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Flashcards in science: chpt. 9 test Deck (31):
0

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

True

1

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

False (interphase mitosis and cytokinesis)

2

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

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

3

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

False

4

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

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

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

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

6

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

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

7

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

True

8

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

False, cell division is complete after cytokinesis.

9

True/false: prokaryotes divide by mitosis

False, prokaryotes divide by binary fission

10

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

False, they initiate the different stages in the cell cycle

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

C. Ratio of surface area to volume increases

12

Why is the synthesis stage called this?

Because DNA synthesis is taking place

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

D. The nuclear membrane has disappeared

14

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

12

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…

The centrioles migrating

16

Cancer cells can reproduce rapidly because they…

Spend less time in interphase

17

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

They initiate various stages of the cell cycle.

18

DNA replication occurs during…

Interphase

19

Which of the phases of mitosis has the shortest duration?

Metaphase

20

A cell that undergoes repeated mitosis without cytokinesis would have…

Many nuclei

21

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

Gap 1

22

A stem cell has potential medical uses because it…

Is not specialized in structure and function

23

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

Synthesis

24

The longest stage of mitosis is __________.

Prophase

25

Cytokinesis is division of the ___________.

Cytoplasm

26

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

Checkpoints

27

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

Apoptosis

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?

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

29

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

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.

30

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

A cell divides into two cells with identical genetic info

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