Honors Biology EXAM 8

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A brilliant zoologist examined an intestine cell from a crayfish and counted 200 single chromosmes. What was the chromosome count of the eggs in the crayfish was carrying?

100 single chromosomes

A world renowned cell biologist, carefully measured the quantity of DNA in grasshopper cells growing in cell culture. Cells examined during the G2 phase of the cell cycle contained 200 units of DNA. What would be the amount of DNA in one of the grasshopper daughter cells seen in telophase of mitosis?

100 units

In a human cell at prophase I, there are ___ tetrads

23

The kinetochore serves which of the following functions?

Kinetochores attach to microtubules during mitosis

Chromosomes are duplicated during ___ of the cell cycle?

S phase

If meiosis did not occur in sexually reproducing organisms, then:

chromosome number would double in each generation

The sources of genetic variation during meiosis are:

crossing-over and the random assortment of maternal and paternal chromosomes

A zygote contains the ____ complement of chromosomes.

diploid

A cell in G2

has twice the amount of DNA present in a telophase nucleus.

The correct number of chromosomes is maintained during sexual reproduction sexual reproduction by:

meiosis, which reduces the chromosome number by half

The M phase of the cell cycle involves two main processes, ____.

mitosis and cytokinesis.

The ___ is responsible for the separation of the chromosomes during ___ of mitosis.

mitotic spindle; anaphase

Which of the following represents the sequence of events during mitosis?

prophase- metaphase- anaphase- telophase

A cell is in metaphase if

the chromosomes are aligned on the equatorial plane of the cell

What is the function of nucleosomes?

to help DNA replicate

An animal with a diploid number of 36 chromosomes will have ___ chromosomes in its gammetes and ___ chromosomes in its somatic cells.

18;36

A human bone marrow cell, in prophase of mitosis contains 46 chromosomes. How many chromatids does it contain altogether?

92

___ contain identical DNA sequences and are held together by ____ during mitosis.

Sister chromatids; centromeres

To prevent disastrous consequences, the eukaryotic cell cycle is controlled by:

a series of cell cycle checkpoints

A maternal homologue and a paternal homologue synapse to form:

a tetrad

During which of the following stages of meiosis do the sister centromeres separate?

anaphase II

The functions of mitotic cell division in the life cycles of an organism may include:

asexual reproduction growth replacement of order cells repair of injured tissues

Cytokinesis in plant cell mitosis occurs by the formation of a(n):

cell plate

A culture of mouse cells is treated with a chemical that interferes with the activity of micro-filaments. Which of the following will probably be affected the most?

cytokinesis

Most human somatic cells are

diploid

Which of the following events does not occur in prophase II

formation of a new cell membrane

The image of the chromosomes of an individual organism is called a :

karyotype

The chromosomes are aligned at the spindle equator during

metaphase

A picture of a dividing pigeon cell taken through a microscope shows that the cell contains 7 chromosomes, each consisting of 2 chromatids. This picture could have been taken during

metaphase of mitosis S phase of the cell cycle G2 of the cell cycle prophase of mitosis

The mitotic spindle is made of

microtubules

The formation of female gamates is termed

oogenesis

Which of the following is not a location where meiosis occurs?

plant root tip

Which of the following are produced by meiosis?

polar bodies animal eggs animal sperm plant sperm

During which phase does crossing-over occur?

prophase I

Homologous chromosomes synapse or pair during

prophase I

Which of the following events does not occur during meiosis !

separation of sister chromatids

During prophase I of meiosis, homologous chromosomes lie side by side. This phenomenon is known as:

tetrad formation

Nucleosomes are best described as

Eukaryotic DNA associated with histone proteins

Mature nerve cells, which don't undergo cell division, are arrested in ____ of the cell cycle.

G1 phase


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