ch 15 biology
Terms in this set (30)
True or false: Nondisjunction is when sister chromatids fail to separate during anaphase of cell division.
Which of the following is an advantage of DNA typing?
Only small amounts of DNA are needed.
True or false: Alleles are alternate molecular forms of a gene.
True or false: Much of the genetic variation seen in the human population is neutral.
SNPs within a gene called FOXO correlate with increased longevity in humans. You are a researcher in a lab and wish to determine if you possess this SNP.
Which of the following techniques would allow you to accomplish this?
True or false: Some mutations have no effect on the organism and are therefore considered neutral.
True or false: Harmful mutations are always quickly weeded out of a population.
True or false: Some alleles in the heterozygous state are beneficial, whereas in the homozygous state they are harmful.
True or false: Gel electrophoresis is the preferred method for detecting single nucleotide polymorphisms.
What is the difference between a gene and an allele?
A gene is a segment of DNA that codes for a protein or RNA; an allele is an alternate form of a gene.
Which of the following statements explains why restriction enzymes are not useful for genome-wide studies of genetic variation?
None of the answer options is correct.
True or false: A karyotype is a technique by which a researcher can see and count chromosomes.
The ability to perceive a bitter taste from certain chemicals including PTC has been linked to certain alleles. Which of the following would provide an explanation for the fact that almost all nonhuman primates have the "taster" phenotype, whereas the human population has a significant percentage of "nontaster" phenotypes?
The advantage to being able to taste bitter compounds would keep you from eating poisonous compounds, an advantage not needed in the human population anymore.
The number of tandem repeats in an individual:
will vary from chromosome to chromosome.
Short repeated sequences of DNA that vary in number from one chromosome to the next are called:
variable number tandem repeats.
can be subject to environmental conditions.
In mammals, females have two copies of the X chromosome, whereas males have only one copy. Dosage compensation is accomplished in mammals by:
females possessing a randomly inactivated X chromosome in all cells.
True or false: In microarrays, the oligonucleotides that are attached have the fluorescent tag, whereas the DNA fragments being tested do not.
Which of the following could explain how some (although rare) people can have Down syndrome and have a normal chromosome number?
A large enough fragment of chromosome number 21 underwent a duplication event.
If an individual is homozygous for a certain trait, it means that:
the individual received the same allele from each parent.
True or false: The genotype of an organism constitutes its observable characteristics.
A new gene is discovered that dramatically aids in the digestion of fish. You hypothesize that populations with a history of being near the shoreline would have more copies of this gene than populations found farther inland.
What technique would you use to test this?
You are working in a medical research lab and have to determine if a patient is heterozygous or homozygous for a particular restriction site. After treating the DNA with a restriction enzyme that cuts at that site, you subject the sample to gel electrophoresis.
How many bands would be indicative of the heterozygous condition?
What is one reason why women with the genotype XXX are not phenotypically different from an XX female?
Because only one X is active in each cell, regardless of how many X chromosomes there are in a cell.
True or false: In a person with the genotype XXY, we can tell that nondisjunction took place in the mother.
Genetic studies have identified an allele (Δ32) that seems to provide protection against AIDS. Which of the following would most likely explain the reason why our population has this mutation?
This mutation likely benefited the human population against some other early pathogen.
True or false: A single nucleotide polymorphism (SNP) and a point mutation are the same thing.
True or false: The biggest difference between CNV and VNTRs is the size of the DNA being studied.
True or false: A phenotype refers to something that you can see with your eyes, like hair color or eye color.
An organism that has two different alleles for a given trait is said to be: