day 4

What could the phenotypes of the children of a red-green color-blind woman and a man with normal vision be?

Daughters will be carriers. Sons will be color-blind

If a child has blood type AB what must the parents provide?

One parent provides A and the other B

Which of the following is not an autosomal dominant disorder?

Depends on the answer choices. Cystic fibrosis. PKU. And albinism are recessive

True or False: Some autosomal dominant disorders are only seen in heterozygous individuals because the homozygous dominant condition is lethal?

True

Individuals with albinism produce very little to no ___?

Melanin

In a dihybrid cross what is the expected frequency of offspring that show the recessive forms of both traits?

1/16 (6.25%)

Even though sickle-cell anemia is usually fatal to homozygous individuals why does the disease persist?

Heterozygous carriers have increased resistance to malaria

Artificial sweetener and a high-protein diet can lead to brain damage in which genetic disorder?

Phenylketonuria (PKU)

Which disorder is due to a genetic mutation during early development and is not inherited?

somatic mosaic disorder or a condition arising from post-zygotic de novo mutations

Which of the following is NOT a symptom of Marfan syndrome?

Short stature

What type of life cycle is exhibited by most animals?

Diploid dominant

What is meant by alternation of generations in the life cycle of plants?

Alternating haploid and diploid generations

What is the major advantage of sexual reproduction?

Increased genetic variation

What are the disadvantages of sexual reproduction?

Requires more time and energy. Usually requires finding a mate

Which of the following most correctly describes a human somatic cell?

A diploid body cell with 46 chromosomes

Which of the following most correctly describes a human germ cell?

A reproductive cell (egg or sperm) with 23 chromosomes

After meiosis resulting daughter cells will contain ___?

Half the original number of chromosomes

Asexual reproduction ___?

One parent. Offspring are genetically identical

Sexual reproduction ___?

Two parents. Offspring are genetically different

A cell cycle checkpoint for S phase would likely inhibit progression through the cell cycle if ___?

DNA is damaged or replication is incomplete

Meiosis in a diploid organism typically produces ___?

Four haploid cells

A chicken somatic cell carries 78 chromosomes. How many chromosomes will a chicken sperm cell contain?

39

Which of the following are sources of genetic variation in gametes?

Crossing over. Independent assortment. Random fertilization

During which phase of meiosis will a pair of chromosomes appear as a unit of four chromatids?

Prophase I

The pairing of chromosomes and crossing over occur during which stage of meiosis?

Prophase I

Paired homologous chromosomes are found at the center of the cell during which stage of meiosis?

Metaphase I

Why is crossing over one of the most important events in meiosis?

It creates genetic variation

The fusion of egg and sperm cells results in a(n) ___?

Zygote

Sister chromatids separate during which phase of mitosis and which phase of meiosis?

Anaphase of mitosis. Anaphase II of meiosis

Which statement describes the function of telomeres?

They protect the ends of chromosomes

Mutations in genes that control what process are likely to cause cancer?

Cell division

In meiosis what is separated during anaphase I and what is separated during anaphase II?

Homologous chromosomes. Sister chromatids

Meiosis II is similar to mitosis because ___?

Sister chromatids separate

Meiosis in plants produces ___?

Haploid spores

Failure of chromosomes or chromatids to separate properly is known as ___?

Nondisjunction

Which disorders are due to an extra chromosome?

Down syndrome. Edwards syndrome. Patau syndrome

An individual with Turner syndrome has how many sex chromosomes and usually develops as which biological sex?

One sex chromosome. Female

Which statement is correct regarding the relationship between maternal age and risk of having a child with Down syndrome?

Risk increases with maternal age

Down syndrome is due to having how many copies of chromosome number 21?

Three copies

What is a Barr body?

An inactive X chromosome

Which of the following is an example of the visible effects of X-inactivation?

Calico cat fur color