Exam 3: UNCP Genetics

Cystic fibrosis is caused by a single recessive gene. A couple has a child with cystic fibrosis, who dies when she is eight years old. They want another child and are trying to decide whether to adopt or to have a second natural child. What are the chances that their second child will have cystic fibrosis?

1/4

Ima MendelTu, little known niece of Gregor, investigated flower colors in white clover. Unfortunately Ima did not read her uncle's manuscript and made critical mistakes in her protocol. Eventually it was discovered that a white flower is dominant to a red flower. In one experiment, Ima crossed two white flowered plants and obtained 48 white flower progeny and 16 red flower progeny. Since we know so much more than Ima, how many of the progeny plants from this cross would you expect to be homozygous (true-breeding) for the white flower trait?

16

If two heterozygous organisms are crossed (Aa X Aa) what is the expected genotypic ratio among their offspring

1:2:1

With incomplete dominance, a likely ratio resulting from a monohybrid cross would be

1:2:1

Assume that a cross is made between two organisms that are both heterozygous for a gene that shows incomplete dominance. What phenotypic and genotypic ratios are expected in the offspring?

1:2:1 (genotypic & phenotypic)

A true-breeding black rodent is crossed with a true-breeding white rodent. All of the offspring are speckled black and white. Which inheritance pattern is represented?

Codominance

What word describes mating between individuals who are blood relatives?

Consanguineous

The observable manner in which an organism expresses a particular characteristic is called the ____________________

Phenotype

Scientific name of the organism used by Mendel to conduct genetic crosses?

Pisum Sativum

Which two genotypes in an individual would be expressed as the same phenotype in a diploid organism?

homozygous dominant and heterozygous

Mendel crossed two pea plants with round seeds. All seeds of the offspring were round. He then crossed a plant with round seeds to a plant with wrinkled seeds and all offspring had wrinkled seeds. Which of the following is true?

wrinkled is dominant

What term is used to indicate the alternative forms of genes?

Alleles

Albinism in humans is inherited as a simple recessive trait. In one family two nonalbino (normal) parents have five children, four normal and one albino. And in another a normal male and an albino female have six children, all normal. Which of Mendel's postulates were demonstrated?

-Unit factors separate from each other during gamete formation. -Unit factors have dominance/recessive relationships. -Unit factors exist in pairs.

In a mating between individuals with the genotypes IAIB × ii, what percentage of the offspring are expected to have the O blood type?

0

If P produces yellow flowering soybean plants and pp produces white flowering plants, what ratio from a testcross of a yellow flowering plant would indicate the yellow flowering plant was heterozygous?

1 yellow : 1 white

Polydactyly is expressed when an individual has extra fingers and/or toes. Assume that a man with six fingers on each hand and six toes on each foot marries a woman with a normal number of digits. Having extra digits is caused by a dominant allele. The couple has a son with normal hands and feet, but the couple's second child has extra digits. What is the probability that their next child will have polydactyly?

1/2

Assuming a typical monohybrid cross in which one allele is completely dominant to the other, what ratio is expected if the F1s are crossed?

3:1

Which phenotypic ratio is observed among the F2 offspring of two heterozygotes?

3:1

If two heterozygous organisms are crossed (Aa X Aa) what percentage of offspring are expected to be heterozygous

50%

A recessive allele in dogs causes white spots. If two solid colored dogs are mated and produce a spotted offspring, what is the percentage chance their next puppy would be solid colored?

75%

Chi-square Test

A statistical test that determines how frequently an observed deviation can be expected to occur strictly as a result of chance

If an F2 generation from a self-cross always yields offspring in a 3:1 phenotypic ratio, which of the following P crosses could have occurred?

AA × aa

Disease inherited in an autosomal recessive pattern

Albinism

Term used to describe the variant forms of unit factors for a given characteristic

Allele

Mendel indicated that traits were made up of unit factors. Today we call unit factors _________

Alleles

Which type of trait is normally observed in an F1 hybrid organism

Dominant

The development of organs in a multicellular organism involves a sequence of events, with each step increasing the complexity of the organism. What is this phenomenon called?

Epigenesis

If an organism whose genotype is BbDd is used in a test cross, how many different types of offspring are expected?

Four

Genotype of an organism that possesses two alleles of the same type for a certain characteristic

Homozygous

Which type of cross follows the inheritance of one characteristic, using parents with contrasting forms of the characteristic?

Monohybrid

Which hypothesis states that there is no significant difference between the expected outcome of an experiment and the outcome that is actually observed?

Null hypothesis

Assume that in a series of experiments, plants with round seeds (W) were crossed with plants with wrinkled seeds (w) and the following offspring were obtained: 220 round and 180 wrinkled. What is the most probable genotype of each parent?

One parent is ww, the other is Ww.

What is a chart that outlines several generations of a trait's occurrence in an extended family?

Pedigree

Which of the following characteristics is not beneficial for selecting a test organism for genetic crosses

Produces a small number of offspring

Which mathematical rule explains the relationship between monohybrid and dihybrid ratios

Product law

Which product is the end point if the expression of a gene

Protein

Which part of meiosis correlates directly with independent assortment

Random alignment at metaphase I

Mendel's principle of _______________ states that an organism's pair of unit inheritance factors separates from one another during meiosis

Segregation

Which researchers used cytological studies to support the conclusions drawn by Mendel?

Sutton & Boveri

Which field of biology was officially founded by Mendel's work?

Transmission Genetics

What does the term multiple alleles mean?

There are more than two possible alleles for one gene in a population

Sexually reproducing organisms have a diploid chromosome content. What does this mean?

There are two copies of each chromosome type on these organisms

A cross between two individuals with different phenotypes that resulted in approximately 50% of each type of offspring would indicate the cross was ________.

a heterozygous dominant crossed to a homozygous recessive

The process that leads to development haploid gamete is best described as ________.

segregation

Mendel's unit factors in pairs are most accurately known to be

two alleles on paternal and maternal homologs