science: chpt. 9 test

Question 0

True/false: the cell cycle is divided into interphase and mitosis

Answer 0

False (interphase mitosis and cytokinesis)

Question 1

True/false: Diffusion over large distances is slow and inefficient because it relies on random movement of molecules and ions

Answer 1

True

Question 2

True/false: During prophase in an onion root tip cell, centrioles migrate to the poles of the cell.

Answer 2

False, because centrioles are not present in plant cells, only spindle fibers

Question 3

True/false: In plant cells, cytokinesis begins with a furrow that pinches the cell.

Answer 3

False

Question 4

True/false: stem cells are only of one type: embryonic

Answer 4

False, there are two types of stem cells: embryonic and adult

Question 5

True/false: embryonic stem cells are found in various tissues in the body and might be used to maintain and repair the same kind of tissue in which they are found

Answer 5

False, the answer is adult. Embryonic cells are unspecialized.

Question 6

True/False: A cell such as a nerve cell, that exits the cell will do so after Gap2

Answer 6

False, it will exit after gap one before DNA is replicated

Question 7

True/false: the structure on a chromosome where sister chromatids attach is the centromere

Answer 7

True

Question 8

True/false: after telophase, the process of cell division is complete.

Answer 8

False, cell division is complete after cytokinesis.

Question 9

True/false: prokaryotes divide by mitosis

Answer 9

False, prokaryotes divide by binary fission

Question 10

True/false: cyclins bind with cyclin-dependent kinases to initiate different stages of mitosis.

Answer 10

False, they initiate the different stages in the cell cycle

Question 11

Which of the following does not occur as a cell grows larger and larger in size?
A. Difficulty obtaining nutrients
B. Difficulty eliminating wastes
C. Ratio of surface area to volume increases
D. Diffusion across the cell membrane is impaired

Answer 11

C. Ratio of surface area to volume increases

Question 12

Why is the synthesis stage called this?

Answer 12

Because DNA synthesis is taking place

Question 13

Which of these has occurred by the end of prophase?
A. Sister chromatids are separated
B. The spindle is beginning to form
C. The cell membrane has begun to pinch inward
D. The nuclear membrane has disappeared

Answer 13

D. The nuclear membrane has disappeared

Question 14

A cell has 12 chromosomes. How many chromosomes will each daughter cell have?

Answer 14

12

Question 15

A cell that is undergoing mitosis is examined with a light microscope. An observation that would allow for identification of the cell as an animal cell rather than a plant cell would be…

Answer 15

The centrioles migrating

Question 16

Cancer cells can reproduce rapidly because they…

Answer 16

Spend less time in interphase

Question 17

What is the role of the cyclin-dependent kinases in the cell cycle?

Answer 17

They initiate various stages of the cell cycle.

Question 18

DNA replication occurs during…

Answer 18

Interphase

Question 19

Which of the phases of mitosis has the shortest duration?

Answer 19

Metaphase

Question 20

A cell that undergoes repeated mitosis without cytokinesis would have…

Answer 20

Many nuclei

Question 21

The typical growth period of a cell occurs during which stage of the cell cycle?

Answer 21

Gap 1

Question 22

A stem cell has potential medical uses because it…

Answer 22

Is not specialized in structure and function

Question 23

Interphase is divided into three stages: G1, __________, and G2

Answer 23

Synthesis

Question 24

The longest stage of mitosis is __________.

Answer 24

Prophase

Question 25

Cytokinesis is division of the ___________.

Answer 25

Cytoplasm

Question 26

Once the cell cycle begins, there are built in ___________ that can stop it at any time.

Answer 26

Checkpoints

Question 27

During development some cells go through a programmed cell death called _________.

Answer 27

Apoptosis

Question 28

In an animal cell undergoing mitosis, the spindle first appears as two asters, a structure in which fibers radiate out from each centriole. Would you expect to find asters in plant cells? Why or why not?

Answer 28

No, because the plant cells have no centrioles, there would be no structures from which the fibers could radiate.

Question 29

How does a high ratio of surface area to volume benefit a sale?

Answer 29

A smaller cell can more efficiently transport substances. In addition waste will be expelled better and it will be easier to obtain nutrients. For the cytoskeleton to be in efficient transport mechanism, the cell must be small.

Question 30

Prokaryotes divide by binary fission, a form of asexual reproduction in which…

Answer 30

A cell divides into two cells with identical genetic info