Vocab
The genetic makeup, or the letter.
Genotype
A gene that is hidden when a dominant trait is present
recessive
In pea plants, tall T is dominant over short t. If two heterozygous tall parents are crossed, what are the possible genotypes and phenotypes of the offspring?
Genotype: 25% TT, 50% Tt, 25% tt
Phenotype: 75% tall, 25% short
Who is the man who first experimented to discover how traits are passed down?
Gregor Mendel
The physical expression of traits.
Phenotype
The gene that will always be shown if it is present.
Dominant
In rabbits, black fur B is dominant over white fur b. A white rabbit is crossed with a black rabbit. Half of the offspring are white, and half are black.
What must the genotype of the black rabbit be?
Bb heterozygous
Having freckles is dominant to not having freckles in humans. Using the letter F, cross a homozygous male with freckles with a female who has no freckles. Will any of their offspring not have freckles?
NO
The passing of traits from parent to offspring.
Heredity
The combination of genes that codes for a specific trait.
Genotype
B = pointy ears and b = floppy ears. Cross a heterozygous pointy eared dog with a floppy eared dog. Show your work in your punnett square. What percentage of offspring would have pointy ears?
50%
In fish, soft scales are dominant to hard scales. Using the letter S, create a punnett square crossing two heterozygous fish. Give percentages of offspring being homozygous dominant, homozygous recessive, and heterozygous.
25% homozygous dom
50% heterozygous
25% homozygous recessive
Structures made of DNA, located in the nucleus.
Chromosomes
What is the difference between homozygous and heterozygous?
Homozygous will show the same letters (either AA or aa). Heterozygous will show different letters (Aa)
P = purple and p=pink. Complete a punnett square for a homozygous purple flower crossing with a heterozygous flower. What is the percentage that the offspring would be pink?
0%
In horses, the dominant color is brown and the recessive color is grey. Using the letter G, create a punnett square crossing a grey horse with a heterozygous horse. Give percentages of homozygous dominant, homozygous recessive, heterozygous.
50% heterozygous
50% homozygous recessive
Different forms of a gene
Allele
Give an example of a homozygous recessive allele pair:
any two of the same lowercase letters.
B = brown eyes and b = blue eyes. Cross a blue eyed male with a blue eyed female using a punnett square. What is the percentage that their offspring will have brown eyes? What is the percentage they will have blue eyes?
100% blue eyes
0% brown eyes
In cats, having a curly tail is dominant to having a straight tail. Using the letter T, cross a homozygous curly tailed cat with a straight tailed cat using a punnett square. What are the chances of the offspring having a curly tail?
100%