Genetics 223 Review

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1. Place the following terms in size order, from largest to smallest, based on the structures or concepts they represent: a. chromosome
b.gene pool
c. gene
d. DNA
e. genome
Gene pool, genome, chromosome, gene, DNA

2. Distinguish between:
a. an autosome and a sex chromosome
b. genotype and phenotype
c. DNA and RNA
d. recessvie and dominant traits
e. pedigrees and karyotypes
f. gene and genome

a. An autosome does not carry genes that determine sex. A sex chromosome does. b.Genotype is the allele constitution in an individual for a particular gene. Phenotype is the physical expression of an allele combination. c.DNA is a double-stranded nucleic acid that includes deoxyribose and the nitrogenous bases adenine, guanine, cytosine and thymine. DNA carries the genetic information. RNA is a single-stranded nucleic acid that includes ribose and the nitrogenous bases adenine, guanine, cytosine and uracil. RNA carries out gene expression. d.A recessive allele determines phenotype in two copies. A dominant allele determines phenotype in one copy. e.A pedigree is a chart of family relationships and traits. A karyotype is a chart of chromosomes. f.A gene is a sequence of DNA that encodes a protein. A genome is a complete copy of the total genetic information for an individual.

3. Explain how DNA encodes information

The sequence of DNA nucleotides (A, G, C, T) in a gene comprises a genetic code that is read three nucleotides at a time to direct the building of proteins from amino acids.

4. Explain how all humans have the same genes, but vary genetically

Humans may have the same genes but differ genetically in the alleles (gene variants) that they have.

5. Explain how a genome-wide association study, gene expression profiling,and DNA sequencing of a gene or genome differ.

A genome-wide association study examines the whole genome for variations such as SNPs that can be associated with (are found much more often among individuals with) certain conditions or traits of interest. Gene expression profiling measures patterns and levels of mRNA to reveal cellular activity. DNA sequencing analyzes the order of DNA nucleotides (A, G, C, T) in a molecule of DNA or across the entire genome.

6.Explain how all cells in a person’s body have the same genome but are of hundreds of different types that look and function differently.

Differential expression of genes creates distinctive cell types

7.Suggest a practical example of gene expression profiling

Gene expressing profiling can be used to identify a drug to which a person’s cancer cells are likely to respond.

8.Expain the protections under the Genetic Information Nondiscrimination Act, and the Limitations

GINA protects people from being fired or denied health insurance based on genetic testing, for companies or organizations above a certain size. Limitations include extent and type of coverage (no life insurance) and specific sanctions for violations.

9.Explan what an application of a “diseasome” type of map (figure 1.8 might provide help)

A diseasome might show that drugs effective for one disease might be useful in treating another disease, to which it is linked by gene expression patterns.

10.Cite an example of phrase that illustrates genetic determinism

Answers vary depending on student experience. “He has the gene for sense of humor,” or “She has the gene for a great sense of style.”

11.Give an example of a genome that is in a human body, but is not human

The genome of a bacterial species that lives in the human gut.


1. If you were ordering a genetic test panel, which traits and healthy risks would you like to know about, and why? Students may be concerned about specific diseases in their families, common conditions such as Alzheimer disease and cardiovascular disease, or...
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