BIOL 1408 Ch. 9

Tank the steps of meiosis I in the order in which they occur, beginning with the first phase at the top.

1. prophase I 2. metaphase I 3. anaphase I 4. telophase I

Rank the steps of meiosis II in the correct order in which they occur, beginning with the first step at the top.

1. prophase II 2. metaphase II 3. anaphase II 4. telophase II

Consider a cell that has three pairs of chromosomes. What are the chances that a gamete produced from this cell will contain only maternal chromosomes?

1/8

Individuals have _ chromosomes in haploid cells.

12

How many rounds of division occur in meiosis?

2

If nondisjunction occurs during meiosis I, as shown in the image below, what are the possible gametes that can be produced? Click on all the boxes that apply.

Abnormal (n+1) Abnormal (n-1)

If nondisjunction occurs during meiosis II, as shown in the image below, what are the possible gametes that can be produced? Click on all the boxes that apply.

Abnormal (n+1) Abnormal (n-1)

Which of the following choices describes Interphase?

All of the above. Includes G1, S and G2 stages. Results in an increase in cell size. Occupies the majority of the cell cycle.

The function of mitosis is _.

All of the choices are correct. growth of the organism and tissue repair. to ensure that each new cell receives a complete set of genetic information. asexual reproduction in some species.

During which phase of mitosis do the sister chromatids separate and head towards opposite poles of the cell?

Anaphase

During which phase of meiosis do the homologous chromosomes separate and head towards opposite poles of the cell?

Anaphase I

During which phase of meiosis do the sister chromatid separate and head towards opposite poles of the cell?

Anaphase II

Consider the image below, which shows a cell nucleus with one pair of homologous chromosomes. Then, click on all of the true statements.

Chromatid A will separate from chromatid B during anaphase II. Chromosome AB will separate from chromosome CD during anaphase II. Chromatid D will line up next to chromatid A during metaphase II. Chromatid C will separate from chromatid D during anaphase I.

Which of the following events does NOT occur during prophase?

Chromosomes replicate themselves.

True or False: Daughter cells produced in meiosis are identical.

False

True or False: Germ cells are haploid but gametes are diploid.

False

True or false: The younger the mother, the higher the chance of producing a child with Down syndrome.

False

_ is the merging of a sperm and an egg to create a diploid zygote.

Fertilization

Which represents the correct sequence of stages in the cell cycle?

G1, S, G2, M

Place the images in the correct order of stages of mitosis.

Hover over images to reveal text Left to right During this phase, chromatin is condensing into chromosomes The nuclear membrane has disappeared during this stage Spindle fibers begin to attach to kinetochores during this stage Chromosomes align down the center of the cell during this stage The daughter chromosomes form during this stage Cytokinesis occurs during this stage

Consider the image below, which shows a cell nucleus with one pair of homologous chromosomes that has not undergone crossing over. Then, click on all of the true statements.

If this cell undergoes mitosis, the daughter cells will each contain two chromosomes. Chromatids C and D carry the same alleles. The diploid number of this cell is 2n = 4.

Why is meiosis useful? Select all that apply.

It produces genetically variable offspring. It provides an alternate route to cell division for cells that fail to complete mitosis.

Which of the following statements about nondisjunction is FALSE?

It rarely causes medical problems for humans that are born with cells that underwent nondisjunction.

Label the image below. Not all labels will be used.

Left to Right Homologous pair of chromosomes Sister chromatids Site of crossing over Meiosis I Recombinant chromatid Parental chromatid

In humans, what is the biological sex of an individual with XY sex chromosomes?

Male

Which of the following statements is/are true about meiosis? Select all that apply.

Meiosis produces nonidentical cells. Meiosis produces four haploid cells. The daughter cells of meiosis have half as many chromosomes as the parent cell. Meiosis produces gametes.

During which phase of mitosis do the chromosomes line up in the center of the cell?

Metaphase

During this phase of the cell cycle, the chromosomes are replicated.

S phase

Place the correct phase of meiosis in the proper sentence. Then list the phases of meiosis in the correct order.

Synapsis and crossing over occur during prophase I. During metaphase I the bivalents (pairs of homologous chromosomes) are organized along the metaphase plate. During anaphase I, the homologous chromosomes (paired bivalents) separate from each other. Homologues reach their respective poles during telophase I, the nuclear membrane re-forms to produce two separate nuclei. At the beginning of prophase II, homologues have already separated; nuclear membrane dissociates; chromatids condense; spindle apparatus forms and the nucleolus disappears. During metaphase II, all sister chromatids align themselves along the metaphase plate. As anaphase II proceeds sister chromatids are separated and are pulled toward the pole to which they are attached. During telophase II, sister chromatids reach their respective poles and decondense; nuclear membrane re-forms and nucleoli reappear.

The cell images below were taken from an organism with a diploid number of 4. Drag and drop a label to identify the stage of mitosis or meiosis shown in each cell image.

Top left to right Prophase I Prophase II Metaphase II Bottom left to right Metaphase I Metaphase of mitosis

True or False: At the end of meiosis I, there are two haploid cells, each with two sister chromatids per chromosome.

True

True or False: Chromosome duplication occurs prior to both mitosis and meiosis.

True

True or False: Crossing over occurs during prophase I of meiosis.

True

After this homologous pair undergoes crossing over and meiosis, what resulting chromatids will be segregated into different haploid cells?

Two unchanged chromatids, two chromatids with recombined alleles.

Select all of the following that are true about the X and Y chromosomes in humans.

X is much bigger than Y carry different genes

Match each sex chromosome abnormality with the correct name of the condition.

XXX - triplo-X XO - Turner syndrome XYY - Jacobs syndrome XXY - Klinefelter syndrome

What is a karyotype?

a chart showing size-ordered images of chromosomes in a cell

The purpose of the spindle fibers is to _.

aid in sorting and aligning the chromosomes for their movement to opposite ends of the cell.

A gene has different versions, or _, which are carried on homologous chromosomes and encode different versions of the gene's protein product.

alleles

Select all of the following that can result from nondisjunction in humans.

an extra copy of a chromosome failed development due to missing genetic material trisomy

During _, the homologous chromosomes (paired bivalents) separate from each other.

anaphase I

As _ proceeds sister chromatids are separated and are pulled toward the pole to which they are attached.

anaphase II

Bacteria and archaea reproduce by _ reproduction when they produce genetically identical offspring.

asexual

While _ reproduction is less costly, _ reproduction is commonly utilized because it generates genetic diversity.

asexual; sexual

The 22 pairs of human chromosomes that are the same in both males and females are called _.

autosomes

What occurs during the interphase that precedes meiosis II?

manufacture of proteins

Select all of the following organisms that commonly survive as polyploids, which are organisms that have one or more complete sets of extra chromosomes.

many crop plants durum wheat - *Durum wheat is tetraploid, which is a type of polyploidy in which there are four sets of chromosomes.* some flowering plants

A process called _ occurs throughout the life cycle of an organism, whereas _ occurs only at some stages of life.

mitosis; meiosis

Which of the following represents the correct order of the phases of mitosis?

prophase - metaphase - anaphase - telophase

Synapsis and crossing over occur during _.

prophase I

Crossing over only occurs in _.

prophase I of meiosis.

Which of the following events occurs during anaphase I?

separation of homologous chromosomes

In a human karyotype, there are 22 pairs of autosomes and 1 pair of _ chromosomes.

sex

During _ reproduction, genetic information from two parents combines to form an offspring.

sexual

What is the overall purpose of meiosis?

to produce four genetically different haploid cells

The most common cause of Down syndrome is _.

trisomy 21.

The first diploid cell of a new organism, called a(n) _, has a set of chromosomes from each parent.

zygote

If a sperm cell contains 8 chromosomes, it comes from an animal that has _ chromosomes.

16

There are a total of _ pairs of chromosomes in a human diploid cell.

23

When two haploid gametes combine, a zygote with _ chromosomes forms.

24

Cytokinesis occurs _ time(s) during the process of meiosis, whereas cytokinesis occurs _ time(s) during the process of mitosis.

2; 1

If a cell has 16 pairs of chromosomes, how many unique configurations of chromatids can be produced in gametes as a result of random orientation during meiosis?

2^16

A diploid cell is indicated by what abbreviation?

2n

Which of the following is used to denote diploid cells?

2n

Match the number of chromosomes in a human diploid cell with the correct description.

46 - total number of chromosomes 22 pairs - autosomes 1 pair - sex chromosomes

Suppose an error in meiosis produced diploid gametes. After two diploid gametes unite in fertilization, the offspring would have _ chromosomes in its diploid cells.

48

If a parent cell has 48 chromosomes, how many chromosomes will each daughter cell have after mitosis and cytokinesis occurs?

48 chromosomes

Consider one chromosome that contains alleles A, B, and C, and the homologous chromosome that contains the alleles a, b, and c. If crossing over occurred once during meiosis at a site on the chromosome between the B gene and the C gene, then what alleles could a resulting chromatid contain? Select all that apply.

A, B, c a, b, C *If a chromatid containing alleles A, B, and C crossed over with a chromatid containing alleles a, b, and c at a site between the B gene and the C gene, then one resulting chromatid would contain A, B, and c and the other resulting chromatid would contain a, b, and c.*

What type of reproduction produces offspring that are identical to the parent (except for mutations)?

Asexual

What type of twins is produced if two sperm cells fertilize two separate egg cells, as shown in the image?

Dizygotic twins

_ are haploid sex cells which combine to form new offspring.

Gametes

What correctly describes metaphase I of meiosis I?

Homologous chromosomes line up as pairs along the center of the cell.

During which phase of meiosis do the homologous chromosomes line up across from each other in the center of the cell?

Metaphase I

During which phase of meiosis do the sister chromatids line up across from each other in the center of the cell?

Metaphase II

Classify the following phrases as related to mitosis or meiosis. If it relates to both, then place the label in the "both" dock. Some labels may not be used.

Mitosis - Participates in growth Asexual reproduction uses this process Daughter cells have the same chromosome number as the parent cell Meiosis - Produces gametes Crossing over occurs during this process Daughter cells have half of the chromosome number as the parent cells Both - Interphase precedes this process This process begins with replicated chromosomes Ends with unreplicated chromsomes.

What is produced in the picture shown?

Monozygotic twins

Use the animation and your knowledge of crossing over to select the true statement.

No answer is correct.

What occurs when chromosomes do not separate during meiotic divisions?

Nondisjunction

What produces gametes with a missing or extra chromosome and may result in embryonic, fetal, or infant death or a trisomic individual?

Nondisjunction

Select all of the following that occur in prophase I of meiosis.

Nuclear envelope breaks up. Chromosomes condense. Crossing over occurs. Spindle forms from microtubules.

What is a cell with a complete extra set of chromosomes called?

Polyploid

Click on all of the true statements about sexual and asexual reproduction.

Prokaryotes and many single-celled eukaryotes reproduce asexually. Sexual reproduction creates offspring that are genetically different from one another and from the parent. Asexual reproduction is most advantageous when environmental conditions are constant. Asexual reproduction requires only one parent. Cats produce kittens via sexual reproduction. In general, sexual reproduction requires more energy than asexual reproduction.

During which stage of meiosis does crossing-over occur?

Prophase I of meiosis I

True or False: Meiosis produces four nonidentical cells, each containing neither homologous chromosomes nor sister chromatids.

True

True or False: Mitosis and cytoplasmic division result in the formation of two genetically identical cells.

True

True or false: In some species, the chromosomes uncoil into thin thread between meiosis I and meiosis II.

True

In plant life cycles, what stages can be multicellular?

both diploid and haploid stages

Which of the following choices lists events in order as they occur during cell division through mitosis. Keep in mind that not all events may occur during the process of mitosis itself.

chromatin replicates and condenses into chromosomes - spindle fibers attach to sister chromatids and align them at the center of the cell - spindle fibers begin to shorten and drag the sister chromatids to opposite ends of the cell - the nucleus re-forms around the chromosomes - the plasma membrane pinches apart into two distinct cells.

In eukaryotes, a molecule of genetic material and its associated proteins form a(n) _, of which humans have 46 in each cell.

chromosomes

This image shows two ways that _ during meiosis I to generate different combinations of chromatids in resulting gametes.

chromosomes can orient

Select all of the following that are true about meiosis.

creates four haploid cells from one diploid cell produces gametes with half the number of chromosomes as compared to somatic cells includes two cell divisions

Short segments of DNA are exchanged between homologous chromosomes during prophase I in a process called _ over.

crossing

In prophase I, allele shuffling between homologous chromosomes occurs in a process called _.

crossing over

Select all of the following that are true about cells undergoing meiosis.

cytokinesis occurs after the distribution of genetic material interphase precedes meiosis I

Categorize the types of cells as diploid or haploid.

diploid - somatic cell; zygote haploid - egg cell; gamete

Located in the ovaries and testes of animals, specialized cells called germ cells are _ and undergo meiosis to produce _.

diploid; gametes

Fusion of gametes produces a _ zygote that carries genetic information from _.

diploid; two parents

Select all of the following that describe meiosis.

divides eukaryotic chromosomes of one cell into daughter cells that contain half as many chromosomes as the parent cell cell division needed to produce gametes, or sex cells

Trisomy 13, 18, and 21 are all the result of a(n) _, although infants with trisomy 13 and 18 don't often survive.

extra autosome

At the end of meiosis II, there are _.

four haploid cells, with each chromosome consisting of a single chromatid.

Select all the possible results of nondisjunction in sex chromosomes.

gamete contains an extra X gamete contains an extra Y XXX zygote gamete is missing a sex chromosome

The chromosomes of offspring are not identical to those of their parents or siblings because _ is shuffled during meiosis.

genetic information

In animals, specialized diploid cells that undergo meiosis are called _.

germ cells

Daughter cells produced in meiosis have _.

half the number of chromosomes as the parent cell.

A(n) _ cell contains only one copy of each chromosome.

haploid

Sexually reproducing organisms produce _ gametes when _ cells undergo meiosis.

haploid; germ

Two chromosomes with the same size, centromere location, and gene sequence are called a(n) _ pair.

homologous

During meiosis I, what do spindle fibers pull apart?

homologous chromosomes

A crossover in meiosis is an exchange of genetic material between _.

homologous chromosomes.

Select all of the following that are able to reproduce by asexual reproduction.

many unicellular eukaryotes bacteria many plants and fungi archaea

Homologous chromosomes are slightly different from each other because they _.

may carry different alleles for the same genes.

A cell in which homologous chromosomes arrange in pairs along the equator of the cell is in what stage of cell division?

meiosis I

Crossing over and random orientation of chromosomes lead to genetic variability in the process of _, but the process of _ does not generate genetic variability because it lacks these mechanisms.

meiosis; mitosis

During _ the bivalents (pairs of homologous chromosomes) are organized along the metaphase plate.

metaphase I

Random orientation of homologous chromosomes occurs in _ of meiosis.

metaphase I

During _, all sister chromatids align themselves along the metaphase plate.

metaphase II

In cell division called _, the chromosome number in the daughter cells is the same as that in the parent cell, but in cell division called _, the chromosome number in the daughter cells is half the number present in the parent cell.

mitosis; meiosis

Which of the following is used to denote haploid cells?

n

Monozygotic twins, or identical twins, are produced from _.

one zygote

A chromatid that has undergone meiosis and has the same alleles as one of the parent chromatids is called a _.

parental chromatid

The exchange of genetic material between nonsister chromatids is called crossing-over and occurs during which phase of meiosis?

prophase I

At the beginning of _, homologues have already separated; nuclear membrane dissociates; chromatids condense; spindle apparatus forms and the nucleolus disappears.

prophase II

Match each phase with its correct description.

prophase II - chromosomes condense; nuclear envelopes break up; spindles form metaphase II - chromosomes are arranged along equator of cell anaphase II - sister chromatids are pulled apart and move to opposite poles telophase II - nuclear envelopes form, spindles disappear cytokinesis - four separate haploid daughter cells are formed

In sexual reproduction, exactly what egg cell matures and what sperm cell fertilizes the egg is _.

random and results in genetic variability.

Select all of the mechanisms that generate genetic variability in sexual organisms.

random fertilization random orientation of chromosomes crossing over

Separation of _ occurs in anaphase II of meiosis.

sister chromatids

Diploid cells called _ cells do not undergo meiosis and make up most of the body's diploid cells.

somatic

Other than the germ cells, all diploid cells in the body are called _ cells, which are able to undergo mitosis but not undergo meiosis.

somatic

What cells in the body are most likely to have originated through the process of meiosis?

sperm and egg cells

Select all of the following that take place during interphase preceding meiosis.

synthesis of proteins and enzymes needed for cell division replication of DNA production of two identical sister chromatids attached at the centromere

Homologues reach their respective poles during, the nuclear membrane re-forms to produce two separate nuclei.

telophase I

During meiosis I, homologous chromosomes have completed their movement to opposite poles in _.

telophase I.

During _, sister chromatids reach they respective poles and decondense; nuclear membrane re-forms and nucleoli reappear.

telophase II

Sister chromatids can best be described as _.

the two genetically identical chromatids that result from the replication of the chromosome.

The number of cells produced in meiosis is _.

twice the number of cells produced in mitosis.

The overall purpose of mitosis is to produce _.

two daughter cells that are genetically identical to one another.

Select the features of Down syndrome from the list below.

varying degrees of mental impairment increased chance of congenital heart defects distinctive facial features