Chapter 12 😒

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

100 unit

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

how many maternal chromosomes are present in a somatic human cell not engaged in cell division?

23

If a cell contains 60 chromatids at the start of mitosis, how many chromosomes will be found in each daughter cell at the completion of the cell cycle?

30

If a human somatic cell is just about to divide, it has __________ chromatids.

92

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

94

The person credited with first recognizing (in the 1860s) that living cells cannot arise spontaneously, but arise only from previously existing cells, is _

Rudolf Virchow

The function of the mitotic cell cycle is to produce daughter cells that

are genetically identical to the parent cell (assuming no mutation has occurred)

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

Which of the following is involved in the binary fission of most bacteria? prophase, prometaphase, metaphase, anaphase, and telophase formation of a cell plate distribution of a copy of the single parental chromosome to each daughter cell formation of a spindle apparatus disintegration of the nuclear membrane

distribution of a copy of the single parental chromosome to each daughter cell

Cytokinesis" refers to

division of the cytoplasm

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

chromatin

In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle?

cytokinesis

Which of the following does NOT occur during mitosis? separation of chromatids replication of chromosomes alignment of chromosomes along the cell's equator condensation of chromatin the movement of chromosomes to opposite poles

replication of chromosomes

The centromere is a region in which

sister chromatids are attached to one another in prophase

Which of the following phases of mitosis is essentially the OPPOSITE of prometaphase in terms of the nuclear envelope? (Concept 12.2) SHOW HINT anaphase S phase metaphase interphase telophase

telophase

DNA replication occurs in

the S phase of interphase in both somatic and reproductive cells

One event occurring during prophase is

the beginning of the formation of a spindle apparatus

During binary fission in a bacterium,

the origins of replication move apart

Which event or events occur during anaphase? A spindle made of microtubules is present during anaphase. Cohesins joining sister chromatids at the centromeres are cleaved during anaphase. The centrioles are at opposite poles during anaphase. Genetically identical chromosomes (previously sister chromatids) move to opposite poles during anaphase. All of the listed responses are correct.

All of the listed responses are correct.

Which of the following is FALSE regarding sister chromatids? (Concept 12.1) SHOW HINT Sister chromatids are separated during mitosis. Sister chromatids form in the S-phase stage of the cell cycle. Sister chromatids are created when DNA is replicated. Sister chromatids are attached to one another at the centromere. Both of the sister chromatids end up in the same daughter cell after cytokinesis has occurred.

Both of the sister chromatids end up in the same daughter cell after cytokinesis has occurred.

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

Cells of benign tumors do not metastasize; those of malignant tumors do.

When a cell in S phase is fused with a cell in G1,

DNA synthesis begins immediately in the original G1 nucleus

During what phase in the cell cycle would you find the most DNA per cell?

G2

Which of the following hypotheses is best supported by observing cancer cells in a culture? The cancer cells exhibit anchorage dependence. The cancer cells spend the majority of their time in the G0 phase. The cancer cells produce molecules that inhibit the growth factors required for cell division. The cancer cells do not exhibit density-dependent inhibition. All of the listed responses are correct.

The cancer cells produce molecules that inhibit the growth factor

Following cytokinesis in an animal cell, how many centrioles does each new daughter cell possess? zero one two four eight

Two

The region of a chromosome in which the two double strands of replicated DNA are held together is called

a centromere

During what stage of the cell cycle do sister chromatids separate?

anaphase

The phase of mitosis during which the chromosomes move toward separate poles of the cell is

anaphase

Tissue culture experiments with PDGF demonstrate that without this substance

fibroblasts fail to divide

Chromatids are

identical copies of each other if they are part of the same chromosome

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

it had formed a cell plate

t which stage of mitosis are chromosomes lined up in one plane in preparation for their separation to opposite poles of the cell? (Concept 12.2) SHOW HINT anaphase metaphase interphase telophase prophase

metaphase

Which of the following represents a mismatch or incorrect description? (Concept 12.2) SHOW HINT anaphase: there is movement of the chromosomes to the poles telophase: chromosomes become more extended metaphase: the nuclear envelope disappears prophase: chromosomes become more tightly coiled metaphase: chromosomes line up on the equatorial plane

metaphase: the nuclear envelope disappears

Which of the following processes does NOT occur in dividing bacteria? mitosis inward growth of the plasma membrane separation of the origins of replication replication of DNA binary fission

mitosis

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

nerve cell

A cell entering the cell cycle with 32 chromosomes will produce two daughter cells, each with __________. 16 chromosomes 64 chromosomes 32 pairs of chromosomes 64 pairs of chromosomes none of the listed numbers of chromosomes

none of the listed numbers of chromosomes

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

prophase

In telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in _

prophase