Lesson 5: genetics Flashcards
mendel’s particulate theory
characteristics are determined by “particulate factors”
genes come in pairs
when sex cells form, the genes are transferred as discrete entities
gametes
haploid sex cells
particulate factors
genes
what does it mean when you say “inherited characteristics are determined by genes”
genes are DNA sequences that are transcribed into mRNA
gene
DNA transcription unit
promoter
promoter is a region of DNA that leads to initiation of transcription of a particular gene
transcribed region
the part that is copied
terminator
a section of nucleic acid sequence that marks the end of a gene
what does it mean when you say gametes form and are transferred as discrete entities
sex cells are made by meiosis and are haploid
genes are found
on chromosomes
phenotype
the trait that shows up
each gene corresponds to a
specific region of the DNA that is used as a template to produce mRNA
allele
there are alternative forms of genes
each gene corresponds to a
specific region of the DNA that is used as a template to produce mRNA
mendels first law of inheritance
law of segregation:
- there are alternative forms of genes (alleles)
- organisms have pairs of genes, inheriting one set from each parent
- if the organism has two alleles, the dominant will come forward to the recessive
- when gametes form, they contain a complete set of genes. the allele pairs segregate independently from each other
independent assortment
increases genetic variability. contributes to the next generation because orientation of the chromosomes on the metaphase plate is random
homozygous alleles
when an organism has identical alleles for a gene
can be dominant (Aa or recessive (aa)
heterozygous
when an organism has different alleles for a gene
menders principle of segregation describes
inheritance of a single characteristic.
inheritance of single characteristicq
p0 is the true breeding parents (purple and white flowers) f1 generation: all plants are purple flowers (dominant) self cross (f1 and f1) yields f2 generation. 3/4 of plants are purple and 1 is white
punnet squares
represent the gametes made by meiosis
if a parent Is 2N with Pp, gametes are
PP purple, Pp purple, Pp purple and pp white
law of independent assortment
during gamete formation, each pair of alleles segregates independently from the other pair of alleles. flower colour will assort differently from seed shape
dihybrid crosses
shows two characteristics at the same time. the “father” goes on the top. if its PP and gg, each gamete is gonna be PG, Pg, pG and pg. write out a fraction at the end showing which characteristics show ed up
sex determination
is done by the sperm gamete
incomplete dominance
homozygous dominant: 2 copies of the functional allele
heterozygous: only 1 copy of the functional allele
homozygous recessive: 0 copies of the functional allele
codominance
when the allele can exist together and combine to be something ex. blood type
multiple alleleism
lots of alleles for a gene
incomplete dominance
results in a third phenotype that is a blend (ex red and white make pink)
homozygous dominant: 2 copies of the functional allele
heterozygous: only 1 copy of the functional allele
homozygous recessive: 0 copies of the functional allele
practice punnet squares
Ah
practice punnet squares
Ah
genotype
the actual letter part
