Diploid
cells that have 46 chromosomes (somatic cells)
Haploid
cells that have 23 chromosomes (sex cells)
Somatic cells
all cells in the body other than gametes
Gametes
sex cells
Mitosis
division somatic cells undergo
Meiosis
division gametes undergo
Homologous chromosomes
chromosomes that are identical to each other
Autosomes
22 of the 23 pairs (not sex chromosomes)
Sex chromosomes
the 23rd pair of chromosomes
Karyotype
an ordered display of chromosomes
XXXY
Male
XXXX
Female
XO
Female
What gene on what chromosome determines gender?
The SRY gene on the Y-chromosome determines gender
Polyploidy
cell that has more than the diploid number
Aneuploidy
a somatic cell that has one or two missing or extra chromosomes (caused by non-disjunction: failure of chromosomes to separate normally)
Triploidy
cell that has 3 copies of each chromosome rather than 2
Tetraploidy
cell that has 4 copies of each chromosome rather than 2
Trisomy
cell containing 3 copies of one chromosome
Monosomy
cell containing 1 copy of one chromosome
Compare the survival rate of children born with polyploidy and aneuploidy (both autosomes and sex chromosomes).
Polyploidy: Autosomes: lethal Sex chromosomes: not lethal Aneuploidy: Autosomes: Monosomy is lethal, trisomy is not necessarily lethal Sex chromosomes: less serious than that of autosomes
Describe the genotype and phenotype of persons with Down syndrome
Genotype: trisomy of the 21st chromosome, Phenotype: slanting of the eyelids, small mouth, ears, hands and feet
What are the major health concerns of Down syndrome?
Major health concerns: hearing deficits, CHD, hypothyroidism, higher risk for early onset of Alzheimer's Disease
Is Down syndrome an example of autosomal aneuploidy or sex chromosome aneuploidy?
Example of autosomal aneuploidy
What does 47, XY, +21 mean?
47, XY, +21 means: aneuploidy (47 chromosomes rather than 46) male, extra chromosome is on the 21st pair
What is the most common kind of chromosomal mosaicism?
Down syndrome mosaicism
Diploid
cells that have 46 chromosomes (somatic cells)
Haploid
cells that have 23 chromosomes (sex cells)
Somatic cells
all cells in the body other than gametes
Gametes
sex cells
Mitosis
division somatic cells undergo
Meiosis
division gametes undergo
Homologous chromosomes
chromosomes that are identical to each other
Autosomes
22 of the 23 pairs (not sex chromosomes)
Sex chromosomes
the 23rd pair of chromosomes
Karyotype
an ordered display of chromosomes
XXXY
Male
XXXX
Female
XO
Female
What gene on what chromosome determines gender?
The SRY gene on the Y-chromosome determines gender
Polyploidy
cell that has more than the diploid number
Aneuploidy
a somatic cell that has one or two missing or extra chromosomes (caused by non-disjunction: failure of chromosomes to separate normally)
Triploidy
cell that has 3 copies of each chromosome rather than 2
Tetraploidy
cell that has 4 copies of each chromosome rather than 2
Trisomy
cell containing 3 copies of one chromosome
Monosomy
cell containing 1 copy of one chromosome
Compare the survival rate of children born with polyploidy and aneuploidy (both autosomes and sex chromosomes).
Polyploidy: Autosomes: lethal Sex chromosomes: not lethal Aneuploidy: Autosomes: Monosomy is lethal, trisomy is not necessarily lethal Sex chromosomes: less serious than that of autosomes
Describe the genotype and phenotype of persons with Down syndrome
Genotype: trisomy of the 21st chromosome, Phenotype: slanting of the eyelids, small mouth, ears, hands and feet
What are the major health concerns of Down syndrome?
Major health concerns: hearing deficits, CHD, hypothyroidism, higher risk for early onset of Alzheimer's Disease
Is Down syndrome an example of autosomal aneuploidy or sex chromosome aneuploidy?
Example of autosomal aneuploidy
What does 47, XY, +21 mean?
47, XY, +21 means: aneuploidy (47 chromosomes rather than 46) male, extra chromosome is on the 21st pair
What is the most common kind of chromosomal mosaicism?
Down syndrome mosaicism