Biology by Bradford
5.3.AA pedigree
12345
- 1
- 2
- 3
- 4
- 5
5.3 Mendelian Genetics: revision map
The subtopic in the middle and five tasks round it: label two diagrams, complete two tables and fill 17 gaps. Every box rests on a learning objective of the topic in the AP Biology course and exam description. Type into the blanks and check them, or print it on A4, Letter or A3 with an answer key.
Mendelian Genetics
AP Biology · Unit 5 HeredityHover over a box to see it. Untick it to leave it off this sheet and its printout.
Name5.3.AMendel's laws
The law of says that the two alleles for a gene separate when gametes form, so each gamete carries one. The law of independent assortment says that alleles of genes on different chromosomes are sorted into gametes independently. Both laws are explained by the behavior of chromosomes in meiosis. A test cross of an unknown dominant phenotype with a homozygous recessive reveals the genotype: any recessive offspring show the parent was heterozygous.
5.3.AThe vocabulary
| Term | Meaning |
|---|---|
| one version of a gene | |
| the alleles an individual has | |
| the trait that results | |
| Heterozygous | two different alleles of a gene |
| Dominant | expressed in a heterozygote; recessive is hidden |
Topic 5.3Mendelian Genetics
5.3.AA monohybrid cross
1234
- 1
- 2
- 3
- 4
5.3.AProbability rules
| Rule | When used | Example |
|---|---|---|
| independent events happening together | Aa × Aa and Bb × Bb: probability of aabb = ¼ × ¼ = 1/16 | |
| either of two exclusive outcomes | probability of a heterozygote from Aa × Aa = ¼ + ¼ = ½ |
A monohybrid cross between two heterozygotes gives a phenotype ratio of , and a dihybrid cross gives , when the genes are on different chromosomes.
Word bank 3 : 19 : 3 : 3 : 1Additionaffected femaleaffected maleAllelegameteGenotypeheterozygoushomozygous dominanthomozygous recessivematingMultiplicationoffspringPhenotypesegregationunaffected female
Answer key
Every box on the sheet with its gaps filled in, as the subtopic reads in full.
LabelA monohybrid cross
- gamete
- homozygous dominant
- heterozygous
- homozygous recessive
LabelA pedigree
- affected male
- unaffected female
- offspring
- mating
- affected female
TableThe vocabulary
Term Meaning Allele one version of a gene Genotype the alleles an individual has Phenotype the trait that results Heterozygous two different alleles of a gene Dominant expressed in a heterozygote; recessive is hidden TableProbability rules
Rule When used Example Multiplication independent events happening together Aa × Aa and Bb × Bb: probability of aabb = ¼ × ¼ = 1/16 Addition either of two exclusive outcomes probability of a heterozygote from Aa × Aa = ¼ + ¼ = ½ A monohybrid cross between two heterozygotes gives a phenotype ratio of 3 : 1, and a dihybrid cross gives 9 : 3 : 3 : 1, when the genes are on different chromosomes.
GapsMendel's laws
The law of segregation says that the two alleles for a gene separate when gametes form, so each gamete carries one. The law of independent assortment says that alleles of genes on different chromosomes are sorted into gametes independently. Both laws are explained by the behavior of chromosomes in meiosis. A test cross of an unknown dominant phenotype with a homozygous recessive reveals the genotype: any recessive offspring show the parent was heterozygous.