B1: The Cell Cycle

Question 1

The continuity of life depends on cells growing, replicating their genetic material (DNA) and then dividing - a process called ____.

Answer 1

cell cycle

Question 2

The cell cycle has two major phases: interphase and the mitotic phase.

During interphase, _____.
During the mitotic phase, _____.

Answer 2

the cell grows and DNA is replicated;
the replicated DNA and cytoplasmic contents are separated, and the cell divides.

Question 3

Three stages of interphase: (3)

Answer 3

1. G1 Phase (First Gap) - normal cell function.
2. S Phase (Synthesis of DNA) - DNA replication and repair of damaged DNA.
3. G2 Phase (Second Gap) - continued growth and preparation for division.

Question 4

In this stage of interphase, cellular contents, excluding the chromosomes, are duplicated.

Answer 4

G1

Question 5

In this stage of interphase, each of the 46 chromosomes is duplicated by the cell.

Answer 5

S Phase

Question 6

In this stage of interphase, the cell DOUBLE CHECKS the duplicated chromosomes for error, making any needed repairs.

Answer 6

G2

Question 7

In the S phase, DNA replication can proceed through the mechanisms that result in the formation of identical pairs of DNA molecules — _______ — that are firmly attached to the centromeric region.

Answer 7

sister chromatids

Question 8

The centrosome is duplicated during the S phase. The two centrosomes will give rise to the _____, the apparatus that orchestrates the movement of chromosomes during mitosis.

Answer 8

mitotic spindle

Question 9

At the center of each animal cell, the centrosomes of animal cells are associated with a pair of rod‐like objects, the ____, which areatrightanglesto each other.

Answer 9

centrioles

Question 10

____ help organize cell division. They are not present in the centrosomes of other eukaryotic species, such as plants and most fungi.

Answer 10

centrioles

Question 11

In the G2 phase, ___. (2)

Answer 11

1. The cell replenishes its energy stores and synthesizes proteins necessary for chromosome manipulation.
2. Some cell organelles are duplicated, and the cytoskeleton is dismantled to provide resources for the mitotic phase.

Question 12

True or False

There may be additional cell growth during G2.

Answer 12

True

Question 13

The _____ is a multistep process during which the duplicated chromosomes are aligned, separated, and move into two new, identical daughter cells.

Answer 13

mitotic phase

Question 14

The first portion of the mitotic phase is called ___, or ____.

Answer 14

karyokinesis, or nuclear division

Question 15

The second portion of the mitotic phase, called ____, is the physical separation of the cytoplasmic components into the two daughter cells.

Answer 15

cytokinesis

Question 16

___ is a form of eukaryotic cell division that produces two daughter cells with the same genetic component as the parent cell.

Answer 16

mitosis

Question 17

Karyokinesis is unnecessary because there is no nucleus and thus no need to direct one copy of the multiple chromosomes into each daughter cell. This type of cell division is called ____.

Answer 17

binary (prokaryotic) fission)

Question 18

In diploid multicellular organisms sexual reproduction involves the ___ to produce a diploid zygote.

Answer 18

fusion of two haploid gametes

Question 19

In the adult organism, mitosis plays a role in ___. (3)

Answer 19

1. Cell Replacement: In tissues with a high turnover rate, such as the skin, blood, and the lining of the gastrointestinal tract, mitosis ensures a constant supply of new cells to replace those that are naturally lost or damaged over time.
2. Wound Healing: It allows for the rapid division of nearby cells to replace damaged ones and promote the regeneration of the injured tissue.
3. Tumor Formation: In cancer, cells may acquire mutations that disrupt the normal controls on cell division. As a result, they can undergo uncontrolled and excessive mitotic divisions, leading to the formation of a tumor.

Question 20

Karyokinesis, also known as mitosis, is divided into a series of phases – ____ (5) – that result in the division of the cell nucleus.

Answer 20

1. Prophase
2. Prometaphase
3. Metaphase
4. Anaphase
5. Telophase