Lc. 11 (cell reproduction)

Question 1

A diploid cell has_______ the number of chromosomes as a haploid cell.
a) one-fourth
b) half
c) twice
d) four times

Answer 1

c) twice

Question 2

An organism’s traits are determined by the specific combination of inherited _____.
a) cells.
b) genes.
c) proteins.
d) chromatids.

Answer 2

b) genes.

Question 3

The first level of DNA organization in a eukaryotic cell is maintained by which molecule?
a) cohesin
b) condensin
c) chromatin
d) histone

Answer 3

d) histone

Question 4

Identical copies of chromatin held together by cohesin at the centromere are called _____.
a) histones.
b) nucleosomes.
c) chromatin.
d) sister chromatids.

Answer 4

d) sister chromatids.

Question 5

Chromosomes are duplicated during what stage of the cell cycle?
a) G1 phase
b) S phase
c) prophase
d) prometaphase

Answer 5

b) S phase

Question 6

Which of the following events does not occur during some stages of interphase?
a) DNA duplication
b) organelle duplication
c) increase in cell size
d) separation of sister chromatids

Answer 6

d) separation of sister chromatids

Question 7

The mitotic spindles arise from which cell structure?
a) centromere
b) centrosome
c) kinetochore
d) cleavage furrow

Answer 7

b) centrosome

Question 8

Attachment of the mitotic spindle fibers to the kinetochores is a characteristic of which stage of mitosis?
a) prophase
b) prometaphase
c) metaphase
d) anaphase

Answer 8

b) prometaphase

Question 9

Unpacking of chromosomes and the formation of a new nuclear envelope is a characteristic of which stage of mitosis?
a) prometaphase
b) metaphase
c) anaphase
d) telophase

Answer 9

d) telophase

Question 10

Separation of the sister chromatids is a characteristic of which stage of mitosis?
a) prometaphase
b) metaphase
c) anaphase
d) telophase

Answer 10

c) anaphase

Question 11

The chromosomes become visible under a light microscope during which stage of mitosis?
a) prophase
b) prometaphase
c) metaphase
d) anaphase

Answer 11

a) prophase

Question 12

The fusing of Golgi vesicles at the metaphase plate of dividing plant cells forms what structure?
a) cell plate
b) actin ring
c) cleavage furrow
d) mitotic spindle

Answer 12

a) cell plate

Question 13

Which of the following is the correct order of events in mitosis?
a) Sister chromatids line up at the metaphase plate. The kinetochore becomes attached to the mitotic spindle. The nucleus reforms and the cell divides. Cohesin proteins break down and the sister chromatids separate.
b) The kinetochore becomes attached to the mitotic spindle. Cohesin proteins break down and the sister chromatids separate. Sister chromatids line up at the metaphase plate. The nucleus reforms and the cell divides.
c) The kinetochore becomes attached to the cohesin proteins. Sister chromatids line up at the metaphase plate. The kinetochore breaks down and the sister chromatids separate. The nucleus reforms and the cell divides.
d) The kinetochore becomes attached to the mitotic spindle. Sister chromatids line up at the metaphase plate. Cohesin proteins break down and the sister chromatids separate. The nucleus reforms and the cell divides.

Answer 13

d) The kinetochore becomes attached to the mitotic spindle. Sister chromatids line up at the metaphase plate. Cohesin proteins break down and the sister chromatids separate. The nucleus reforms and the cell divides.

Question 14

At which of the cell-cycle checkpoints do external forces have the greatest influence?
a) G1 checkpoint
b) G2 checkpoint
c) M checkpoint
d) G0 checkpoint

Answer 14

a) G1 checkpoint

Question 15

What is the main prerequisite for clearance at the G2 checkpoint?
a) cell has reached a sufficient size
b) an adequate stockpile of nucleotides
c) accurate and complete DNA replication
d) proper attachment of mitotic spindle fibers to kinetochores

Answer 15

c) accurate and complete DNA replication

Question 16

If the M checkpoint is not cleared, what stage of mitosis will be blocked?
a) prophase
b) prometaphase
c) metaphase
d) anaphase

Answer 16

d) anaphase

Question 17

Many of the negative regulator proteins of the cell cycle were discovered in what type of cells?
a) gametes
b) cells in G0
c) cancer cells
d) stem cells

Answer 17

c) cancer cells

Question 18

___________ are changes to the order of nucleotides in a segment of DNA that codes for a protein.
a) Proto-oncogenes
b) Tumor suppressor genes
c) Gene mutations
d) Negative regulators

Answer 18

c) Gene mutations

Question 19

A gene that codes for a positive cell-cycle regulator is called a(n) _____.
a) kinase inhibitor.
b) tumor suppressor gene.
c) proto-oncogene.
d) oncogene.

Answer 19

c) proto-oncogene.

Question 20

Which eukaryotic cell-cycle event is missing in binary fission?
a) cell growth
b) DNA duplication
c) karyokinesis
d) cytokinesis

Answer 20

c) karyokinesis

Question 21

FtsZ proteins direct the formation of a _______ that will eventually form the new cell walls of the daughter cells.
a) contractile ring
b) cell plate
c) cytoskeleton
d) septum

Answer 21

d) septum

Question 22

Nucleoli are present during

Answer 22

interpahse

Question 23

cytokinesis often, but not always, accompanies

Answer 23

telophase

Question 24

chromosomes become visible during

Answer 24

prophase

Question 25

centromeres divide and sister chromatids become full-fledged chromosomes during

Answer 25

anaphase

Question 26

spindle fibers attach to kinetochores during

Answer 26

prometaphase

Question 27

During interphase, the cell’s DNA replicates, producing an identical copy of each DNA molecule. By the end of mitosis, one copy of each DNA molecule has been moved to each daughter cell.

Answer 27

unreplicated chromosome -> (DNA replication) replicated chromosomes -> sister chromatid -> (mitosis) unreplicated chromosomes

Question 28

Which of the following statements does not correctly describe the role of a cellular structure in mitosis? a) The centrosomes are the organizing centers for the formation of the mitotic spindle in animal cells. b) The kinetochore is the structure that holds the sister chromatids together. c) During mitosis, the attachment of the sister chromatids to each other at the centromere is broken, permitting the chromatids to separate. d) Every chromosome is attached to the mitotic spindle by two sets of microtubules, one extending from each pole of the cell.

Answer 28

b) The kinetochore is the structure that holds the sister chromatids together.

Question 29

Which of the following correctly matches a phase of the cell cycle with its description? a) M: duplication of DNA b) G1: follows cell division c) S: immediately precedes cell division d) none of these are correctly matched e) G2: cell division

Answer 29

b) G1: follows cell division

Question 30

A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in a) G2 b) prophase c) S d) G1

Answer 30

d) G1

Question 31

During mitosis, microtubules attach to the chromosomes at the

Answer 31

kinetochores

Question 32

in dividing cells, most of the cells growth during

Answer 32

interphase

Question 33

the ________ are the organizing centers for microtubules involved in separating chromosomes during mitosis

Answer 33

centrosomes

Question 34

after chromosomes condense, the _______ is the region where the identical DNA molecules are most tightly attached to each other

Answer 34

centromere

Question 35

DNA replication produces two identtical DNA molecules, called_______, which seperate during mitosis

Answer 35

sister chromatids

Question 36

the _______ is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division

Answer 36

mitotic spindles

Question 37

A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain? 92 No answer text provided. 23 46

Answer 37

92

Question 38

Which is an enzyme? a) cyclin-dependent kinase b) cyclin

Answer 38

a) cyclin-dependent kinase

Question 39

The cyclin dependent kinase is active when bound to the cyclin. (T/F)

Answer 39

false