GED Science Practice Questions: Heredity
When someone tells you that you look like your parents or that you remind them of another relative, they’re talking about heredity. Reading a bit about heredity in biology-related books can help you prepare for the questions on the GED Science test.
Keep in mind that you don’t have to dive too deep; you just need a basic understanding of how heredity works. (Hint: concentrate on the molecular level—DNA, chromosomes, alleles, and so on.) At first glance, the following practice questions may appear difficult, but if you have a general knowledge of how DNA works, you should be able to answer them fairly quickly.
The first question refers to the following passage, which is adapted from The Sciences: An Integrated Approach, 3rd Edition, by James Trefil and Robert M. Hazen (John Wiley & Sons, Inc.).
Copying DNA Sequence
The polymerase chain reaction (PCR) copies a sequence of DNA. To do this, a strand of DNA is mixed with nucleotides (DNA precursors). Nucleotides target a specific piece of DNA, as well as polymerase, an enzyme that helps to assemble DNA. Heat is applied until the temperature reaches 200 degrees F. The energy from the heating separates the DNA strands. The mixture is then cooled to 140 degrees F. At this temperature, the primers attach themselves to the DNA strands. Raising the temperature to 160 degrees F causes the nucleotides to begin to attach to the DNA strands. After all this, two copies of the DNA are created.
- To separate the DNA strands during the polymerase chain reaction, the addition of
The second question refers to the following passage.
DNA has become part of everyone’s vocabulary, and several crime shows on television use it as a key plot element. DNA has put criminals in jail and freed others. It is used as proof in trials and is an important dramatic tool on many television dramas and talk shows.
Another use for DNA is not as dramatic. Because a child inherits the DNA of his or her parents, DNA testing can prove paternity. This is an example of a practical use for a scientific discovery.
- Because every person’s DNA is unique (except for identical twins), what forensic tool can DNA testing replace?
A. eyewitness accounts
B. shoe prints
D. sketch artist renderings
Answers and explanations
- The correct answer is heat.
The fourth sentence in the passage tells you that heating is the process that separates DNA strands.
- The correct answer is Choice (C).
Although identical twins have the same DNA but different fingerprints, DNA evidence is often easier for crime lab specialists to find than intact fingerprints. Eyewitness accounts, shoe prints, and artist sketches aren’t as reliable as DNA or fingerprints.