19378391
Description
Flashcards by Paulina Smith, updated more than 1 year ago
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Created by Paulina Smith
over 4 years ago
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| Question | Answer |
| DNA | A protein which codes for specific RNA |
| chromosome | unit of DNA which carries many genes... ea. consists of a very long molecule of duplex DNA and an approx. equal mass of proteins |
| homologous chromosomes | occur at the same loci on accompanying chromosomes |
| gene locus | location of the specific gene in question |
| allele | one or more forms of a gene (mutated) found at the same locus (A + a) |
| locus | a particular "address" on a gene |
| intergenic DNA | Regulatory DNA (often doesn't code for anything). Exists between genes |
| centromere | point at center of chromosomes where spindles attach (anaphase) |
| telomere | the ends of chromosomes; relate to duplication |
| haploid genome | one copy |
| diploid genome | complete DNA valid for reproduction (2 copies) |
| linked genes | typically co-occurring on a single chromosome |
| unlinked genes | segregate independently |
| homozygous | same alleles at any given locus |
| heterozygous | opposite alleles at any given locus |
| linked genes | tend to be inherited together as a result of their location on the same chromosome |
| homologs | similar DNA sequences |
| avirulent | not harmful to host |
| virulent | cannot be combated by host's immune system |
| nucleotide | nucleoside + phosphate group |
| insertions | addition; transposable elements can revert |
| deletions | removal of nucleotides; not reversible |
| large chromosome aberrations (name 3) | chromosome double strand breaks due to irradiation, unequal crossing over during meiotic recombination, and homologous recombination between repeat regions ON same chromosome |
| ORF- open reading frame | start codon, AUG (methianine) and stop codon. (Sequence of DNA consisting of triplets that can be translated into amino acids.) |
| haplo-insufficiency | a dominant phenotype in diploid organisms that are heterozygous for a loss-of-function allele |
| loss-of-function mutations | usually recessive, null mutation/amorphic allele = nonfunctioning protein |
| hypomorphic mutations | causes a partial loss of gene function. A hypomorph is a reduction in gene function through reduced (protein, RNA) expression or reduced functional performance, but not a complete loss |
| gain-of-function mutations | usually dominant, hypermorphic, neomorphic (new function) |
| gene | fundamental unit of heredity, DNA sequence that codes for a specific cellular product (RNA or polypeptide) |
| complementation | mutations are in different genes (neither mutation expressed) |
| fail to complement | mutant offspring because mutations are in the SAME GENE |
| point mutations | affect only one base |
| transitions | purine to purine / pyrimidine to pyrimidine |
| transversions | purine to pyrimidine / pyrimidine to purine |
| missense mutation | point mutation in which a single nucleotide change results in a codon that codes for a different amino acid |
| nonsense mutation | point mutation in a sequence that results in a premature stop codon |
| pathogenicity islands | DNA segments present in pathogenic bacterial genomes but absent in their nonpathogenic relatives |
| horizontal transfer | transfer of DNA from one cell to another by a process other than cell division, such as bacterial conjugation |
| c-value | term used to describe amount of DNA content in terms of number of nucleotides per haploid genome |
| orthologous genes | related genes in diff. species |
| synonymous mutation | a change in DNA sequence coding region that does not alter the amino acid that is encoded |
| non-synonymous mutation | a change in DNA sequence coding region that alters the amino acid that is encoded |
| pseudogenes | inactive but stable portions of the genome derived by mutation of an ancestral active gene, usually inactive due to mutations that block translation, transcription, or both. |
| processed pseudogenes | result from reverse transcription and integration or mRNA transcripts |
| nonprocessed pseudogenes | result from incomplete duplication or second-copy mutation of functional genes |
| transposons/jumping genes | can copy + paste or cut + paste to different loc. within the genome |
| mRNA | Has ONLY EXONS. the intermediate that represents one strand of a gene coding for polypeptide. Its coding region is related to the polypeptide sequence by the genetic code. |
| satellite DNA | consists of many tandem repeats (identical or related) of a short, basic repeating unit; important for packing of DNA in heterochromatin region. Diff btwn indiv. is basis for DNA forensics! |
| complex satellite | length > 100bp |
| minisatellite | 10bp < length < 100bp |
| microsatellite | length < 10bp |
| haplotype | a large stretch of a chromosome and all the genes, repeats, and polymorphisms contained in the DNA sequence |
| packing ratio | Ratio of the length of DNA to the unit length of fiber containing it. |
| chromatin | DNA and the proteins it is wrapped around |
| capsid | the external protein coat of a virus particle |
| euchromatin | light in color, open. USED DURING TRANSCRIPTION |
| heterochromatin | dark, closed. constitutive = always highly condensed (like telomeres and centromeres) facultative = sometimes converted from highly packed form to euchromatin state |
| g-bands | staining which causes the chromosomes to appear with striations |
| chromosome locus numbering system | count out in either direction from centromere. smaller arm is p (petite), larger is q. |
| kinetochore proteins | this is where microtubules attach before attaching to the centromere |
| acentric fragment | a fragment of a chromosome (by breakage) that lacks a centromere and is lost at cell division |
| nucleosome | basic structural subunit of chromatin, ~200bp of DNA and an octamer of histone proteins |
| histone tails | flexible or amino- or carboxy-terminal regions of the core histones that extend beyond the surface of the nucleosome |
| linker histones | a family of histones (such as histone H1) that are not components of the nucleosome core |
| 30nm fiber | a coil of nucleosomes (width) |
| non-histone | any structural protein found in a chromosome that is NOT a histone |
| suppressor mutation | a second mutation in a different gene that compensates for the primary mutation |
| second-site reversion | a second mutation in the same gene that compensates for the primary mutation |
| antimorphic mutation | the newly-acquired function is against old activity |
| pleiotropic genes | genes which code for a polypeptide with more than one function |
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