Bio 210 Exam 3 Study Guide
Haploidy - answer Having one set of chromosomes
Diploidy - answerHaving two sets of chromosomes
Homologous chromosomes - answer Chromosomes with the same genes in the same
order
How many rounds of homologous chromosomal replication occurs during meiosis? -
answerOne round
When do the chromosomes replicate during meiosis? - answer Before meiosis I
Are the products (cells) of meiosis 1 haploid or diploid? - answer Haploid cells
Are the products of meiosis 2 haploid or diploid? - answer Haploid cells
What's the key event during meiosis 1? - answer(Crossover) Pairing of Homologous
chromosomes
What's the key event during meiosis 2? - answerSister chromatids separate
Synapsis - answerPairing of homologous chromosomes (during meiosis 1), makes a
tetrad
Crossover - answerExchange of genetic material between homologous chromosomes
Tetrad - answerA group of four chromatids formed during meiosis
Why is meiosis called a reduction division? - answerbecause it reduces the number of
chromosomes to half the normal number so that, when fusion of sperm and egg occurs,
baby will have the correct number. Results in haploid cells
P0 generation - answerParental generation
F1 generation - answerFirst filial generation
F2 generation - answerSecond filial generation
Dominant trait - answerTrait that is expressed
Recessive trait - answerTrait masked by dominant allele
, Allele - answerDifferent forms of a gene
Phenotype - answerPhysical expression of genotype
Genotype - answerGenetic makeup of an organism
Homozygosity - answerHaving two identical alleles for a gene
Heterozygosity - answerHaving two different alleles for a gene
Phenotypic ratio in mono hybrid cross - answer3:1
Genotypic ratio in mono hybrid cross - answer1:2:1
Hemizygosity - answerPresence of only one allele for a gene
Do X-linked disorders disproportionately affect males or females? Why - answerMales,
because males only have 1 X chromosome (hemizygosity) and females have 2.
Carrier of X-linked recessive allele - answerFemale with one affected X chromosome
and a dominant without
Phenotypic ratio in dihybrid cross - answer9:3:3:1
Linkage (physical linkage) - answerGenes on the same chromosome tend to be
inherited together
Epistasis (functional linkage) - answerOne gene masks the effect of another gene
how distance between two genes and the recombination frequency are related -
answera pair of genes with a larger recombination frequency are likely farther apart,
while a pair with a smaller recombination frequency are likely closer together.
What are the two kinds of nondisjunction that can occur during meiosis? - answerduring
meiosis I, homologous chromosomes fail to segregate at anaphase I and lead to all the
haploid cells with an abnormal number of chromosomes. The second type of
nondisjunction occurs during meiosis II when sister chromatids fail to segregate.
Aneuploidy - answerless then normal number of chromosomes
Polyploidy - answerExtra sets of chromosomes
X-inactivation significance - answerBalances gene expression between sexes
Chromosomal inversion - answerReversal of a segment within a chromosome
Haploidy - answer Having one set of chromosomes
Diploidy - answerHaving two sets of chromosomes
Homologous chromosomes - answer Chromosomes with the same genes in the same
order
How many rounds of homologous chromosomal replication occurs during meiosis? -
answerOne round
When do the chromosomes replicate during meiosis? - answer Before meiosis I
Are the products (cells) of meiosis 1 haploid or diploid? - answer Haploid cells
Are the products of meiosis 2 haploid or diploid? - answer Haploid cells
What's the key event during meiosis 1? - answer(Crossover) Pairing of Homologous
chromosomes
What's the key event during meiosis 2? - answerSister chromatids separate
Synapsis - answerPairing of homologous chromosomes (during meiosis 1), makes a
tetrad
Crossover - answerExchange of genetic material between homologous chromosomes
Tetrad - answerA group of four chromatids formed during meiosis
Why is meiosis called a reduction division? - answerbecause it reduces the number of
chromosomes to half the normal number so that, when fusion of sperm and egg occurs,
baby will have the correct number. Results in haploid cells
P0 generation - answerParental generation
F1 generation - answerFirst filial generation
F2 generation - answerSecond filial generation
Dominant trait - answerTrait that is expressed
Recessive trait - answerTrait masked by dominant allele
, Allele - answerDifferent forms of a gene
Phenotype - answerPhysical expression of genotype
Genotype - answerGenetic makeup of an organism
Homozygosity - answerHaving two identical alleles for a gene
Heterozygosity - answerHaving two different alleles for a gene
Phenotypic ratio in mono hybrid cross - answer3:1
Genotypic ratio in mono hybrid cross - answer1:2:1
Hemizygosity - answerPresence of only one allele for a gene
Do X-linked disorders disproportionately affect males or females? Why - answerMales,
because males only have 1 X chromosome (hemizygosity) and females have 2.
Carrier of X-linked recessive allele - answerFemale with one affected X chromosome
and a dominant without
Phenotypic ratio in dihybrid cross - answer9:3:3:1
Linkage (physical linkage) - answerGenes on the same chromosome tend to be
inherited together
Epistasis (functional linkage) - answerOne gene masks the effect of another gene
how distance between two genes and the recombination frequency are related -
answera pair of genes with a larger recombination frequency are likely farther apart,
while a pair with a smaller recombination frequency are likely closer together.
What are the two kinds of nondisjunction that can occur during meiosis? - answerduring
meiosis I, homologous chromosomes fail to segregate at anaphase I and lead to all the
haploid cells with an abnormal number of chromosomes. The second type of
nondisjunction occurs during meiosis II when sister chromatids fail to segregate.
Aneuploidy - answerless then normal number of chromosomes
Polyploidy - answerExtra sets of chromosomes
X-inactivation significance - answerBalances gene expression between sexes
Chromosomal inversion - answerReversal of a segment within a chromosome
