Punnet Squares

Week 1: Wednesday, August 27th: Lab Worksheet 1B: Punnett; Week 3: Monday, September 8th

genes code for specific _______ (hair color)

traits

_______ are varations of genes (brown hair vs. black hair)

alleles

the _______ is the trait you can physically see (hair color)

phenotype

the _______ is the alleles producing a trait (B)

genotype

_______ is one set of chromosomes (B)

haploid

_______ is 2 sets of chromosomes (BB)

diploid

_______ alleles are the same (AA or aa)

homozygous

_______ alleles are different (Aa)

heterozygous

_______ traits are viewed in heterozygote and homozygote dominant conditions

dominant

true or false: both Aa and AA genotypes will look like an a phenotype

false. both Aa and AA genotypes will look like an A phenotype

_______ traits are only viewed in homozygous recessive

recessive

true or false, an aa genotype will look like an a phenotype

true

in Mendelian inheritance, _______ of alleles requires that genes are on separate chromosomes

independent assortment

offsprings that are identical because parents are homozygous for a specific trait come from _______ parents

pure-breeding

what ratio does pure-breeding always give (AA x AA, aa x aa, or AA x aa)?

4:0

what phenotypic ratio does Aa x Aa give?

3:1

what genotypic ratio does Aa x Aa give?

1:2:1

doing a test-cross with a heterozygote gives what ratio?

1:1

what phenotypic ratio does AaBb x AaBb give?

9:3:3:1

what geenotypic ratio does AaBb x AaBb give?

1:2:1:2:4:2:1:2:1

A_ means the 2nd allele can be _______ or _______, but both prodice an A phenotype

A or a

_______ is used to determine an unknown genotype of any organism, in which the tester is always homozygous _______

test-crossing, recessive

when two dominant alleles can be expressed at the same time (AB blood), this is referred to as _______

codominance

when neither allele is fully expressed, so the heterozygous condition is intermediate (blended) between the homozygous dominant and recessive genotypes, this is referred to as _______

incomplete/semi dominance

when the recessive allele (-) behaves as a dominant allele in the heterozygous state because it causes a dimerized protein (proteins that work together) in the double recessive condition to misfold, and the heterozygous dimer to misfold too, this is referred to as a _______

dominant negative mutation

when three phenotypes occur in a dihybrid heterozygous cross instead of four, this is referred to as _______

epistasis

_______ interferes with Mendelian inheritance patterns when certain genes are located close together on a single chromosome, and the combination tends to be inherited as a unit, creating a gene sweep that wipes away future heterozygosity.

gene linkage