exam 4 mod 7 and 9 Flashcards
mitosis
nuclear division associated with somatic cells, producing 2 genetically identical daughter cells
if you had a 2N diploid mother cell, how many daughter cells would you get? in mitosis
-2 diploid daughter cells, identical to the mother
diploid
2 copies of each type of chromosome
-e.g) 2 types of chromosome long and short, they are the same type (carry the same genetic information)
mitosis stages
1)interphase
2) prophase
3) metaphase
4) anaphase
5) telophase and cytokinesis
homologous chromosomes usually have the same
genes and same relative locations
chromosome vs chromatin
chromatin: lower order, less condensed versions of DNA
Chromosomes: higher order and more condensed versions of DNA
in sexually reproducing organisms, the chromosome number needs…
to be reduced to one complete set so that the diploid state is restored following fertilization
Mendel’s experiment summary of key points
1) he crossed members of a parental, true-breed, with another parental seed of a different true breed
2) he grew seeds with the original mating, F1
3) he mated the F1 together at random and recorded the phenotypes in the F2 generation
key insight one from mendels experiment: genes don’t ____
-blend
-they act like particles and keep their information from generation to generation
key insight two from mendels experiment: each plant had ____
-two copies or versions of the genetic information for the trait studied, alleles
key insight three from mendels experiment: the copies of the genetic information present in a parent are ____
-separate from each other when eggs and sperm form
-each sperm and egg carry one copy of the genetic information for the traits, alleles of the gene
key insight four from mendels experiment: some alleles were____ and others ____
-dominate and others recessive
homozygous
individuals who have 2 copies of the same allele at a gene
heterozygous
individuals who have 2 different alleles at a gene
mendel concluded that
1) 2 alleles of each gene are present in a parent separate from gamete formation; parent diploid and offspring haploid
2) alleles of different genes assort independently from each other
complications relating to genotype and phenotype (four things)
-dominance is not always complete (co-dominance)
-there could be multiple alleles
-lethal alleles can cause skewed phenotypic ratios
-a gene may affect more than one trait (pleiotropy)
codominance
-inheritance in which 2 versions, alleles, of the same gene are expressed separately to yield different traits in an individual
-one trait is not completely dominant over another, so both are expressed
multiple alleles
there may be more than 2 alleles for a gene and those genes may have complicated dominance relationships
pleiotropy
a gene may affect more than one trait
tetrad
-two pairs of homologues chromosomes next to each other
-four homologues chromatids or 2 homologues chromosomes
