Lab 8 - Mitosis, Meiosis, & Inheritance

mitosis

single cell divided its chromosomes and its cytosol to produce two identical daughter cells

used for growth, maintenance, repair of tissues

one cell cycle

interphase and mitotic phase

S phase

DNA copied and separated into sister chromatids

mitosis

PMAT

spindle fibers

attach chromosomes, align them down the middle, and pull sister chromatids apart

telophase

cytoplasm divides so that both new cells have own fluid, organelles, etc.

cytokinesis

cytoplasm divides

mitotic index

ratio of number of cells undergoing mitosis divided by total number of cells

tells cells’ ability and rate of dividing

meiosis

two divisions reducing chromosomes by half

homologous chromosomes

similar by having same genes in same positions

one of each pair from each parent ( I + I = X )

meiosis 1

divides homologous pairs into daughter cells

diploid (2n) to haploid (1n)

reduction division

meiosis 2

divides sister chromatids into daughter cells like mitosis

genetics

study of heredity, passing of traits from parents to offspring

genes

specific segment of DNA molecule that holds information for one specific protein

determines a trait

alleles

different versions of genes

traits, individuals, alleles

different

diploid

two alleles at each genetic locus, one allele inherited from each parent

genotype

pair of alleles of specific gene of an individual

phenotype

specific combination of alleles, or genotype, for each trait

physical expression of genes

homozygous genotypes

two identical alleles at particular locus

heterozygous genotypes

two alleles differ

dominant allele

always expressed, masks recessive allele

recessive allele

only expresses in absence of dominant allele

autosomes

22 pairs of chromosomes

dominant = R

recessive = r

allosomes or sex chromosomes

23rd pair of chromosomes

traits located on X chromosome; alleles are represented by…

superscript (X^R, X^r)

hemizygous

genes located on X chromosome and will express all X-linked recessive traits

principle of segregation

pairs of genes segregate during the formation of gametes in meiosis so that each gamete has one of each gene pair but not both

principle of independent assortment

each gene pair assorts independently of other gene pairs during the formation of gametes in meiosis

punnett square

make predictions about various genetic problems, not actual results

monohybrid cross

examines one trait

modes of inheritance

autosomal dominant, autosomal recessive, and X-linked recessive

pedigree

way to follow a trait in a family by representing members who did or did not express the trait

true breeding

all offspring had same traits generation after generation when self-fertilizing, because of homozygous trait

dihybrid cross

examines two separate traits

law of independent segregation causes different alleles to distribute into gametes randomly

predict genotypes using FOIL

albinism

Aa x aa

huntington’s disease

Hh x hh = 50%, Hh = 50%

colorblindness

XNY (father) → XNXn (woman) x XNY (man)

mode of inheritance for allele b for pedigree

Bb x Bb (parents)