Nature of Science: Scientific Inquiry, Methodology, Techniques, and History Flashcards
What are scientific theories
A scientific theory is an explanation that is generally broad in scope, is supported by a large body of evidence, and that can serve as the basis for new hypotheses and experimentation.
10 microns is equivalent to
1 micron ( μm) equals 10–6 m, 10–4 cm, and 10–3 mm. Hence, 10 microns equals 10–2 mm or .01 mm.
Bacterial samples were counted every hour from a flask being incubated at 37°C on a shaker. Which of the following was most likely being studied?
The growth rate of bacteria
Depending on the concentration of particular nutrients in bacterial broth, bacteria exhibit exponential growth (log phase) or are not growing and are in lag phase or stationary phase. The number of bacteria present in samples of equal size can be determined and plotted on a semilog graph (time versus log of numbers of bacteria) to analyze bacterial growth rate.
Best practice for using a light microscope
It is far easier to find a specimen under low power because a larger portion of the slide is visible. It is also easiest to bring a specimen into focus under low power, and this is done primarily by using the coarse adjustment knob.
What are the roles of buffers in living systems
A buffer minimizes changes in the concentration of H+ and OH– ions in a solution. An approximately neutral pH must be maintained in human blood and many other biological solutions. This is accomplished by buffers such as the carbonic acid-bicarbonate buffering system in the blood.
What is the worth of peer reviewed research articles
Research papers that appear in scientific journals undergo extensive peer review before they are published. A recent research paper will be both current and reliable. The sources in the other options may provide information that is either unreliable or not current.
Which of the following is the most appropriate method for safely handling an acid spill in a laboratory?
The pH of the acid should be neutralized before handling, but never by increasing the volume of the spill with a strong base. Laboratory safety kits typically include absorbent pads or baking soda to help neutralize and absorb acid spills.
The stomach enzyme pepsin functions best in a narrow range of high hydrogen ion concentrations. Which of the following graphs represents the relationship between optimal pepsin enzyme activity and pH?
The question states that pepsin functions best in a narrow range of high hydrogen ion concentrations. At pH 2.0, the hydrogen ion (H+) concentration is very high
Lower number equals high concentration
What is the dependent variable
The dependent variable is the variable that changes in response to a change in the independent variable.
Where should highly flammable and volatile substances be handled
Fume hoods are typically designed so that air is drawn in from the front of the hood and exhausted to the outside or filtered before recirculation back into the hood. With correct use of the hood, neither the individual removing a few drops of ether from the bottle nor anyone else in the lab will be exposed to the ether fumes.
Which graph types should be used to illustrate the percent
Pie charts are circular graphs in which each sector illustrates a proportion of a whole
The concentration of a stock solution of sulfuric acid is 18 M. Of the following, which describes the correct way to prepare 500 mL of a 1 M solution of sulfuric acid?
Concentrated acids are always diluted by adding the stock acid solution to water. If the stock solution of sulfuric acid is 18 M, it must be diluted 18‑fold to bring it to a 1 M concentration. 500 mL/18 is approximately 28 mL, so 28 mL of the 18 M stock sulfuric acid is added to approximately 400 mL of water, and then the final volume of the solution is brought to 500 mL. 28 mL of acid is not added to 472 mL of water, in case the volume of the solution increases when the acid and water are mixed.
Explain significant figures
The measurement 105.030 contains six significant figures. All nonzero numbers are significant, zeros between nonzero numbers are significant, and zeros to the right of the decimal point and at the end of the number are significant.
Research that uses DNA to study human diversity is known as
Bioinformatics is a multidisciplinary field that is heavily dependent on computer software tools, mathematics, and engineering for storing, analyzing, and retrieving biological data such as the sequences of DNA from many different sources.
Exergonic and endergonic reactions in cells are interrelated in that
Many reactions in cells are energetically coupled. Energy released during an exergonic reaction is often equal to or greater than the amount of energy required for a simultaneous or sequential endergonic reaction to occur.
