LECTURE 2 - STUDY GUIDE Flashcards
What is the definition of a gene?
DNA nucleotide sequence
What is the definition of an allele?
varying genetic traits
What is the definition of a locus?
Particular location of a gene on a chromosome
What is the difference between a homozygous and heterozygous individual?
Homozygous- same type of allele. Homo means the same
Heterozygous- one of each type of allele, varying alleles. Think Hh. Hetero means different.
What is the difference between a genotype and phenotype?
Genotype- alleles
Phenotype- physical representation that you are going to display
(Words of the possibilities)
What does it mean that Mendelian genetics are considered “discrete” genetics?
Discrete Genetics-
- Discrete genetics: the dominant will always show up if present (one or the other)
Which statement does not describe Mendel’s First Law of Heredity: Segregation?
Alternative alleles of character segregate from each other in heterozygous individuals and remain distinct
during miosis
What is the difference between completing a monohybrid verses dihybrid test cross?
Monohybrid-produce 4 possibilities
Dihybrid: mixing 2 different set of alleles (use foil to determine outsides)
- Which statement does not describe how Mendel found his phenotype ratio for the 𝐹1 and 𝐹2 generations from dihybrid crosses? (know all experimental design and which genotypes he breed)
1)Took purebreeds of RRYY he mixed that with rryy
2)Every single offspring would be carriers like RrYy
3)Then he did self-fertilization to breed RrYy with RrYy
4)He always got a 9:3:3:1 ratio all the time
9→RRYY
3→RRyy
3:rrYY
1:rryy
Which statement describes the results of Mendel’s experiments for dihybrid crosses?
9:3:3:1
What do the letters on the outside of the Punnett square stand for?
The parent’s genotypes
What do the letters on the inside of the Punnett square stand for?
They represent the possible genotypes for offspring.
What is the (a) genotypic and (b) phenotypic ratio of the offspring of a dihybrid cross of a homozygous tall and green male and homozygous short and yellow female plant? H = tall, h = short, G = green, and g = yellow
genotypic ratio: 1HhGg (100% HhGg)
phenotypic ratio: 100% tall and green
What is the phenotypic ratio of the offspring of a dihybrid cross of a heterozygous male and a heterozygous female plant? H = tall, h = short, G = green, and g = yellow
phenotypic ratio: 9:3:3:1
19% short and Green
19% tall and yellow
6% short and yellow
Hornless (H) in cattle is dominant over horned (h). A homozygous hornless bull mated with a homozygous horned cow. What will be the genotype and phenotype of the first generation?
p1: HH x hh
f1: Hh
In tomatoes, red fruit (R) is dominant over yellow fruit (r). A plant that is homozygous for red fruit is crossed with a plant that has yellow fruit. What would be the genotypes and phenotypes of the P1 and F1 generations?
Phenotype: 100% will be red fruit
Genotype: Rr
In humans, being a tongue roller (R) is dominant over non-roller (r). A man who is a non-roller marries a woman who is heterozygous for tongue rolling. What is the probability of this couple having a child who is a tongue roller?
Phenotype: 50% of offspring becoming tongue rollers
Genotypes: Rr, rr
Brown eyes in humans are dominant over blue eyes. A brown-eyed man, whose mother was blue-eyed, marries a brown-eyed woman whose father had blue eyes. What is the probability that this couple will have a blue-eyed child?
Phenotype: 25% of offspring becoming blue-eyed
Genotype: BB, Bb, bb
What is the Law of Independent Assortment regarding genetics?
Genes located on different chromosomes assort independently of one another
