Ch 4 - genetics Flashcards
biology :(
What are homologous chromosomes?
two genetically SIMILAR chromosomes, one from each parent
Random segregation of one member of each homologous pair of chromosomes into games defines…
Law of independent assortment
Chromosomal basis of down syndrome
Trisomy 21
karyotype has a total of 47 chromosomes
If diploid number is 14, haploid number is…
7
What events contribute to genetic diversity
independent assortment
crossing over
random fertilization of gametes
After telophase 1, chromosomal makeup of each daughter cell is…
haploid, and the chromosomes are each composed of two chromatids
tetrads of chromosomes are aligned at the equator of the cell; alignment determines indep assortment defines…
metaphase 1
Recombinants
crossed over genes
Prophase 1
Homologous pairs pair up
crossing over
spindle forms
Metaphase 1
chromosomes pair line up at the equator randomly
Law of indep assortment
the homologous pairs line up randomly; adds gen. variety
Anaphase 1
homologous pairs separate
When can nondisjunction happen?
Anaphase 1 or 2
When is nondisjunction more damaging?
Anaphase 1 - will result in all 4 cells being wrong
Law of segregation
separating conflicting alleles
nondisjunction
when homologous pairs/chromatids stick together and results in gametes with a wrong number of chromosomes
telophase 1
cell pinches in and separates into 2 HAPLOID cells