same nursery room her entire life. By the time she was eighty (an uncredited Amy Dalby) she was a bedridden invalid. Her nurse-companion (an uncredited Rosemary Dorken) was a local girl and, it is with this young companion the evil reputation of Hill House really begins. The old lady died while calling for help. The companion was trysting on the verandah with a farm hand. The companion inherited Hill House and occupied it for many years, but eventually hanged herself. The house then passed to a distant relative, named Mrs. Sanderson (Fay Compton).Markway visits Mrs. Sanderson where he convinces her to let him use the house for psychic research. He explains, "I shall occupy the house with a group of carefully selected assistants...I must have specially qualified help to take notes and document any evidence of the supernatural I may find." Eldridge Harper (Ronald Adam), Mrs. Sanderson's lawyer, voices his concern about publicity seekers and the propriety of having women in the house. Harper suggests to Mrs. Sanderson that her nephew, Luke, joins the doctor at Hill House, as he expects to inherit the property. Mrs. Sanderson asks point blank, "Exactly what do you and your assistants expect to find at Hill House?" Markway replies, "Maybe only a few loose floorboards, and maybe, I only say maybe, the key to another world."Dr. Markway, taking a leave of absence from his university professorship, finalizes his list of assistants. Only two end up accepting, Eleanor Lance and Theodora (no last name).Eleanor Lance (Julie Harris) is living with her sister. She is nearly broke and weary after looking after her invalid mother non-stop for eleven years. Mother is now dead, and she fights with her sister over just about everything. She begs to use the car, which is after all, half hers. Her brother-in-law, Bud Fredericks (an uncredited Paul Maxwell) tries to act as mediator between Eleanor and his wife, Carrie (Diane Clare). He is sympathetic to Eleanor's plight, but their daughter, Dora (an uncredited Verina Greenlaw) takes her cues from her mother, and taunts her Aunt Eleanor. On the vacation plan, Bud sides with Eleanor, "I think you should have a vacation, Nell." Carrie objects, but Eleanor is not to be deterred and she shows her family how she reacts when pushed to her breaking point. She is normally quiet and meek, but when pushed is loud and assertive.Nell decides to take the car and confronts the garage attendant (an uncredited Claude Jones) for the keys. She departs Boston along U.S. 50 and Route 238 to Hill House. We hear Nell thinking and she reveals she will never return to live with her sister. In fact, most of what we learn of Eleanor is hearing her thoughts.Eleanor 
 Question: What is the ghost's name?
[EX A]: hugh crain

[EX Q]: Context: A chemical reaction is a process in which some substances change into different substances. Substances that start a chemical reaction are called reactants. Substances that are produced in the reaction are called products. Reactants and products can be elements or compounds. A chemical reaction can be represented by this general equation: Reactants ! Products The arrow (!) shows the direction in which the reaction occurs. The reaction may occur quickly or slowly. For example, foam shoots out of a fire extinguisher as soon as the lever is pressed. But it might take years for metal to rust. In chemical reactions, bonds break in the reactants and new bonds form in the products. The reactants and prod- ucts contain the same atoms, but they are rearranged during the reaction. As a result, the atoms are in different combinations in the products than they were in the reactants. Look at the example in Figure 8.2. It shows how water forms. Bonds break in molecules of hydrogen and oxygen. Then new bonds form in molecules of water. In both reactants and products, there are four hydrogen atoms and two oxygen atoms. But the atoms are combined differently in water. You can see another example at this URL: [Link] The arrow in Figure 8.2 shows that the reaction goes from left to right, from hydrogen and oxygen to water. The reaction can also go in the reverse direction. If an electric current passes through water, water molecules break down into molecules of hydrogen and oxygen. This reaction would be represented by a right-to-left arrow ( ) in Figure Many other reactions can also go in both forward and reverse directions. Often, a point is reached at which the forward and reverse reactions occur at the same rate. When this happens, there is no overall change in the amount of reactants and products. This point is called equilibrium, which refers to a balance between any opposing changes. You can see an animation of a chemical reaction reaching equilibrium at this URL: Not all changes in matter involve chemical reactions. For example, there are no chemical reactions involved in changes of state. When liquid water freezes or evaporates, it is still water. No bonds are broken and no new products are formed. How can you tell whether a change in matter involves a chemical reaction? Often, there is evidence. Four common signs that a chemical reaction has occurred are: Change in color: the products are a different color than the reactants. Change in temperature: heat is released or absorbed during the reaction. Production of a gas: gas bubbles are released during the reaction. Production of a solid: a solid settles out of a liquid solution. The solid is called a precipitate. You can see examples of each type of evidence in Figure 8.3 and at this URL: MEDIA Click image to the left or use the URL below. URL: 
 Question: process in which some substances become different substances
[EX A]:
chemical reaction