The Cell Cycle

Assume that you are dealing with a species in which the number of chromosomes in each somatic cell is 14. How many sister chromatids are present in the early telophase of mitosis?

0 - Chromatids disappear after anaphase -Each sister chromatid has a centromere, a region containing specific DNA sequences, where the chromatid is attached most closely to its sister chromatid. Once separated during anaphase of mitosis, the chromatids become full-fledged chromosomes that move toward opposite ends of the cell. Therefore, in the last stage of mitosis, telophase, there are no longer any chromatids present.

A 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 each contained 200 units of DNA. What would be the amount of DNA at G1 of the cell cycle in a daughter cell of one of these cells?

100 units

When not engaged in the processes leading to cell division, how many chromosomes from your mother are present in the nucleus of each of your somatic cells?

23

If a human somatic cell is in metaphase, it has __________ chromatids.

92 - During interphase of the cell cycle, all of a eukaryotic cell's chromosomes are duplicated

Down syndrome is characterized by cells having three copies of chromosome 21. As a somatic cell in an individual with Down syndrome prepares to enter mitosis, how many chromatids would be present in the cell's nucleus?

94

Which of the following represents a mismatch or incorrect description?

Metaphase: the nuclear envelope disappears

Which of the following processes does not occur in dividing bacteria?

Mitosis

You would be unlikely to see which of the following human cells dividing?

Nerve cell

A cell entering mitosis with 32 chromosomes will produce daughter cells with __________.

None of the listed responses is correct

In a human skin cell that is going through the cell cycle, when do the centrosomes separate?

Prophase

The person credited with the axiom, "Every cell from a cell" is

Rudolf Virchow - "Where a cell exists, there must have been a preexisting cell, just as the animal arises only from an animal and the plant only from a plant.

A biochemist measured the amount of DNA in cells growing in the laboratory and found that the quantity of DNA in the cells doubled

between the G1 and G2 phases

During interphase, the genetic material of a typical eukaryotic cell is

dispersed in the nucleus as long strands of chromatin - a cell that is about to divide grows and copies its chromosomes in preparation for cell division

Observations of cancer cells in culture support the hypothesis that cancer cells __________.

do not exhibit density-dependent inhibition - Density-dependent inhibition is a phenomenon in which crowded cells stop dividing.

Tissue culture experiments with PDGF demonstrate that without this substance __________.

fibroblasts fail to divide

The complex of DNA and protein that makes up a eukaryotic chromosome is properly called

chromatin

One event occurring during prophase is

the beginning of the formation of a mitotic spindle

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

Cells of benign tumors do not metastasize; those of malignant tumors do. Malignant tumors - tumor includes cells whose genetic and cellular changes enable them to spread to new tissues and impair the functions of one or more organs. This spread of cancer cells to locations distant from their original site is called metastasis.

The cleavage furrow forms during which stage of mitosis and cell division of an animal cell?

Cytokinesis

The function of mitosis and cytokinesis is to produce daughter cells that __________.

are genetically identical to the parent cell

Sister chromatids are

identical copies of a chromosome Prior to the S phase of interphase, chromosomes are present only as single copies, not sister chromatids. Bacterial cells have a single, circular chromosome. Chromatids are found only in eukaryotic cells. Centrioles do not hold chromatids together. Centrioles are involved in distributing chromosomes during mitosis in eukaryotic cells.

You would know a dividing cell was a plant cell rather than an animal cell if you saw that

it had formed a cell plate

During binary fission of a bacterium

origins of replication move apart