My Exam 3 Cram set - genetics

Nondisjunction

Chromosomes fail to separate during meiosis or mitosis

Complete nondisjunction

All chromosomes mis-segregate

Mitotic nondisjunction

Error in somatic cell division causing mosaicism or segmental aneuploidy

Polyploidy

Organism has extra whole sets of chromosomes; can result in larger cells and sometimes increased fertility in plants

Endopolyploidy

Tissue-specific doubling of the genome

Allopolyploidy

Hybridization followed by chromosome doubling

Allotetraploidy

Organism has two sets of chromosomes from each parent

Aneuploidy

Presence of extra or missing single chromosomes

Polytene chromosome

Chromosome undergoes repeated DNA replication without cell division

Inversion heterozygotes

Chromosomes with a segment inverted; can affect recombination and produce abnormal gametes

Dicentric chromosomes

Chromosomes with two centromeres

Acentric chromosomes

Chromosomes lacking a centromere

Translocations

Rearrangement of chromosome segments; involves nonhomologous crossover

Simple translocation

Single segment moves from one chromosome to another; may be unbalanced

Reciprocal translocation

Two nonhomologous chromosomes exchange segments; can be balanced if no genetic material is lost

Balanced translocation

Chromosomal rearrangement where genetic material is exchanged without net loss or gain

Unbalanced translocation

Chromosomal rearrangement that results in extra or missing genetic material

LTR Retrotransposons

Transposable elements with long terminal repeats that move via RNA intermediate using reverse transcription

Non-LTR Retrotransposons

Retrotransposons that lack long terminal repeats but still transpose via RNA intermediate

Simple transposition

DNA element moves directly from one site to another in the genome

Retrotransposition

RNA intermediate is reverse-transcribed and inserted into a new genomic location

Autonomous element

Transposable element capable of moving on its own because it encodes necessary enzymes

Nonautonomous element

Transposable element that requires enzymes from autonomous elements to move

NAPs (Nucleoid-associated proteins)

Proteins that organize bacterial DNA and regulate transcription

MRSA (Methicillin-resistant Staphylococcus aureus)

Bacterial strain resistant to beta-lactam antibiotics

HIV latency

Dormant state of HIV in host cells where viral replication is suppressed

Heteroduplex

DNA molecule formed from two complementary strands from different sources

Episome

Plasmid that can integrate into the bacterial chromosome or replicate independently

Competent cells

Bacterial cells able to take up foreign DNA naturally or artificially

F′ (F prime) factors

Plasmids carrying extra chromosomal genes that can be transferred via conjugation

Relaxosome

Protein complex that initiates plasmid transfer during bacterial conjugation

F-factors

Fertility plasmids in bacteria that enable conjugation

Resistance plasmids

Plasmids carrying antibiotic resistance genes

Col-plasmids

Plasmids that produce bacteriocins to kill competing bacteria

Virulence plasmids

Plasmids carrying genes that enhance pathogenicity

Hfr strains

Bacteria with F plasmid integrated into the chromosome

Sex pili

Appendages used by bacteria to attach and transfer DNA during conjugation

Degradative plasmids

Plasmids that encode enzymes to metabolize unusual substances