Biology - Ch. 8

Cell division will accomplish which of the following functions in your body? Select all that apply.

-Growth and development -Cell replacement -Production of gametes

What is different concerning the DNA in bacterial cells as opposed to eukaryotic cells? (Select all that apply.)

-Whether the DNA is housed in a nucleus or not -Whether the DNA is linear or circular -The amount of DNA present

Homologous chromosomes

-are the same size -have the same genes at the same loci -can contain different versions of the same gene at the same loci

Humans have __ pairs of chromosomes. ___ pair(s) are autosomes and ____ pair(s) are sex chromosomes.

23...22...1

If a species of animal has six pair of chromosomes, how many DNA molecules would be present at the end of the S phase of Interphase?

24

A male organism of a species produces a sperm that is 4n, and the female produces an egg that is also 4n. If those two gametes fused, what would the resulting zygote be?

8n

How can you tell that the following image is a picture of a plant finishing cytokinesis?

A cell plate is forming.

Benign tumor

A lump of abnormal cells, that although growing out of control, remains at the original site

Cancer

A malignant tumor

Malignant tumor

Abnormally growing mass of cells that is actively spreading through the body

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

Benign tumors do not metastasize; malignant tumors do.

Haploid

Cell with a single set of chromosomes, n

Diploid

Cell with pairs of homologous chromosomes, 2n

Anaphase

Centromeres come apart and daughter chromosomes move toward opposite sides of the cell

Metaphase

Chromosomes aline at equator; mitotic spindle fully formed

Prophase

Discrete chromosomes appear; mitotic spindle begins to form; nuclear envelope begins to dissolve

Mitosis

Division of a cell's chromosomes; consists of PMAT

Cytokinesis

Division of the cytoplasm including organelles

True or false. Mitosis takes place during M phase of the cell cycle, which is longer than interphase.

False; interphase is the longest phase of the cell cycle

G1

First gap; normal cell functions occur

The function of meiosis is to make __________.

Four cells each with a haploid number of chromosomes

Fertilization

Fusion of an egg and sperm cell

Where are the three cell cycle checkpoints located in the cell cycle?

G1, G2, and Metaphase

The cell is performing normal functions

Interphase

After fertilization, the resulting zygote begins to divide by __________.

Mitosis

Accounts for only 10% of the cell cycle:

Mitosis/Mitotic phase

Carcinoma

Most common type of cancer, originates in tissues that line organs or epithelial tissues of the skin

Interphase

Normal cell functions; consists of G1, S, G2.

Telophase

Nuclear envelopes develop; chromatin fiber uncoils; end of mitosis

Crossing over occurs during _____.

Prophase I

During which stage of meiosis do synapsis and crossing over occur?

Prophase I

DNA replication occurs

S phase

G2

Second gap; cell completes preparations for cell division

Which of the following statements regarding mitosis and meiosis is true?

Sister chromatids separate during anaphase of mitosis and anaphase II of meiosis.

Metastasis

Spread of cancer cells from their site of origin to other sites in the body

S

Synthesis of DNA; chromosomes are duplicated

You and your lab partner are observing a cell under a microscope, but you do not know whether it is a eukaryote or a prokaryote. Which of the following observations regarding the chromosomes would you use to immediately conclude that the cell is a eukaryote?

The chromosomes are housed in a membrane-enclosed nucleus.

True or false: Binary fission is considered asexual reproduction.

True

Which of the following would result in a normal individual?

XYY

According to the graph, at what maternal age is the incidence of Down syndrome equal to five times the incidence at age 40?

about 46 or 47

Crossing over is important because it _____.

allows the exchange of genes between homologous chromosomes

The creation of genetically identical offspring by a single parent, without the participation of sperm and egg, is called

asexual reproduction.

Asexual and sexual reproduction differ in that sexual reproduction _____.

can produce great variation among the offspring

Karyotyping

can reveal alterations in chromosome number.

Which of the following occurs during interphase?

cell growth and duplication of the chromosomes

A cleavage furrow forms in animal cells during

cytokinesis

Division of the cytoplasm

cytokinesis

The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called

cytokinesis

As a patch of scraped skin heals, the cells fill in the injured area but do not grow beyond that. This is an example of

density-dependent inhibition.

Zygote

fertilized egg, has 2n set of chromosomes and begins division via mitosis.

Without crossing over,

genetic recombination could not occur.

During anaphase I, _____ and during anaphase II, _____ .

homologous chromosomes separate.... sister chromatids separate

Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are

homologous chromosomes.

Both mitosis and meiosis are preceded by

interphase.

During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles?

metaphase

The chromosomes divide

mitosis

Gamete

name for egg and sperm cells, contain single set of chromosomes, n

Somatic cells

non-sex cells

Independent orientation of chromosomes at metaphase I results in an increase in the number of

possible combinations of characteristics.

Gonad cell

sex cells, produce gametes

Prior to mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called

sister chromatids.

The genetic material is duplicated during

the S phase.

At the start of mitotic anaphase,

the centromeres of each chromosome come apart.

Mitosis and cytokinesis result in the formation of __________; meiosis and cytokinesis result in the formation of __________.

two diploid cells .... four haploid cells

When comparing the base sequence in sister chromosomes, they

will be identical.

Prokaryotic DNA differs from eukaryotic DNA because it

consists of a single circular chromosome.

Meiosis

division of nuclei, ending with four n cells

Mitosis

division of nuclei, ending with two 2n cells

Crossing over

exchange of corresponding segments of non-sister chromatids of homologous chromosomes

If these four cells resulted from cell division of a single cell with diploid chromosome number 2n = 4, what best describes what just occurred?

nondisjunction

In meiosis, a mistake where homologous chromosomes do not separate properly is called _____.

nondisjunction

Down syndrome results from

nondisjunction where the person has 3 copies of chromosome 21.

Karyotype

ordered display of an organisms chromosomes.

Synapsis

pairing of homologous chromosomes during prophase I

A cell that has a cell wall is undergoing cell division, and the following events are observed: the formation of a cell plate and the division of the cell into two daughter cells. What type of cell is being observed and what process(es) is it going through?

plant cell; telophase and cytokinesis of mitosis

Looking into your microscope, you spot an unusual cell. Instead of the typical rounded cell shape, the cell has a very narrow middle separating two bulging ends. It sort of looks like the number 8! You realize that this cell is

undergoing cytokinesis.