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PCB 3063
Exam 3
| Term | Definition |
|---|---|
| Coupling Conformation | linked heterozygous gene pairs in the arrangement AB | | ab; most of the progeny will be either wild type for both genes or mutant for both genes |
| Repulsion Conformation | linked heterozygous gene pairs in the arrangement of Ab | | aB; most of the progeny will be mutant for only one gene and wild type for the other |
| A 1:1:1:1 frequency generally means | independent assortment. |
| A 4:4:1:1 frequency generally means | linkage |
| Evolutionary Significance of Crossing Over | Insures the genetic variability upon which natural selection acts; Other factors influencing genetic variability are: Mutation and Independent Assortment |
| Fertility (F) factor | small circular self-replicating DNA element with ~100 genes called plasmid; F+ cells produce pili allowing them to attach to F- cells that lack pili; F may integrate itself into bacterial chromosome, making the cell Hfr (high frequency recombination). |
| Sexduction | sexual transmission of donor E. coli chromosomal genes on the fertility factor. |
| F+ x F- | Two F+ |
| Hfr x F- | One Hfr and one F-; rarely, the F- may become F+ if the entire Hfr chromosome is transferred during conjugation |
| F' x F- | Two F' |
| Karyotype | A matched array of chromosomes. The homologous pairs are sequenced; does not occur like this in the cell |
| Metacentric chromosomes | centromere 50% up the sister chromatids |
| Submetacentric chromosomes | centromere 75% up the sister chromatids |
| Acrocentric chromosomes | centromere 90% up the sister chromatids |
| Telocentric chromosomes | centromere 100% up the sister chromatids |
| Types of Chromosmal Mutations | Deletion, Duplication, Inversion, and Translocation |
| Pseudodominance | phenotypic expression of recessive gene with deletion on homologous chromosome (when you’re Cc and the C gets deleted, you’re now dominant for c) |
| Pseudogenes | “junk DNA”, produced by duplications, may lead to new functions, evolution |
| Transformation | Bacteria lysed, DNA breaks up, other bacteria can take up and integrate into chromosome |
| Transduction | Bacteriophage makes bacteria enter lytic cycle, make new viral proteins that may take bacterial DNA instead and insert into other bacteria |
| Aneuploidy | wrong number of chromosomes |
| Robertsonian translocation | when part of number 21 sticks to a large part of number 14 |
| Down's Syndrome | Most common autosomal aneuploidy; 92% due to trisomy w/ full chromosome 21; 4% due to Robertsonian translocation; Can arise from maternal or paternal lines |
| Translocation carriers are | phenotypically normal but genotypically not normal |
| Genotypically normal x Translocation Carrier (Down Syndrome Ratio) | 1/2 die; 1/3 genotypically normal, 1/3 Down's Syndrome, and 1/3 translocation carriers |
| Any deletion of chromosomes 1,2,3,4 | dead embryo |
| percentage of spontaneous abortions are due to chromosomal abnormalities | 15-20% |
| Nulisomy | loss of both members of homologous pair |
| Monosomy | loss of a single chromosome |
| Trisomy | Gain of a single chromosome |
| Tetrasomy | gain of two homologs |
| Uniparental disomy | when you get two homologs from one parent |
| Factors that can disrupt equilibrium | mutation, natural selection, random genetic drift, migration, and meiotic drive (one allele recovered more frequently than other). |
| CCR5 | mutation can cause a faulty cell membrane coreceptor that allows the HIV virus to attach to the cell but not to inject it’s genetic material; caused by a deletion of 32 bp on the homozygous chromosomes; makes your WBCs resistant to HIV |
| linkage strength | (uncrossovered/total) OR (parentals/total) |
| Autosomal gene frequency | p + q = 1 |
| genotypic frequency | p2 + 2pq + q2=1 |
Created by:
JacobGant
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