TASK DEFINITION: Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.
PROBLEM: The antiparallel side-to-side association of spectrin alpha and beta monomers is a two-step process which occurs in seconds even at 0 degrees C and at low concentrations. Assembly involves initial contact of complementary nucleation sites on each subunit, which are located near the actin binding end of the long, flexible heterodimer rod. The minimum nucleation sites are comprised of approximately four contiguous 106-residue homologous segments or repeats. Three repeats in the nucleation site contain an 8-residue insertion and have the highest homology to the four spectrin-like repeats in alpha-actinin. The adjacent actin binding domain on the beta subunit and the adjacent EF hand motifs on the alpha subunit are not required for heterodimer assembly. The nucleation sites probably have a specific lock and key structure which defines the unique side-to-side pairing of the many homologous segments in both subunits. Assembly of spectrin heterodimers is probably most analogous to a zipper. After initial nucleation site binding, the remainder of the subunits quickly associate along their full lengths to reconstitute a normal dimer by supercoiling around each other to form a rope-like, flexible rod. Assembly is terminated if either polypeptide is interrupted by a protease cleavage. Heterozygotic mutations involving either nucleation site are predicted to affect allele incorporation into the mature membrane skeleton.

SOLUTION: Alpha-spectrin and beta-spectrin subunits form parallel or antiparallel heterodimers?

PROBLEM: Temperature is a measure of how fast the atoms in a material are vibrating. High temperature particles vibrate faster than low temperature particles. Rapidly vibrating atoms smash together, which generates heat. As a material cools down, the atoms vibrate more slowly and collide less frequently. As a result, they emit less heat. What is the difference between heat and temperature? Temperature measures how fast a materials atoms are vibrating. Heat measures the materials total energy. Heat energy is transferred between physical entities. Heat is taken in or released when an object changes state, or changes from a gas to a liquid, or a liquid to a solid. This heat is called latent heat. When a substance changes state, latent heat is released or absorbed. A substance that is changing its state of matter does not change temperature. All of the energy that is released or absorbed goes toward changing the materials state. For example, imagine a pot of boiling water on a stove burner: that water is at 100o C (212o F). If you increase the temperature of the burner, more heat enters the water. The water remains at its boiling temperature, but the additional energy goes into changing the water from liquid to gas. With more heat the water evaporates more rapidly. When water changes from a liquid to a gas it takes in heat. Since evaporation takes in heat, this is called evaporative cooling. Evaporative cooling is an inexpensive way to cool homes in hot, dry areas. Substances also differ in their specific heat, the amount of energy needed to raise the temperature of one gram of the material by 1.0o C (1.8o F). Water has a very high specific heat, which means it takes a lot of energy to change the temperature of water. Lets compare a puddle and asphalt, for example. If you are walking barefoot on a sunny day, which would you rather walk across, the shallow puddle or an asphalt parking lot? Because of its high specific heat, the water stays cooler than the asphalt, even though it receives the same amount of solar radiation.

SOLUTION: the amount of energy needed to raise the temperature of one gram of material by 1.0oc.

PROBLEM: Wave speed is the distance a wave travels in a given amount of time, such as the number of meters it travels per second. Wave speed (and speed in general) can be represented by the equation: Speed = Distance Time Wave speed is related to both wavelength and wave frequency. Wavelength is the distance between two correspond- ing points on adjacent waves. Wave frequency is the number of waves that pass a fixed point in a given amount of time. This equation shows how the three factors are related: Speed = Wavelength x Wave Frequency In this equation, wavelength is measured in meters and frequency is measured in hertz (Hz), or number of waves per second. Therefore, wave speed is given in meters per second, which is the SI unit for speed. Q: If you increase the wavelength of a wave, does the speed of the wave increase as well? A: Increasing the wavelength of a wave doesnt change its speed. Thats because when wavelength increases, wave frequency decreases. As a result, the product of wavelength and wave frequency is still the same speed. Click image to the left or use the URL below. URL: The equation for wave speed can be used to calculate the speed of a wave when both wavelength and wave frequency are known. Consider an ocean wave with a wavelength of 3 meters and a frequency of 1 hertz. The speed of the wave is: Speed = 3 m x 1 wave/s = 3 m/s Q: Kim made a wave in a spring by pushing and pulling on one end. The wavelength is 0.1 m, and the wave frequency is 2 hertz. What is the speed of the wave? A: Substitute these values into the equation for speed: Speed = 0.1 m x 2 waves/s = 0.2 m/s The equation for wave speed (above) can be rewritten as: Frequency = Speed Wavelength or Wavelength = Speed Frequency Therefore, if you know the speed of a wave and either the wavelength or wave frequency, you can calculate the missing value. For example, suppose that a wave is traveling at a speed of 2 meters per second and has a wavelength of 1 meter. Then the frequency of the wave is: Frequency = 2m/s 1m = 2 waves/s, or 2 Hz Q: A wave is traveling at a speed of 2 m/s and has a frequency of 2 Hz. What is its wavelength? A: Substitute these values into the equation for wavelength: Wavelength = 2m/s 2waves/s =1m The speed of most waves depends on the medium, or the matter through which the waves are traveling. Generally, waves travel fastest through solids and slowest through gases. Thats because particles are closest together in solids and farthest apart in gases. When particles are farther apart, it takes longer for the energy of the disturbance to pass from particle to particle through the medium. Click image to the left or use the URL below. URL:

SOLUTION:
speed can be calculated with the equation