Bio 1201 gregg Exam 2 (100% correct and graded A+)
the units of heredity and are made up of segments of DNA - -genes
how many chromosomes do humans have in the nucleus of their somatic cells? - -46
chromosomes (23 pairs)
the two chromosomes in each pair are called... - -homologous
chromosomes/homologs
each pair of homologous chromosomes includes... - -one chromosome from each
parent
what does meiosis result in - -4 haploid daughter cells
what does meiosis 1 do - -separates homologous chromosomes
when does crossing over and synapsis occur - -prophase 1
what does meiosis 2 do - -separates sister chromatids
mitosis vs meiosis - -Mitosis: one division forming 2 identical cells (clones); Meiosis:
two divisions forming 4 genetically different cells
meiosis 2 is similar to mitosis because... - -sister chromatids separate
how do different alleles occur - -through mutation
what 3 things contribute to genetic variation - -crossing over, independent
assortment, random fertilization
when does independent assortment occur? - -metaphase I of meiosis
random fertilization - -any sperm can fertilize any egg
the mating of 2 true-breeding varieties - -hybridization
p generation - -true-breeding parents
f1 generation - -hybrid offspring of the P generation
f2 generation - -offspring of the F1 generation
alternative versions of a gene - -alleles
the specific spot where a gene resides on a chromosome - -locus
two alleles for a heritable character separate during gamete formation and end up in
different gametes - -law of segregation
, Bio 1201 gregg Exam 2 (100% correct and graded A+)
organism with two identical alleles for a character - -homozygote
organism with two different alleles for a gene - -heterozygote
to determine the genotype, breed the mystery individual with a homozygous recessive
individual - -testcross
crossing two true-breeding parents differing in two characters produces ______ in the F1
generation, heterozygous for both characters - -dihybrids
a cross between F1 which can determine whether two characters are transmitted to
offspring as a package or independently is called? - -a dihybrid cross
law of independent assortment - -each pair of alleles segregates independently of
any other pair of alleles during gamete formation
do genes located near each other on the same chromosome tend to be inherited together?
- -yes
occurs when phenotypes of the heterozygote and dominant homozygote are identical -
-complete dominance
the phenotype of F1 hybrids is somewhere between the phenotypes of the two parental
varieties - -incomplete dominance
two dominant alleles affect the phenotype in separate, distinguishable ways - -
codominance
when one gene has multiple phenotypic effects - -pleiotropy
what hereditary diseases are caused by pleiotropic alleles - -cystic fibrosis and
sickle-cell disease
when expression of a gene at one locus alters the phenotypic expression of a gene at a
second locus - -epistasis
when multiple genes independently affect a single trait - -polygenic inheritance
example of epistasis - -labrador retriever coat color: one gene determines the
pigment color and the other gene determines if the pigment is deposited in the hair
example of polygenic inheritance - -over 180 genes affect height
heterozygous individuals who carry the recessive allele but are phenotypically normal -
-carriers
recessive disorders show up only in individuals ____ - -homozygous for the allele
the units of heredity and are made up of segments of DNA - -genes
how many chromosomes do humans have in the nucleus of their somatic cells? - -46
chromosomes (23 pairs)
the two chromosomes in each pair are called... - -homologous
chromosomes/homologs
each pair of homologous chromosomes includes... - -one chromosome from each
parent
what does meiosis result in - -4 haploid daughter cells
what does meiosis 1 do - -separates homologous chromosomes
when does crossing over and synapsis occur - -prophase 1
what does meiosis 2 do - -separates sister chromatids
mitosis vs meiosis - -Mitosis: one division forming 2 identical cells (clones); Meiosis:
two divisions forming 4 genetically different cells
meiosis 2 is similar to mitosis because... - -sister chromatids separate
how do different alleles occur - -through mutation
what 3 things contribute to genetic variation - -crossing over, independent
assortment, random fertilization
when does independent assortment occur? - -metaphase I of meiosis
random fertilization - -any sperm can fertilize any egg
the mating of 2 true-breeding varieties - -hybridization
p generation - -true-breeding parents
f1 generation - -hybrid offspring of the P generation
f2 generation - -offspring of the F1 generation
alternative versions of a gene - -alleles
the specific spot where a gene resides on a chromosome - -locus
two alleles for a heritable character separate during gamete formation and end up in
different gametes - -law of segregation
, Bio 1201 gregg Exam 2 (100% correct and graded A+)
organism with two identical alleles for a character - -homozygote
organism with two different alleles for a gene - -heterozygote
to determine the genotype, breed the mystery individual with a homozygous recessive
individual - -testcross
crossing two true-breeding parents differing in two characters produces ______ in the F1
generation, heterozygous for both characters - -dihybrids
a cross between F1 which can determine whether two characters are transmitted to
offspring as a package or independently is called? - -a dihybrid cross
law of independent assortment - -each pair of alleles segregates independently of
any other pair of alleles during gamete formation
do genes located near each other on the same chromosome tend to be inherited together?
- -yes
occurs when phenotypes of the heterozygote and dominant homozygote are identical -
-complete dominance
the phenotype of F1 hybrids is somewhere between the phenotypes of the two parental
varieties - -incomplete dominance
two dominant alleles affect the phenotype in separate, distinguishable ways - -
codominance
when one gene has multiple phenotypic effects - -pleiotropy
what hereditary diseases are caused by pleiotropic alleles - -cystic fibrosis and
sickle-cell disease
when expression of a gene at one locus alters the phenotypic expression of a gene at a
second locus - -epistasis
when multiple genes independently affect a single trait - -polygenic inheritance
example of epistasis - -labrador retriever coat color: one gene determines the
pigment color and the other gene determines if the pigment is deposited in the hair
example of polygenic inheritance - -over 180 genes affect height
heterozygous individuals who carry the recessive allele but are phenotypically normal -
-carriers
recessive disorders show up only in individuals ____ - -homozygous for the allele
