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32 Cards in this Set
- Front
- Back
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What is a gene? |
A section of DNA that codes for a specfic protein or characteristic |
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What is an allele? |
Different forms of the same gene |
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What is a genome? |
All the genetic information contained in an organism |
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What are the three methods of gene mutation? |
Deletion, addition, substition (of nucleotides) |
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What are the 3 possible outcomes of genetic mutations? |
no change (may still code for the same amino acid), harmful change, beneficial change |
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What is a homologous chromosome? |
A pair of matching chromosomes with the same genes (though not necessarily same alleles), most organisms inherit one from each parent |
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What is nondisjuction? with example |
The failure of homologous chromosomes to separate properly during cell divison, which results in cells with too many or too few chromosomes (Down's syndrome, extra chromsome on 21) |
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What is a karyogram? |
A picture of homologous chromosomes in decreasing length, can only be taken during mitosis |
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What is haploid and diploid? |
Haploid: cell with one set of chromosomes (n) such as gametes Diploid: cell with two sets of chromosomes (2n) |
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What is meiosis? |
Production of 4 haploid daughter cells from 1 diploid cell |
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What are the phases in the first division of meiosis? |
Prophase I (crossing over occurs) Metaphase I Anaphase I Telophase I Ends with two haploid nuclei |
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What are the phases in the second division of meiosis? |
Prophase II Metaphase II (individual chromosomes line up) Anaphase II Telophase II Produces 4 genetically different haploid cells |
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What are two methods of genetic variation meiosis provides? |
Independent assortment of chromosomes, crossing over |
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What is the genotype and what is the phenotype? |
Genotype: the genes of an organism Phenotype: the physical expression of those genes resulting in characteristics |
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How are recessive and dominant alleles symbolized? |
Recessive: lowercase latter Dominant: capital letter |
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What are co-dominant alleles? |
Pairs of alleles that both have an effect on the phenotype |
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What is a locus? |
The location of a gene on the chromosome |
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What is a test cross? |
Crossing an organism expressing a dominant trait with an organism known to be homozygous recessive to determine if a heterzygous or homozygous combination of alleles is present |
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What is multiple alleles? |
When more than two alleles are available for the population to code for a trait |
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What are sex-linked genes? |
Genes located on either the X or the Y chromosome |
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Review how to draw a pedigree chart |
Label the generations after start with F1, F2 etc, women are circles and men are squares, color in affected individuals, carriers cross-hatched |
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What is an autosomal dominant genetic disease? with example |
A disease that is inhertated on the mutated gene of a dominant allele (Huntington's disease) |
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What is a point mutation? with example |
The change of a single base which changes the protein so that it can no longer function (cystic fibrosis) |
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What is a mutagen? |
A chemical that increases the frequency of genetic mutations |
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What are the three steps of PCR and what is it used for? |
Polymerase Chain Reaction is used to replicate DNA 1. Denature: heat solution of Taq polymerase, free nucleotides and DNA 2. Anneal: cool so primers attach 3. Extend: Taq polymerase adds nucleotides |
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What is gel electrophoresis? |
A process that separates DNA fragments by size and charge, the smaller molecules move faster through the gel while larger ones are slower |
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What is a plasmid? |
A small circular piece of prokaryotic DNA |
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What is recombinant DNA? |
DNA that contains both original and foreign DNA |
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What is the process for gene modiciation? |
A plasmid is obtained and foreign DNA is cut with restriction enzymes, joined together by DNA ligase |
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What are two potential risks and three potenial benefits of genetically modifying plants? |
Benefits: larger crop yield, less use of pesticides, increased global food supply Risks: can negatively affect ecosystem, people could be allergic to foreign pollen |
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What are clones? |
Organisms that are exact genetic copies of each other |
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How is an animal cloned? (4 steps) |
1. DNA is taken from somatic cell 2. DNA is removed from egg cell 3. The somatic DNA is put into the egg cell and they are fused through electric shock 4. The egg is placed in a nutritious environment and begins dividing |
