genetics Flashcards
centromere
part of the chromosome that attaches to the spindle during cell division
telomere
protective ends of the chromosomes
chromosome types
metacentric, acrocentric, telocentric
karyotype
representation of a complete set of chromosomes for an individual organism
what do karyotypes tell us?
- # of chromosomes in species does not change
- that there are two types of eukaryotic cells (differ in ploidy)
- the banding pattern of each chromosome does not change
- closely related species have similar banding patterns
asexual reproduction
mitosis
stages of mitosis
interphase, prophase, metaphase, anaphase, telophase
interphase
chromosomes replicated by G2
prophase
chromosomes condense, centromeres nucleate mitotic spindle, nuclear envelope breaks down and chromosomes begin to align at spindle
metaphase
chromosomes line up at the equator of the cell, centromeres connect kinetochores to mitoic spindle, sister chromatids of each chromosome are attached to microtubules from opposite poles
anaphase
sister chromatids separate
telophase
cytokinesis; nuclear envelop starts to reform, chromosomes begin to decondense, cell completes division to form two daughter cells
sexual reproduction
meiosis
aneuploidy
changes in the number of individual chromosomes, occurs through non-disjunction
non-disjunction
the incorrect segregation of chromosomes during cell division
genetics
study of heredity
meiosis
reduction division
interphase meiosis
genetic material is duplicated
prophase i
chromosome arms condense and become visible, recombination between homologous chromosomes
metaphase i
homologous stay together, kinetochores tether homologs to MTs from opposite poles
anaphase i
homologs in each tetrad move to separate poles, sister chromatids remain joined
telophase i
each nucleus contains one set of homologs after cell division
meiosis ii
same steps as mitosis but telophase ii ends with four daughter cells
