Unit 1 - Definitions Flashcards
DNA
hereditary material in humans & most living organisms
chromatin
complex of DNA and protein in eukaryotic cells
eukaryotic chromosome
linear molecule of DNA associated with histone proteins and packaged into higher order structures
telomere
stable ends of a linear chromosome
centromere
constricted region of chromosome where kinetochore forms and spindle microtubules attach during the cell division (sister chromatids held together by these too)
locus
position of a gene on a chromosome
haploid (n)
one set of Chromosomes
diploid (2n)
two sets of Chromosomes
non-homologous chromosomes
like XY sex chromosomes, have alleles on different genes.
autosomes vs sex chromosomes
chromosomes that are the same in M/F
vs
a pair of chromsomes that differ in M/F
homologous chromosomes
chromosome pairs of approximately the same length, centromere position, and staining pattern, for genes with the same corresponding loci
- may show allelic variation at a locus
kinetochore
complex of proteins that assembles at the centromere and serves as site of mircotubule attachment during cell division
spindle microtubules
filaments responsible for moving chromosomes during cell division
sister chromatids
2 linear chromatids that are connected by a centromere, they will be genetically identical
meiosis vs fertilization
production of haploid gametes (n)
vs
restoration of the diploid state (2n) in the next generation
genotype
the complete genetic makeup of an individual organism.
- determines phenotype
phenotype
a measurable trait of an organism that is controlled by one or more genes but can be influenced by environmental effects.
dominant allele
an allele whose trait is expressed in heterozygous individuals (ex: RR, R_)
recessive allele
an allele whose trait is NOT expressed in heterozygous individuals (ex: rr)
monohybrid cross
a cross between parents that differ by a single trait (RR x rr)
dihybrid cross
a cross between parents that differ by two traits (RR YY x rr yy)
Probability
No. of times a particular event is expected to occur out of the total number of possible outcomes
product v sum rule
product rule
- joint events, multiply together probabilities
sum rule
- disjoint events, add together probabilities
wild type gene
the allele most often found in natural populations.
Often symbolized by one or more letters and a plus sign (+).