Chapter 8 mastering biology

At the end of telophase 1 of meiosis, as cytokinesis occurs, there are _____

2 haploid cells

Crossing over chromosomes during meiosis shuffles parental chromosomes resulting in a genetically unique child

A hybrid chromosome that has crossover will contain pieces of both the maternal and paternal chromosomes During meiosis 2 sister chromatids separate into four different gametes During prophase 1 of meiosis 1, homologous paternal and maternal chromosomes pair up and undergo crossing over

Cytokinesis often but not always accompanies _____.

Telophase

The chromosomes arrive at the polls in nuclear envelopes form during which phase of mitosis

Telophase

At the end of _____ and cytokinesis haploid cells contain chromosomes that each consist of two sister chromatids

Telophase 1

At the end of ____ and cytokinesis there are four haploid cells

Telophase 2

Fertilization joins ______ to produce a ______.

Haploid gamates; diploid zygote

During anaphase 1, ____

Homologous chromosomes separate and migrate towards opposite poles

Nucleoli are present during _____

Interphase

A fragment of chromosome 21 reattachattaches to chromosome 21 but in the reverse direction what is the name given to this change

Inversion

During binary fission each copy of the duplicating chromosome moves to the opposite end of the cell what does this achieve

It ensures that each daughter cell receives one copy of the chromosome

Centromeres divide and sister chromatids become full-fledged chromosomes during _____.

Anaphase

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

Anaphase

Homologous chromosomes migrate to opposite poles during _____

Anaphase 1

During _____ sister chromatids separate

Anaphase 2

A cell replicates its entire chromosomal DNA only _____

Before it is about to divide

Which of the following conditions would prevent cell division due to density dependent factors

Being completely surrounded by other cells

A ____ is a lump of abnormal cells that although growing out of control remains at its original site

Benign tumor

Asexual and sexual reproduction differ in that sexual reproduction

Can produce great variation among the offspring

An individual with a malignant tumor is said to have ______

Cancer

In the laboratory cancer cells fail to show density-dependent inhibition of growth in cell culture. What is one explanation that could account for this?

Cancer cells continuously secrete growth factors into cell culture medium

The most common type of cancer is a _____ this type always originates in tissues that lines organs

Carcinoma

Which processes lead to most genetic variation in sexually reproducing organisms

Crossing over Random fertilization Independent orientation of chromosomes in meiosis

At the end of the mitotic (M) phase, the cytoplasm divides in a process called _____.

Cytokinesis

You can determine this is a plant cell rather than an animal cell because it has

Formed a cell plate

Meiosis 2 typically produces ____ cells, each of which is _____

Four; haploid

Cells will usually divide if they receive the proper signal at the checkpoint in the _____ phase of the cell cycle

G1

When examining cells in the laboratory you noticed that a particular cell has half as much DNA as the surrounding cell it appears that this cells cell cycle halted at checkpoint

G1

A _______ is an abnormally growing mass of cells that is actively spreading through the body

Malignant tumor

If it weren't for _____ chromosome number what double with every generation of sexual reproduction

Meiosis

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

Metaphase

Which of the following is a correct representation of an event that occurs in mitosis

Metaphase - chromosomes line up on the equatorial plane

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

Metaphase 2

Looking through a light microscope at a cell undergoing division you see that condensed chromosomes have lined up along the midline of the cell. The homologous pairs are NOT joined at tetrads. Each chromosome takes its own place in line, independent of homolog. You are witnessing _______

Metaphase of mitosis

______ is the spread of cancer cells from their site of origin to other sites in the body

Metastasis

Duplication of the chromosomes to produce sister chromatids _____

Occurs in both mitosis and meiosis

Spindle fibers attach to kinetochores during _____.

Prometaphase

Chromosomes become visible during _____.

Prophase

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

Prophase

Synapsis occurs during ____

Prophase 1

During ____ a spindle forms in a haploid cell

Prophase 2

One version of a gene may encode _____ whereas a different version of the same gene may encode ____

Red eyes; white eyes

During anaphase 2, ___

Sister chromatids separate and migrate towards opposite poles

An example of a cell that is 2n is a

Somatic cell

Mitosis occurs in ____; meiosis occurs in ______

Somatic or body cells; germ cells in testes or ovaries

What must happen before a cell can begin mitosis

The chromosomes must be duplicated

Within one chromosome what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other

The sequences are identical

During mitosis the chromosomes move because

They attach to a dynamic precisely regulated mitotic spindle

During prophase a homologous pair of chromosomes consists of ______

Two chromosomes and four chromatids

Meiosis 1 produces _____ cells each of which is _____

Two; haploid