20 terms

Biology unit 7 test: Genetics

alleles are described as
alternate forms of a gene
In carrier pigeons there is a rare inherited condition that causes the death of the chicks before hatching. In order for this disease to be passed from generation to generation there must be parent birds that
are heterozygous for the disease
Mendel hypothesized that reproductive cells have only one factor for each inherited trait. This hypothesis is supported by the observation that
haploid cells are produced by meiosis
Fur color in cats is controlled by an autosomal gene that can occur in the dominant form, (B), or the recessive form, (b). The length of the cat's fur is controlled by another autosomal gene that occurs in the dominant form, (S), or the recessive form, (s). The table below shows the traits for these allele codes.
Gene B= trait black fur
Gene b= trait white fur
Gene S= trait short-haired fur
Gene s= trait long-haired fur
The following genotypes were found in a male cat and a female cat: BbSs (male) bbSS (female)
which one of the following choices is true of the phenotype of offspring from these parents?
All offspring will have short-haired fur
A homozygous dominant plant that produces yellow seeds is crossed with a homozygous recessive plant that produces green seed. The F1 plants have yellow seeds. What is the expected phenotype ratio of seed color of the offspring of an F1x F1 cross?
3 yellow:1 green
According to Mendel's Law of Segregation
Gametes have one copy of each allele
What is the basis of Mendel's Laws?
The behavior of chromosomes during anaphase 1 and anaphase 2
To determine the genotype of an individual who expresses a dominant trait, you would cross that individual with an individual who
is homozygous recessive for that trait
A couple has two female children. What is the probability that their next child will be male?
The parents of a child with unusual disease symptoms took the child to a doctor for help. The doctor was unsuccessful treating the disease and felt that it might have a genetic basis. He explained that if that was true, it could have possibly been inherited. He recommended that the child be taken to a specialty clinic where physicians and staff member were trained to diagnose genetic diseases and counsel parents. Ultimately, the child was shown to have a rare recessively inherited disease. The parents were tested for the gene, and both were found to be heterozygous. The parents wanted to have another child but were afraid this child would also be affected. What would genetic counselors say is the probability of the second child having the disease?
Round seeds (R) are dominant to wrinkled seeds (r), and yellow seeds (Y) are dominant to green seeds (y). What is the expected phenotype ratio of a cross between an RrYy and an rryy individual?
1 round yellow:1 round green:1 wrinkled yellow:1 wrinkled green
The chart shows four alleles for the same gene that affects rabbit's coat color. Each allele is dominant to the ones below it. Rabbits with an albino or Himalayan coat are more susceptible to predators. Which of the following genotypes will produce a rabbit that is least likely to survive?
An individual with (naturally) curly hair and an individual with (naturally) straight hair mate; all of their offspring have (naturally) wavy. What is the relationship between the alleles for hair texture?
incomplete dominance
An individual with the genotype AB has the blood type AB.What is the relationship between the A and B alleles?
The gene for human blood type has three alleles A, B and O that result in four different blood types: type A, type B, type AB and type O. An individual with the genotype AB has the blood type AB. The only genotype that results type O blood is OO. What is the expected phenotype ratio of a cross between a heterozygous person with blood type B and a person with blood type AB?
1 type A:1type AB: 2 type Bmia
Red-green color blindness is inherited as an x-linked recessive. How can a man with normal color vision have a daughter who is red-green color-blind?
He can't (unless there is a mutation)
Hypophosphatemia (vitamin D-resistant rickets) is inherited as an X-linked dominant. What is the expected outcome of a cross between a homozygous recessive woman and a man with Hypophosphatemia?
All of their daughters and none of their sons exhibit Hypophosphatemia
What is the probability that a daughter will inherit an X-linked recessive allele from her father?
Dwarfism is a genetic trait caused by a dominant allele. It can traced back through a family's history using pedigree analysis. The pedigree here shows three generations of a family-some individuals have dwarfism. (D= dominant allele and d= recessive allele) Susan's genotype is
This pedigree supports the fact that dwarfism is due to a dominant allele, because if it were due to a recessive allele and both parents show the recessive phenotype, then
all of the offspring would have a dwarfism