Bio Exam 3 Review
Exam 3 Review Sheet
Genetics terms: phenotype, genotype, allele, dominant, recessive, homozygous, heterozygous, multiple alleles, codominance
Phenotype: physical appearance
Genotype: genetic composition
Allele: alternate form of a gene
Dominant: trait that will be expressed
Recessive: trait that will be masked by dominant trait
Homozygous: both alleles are the same
Heterozygous: the alleles are different
Multiple Alleles:
Codominance:
Sex determination – all possibilities
Xyy:
Xxy (klinefelter’s syndrome):
Xo (turners syndrome)
XXX:
One and two trait crosses with punnett squares, sex linked traits\
Questions from “Ghost in your genes video”
Attached on other sheet
Fertilization and polyspermy
Fertilization:
• Sperm squeezes through follicle cells • Sperm releases acrosomal enzymes so it can penetrate the zona pellucida • Sperm cell membrane fuses with egg cell membrane • Sperm enters egg, nucleus is released • Egg nucleus and sperm nucleus fuse forming a zygote
Polyspermy:
More than one sperm fertilizes the egg
Cellular stages of development; Radial and spiral cleavage, formation of blastula
Cleavage:
• Mitotic cell divisions yield a ball of cells (blastula); each cell gets a different bit of the egg cytoplasm • Number of cells increases, but the zygote’s original volume remains unchanged • Cleavage takes the embryo from a zygote to a blastula • There are two type of cleavage, radial and spiral, based on the patterns of cell division
Radial cleavage:
Division of cells in early embryo to produce cells of equal size
Spiral Cleavage:
Division of cells in early embryo to form cells of unequal size
Formation of blastula:
Blastula: hollow ball of cells filled with fluid Pump sodium inside, water flows via osmosis Not all blastulae look exactly alike
Tissue stages of development: early gastrulation, late gastrulation, germ layers
Early gastrulation: •
Genetics terms: phenotype, genotype, allele, dominant, recessive, homozygous, heterozygous, multiple alleles, codominance
Phenotype: physical appearance
Genotype: genetic composition
Allele: alternate form of a gene
Dominant: trait that will be expressed
Recessive: trait that will be masked by dominant trait
Homozygous: both alleles are the same
Heterozygous: the alleles are different
Multiple Alleles:
Codominance:
Sex determination – all possibilities
Xyy:
Xxy (klinefelter’s syndrome):
Xo (turners syndrome)
XXX:
One and two trait crosses with punnett squares, sex linked traits\
Questions from “Ghost in your genes video”
Attached on other sheet
Fertilization and polyspermy
Fertilization:
• Sperm squeezes through follicle cells • Sperm releases acrosomal enzymes so it can penetrate the zona pellucida • Sperm cell membrane fuses with egg cell membrane • Sperm enters egg, nucleus is released • Egg nucleus and sperm nucleus fuse forming a zygote
Polyspermy:
More than one sperm fertilizes the egg
Cellular stages of development; Radial and spiral cleavage, formation of blastula
Cleavage:
• Mitotic cell divisions yield a ball of cells (blastula); each cell gets a different bit of the egg cytoplasm • Number of cells increases, but the zygote’s original volume remains unchanged • Cleavage takes the embryo from a zygote to a blastula • There are two type of cleavage, radial and spiral, based on the patterns of cell division
Radial cleavage:
Division of cells in early embryo to produce cells of equal size
Spiral Cleavage:
Division of cells in early embryo to form cells of unequal size
Formation of blastula:
Blastula: hollow ball of cells filled with fluid Pump sodium inside, water flows via osmosis Not all blastulae look exactly alike
Tissue stages of development: early gastrulation, late gastrulation, germ layers
Early gastrulation: •