Biology 101 With A Lab Ch. 17 Mendelian Genetics & Mechanisms of Heredity

Use a Punnett Square to figure out what percentage of pea plants would have purple flowers in the following cross: A purple flowered pea plant (PP) crossed with a white flowered pea plant (pp).

100% would have purple flowers

How many phenotypes are typically produced by a dihybrid cross

4

Select the DNA sequence that serves as a complementary base pair to 3' TACGCA 5'.

5' ATGCGT 3'

How would you define a dihybrid cross?

A cross between two individuals heterozygous at two different genes.

The locus is _____.

A specific location on a chromosome.

Alleles A and B are linked on chromosome 1 (such that you have A-B and a-b). Alleles C and D are linked on chromosome 2 (you have C-D and c-d). If a crossover event does not occur between either set of genes, which gamete genotype could NOT be produced by an individual heterozygous at each locus?

A-B; C-d

Alleles A, B, C and D are linked on one chromosome, and alleles a, b, c and d are linked on the homolog. During meiosis, a crossover event occurs between genes A and B. Which of the following is an example of a chromatid that could be found in one of the resulting gametes?

A-b-c-d

DNA is a polynucleotide molecule consisting of the following nucleotides:

Adenine, thymine, cytosine, guanine

Consider the following experiment: A scientist determines that the number of dorsal spines of her experimental fish is determined by a single locus. She mates a fish with 1 dorsal spine with a fish of the same species with 2 dorsal spines. The mating produces ten fish, which all have 1 dorsal spine. Which of the following statements does not fit with this result?

All progeny fish are homozygous for the '1-spine' allele.

_____ refer to variations of a gene, pertain to dominant and recessive genes, and play a role in true breeding.

Alleles

You have the following alleles: B=blue, b=green, H=two-horned and h=one-horned: Which of the following crosses most likely produced the following results? 54 blue, two-horned lizards 18 blue, one-horned lizards 18 green, two-horned lizards 6 green, one-horned lizards

BbHh x BbHh

Which phenotype(s) do the red blood cells from a person with AB blood type exhibit?

Both the 'A' and 'B' phenotype in each red blood cell

In a species of rabbits, there are several alleles that control for coat color. The allele B results in a brown coat color. The allele b results in a beige coat color. The two alleles are codominant. What phenotype is a rabbit likely to display with the genotype Bb?

Brown coat with beige patches

If a strand of a DNA molecule has the sequence GTCCAC, what would be the sequence of the complementary section of DNA?

CAGGTG

The following results were observed from a mating between two black and white speckled cats: 5 black cats, 12 black and white speckled cats, and 4 white cats. Which term describes the relationship between the alleles of the coat color gene?

Codominance

All of the following statements are correct EXCEPT:

Creating new combinations of alleles decreases the genetic diversity of the population.

Which of the following is NOT an example of a phenotype?

DNA sequence of the alcohol dehydrogenase gene

What type of organism has two copies of every gene?

Diploid

The trait which is expressed in a heterozygous state is known as

Dominant

Which of the following statements could NOT be used to describe a multifactorial trait?

Gene homozygosity and heterozygosity determine the trait.

You could draw which of the following conclusions from a dihybrid cross which produces a 9:3:3:1 ratio of phenotypes? I. The alleles of one gene sort independently of another gene. II. The alleles of the two genes in question exhibit a simple dominant/recessive relationship. III. The animals which were crossed were both homozygous with respect to at least one locus in question.

I and II

Which of the following statement(s) accurately describes an advantage provided by model organisms? I. The laboratory environment can be controlled. II. True-breeding strains can be generated. III. Specific combinations of alleles can be engineered.

I, II and III

Which of the following statements is true? I. The one thousandth base pair on chromosome one of an organism is an example of a locus. II. Changing the DNA in a gene by one base pair could create a new allele. III. Cells in a diploid organism possess two copies of each homolog (except gametes).

I, II and III

Which of the following statements is/are true? I. A human with an X chromosome and a Y chromosome is male. II. A human with only one type of sex chromosome (an X chromosome) is female. III. All children of a color blind woman and a man who is not color blind will carry a color blind allele.

I, II and III

Genes A and B are located on the same chromosome arm in the following orientation: centromere, gene A, gene B, telomere. Which of the following recombinant chromatids could be produced by a crossover event between B genes in a heterozygote in which the dominant alleles are linked on one homolog and the recessive ones are linked on the other homolog? I. A B II. a B III. A b IV. a b

II and III

Hemophilia is an X-linked recessive trait. Consider a cross between a woman who is a carrier and a man who suffers from hemophilia. Which of the following statements is/are true? I. All sons of these parents will be a hemophiliac. II. A son who suffers from hemophilia received the hemophilia allele from his mother. III. Half of the daughters of this cross are predicted to be hemophiliacs.

II and III

Which of the following statements is true? I. A dihybrid cross is a cross between individuals heterozygous at one gene. II. The law of independent assortment describes the relationship between alleles of a single gene. III. The law of segregation describes the manner in which genes on different chromosomes segregate. IV. Homologous chromosomes segregate into different gametes.

IV

Which type of dominance describes a situation in which heterozygotes demonstrate a phenotype which is intermediate between the homozygotes?

Incomplete dominance

A Punnett square is useful when determining phenotypic output, for all of the following reasons EXCEPT:

It makes you look at only one gene at a time.

Which two laws of Mendel help us predict how chromosomes are allotted to the gametes?

Law of segregation and Law of independent assortment

Joe is in urgent need of a blood transfusion. His blood genotype is AA. Mike has an oo genotype, and Mary has a BB genotype. Who would be able to donate blood to Joe, and why?

Mike can donate, because oo doesn't produce an extracellular sugar

Let's say P is an allele that codes for purple flowers and p is an allele that codes for white flowers. A plant has alleles Pp. According to the Law of Segregation, what alleles would each gamete have?

One gamete would have P and one would have p.

An allele is _____.

One version of genetic variation at a particular locus.

A mother is a carrier of a sex-linked mutation for a particular disease. In total, she has five children, three boys and two girls. Which of the following disease patterns are probable given the existence of the sex-linked mutation?

Proper application of a sex-linked mutation suggests all of these outcomes are possible

the trait which is not expressed in a heterozygous state is known as

Recessive

Which of the following is NOT an example of a homozygous genotype?

Rr

A scientist is studying an animal and determines that a gene is located on autosome two. It controls antler production in the male animals. Note that females do not produce antlers. This is an example of a:

Sex-limited trait

In humans, _____ is determined by the presence or absence of the _____ chromosome.

Sex; Y

Skin cancer is a multifactorial trait. Which of the following is plausible?

Skin cancer is difficult to predict in a susceptible family.

What Mendelian genetics principle is exemplified by the fact that alleles of one gene sort into gametes independently of the alleles of another gene?

The Law of Independent Assortment

The law of independent assortment states that:

The alleles of one gene sort into the gametes independently of the alleles of another gene

Autosomes are

The chromosomes in the genome which are not sex chromosomes

Incomplete dominance governs the pigment gene of a flower. A mating between heterozygotes yields the following phenotypic ratio: 15 red flowers, 32 pink flowers and 14 white flowers. Which statement describes the situation?

The flower pigment gene is defined by a red and a white allele.

Mendel's second law is also known as:

The law of independent assortment

Some people have blue eyes and some people have brown eyes. Which answer best explains why this is the case?

They have different alleles.

Complementary base pairing in DNA assures that only one of the following base pairs exists in DNA. Select the correct base pair.

Thymine - Adenine

Gregor Mendel is famous for his involvement in _____.

genetics

When two genes are located on the same chromosome, they are said to be _____.

linked

The _____ of an organism is (are) determined by its genotype.

phenotype

Given close proximity between two genes on one chromosome, provides a reason for an exception to Mendel's _____ Law, as found when analyzing the progeny of a dihybrid cross that differs from the 9:3:3:1 phenotypic ratio.

second

When an organism is diploid, that means it has _____.

two versions of each chromosome.