Mitosis, Meiosis, Cell Cycle, And Cancer

Question 1

What cellular process(es) is/are responsible for the increase in protein content associated with the gap phases of the cell cycle?

Answer 1

both transcription and translation

Question 2

The microtubules that form the mitotic spindle extend out from the centrosome. Where would you expect to find the plus (fast-assembling) end of a spindle microtubule?

Answer 2

away from the centrosome and toward the kinetochore

Question 3

Synapsis is best described as

Answer 3

the pairing of homologous chromosomes in prophase I.

Question 4

A protein that has regular up-and-down pattern of abundance during the cell cycle and that triggers progress of the cell cycle by activating kinases is called a:

Answer 4

cyclin

Question 5

The protein p53 is an example of:

Answer 5

a tumor suppressor.

Question 6

What characteristics do you expect to observe with a microscope if you investigate the division of mitochondria and chloroplasts in eukaryotic cells?

Answer 6

circular DNA attached to the plasma membrane and binary fission

Question 7

In which phase of mitosis does the mitotic spindle form?

Answer 7

prophase

Question 8

During what step in meiosis do homologous chromosomes separate?

Answer 8

anaphase I

Question 9

At which checkpoint would a cell become arrested if a chromosome was not properly aligned in the spindle?

Answer 9

at a checkpoint early in the mitotic phase

Question 10

Which statement regarding tumor suppressors are true?
Correct: Mutations affecting tumor suppressors can contribute to the development of cancers.

Mutations affecting tumor suppressors can contribute to the development of cancers.

Tumor suppressors act synergistically with proto-oncogenes.

Tumor suppressors promote cell division.

Tumor suppressors include platelet-derived growth factor (PDGF) and cyclins.

None of the answer options is correct.

Answer 10

Mutations affecting tumor suppressors can contribute to the development of cancers.

Question 11

Suppose you are observing some cells with a microscope, and you see a cell that appears to be dividing. You can see that as the cell starts to pinch in half, the DNA seems to be attached to the plasma membrane via a membrane protein. On further analysis, you find that this organism’s DNA is circular – that is, it consists of a closed loop. What can you conclude about this organism and its mode of cell division?

Answer 11

It is a prokaryote that is dividing by binary fission.

Question 12

What protein forms the contractile ring during cytokinesis in animal cells?

Answer 12

actin

Question 13

The second meiotic division resembles mitosis because:

the daughter cells have the same number of chromosomes as the parent cell.

sister chromatids are separated during anaphase II to become the chromosomes of the daughter cells.

All of these choices are correct.

spindle microtubules attach from opposite directions to the centromere of each sister chromatid pair.

chromosomes decondense during telophase II.

Answer 13

All of these choices are correct.

Question 14

Why would a compound that interferes with bacterial cell wall synthesis be useful for treating a bacterial infection?

Answer 14

It would limit growth of the bacterial population through cell division.

Question 15

Why don’t plant cells use a contractile ring to divide their daughter cells?

Answer 15

A contractile ring can’t “pinch” a cell wall.

Question 16

Would genetic recombination result if crossing over occurred between sister chromatids?

Answer 16

No, because sister chromatids are genetically identical or nearly identical.

Question 17

At which stage of the cell cycle could you see sister chromatids with a microscope?

Answer 17

M

Question 18

Genes that promote cancer are called:

Answer 18

oncogenes

Question 19

Genes that participate in cell growth and division, but do not cause cancer, are:

Answer 19

proto-oncogenes

Question 20

A _____ is an enzyme that adds phosphate groups to other proteins. If this enzyme is only active when bound to a specific protein that fluctuates in concentration in synchrony with the cell cycle, then it is a _____.

Answer 20

kinase; cyclin-CDK complex

Question 21

Sexual reproduction results in an increase in genetic diversity because:

All of these choices are correct.

during metaphase I, the bivalents line up in a random orientation so that gametes inherit a random set of maternally and paternally derived chromosomes.

during prophase I, genes that are paternally and maternally derived recombine so that the gametes have chromosomes that are different from the parents’ chromosomes.

during fertilization, the gametes that fuse are random so that a large number of chromosomal combinations are possible in the new organism.

Answer 21

All of these choices are correct.

Question 22

Which of the answer choices could be a proto-oncogene?

All of these choices are correct.

a gene encoding a cell-surface receptor

a gene encoding a protein kinase

a gene encoding a growth factor

a gene encoding a G-protein

Answer 22

All of these choices are correct.

Question 23

Which statement is true regarding binary fission?

DNA replication of the circular bacterial chromosome during binary fission is a bidirectional process, starting at one point but progressing in opposite directions.

In binary fission, cell division is typically asymmetrical, with one daughter cell appearing much smaller than the other.

Tubulin, rather than FtsZ, is responsible for cell division during binary fission.

Proteins only anchor the original circular genome to the plasma membrane; the copy produced by DNA replication is free-floating.

Answer 23

DNA replication of the circular bacterial chromosome during binary fission is a bidirectional process, starting at one point but progressing in opposite directions.

Question 24

An early observation in the study of the development of sea urchin embryos was that there were several proteins that appeared and then disappeared in synchrony with the pattern of rapidly repeating cell divisions. Because of this up-and-down pattern of abundance these proteins became known as:

Answer 24

cyclins

Question 25

Muscle cells in the mammalian heart are multinucleate, meaning that multiple nuclei are present in the cytoplasm of individual large cells. Predict what is different about the cell cycle in a muscle cell.

Answer 25

Cytokinesis does not occur.

Question 26

What would happen to the daughter cells if the G2 phase of the parent cell is shortened?

Answer 26

The cells would be smaller than normal.

Question 27

A malignant cancer differs from a benign tumor in that:

Answer 27

malignant cancers invade surrounding tissue and benign cancers do not.

Question 28

Cell division is regulated by: signals about the nutritional status of the cell. growth factor signals. signals that indicate that the cell has reached a sufficient size. signals that indicate that DNA has been replicated. All of these choices are correct.

Answer 28

All of these choices are correct.

Question 29

Why would a compound that interferes with bacterial cell wall synthesis be useful for treating a bacterial infection?

Answer 29

it would limit growth of the bacterial population through cell division.

Question 30

Predict what would happen if crossing over between homologous chromosomes occurred as part of mitosis.

Answer 30

Daughter cells would not be genetically identical.

Question 31

One of the important cell cycle checkpoints occurs during M phase. It inhibits progression to anaphase until all of the chromosome kinetochores are correctly attached to microtubules of the spindle apparatus. If anaphase of mitosis occurred when the kinetochore microtubule connected to only one of the two spindle poles but not the other, what could result?

Answer 31

nondisjunction

Question 32

Nonproliferating cells in vertebrates exit the cell cycle in G1 and enter:

Answer 32

the G0 state.

Question 33

Which is NOT a part of both meiosis and mitosis? chromosome replication cell division crossing-over events prophase Incorrect: All of these are a part of both meiosis and mitosis. All of these are a part of both meiosis and mitosis.

Answer 33

crossing-over events

Question 34

Which statement is FALSE? Following mitosis, daughter cells contain 2n chromosomes in haploid organisms and 1n chromosomes in diploid organisms. The end of G2 is marked by the onset of mitosis. G1 is the period between the birth of a cell following mitosis and the initiation of DNA synthesis. Cells enter G2 containing twice the number of chromosomes as that in G1. G1, S, and G2 phases are collectively known as interphase.

Answer 34

Following mitosis, daughter cells contain 2n chromosomes in haploid organisms and 1n chromosomes in diploid organisms.

Question 35

Which process/condition regulates entry into the cell cycle? extracellular signals nutritional state presence of mitogens presence of anti-mitogens All of the answers are correct.

Answer 35

All of the answers are correct.

Question 36

TRUE OR FALSE: Protein degradation is reversible.

Answer 36

FALSE

Question 37

S phase CDKs and DDK collaborate to initiate DNA replication. _____ recruits the MCM helicases to sites of replication initiation during G1, when CDK activity is low. ORC Cdc6 Cdt1 All of the answers are correct. None of the answers is correct.

Answer 37

All of the answers are correct.

Question 38

Which statement is TRUE? DNA replication is initiated from helicase loading sites known as origins of replication. Loading and activation of the MCM helicase occur in mutually exclusive cell states. S phase CDKs and DDK trigger the initiation of DNA replication by the recruitment of MCM helicase activators to origins of replication. Initiation of DNA replication occurs at each origin only once during the cell cycle. All of the statements are true.

Answer 38

All of the statements are true.

Question 39

Which is an advantage of meiosis and sexual reproduction? greater genetic diversity random distribution of chromosomes at metaphase crossing over combination of maternal and paternal chromosomes All of the answers are correct.

Answer 39

All of the answers are correct.

Question 40

Why is it important that APC/C and Cdh1 remain active throughout G1?

Answer 40

to prevent premature accumulation of S phase and mitotic cyclins

Question 41

Which statement about tissue culture is FALSE? Researchers can use normal or tumor cells grown in plastic dishes to study the properties of the human cell cycle. Many of the cell types used for tissue culture have altered cell cycle properties due to the genetic alterations that occur during culture. Many of the cell types used for tissue culture have altered cell cycle properties because they were isolated from human tumors. In vitro culture conditions do not resemble those found in a particular organism and could lead to altered behavior of cells. All of these statements are true.

Answer 41

All of these statements are true.

Question 42

What happens if a cell fails to pass a cell cycle

Answer 42

The cell halts progression and attempt to repair the damage

Question 43

How do cyclins and CDKs directly in controlling cell cycle progression

Answer 43

They phosphorylate target proteins to regulate the cell cycle stages

Question 44

What os the role of oncogenes in cancer development?

Answer 44

oncogenes are mutated proto-oncogenes that lead to uncontrolled cell proliferation.

Question 45

describe a key differences between Mitosis and Meiosis

Answer 45

Mitosis results in two diploid cells, while meiosis results in four haploid cells

Question 46

What is the outcome of crossing over during meiosis

Answer 46

Genetically diverse Gametes

Question 47

what occurs during anaphase of Meiosis II

Answer 47

Sister chromatids are separated and pulled to opposite poles of the cell.