biology

The leaf color of a certain plant is controlled by allele G = orange and allele g = green. A plant has orange leaves, but you do not know whether that plant's genotype is GG or Gg. Which of the following would help you determine the plant's genotype?

Cross the plant to a plant with green leaves.

Which of the following represents all of the possible gametes that can be formed by an individual with the genetic makeup FfGgHH?

FGH, FgH, fGH, fgH

Why are X-linked recessive genetic disorders more commonly seen in males?

Females must receive two copies of the recessive allele to exhibit the disorder, but males need only one copy.

If a father is affected by an X-linked recessive condition and the mother is a carrier, what is the probability of their children being affected?

Half of the sons will be affected.

Which of the following statements regarding genes is NOT true?

In sexually reproducing species, each cell contains a single copy of every gene.

Which of the following statements about cell division is correct

It is the process by which organisms grow and maintain their tissues.

Which of the following differentiates meiosis from mitosis?

Mitosis is used for the repair of cells, whereas meiosis creates cells for sexual reproduction.

Which of the following is true for mutations?

Mutations will affect the genotype, which may affect the phenotype.

Because an individual with an XX genotype is a female, is an individual with an XO (no second sex chromosome) a male?

No, because the Y chromosome contains the gene that makes an embryo male.

What are the stages of interphase?

S, G1, and G2

Two organisms that are true-breeding for a certain genetic characteristic are mated and their offspring analyzed. One parent has the dominant phenotype and the other the recessive phenotype. Which of the following statements about this situation is true?

The offspring are 100 percent heterozygotes

The gene for a certain sex-linked trait is found only on the Y chromosome. If the male parent carries this gene, which of the following statements about the inheritance of that trait is true?

The trait will be expressed in 100 percent of the male offspring

Autosomal dominant diseases are exhibited by anyone who carries at least one dominant allele for that gene. How is it that dominant lethal genes, such as the one that causes Huntington disease, can persist in a population?

These diseases usually take effect later in life after people have had children.

Which of the following statements about homologous chromosomes is true?

They contain the same genes in the same locations.

A researcher is recording the process of bacteria cell division using time-lapse microscopy. Which of the following processes would she be observing?

binary fission

All of the following contribute to genetic uniqueness EXCEPT

binary fission

Feather color in a certain species of bird is controlled by a pair of alleles that exhibit codominance. If birds that are homozygous for one allele are black and birds that are homozygous for the other allele are white, then heterozygous birds would be

black and white feathers

Which of the following is a difference between binary fission and mitosis?

breakdown of the nuclear envelope

Which of the following pairs of processes encompasses the entire cell cycle?

cell division and interphase

If two different alleles for the same trait have an equal effect on the phenotype, the alleles are

codominant

Homologous chromosomes

consist of a maternal and paternal copy of each chromosome.

Two copies of the same gene on a single chromosome would indicate a(n) ________ had occurred.

duplication

A carrier is an individual with a ________ genotype who does not express the recessive trait but can pass it along to offspring.

heterozygous

A pool of cells is treated with a chemical that halts progress through the cell cycle. In which stage of the cell cycle would most cells be found?

interphase

Mendel's laws of segregation and independent assortment both have their biological basis in events that take place during

meiosis

Chromosomes are lined up at the middle of the cell during the ________ portion of cell division.

metaphase

A Punnett square is used to

predict the outcome of a genetic cross.

The goal of meiosis is to

produce eggs and sperm

The gender of a human child is determined by the

sperm.

In humans, X-linked genetic diseases

tend to be expressed more in males than in females

In Mendel's experiments, the offspring produced by crossing two true-breeding parents are called

the f1 generation

Which of the following is true of the chromosomes in a homologous pair?

they carry the same genes

In a karyotype of a male, which of the following would indicate an abnormality?

two y chromosomes

What information is NOT visible in a karyotype?

whether the individual carries genetic mutations

Humans have ________ pairs of homologous chromosomes.

23

A pea plant that is heterozygous for the flower color gene makes gametes. What is the probability that a specific gamete contains the recessive allele for flower color?

50 percent

Sickle-cell disease is an inherited chronic blood disease caused by an autosomal recessive allele. Suppose a man who is homozygous recessive for the sickle-cell gene fathers a child by a woman who is a carrier for sickle-cell. What are the chances their children will exhibit the disease?

50 percent

Both members of a couple are carriers for an autosomal recessive disease allele. If the couple has four children, which of the following statements must be true?

50 percent of the children could be carriers of the disease.

Among children with parents who are both carriers of Tay-Sachs, an autosomal recessive disorder, chances are that

50 percent will be carriers.

If a genetic disorder is caused by a dominant allele, individuals with which of the following genotypes would be affected by the disorder?

AA and Aa