Answer the following question given this paragraph: Note The first controlled chain reaction was achieved on December 2, 1942, in an experiment supervised by Enrico Fermi in a laboratory underneath the football stadium at the University of Chicago. Although fairly simple in theory, an atomic bomb is difficult to produce, in part because uranium-235, the isotope that undergoes fission, makes up only 0.7% of natural uranium; the rest is mostly uranium-238, which does not undergo fission. (Remember that the radioactive process that a nucleus undergoes is characteristic of the isotope. ) To make uranium useful for nuclear reactors, the uranium in uranium-235 must be enriched to about 3%. Enrichment of uranium is a laborious and costly series of physical and chemical separations. To be useful in an atomic bomb, the uranium in uranium-235 must be enriched to 70% or more. At lesser concentrations, the chain reaction cannot sustain itself, so no explosion is produced. Fusion is another nuclear process that can be used to produce energy. In this process, smaller nuclei are combined to make larger nuclei, with an accompanying release of energy. One example is the hydrogen fusion, which makes helium. While the steps of the process are complicated, the net reaction is: 41H 4He + 2.58 1012 J Saylor URL: http://www. saylor. org/books. Q: Fusion is another nuclear process that can be used to produce energy. in this process, smaller nuclei are combined to make larger nuclei, with an accompanying release of this? Choices: - food - mineral - cells - energy A:
energy
Answer the following question given this paragraph: The Cytoplasm The cytoplasm comprises the contents of a cell between the plasma membrane and the nuclear envelope (a structure to be discussed shortly). It is made up of organelles suspended in the gel-like cytosol, the cytoskeleton, and various chemicals (Figure 3.7). Even though the cytoplasm consists of 70 to 80 percent water, it has a semi-solid consistency, which comes from the proteins within it. However, proteins are not the only organic molecules found in the cytoplasm. Glucose and other simple sugars, polysaccharides, amino acids, nucleic acids, fatty acids, and derivatives of glycerol are found there too. Ions of sodium, potassium, calcium, and many other elements are also dissolved in the cytoplasm. Many metabolic reactions, including protein synthesis, take place in the cytoplasm. Q: What comprises the contents of a cell between the plasma membrane and the nuclear envelope? Choices: - protoplasm - cerebellum - cytoskeleton - cytoplasm A:
cytoplasm
Q: Answer the following question given this paragraph: Inside every cell of all living things, energy is needed to carry out life processes. Energy is required to break down and build up molecules and to transport molecules across plasma membranes. All life's work needs energy. A lot of energy is also simply lost to the environment as heat. The story of life is a story of energy flowits capture, its change of form, its use for work, and its loss as heat. Energy, unlike matter, cannot be recycled, so organisms require a constant input of energy. Life runs on chemical energy. Where do living organisms get this chemical energy?. Q: What is required to break down and build up molecules and to transport molecules across plasma membranes? Choices: - salt - electricity - calcium - energy A:
A: energy
Question: Answer the following question given this paragraph: Chemists need to be concerned with the rates at which chemical reactions occur. Rate is another word for speed. If a sprinter takes 11.0 s to run a 100 m dash, his rate or speed is given by the distance traveled divided by the time. Q: Distance traveled divided by time yields what measurement, which is another word used to describe the speed of a chemical reaction? Choices: - flow - displacement - acceleration - rate A:
Answer: rate
*Question*
Answer the following question given this paragraph: Neither positive ions nor negative ions are attracted to a nonpolar molecule. In fact, the alkanes undergo so few reactions that they are sometimes called paraffins, from the Latin parum affinis, meaning "little affinity. " Two important reactions that the alkanes do undergo are combustion and halogenation. Nothing happens when alkanes are merely mixed with oxygen (O2) at room temperature, but when a flame or spark provides the activation energy, a highly exothermic combustion reaction proceeds vigorously. For methane (CH4), the reaction is as follows:. Q: What happens when alkanes are mixed with oxygen at room temperature? Choices: - single replacement - redox - combustion - no reaction A:
**Answer**
no reaction
(Q).
Answer the following question given this paragraph: Duplications (or amplifications ) lead to multiple copies of a chromosomal region, increasing the number of the genes located within that region. Some genes may be duplicated in their entirety. Q: What leads to multiple copies of a chromosomal region? Choices: - minimilizations - gene modification - subtractions - duplications (or amplifications ) A:
(A).
duplications (or amplifications )