Chapter 5 Review Flashcards
What is another term to describe the genotype of a “purebred” organism?
homozygous
What is the term used to describe the genotype of an organism that contains 2 different alleles?
heterozygous
What is the term that refers to the observable traits of an organism?
phenotype
What is the term that refers to the alleles that an individual carries?
genotype
List any 2 of the traits of pea plants that Mendel studied?
Any 2 of: seed shape, seed colour, pod shape, pod colour, flower colour, flower position,
stem length
In the following Punnett square, what are the genotype ratios of the F1 generation?
T=tall plant t=short plant
T T
t Tt Tt
t Tt Tt
100% heterozygous (100% Tt)
In the following Punnett square, what are the phenotype ratios of the F1 generation?
B=brown eyes b=blue eyes B b
B BB Bb
b Bb bb
75% brown eyes, 25% blue eyes
What is the purpose of a test cross?
to determine the genotype of an individual showing the dominant phenotype
(the homozygous dominant genotype or the heterozygous genotype)
What does a circle represent in a pedigree chart?
a female
If a circle/square is coloured on a pedigree chart, what does that indicate?
It indicates that that individual expresses that trait.
If a circle/square is half shaded on a pedigree chart, what does that indicate?
It indicates that the individual is heterozygous for the recessive trait (a carrier)
In fruit flies, there are 4 alleles for eye colour, and the dominance hierarchy is:
red > apricot > honey > white. In a female fruit fly, how many possible genotypes
are there for red eye colour?
4 (homozygous, and then heterozygous with each of the other alleles)
In certain types of cows, there are 2 alleles for hair colour: red and white. When a cow
has the heterozygous genotype, its phenotype is roan (red hairs and white hairs present).
What is this an example of?
codominance
Give an example of codominance in human blood type alleles.
AB blood. A (I A) and B (I B) alleles are codominant
When a snapdragon flower is heterozygous and contains both the red allele and the white
allele, its phenotype is a pink flower. This is an example of…
incomplete dominance
If genes are on located on separate chromosomes, they are inherited independently of
each other. This is called the law of …
independent assortment
In guinea pigs, black coat colour (B) is dominant over white (b), and short hair lenth (H) is
dominant over long (h). What is the genotype of a guinea pig that is homozygous for black
and heterozygous for short hair?
BBHh
If a trait is sex-linked, how many possible genotypes are there for this trait in a male?
2
If a trait is sex-linked, how many possible genotypes are there for this trait in a female?
3
What blood type is the “universal donor” (i.e. it will be accepted by people of any blood
type)?
Which is the “universal acceptor” (can accept any type of blood)?
- type O (more specifically type O negative) [O negative blood donors are universal because there’s nothing in their blood for a patient’s antibodies to ‘attack’.]
- type AB (specifically type AB positive) [People with type AB+ blood are universal recipients because they have no antibodies to A, B or Rh in their blood and can receive red blood cells from a donor of any blood type.]
Red-green colourblindness is caused by a recessive sex-linked allele. If you have a mother with normal vision and a father who is colourblind, is it possible for them to have a daughter who is colourblind?
only if the mother is heterozygous for (or a carrier of) coloublindness
