Biology Test 3

If a heterozygous plant is allowed to self-pollinate, what proportion of the offspring will also be heterozygous?

1/2

Ignoring crossover, how many kinds of gametes can be produced by an organism with a diploid number of 8?

16

A cell contains 40 chromatids at the beginning of mitosis. How many chromosomes will it contain at the completion of cytokinesis?

20

The egg (ovum) of a rabbit contains 22 chromosomes. How many chromosomes are in the somatic (body) cells of a rabbit?

44

How many chromatids does a human somatic cell contain after interphase and just prior to mitosis?

92

__________ occurs when a single gene affects the phenotype of many characters in an individual.

A pleiotropic effect

Human blood groups are governed by three alleles, A, B, and O. A and B are codominant and O is recessive to both. A man who has type B blood and a woman who has type A blood could have children of which of the following phenotypes?

A, B, AB, or O

Which of the following structures is/are part of the mitotic spindle?

All of the listed responses are part of the mitotic spindle.

In Klinefelter syndrome, individuals are phenotypically male, but have reduced sperm production and may have some breast development in adolescence. The cells of Klinefelter individuals have two X chromosomes and one Y (they are XXY instead of XY). This occurs because of what meiotic error?

Aneuploidy

Which of the following statements correctly describes the difference(s) between mitosis and binary fission?

Binary fission involves the replication and division of a single chromosome, whereas mitosis involves the division of multiple, replicated chromosomes.

What is the difference between a benign tumor and a malignant tumor?

Cells of benign tumors do not metastasize; those of malignant tumors do.

__________ are a group of genetically identical individuals produced by a process called __________.

Clones; asexual reproduction

What appears to be the mechanism for genomic imprinting?

DNA methylation that silences particular genes and DNA methylation that activates particular genes

Regarding the role of cohesin protein in maintaining cohesion between sister chromatids, which of the following statements is false?

During meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms.

What is the result when a diploid cell undergoes meiosis?

Four haploid cells

A man who can roll his tongue and a woman who cannot roll her tongue have a son who can roll his tongue (R = can roll tongue; r = can't roll tongue). The son is curious about whether his father is homozygous or heterozygous for the tongue-rolling trait. Which of the following facts would allow him to know?

His father's mother cannot roll her tongue.

Which of the following occurs in meiosis, but not mitosis?

Homologous chromosomes separate.

Which life cycle stage is found in plants but not animals?

Multicellular haploid

Which of the following is a function of mitosis in humans?

Multiplication of body cells

In a typical pea experiment, two true-breeding plants with distinct traits of a single character are called the __________, and the offspring are called the __________, which will always be __________.

P (or parental) generation; F1 (or first filial) generation; hybrid

Unless the chromosomes were stained to show band patterns, a karyotype would be least likely to show which of the following?

Part of a chromosome turned around.

Which of the following events does not occur during interphase of the cell cycle?

Separation of the sister chromatids

With a microscope, you examine some somatic cells from a woman and notice that each nucleus has two Barr bodies. What can you infer about the sex chromosomes in this individual?

She is XXX.

Which of the following phases of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope?

Telophase

A cell biologist examined the DNA content of a cell from a fruit fly larva during the G1 phase and determined that it had 150 units of DNA. After measuring the DNA content of the same type of cell after the G2 phase, it was discovered that the cell had 300 units of DNA. How is this possible?

The DNA was replicated during the S phase of interphase, which occurs between the two G phases.

Which choice below is a basic difference between Mendel's particulate hypothesis and the hypothesis of blending inheritance?

The blending inheritance hypothesis, but not the particulate hypothesis, maintained that after a mating, the genetic material provided by each of the two parents is mixed in the offspring, losing its individual identity.

Which of the following statements describes a cell that undergoes mitosis but not cytokinesis?

The cell contains more than one nucleus.

Which of the following events occurs during metaphase of mitosis?

The chromosomes align along the metaphase plate of the cell.

What kind of protection does the Genetic Information Nondiscrimination Act of 2008 provide the public with regard to the use of genetic information?

The law prohibits the use of genetic test information to deny insurance coverage or employment to individuals.

Which of the following events does not occur during prophase of mitosis?

The mitotic spindle breaks down.

How does the process of mitosis differ between most eukaryotes and other eukaryotes such as diatoms and dinoflagellates?

The nuclear envelope fragments in most eukaryotes but remains intact in diatoms and dinoflagellates.

Which of the following events occurs during prometaphase of mitosis?

The nuclear envelope fragments.

What is a locus?

The precise location of a gene on a chromosome.

Pea plants are tall if they have the genotype TT or Tt, and they are short if they have genotype tt. A tall plant is mated with a short plant. Which outcome below would indicate that the tall parent plant was heterozygous?

The ratio of tall offspring to short offspring is 1:1.

Which of the following events occurs during anaphase of mitosis?

The sister chromatids are pulled apart toward opposite sides of the cell.

Which of the following statements about homologous chromosomes is correct?

They have genes for the same traits at the same loci.

Which of the following events occurs during telophase of mitosis?

Two distinct daughter nuclei form in the cell.

The region of a chromosome holding the two double strands of replicated DNA together is called __________.

a centromere

Huntington's disease is an example of a genetic disorder caused by __________.

a lethal dominant allele that afflicts an individual later in life

The F1 generation differed from the F2 in Mendel's experiments in that __________.

all of the F1 showed the dominant phenotype, but only three-fourths of the F2 did

If an organism that is homozygous dominant is crossed with a heterozygote for that trait, the offspring will be __________.

all of the dominant phenotype

An alternative version of a gene is called a(n) __________.

allele

The life cycle called __________ in plants has two multicellular stages: the __________ and the __________.

alternation of generations; haploid gametophyte; diploid sporophyte

Fetal cells may be removed along with fluid from the womb by a process known as __________.

amniocentesis

Down syndrome is an example of __________, and the child is __________ for chromosome 21.

aneuploidy; trisomic

Somatic cells in animals differ from gametes in that somatic cells __________.

are all of the cells of the body except for the gametes and their precursors

The function of the mitotic cell cycle is to produce daughter cells that __________.

are genetically identical to the parent cell (assuming no mutation has occurred)

Linked genes __________.

are located near each other on the same chromosome

Sister chromatids differ from nonsister chromatids in that sister chromatids __________.

are products of the S phase of the cell cycle and are two copies of one chromosome

A clone is the product of __________.

asexual reproduction and mitosis

Mendel studied __________, heritable features that vary among individuals; each variant is called a __________.

characters; trait

The complex of DNA and protein that makes up a eukaryotic chromosome is properly called __________.

chromatin

In addition to the ABO system, humans have other blood groups, including the MN system. Individuals who have alleles for both M and N show __________ for the M and N red blood cell surface antigens.

codominance

A red bull is crossed with a white cow and all of the offspring are roan, an intermediate color that is caused by the presence of both red and white hairs. This is an example of genes that are __________.

codominant

Somatic cells in humans differs from gametes in that human somatic cells __________.

contain two sets of each of the 23 chromosome types

In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle?

cytokinesis

Regardless of whether an organism is an animal, a plant, a fungus, or an algal cell, all zygotes are __________ and are formed during the __________ of two __________ gametes.

diploid; fertilization; haploid

During interphase, the genetic material of a typical eukaryotic cell is __________.

dispersed in the nucleus as long strands of chromatin

Cytokinesis refers to __________.

division of the cytoplasm

Observations of cancer cells in culture support the hypothesis that cancer cells __________.

do not exhibit density-dependent inhibition

Achondroplasia, a type of dwarfism, and Huntington's disease are examples of __________, with the exception that the Huntington's allele is __________.

dominant inherited disorders; lethal

Genomic imprinting in mammals appears to primarily affect genes involved in __________.

embryonic development

Darwin realized the importance of heritable variation to evolution __________.

even though he never read any of Gregor Mendel's work

A life cycle in which the only multicellular form is haploid is most typical of __________.

fungi

The chromosome theory of inheritance states that __________.

genes occupy specific positions on chromosomes, homologous chromosomes segregate from each other during meiosis, and chromosomes assort independently during meiosis

Allelic variation is an important source of __________ in a population.

genetic diversity

Gene silencing is called __________.

genomic imprinting

A pair of genetic structures carrying genes that control the same inherited characters are called __________.

homologous chromosomes

Chromatids are __________.

identical copies of each other if they are part of the same chromosome

If a plant variety is true-breeding for a dominant trait, then __________.

if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait

Characteristic of the bdelloid rotifer is that it __________.

is an example of an animal that has not reproduced sexually in 40 million years

You would know a dividing cell was a plant cell rather than an animal cell if you saw that __________.

it had formed a cell plate

The major contribution of sex to evolution is that __________.

it provides a method to increase genetic variation

The process called __________ reduces the chromosome number by __________.

meiosis; two consecutive cell divisions

The spread of cancer cells to other locations in the body is known as __________.

metastasis

The effect of the environment on a phenotype is referred to as __________.

multifactorial

Human ABO groups are best described as an example of __________.

multiple alleles

In meiosis, __________ of __________ cross over and form __________.

nonsister chromatids; homologous pairs; chiasmata

A family tree that describes traits in families is called a __________.

pedigree analysis

In humans, height and skin color have continuous variation in the population because of __________.

polygenic inheritance

The zipper-like complex that forms in meiosis occurs during __________ and is called the __________.

prophase I; synaptonemal complex

Checkpoints in the cell cycle control system __________.

regulate the cell cycle through a variety of stop and go signals

Besides the fact that pea plants have a short generation time, the key to Mendel's successful plant-breeding experiments was that pea plants usually __________.

self-pollinate

Genetic diversity requires __________.

sexual reproduction, independent assortment, crossing over between nonsister chromatids of homologous chromosomes, and random fertilization

How many genes are present in the human genome?

tens of thousands

The term "true-breeding plants" means __________.

that self-pollinating plants will always produce the same trait of a particular character

DNA replication occurs in __________.

the S phase of interphase in both somatic and reproductive cells

One event occurring during prophase is __________.

the beginning of the formation of a spindle apparatus

Wild type refers to __________.

the most common phenotype thought to be found in the natural population

In an X-linked, or sex-linked, trait, it is the contribution of __________ that determines whether a son will display the trait.

the mother

During binary fission in a bacterium __________.

the origins of replication move apart

In people with sickle-cell disease, red blood cells break down, clump, and clog the blood vessels. The blood vessels and the broken cells accumulate in the spleen. Among other things this leads to physical weakness, heart failure, joint pain, and brain damage. Such a suite of symptoms can be explained by __________.

the pleiotropic effects of the sickle-cell allele

Mendel's law of segregation states that __________

the two alleles for a heritable character segregate (separate from each other) during gamete formation and end up in different gametes

X inactivation occurs when there is/are at least __________ X chromosomes present in an individual, forming a structure called a __________ by a __________ event.

two; Barr body; random

Somatic cells in humans contain __________ set(s) of chromosomes and are therefore termed __________.

two; diploid

At the end of mitosis, __________ daughter cells that are genetically __________ are formed, while at the end of meiosis, __________ daughter cells that are genetically __________ are formed.

two; identical; four; distinct

In incomplete dominance, the offspring __________.

will have an appearance that's intermediate between those of the two parental types

If the two traits that Mendel looked at in his dihybrid cross of smooth yellow peas with wrinkled green peas had been controlled by genes that were located near each other on the same chromosome, then the F2 generation __________.

would have deviated from the 9:3:3:1 phenotypic ratio that is predicted by the law of independent assortment

Color in squash is controlled by epistatic interactions in which color is recessive to no color. At the first locus white squash (W) is dominant to colored squash (w). At the second locus yellow (Y) is dominant to green (y). What is the phenotype of a squash with the genotype wwYy?

yellow

In Labrador retrievers, a dog that has the genotype BBee, where BB produces black-pigmented fur and ee produces yellow-pigmented fur, would have __________ fur and would exhibit __________.

yellow; epistasis