Bio: Ch. 8 - EXAM 3

Meiosis I produces ____ haploid cells?

2

What is the chromosome number found in humans cells after meiosis I is completed?

22 autosomes and a sex chromosome

Meiosis is typically accomplished in _____ many steps.

3 - all of the chromosomes are duplicated in a diploid cell, and then there are two cell divisions to produce a total of four haploid gametes.

Meiosis II produces ___ haploid cells?

4

What chromosomes belong to a typical human female?

44 autosomes and 2 X chromosomes

What chromosomes belong to a typical human male?

44 autosomes, 1 X chromosome and 1 Y chromosome

With the exception of gametes, a human cell contains, how many chromosomes?

46 total. 22 pairs of autosome chromosomes + 2 sex chromosomes.

Sexual reproduction in humans allows what to happen?

A haploid sperm cell to fertilize a haploid egg cell

Homologous chromosomes migrate to opposite poles during_______?

Anaphase I

During Meiosis in the ______ phase, the sister chromatids separate?

Anaphase II

The sister chromatids separate and begin moving toward opposite poles of the cell, during which phase of Mitosis?

Anaphase; sisters separate

What is the difference between a Benign and a Malignant Tumor?

Benign Tumors do not metastasize; Malignant Tumors do.

Mitosis produces?

Cells genetically identical to the parent cell

Most of an organisms DNA is carried by its?

Chromosomes

At the end of the Mitotic (M) phase, the cytoplasm divides in a process called____?

Cytokinesis which occurs in-conjuction with Telophase; last phase in Mitosis

Nucleosomes are made of what?

DNA and histone proteins make

Chromatin consists of?

DNA and protein

Meiosis starts with ______ cells and produces _____ gametes?

Diploid & haploid

Asexual reproduction _________?

Does not happen often, but can produce offspring genetically identical to the one single parent

Karyotype Trisomy 21 is a cause of?

Down Syndrome, triploid for chromosome 21

What is the difference of Prophase I and Prophase II during Meiosis?

During Prophase I there is one diploid cell; during Prophase II there are two haploid cells.

Crossing over during Prophase I, results in?

Genetic recombination

What term is used to describe the way homologous pairs of chromosomes line up at random orientation during Metaphase I?

Independent assortment; daughter cell randomly inherits either the maternal or paternal chromosome from each pair.

Chromosome duplication occurs during what phase?

Interphase

Nucleoli are present during?

Interphase

Chromosomes line up in the middle of the cell, during what phase?

Metaphase

Homologous chromosomes line up in the middle of the cell, during what phase?

Metaphase I (middle phase)

During _____ chromosomes align single file along the equator of a haploid cell?

Metaphase II

The chromosomes line up in the center of the cell during which phase of Mitosis?

Metaphase; the middle phase of Mitosis.

The mitotic phase encompasses both?

Mitosis and Cytokinesis

Accidents can occur in Meiosis wherein members of a chromosome pair fail to separate at Anaphase. This is called ?

Non-disjunction; when gametes have too few and/or many chromosomes

Spindle fibers attach to kinetochores during what phase?

Pro-metaphase; spindle fibers attach

The mitotic spindle begins to form in which phase?

Prophase

Synapsis occurs during______?

Prophase I; pairing of homologous chromosomes.

During ____ a spindle forms in a haploid cells.

Prophase II

Name the correct sequence of stages in Mitosis:

Prophase, Metaphase, Anaphase, Telophase

Chromosomes become visible during______?

Prophase; the chromatin fibers become discrete chromosomes

The centrosomes move away from each other and the nuclear envelope breaks up during which phase of Mitosis?

Prophase; the first phase of Mitosis, when the centrosomes begin moving toward opposite poles and the nuclear envelope breaks up.

The function of Meiosis is/are _________?

Reproduction (production of gametes)

What happens during Anaphase?

Sister chromatids become separate chromosomes.

What happens to the sister chromatids during Anaphase?

Sister chromatids separate and migrate to opposite poles

Cytokinesis often, but not always, accompanies_______?

Telophase

The events of Prophase are revered, during what phase?

Telophase

At the end of _______ and cytokinesis, haploids cells contain chromosomes that each consist of two sister chromatids.

Telophase I

At the end of _____ and Cytokinesis there are four haploid cells.

Telophase II

The chromosomes arrive at the poles and nuclear envelopes form, during which phase of Mitosis?

Telophase; the final phase of Mitosis.

What must happen before a cell can begin Mitosis?

The chromosomes must be duplicated (which occurs during Interphase)

Upon completion of Telophase I and Cytokinesis, there is(are) _______ cell(s).

Two haploid

A cell that completed the cell cycle without undergoing Cytokinesis would have?

Two nuclei

What combination of sex chromosomes results in Turner syndrome?

XO; individuals are females but have only one X chromosome.

During Prophase a homologous pair of chromosomes consists of _____?

at this point, each of the chromosomes consists of two chromosomes and four chromatids

Chromosomes that do not determine the sex of an individual are called _________?

autosomes

Trisomy 21 is the condition of?

being triploid for chromosome 21 (instead of the usual diploid condition), they have 47 chromosomes in total.

Homologous Chromosomes_____?

carry genes controlling the same inherited characteristics

In Mitosis a cell has ?

doubled its genetic material, divides into two diploid daughter cells.

In Meiosis a cell has ?

doubled its genetic material, undergoes two rounds of division, resulting in four haploid cells.

Anaphase II is essentially the same as Mitotic Anaphase,

except that the cell is haploid

Metaphase II is essentially the same as Mitotic Metaphase,

except that the cell is haploid

Prophase II is essentially the same as Mitotic Prophase,

except that the cells are haploid

Meiosis and cytokinesis result in the formation of ______?

four haploid cells

The __________ separate in Meiosis I; the ______ separate in Meiosis II.

homologous chromosomes ; sister chromatids

During ________ the cell grows & replicates both its organelles & its chromosomes.

interphase

Sexual reproduction requires the cellular process of ______ followed by fertilization.

meiosis; produces gametes, and a gamete from one individual unites with a gamete from another individual during fertilization.

Chromosomes of eukaryotic cells are found in the?

nucleus

How many genes are contributed genetically?

only one identical gene from the parent to the offspring.

A duplicated chromosomes consists of two ___?

sister chromatids

Crossing over is ______ ?

the exchange of corresponding portions of homologous chromosomes.

During ______ both the contents of the nucleus and the cytoplasm are divided.

the mitotic phase

The process of Meiosis accomplishes what?

the producing of four haploid cells & allows exchange of genetic material between homologous chromosomes.

Genetic recombination

the result of new combinations of genetic material

The mitotic cell cycle results in the production of?

two cells, each with the same amount of genetic material and the same genetic information