Phenotype. Genotype. physical appearance of an organism. the set of genes (alleles) that an organism possesses. Homozygous. Heterozygous. when two alleles (gene types) are identical. when the two alleles are different. Genetics Buzzwords. Allele. different forms of the same gene.
physical appearance of an organism.
the set of genes (alleles) that an organism possesses
when two alleles (gene types) are identical
when the two alleles are different
different forms of the same gene
allele which controls the characteristic whenever it is present.
BB or Bb
allele whose characteristics only show up when it is present on both chromosomes
In pea plants, tallness (T) is dominant to dwarfness (t)
A tall pea plant could have a genotype of:
Both combinations have the same phenotype- tall.
A dwarf pea plant could only have the genotypett Phenotype- dwarf.
The simplest genetic cross involves one characteristic and is called a monohybrid cross.
In this the parents (P) are crossed (bred) with each other, and the offspring (F1 generation) observed and counted.
Follow the procedure on the board!!
1:1 ratio male to female offspring
Offspring: Male or female?
This explains how the sex of a child is determined by X and Y chromosomes.
This can also be shown and combinations worked out using a Punnett square:
1. Complete the problems in the Monohybrid Crosses booklet
2. Let´s play Traits Bingo! (15 min)
A – normal skin pigmentation
a – albino
What percentage chance is there of producing a child with albinism?
1: Finish the Monohybrid Crosses revision booklet (15 min)
2: Try the problems in the More Monohybrid crosses booklet! (20 min)
3: Let’s play Traits bingo! (15 min)
Who is known as “the man of 1000 peas?”
How long has he been running his experiments for?
How many plants did he grow?
What did he notice when he first grew pea plants?
What field of biology has come about because of his experimenting on peas?