Chapter 5

Mitotic phase is _____% of the cell cycle

10

Interphase is _____% of the cell cycle

90

What is the chromosome abnormality that causes Down syndrome?

A nondisjunction results in a person with an extra copy of chromosome 21.

How does cytokinesis occur in a dividing animal cell?

By the formation of a cleavage furrow

3. A duplicated chromosome remains tightly paired with its partner at a region called the _________________.

Centromere

the molecule of heredity

DNA

If it were to be stretched out, the DNA in one of your cells would be taller than you. How does such a large quantity of DNA fit within the nucleus of one of your cells?

DNA is associated with proteins that compact the DNA to form a package called chromatin.

A breeder wants to set up a program to produce zebrafish with long fins. Having long fins is a dominant trait compared to the short-finned wild type. Before she can market her zebrafish, she needs to perform a test cross on the long-finned fish she plans to use as a breeder. How can she tell whether her fish are homozygous or heterozygous for the long-finned trait?

Do several test crosses between the long-finned fish and the short-finned fish; if the offspring are always long finned, the long-finned parent is probably homozygous.

Guar are increasingly rare wild oxen found in Asia. How would you clone this animal?

Fusing a guar cell nucleus with an egg cell from a domestic cow that has had its nucleus removed

Imagine that five hypothetical genes are arranged on a chromosome in the following order: G--H--I--J--K. Which two genes are most likely to have a crossover occur between them?

G and K explanation - The probability of crossing over increases the farther the genes are from one another on the same chromosome.

Gorillas have 48 chromosomes. How does the number of chromosomes in a gorilla sperm compare with that of a human sperm?

Gorilla sperm have one more chromosome than human sperm.

What is Mendel's law of independent assortment?

Independent assortment means that each pair of alleles segregates independently of the other pairs of alleles.

In a human, which of the following could be identified by the use of a karyotype?

Klinefelter syndrome, where a male has two X and one Y chromosomes

Fur color in rabbits is controlled by multiple alleles. What does this mean?

Rabbit fur color is controlled by a single gene, but there are multiple versions of that gene.

Sickle-cell disease is a rare genetic disorder. Which of the following statements regarding the gene for sickle-cell disease must be true?

Sickle-cell is a mutant trait, but we cannot say whether it is dominant or recessive.

what is crossing over?

The exchange of pieces of homologous chromosomes

The inheritance pattern for red-green color blindness is different for males compared to females. Red-green color blindness is much more common in males than in females. What does this suggest about the gene for red-green color blindness?

The gene for this trait is located on the X sex chromosome.

3. Most human genes come in alternate versions called _________.

alleles

alternate forms of genes are called

alleles

When are the chromosomes of a cell duplicated?

before a cell divides

Sickle-cell disease is caused by a recessive form of hemoglobin. Two parents that do NOT have the disease give birth to a child that does. What are the genotypes of the mother and father for the hemoglobin gene?

both parents are heterozygous

1. A(n) __________ is an inherited feature that varies from individual to individual.

character

4. DNA and protein together form a complex called _______________.

chromatin

where genes are located

chromosomes

5. The DNA of every eukaryotic cell is stored in one or more ____________ located in the _________________.

chromosomes; nucleus

Heterozygous

different alleles

What do we call a genetic cross that follows two separate characters, such as pea seed color and pea seed shape?

dihybrid cross

4. If an organism has two non-identical versions of a gene, the one that is expressed in the organism is called the ___________ allele.

dominant

Imagine that eye color in cats is controlled by a single gene and that there are two alleles: black eyes and orange eyes. All the offspring of a cross between a black-eyed cat and an orange-eyed cat have black eyes. This means that the allele for black eyes is __________ the allele for orange eyes.

dominant to

studies the inheritance of genes

genetics

the ____________ is the genetic makeup of an organism

genotype

homozygous

identical alleles

If a woman with curly hair and a man with straight hair have a child with wavy hair, the gene for this characteristic of hair shows __________.

incomplete dominance

Random orientation of homologous pairs of chromosomes during meiosis I results in alternative arrangements that contribute to genetic variation in offspring. This is called __________.

independent assortment

The physical traits of an organism are called its _______.

phenotype

5. If an organism has two non-identical versions of a gene, the one that is not expressed in the organism is called the ________ allele.

recessive

What process involving cell division results in daughter cells that are NOT identical to the parent cell?

sexual reproduction

As mitosis begins, __________ are linked together at the centromere.

sister chromatids

While the two copies of a chromosome are attached they are called

sister chromatids

2. A(n) ___________ is one particular variation of a character.

trait

Like mitosis, meiosis involves duplication of the chromosomes before division starts. However, there are __________ rounds of cell division during meiosis and __________ during mitosis.

two; one