Chapter 5 Mastering Biology

In a dihybrid cross involving two autosomal traits on different chromosomes in which the parentals are purebred for the opposite forms of both traits, how many of the offspring would be expected to be homozygous recessive for both traits?

1 out of 16

What was the probability that Deirdre and Geoff's first child would express the albino trait?

1/2

If a cell had 12 chromosomes at the beginning of meiosis II, how many would each daughter cell have after the completion of meiosis II?

12

Assuming complete dominance, what is the expected ratio of genotypes of the offspring following the cross of two heterozygotes?

1:2:1

How many chromosomes did you inherit from your father?

23

If a human diploid cell and a human haploid cell somehow managed to fuse together and not lose any of the chromosomes, how many sets of chromosomes would be inside the newly formed cell?

3

Assuming complete dominance, what is the expected ratio of phenotypes of the offspring following the cross of two heterozygotes?

3:1

How many chromosomes would be found in the karyotype of a Down syndrome female?

47

How many chromosomes would a typical human cell have after mitosis but before cytokinesis?

92

Human white blood cells are often multinucleated (in other words, have more than one nucleus). How many chromosomes would be present in a white blood cell with two nuclei?

92

How much of your DNA is identical to that of another person of the same sex?

99.5%

What is the chromosome abnormality that causes Down syndrome?

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

What is a karyotype?

A picture of all the chromosomes in one person's cell

What causes the furrow during cleavage?

A ring of contractile protein fibers pinches the cell in two.

According to the pedigree above, who is a not a carrier of albino?

All of the above are carriers of albino

Which of the following processes does not generate genetic variation during sexual reproduction?

All of the processes above generate genetic variation

When does the cell plate form during cell division?

At the completion of plant cell mitosis

The following F1 cross is made: BBGg × Bbgg. Which is not a possible outcome in the F2 generation?

BbGG

When are the chromosomes of a cell duplicated?

Before a cell divides.

How does cytokinesis occur in a dividing animal cell?

By the formation of a cleavage furrow.

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 fin 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.

How could an embryonic stem cell be used to repair a severed spine?

Embryonic stem cells can grow into any other cell type, including a nerve cell.

If your grandparents were in the F1 generation, what generation are you in?

F3

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 & K

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.

What is the name of the syndrome that produces the XXY combination of sex chromosomes?

Klinefelter syndrome

A zygote (i.e., a fertilized egg) undergoes development to grow. What mechanism is used to generate more cells?

Mitosis

What is Dawn's genotype?

NN or Nn

What is Bill's genotype?

Nn

What is Geoff's genotype?

Nn

Is the number of chromosomes in each cell of an organism a good indicator of the complexity of that organism?

No, the number of chromosomes does not indicate how complex an organism is.

Which of the following is the correct sequence of events during mitosis?

Nuclear membrane dissolves, chromosomes line up, chromosomes split, nuclear membrane forms

Which of the following processes generates a continuum (spectrum) of varying phenotypes?

Polygenic inheritance

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.

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 chromosome.

What is different between two alleles of the same gene?

The information they carry. For example, one allele might carry the information for blue eye pigment, while the other carries the information for brown eye pigment.

Define Mendel's law of independent assortment.

The inheritance of one character has no effect on the inheritance of another character.

What is cytokinesis?

The stage of the cell cycle after the cell has divided its DNA and during which the cytoplasm gets divided

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

a dihybrid cross

What is Deirdre's phenotype?

albino

A homozygous milk chocolate Easter bunny is crossed with a homozygous dark chocolate Easter bunny. Assuming dark chocolate is dominant over milk chocolate and the traits segregate according to Mendelian genetics, which traits will the offspring express?

all dark

Which process requires DNA to undergo duplication before it can proceed?

both of these (meiosis & mitosis)

Two alleles of the same gene ________.

can be the same or can be different

Name the part of the chromosome indicated by the arrow. (center)

centromere

DNA plus its associated proteins is called a ________.

chromatin

Genes are located on ________.

chromosomes

Somatic cells are ________.

diploid (2n)

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

What is the sex of the person indicated in the photograph?

female

What type of cells do not undergo mitosis?

gametes

A test cross is performed to determine if a specific individual is a carrier. The results generate a 50/50 ratio of phenotypes. The test subject is therefore ________.

heterozygous

What specifically separates during meiosis I?

homologous chromosomes

During which phase of the cell cycle are the chromosomes duplicated?

interphase

Genes located near one another on the same chromosome are often inherited together. These are called ________.

linked genes

Is an individual with the XXY combination of chromosomes anatomically male or female?

male

Recessive disorders related to genes found on the X chromosome but not on the Y are more commonly expressed in ________.

males

Crossing happens during __________.

meiosis

What produces four daughter cells?

meiosis

What produces genetically unique daughter cells?

meiosis

When does crossing over occur?

meiosis 1

A zygote (i.e., a fertilized egg) undergoes development to grow. What mechanism is used to generate more cells?

mitosis

Dead or damaged cells are replaced by the process of ________.

mitosis

What leads to an individual having too many or two few chromosomes?

nondisjunction

When I say a flower is "purple," what have I described?

phenotype

Assuming incomplete dominance, if a homozygous red-flowered plant is crossed with a homozygous white-flowered plant, what will be the color of the offspring?

pink

If mitosis makes somatic cells, what does meiosis make?

sex cells

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

What are attached at the centromere?

sister chromatids

What specifically separates during meiosis II?

sister chromatids

What specifically separates during mitosis?

sister chromatids

When one cell goes through cell division, it produces ________.

two identical cells

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

If genes are described as "sex linked," then they are ________.

typically on the X chromosome

The offspring produced via sexual reproduction are genetically ________ to the parents.

unique

Would a human clone have a bellybutton?

yes

Upon fertilization, the egg and sperm fuse to form a single cell called a(n) ________.

zygote