Chapter 10 - Cell Division

Question 1

cell division

Answer 1

The process by which a parent cell divides into two or more daughter cells. Cell division usually occurs as part of a larger cell cycle.

Question 2

chromatin

Answer 2

Mass of genetic material composed of DNA and proteins that condense to form chromosomes during eukaryotic cell division. Chromatin is located in the nucleus of a cell.

During prophase of mitosis, chromatin fibers become coiled into chromosomes with each chromosome having two chromatids joined at a centromere.

Question 3

nucleosomes

Answer 3

The fundamental subunit of chromatin. Each nucleosome is composed of a little less than two turns of DNA wrapped around a set of eight proteins called histones.

Question 4

homologous

Answer 4

Having the same relation, relative position, or structure, in particular. Pairing at meiosis and having the same structural features and pattern of genes.

Question 5

kinetochore

Answer 5

The protein structure on chromatids where the spindle fibers attach during cell division to pull sister chromatids apart.

Question 6

G2

Answer 6

Pre-mitotic phase. The third and final subphase of Interphase in the cell cycle directly preceding Mitosis. It follows the successful completion of S phase, during which the cell’s DNA is replicated.

Question 7

prometaphase

Answer 7

The second phase of mitosis, the process that separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells. During prometaphase, the physical barrier that encloses the nucleus, called the nuclear envelope, breaks down.

Question 8

kinetochore microtubules

Answer 8

Any of the spindle microtubules that attach to the kinetochores of chromosomes by their plus ends, and maneuver the chromosomes during mitotic or meiotic chromosome segregation.

Question 9

cleavage furrow

Answer 9

A groove formed from the cell membrane of animal cells in a dividing cell as the contractile ring tightens.

Question 10

binary fission

Answer 10

Primary method of reproduction of prokaryotic organisms. Organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA.

Question 11

histone proteins

Answer 11

Proteins whose positive charges allow them to associate with DNA, which is negatively charged. Function as spools for the thread-like DNA to wrap around.

Question 12

karyotype

Answer 12

The number and appearance of chromosomes in the nucleus of a eukaryotic cell. The term is also used for the complete set of chromosomes in a species, or an individual organism.

Question 13

cohesin

Answer 13

A protein complex that regulates the separation of sister chromatids during cell division, either mitosis or meiosis.

Question 14

cell cycle

Answer 14

The series of events that take place in a cell leading to its division and duplication (replication) that produces two daughter cells.

Question 15

cytokinesis

Answer 15

Occurs in mitosis and meiosis. Divides the cytoplasm of a parental cell into two daughter cells.

Question 16

mitosis

Answer 16

Stage of mitosis in the eukaryotic cell cycle in which chromosomes are at their most condensed and coiled stage.

Question 17

spindle

Answer 17

The subcellular structure of eukaryotic cells that segregates chromosomes between daughter cells during cell division.

Question 18

Cell plate

Answer 18

A plate that develops at the midpoint between the two groups of chromosomes in a dividing cell and that is involved in forming the wall between the two new daughter cells.

Question 19

mitosis

Answer 19

A part of the cell cycle process by which chromosomes in a cell nucleus are separated into two identical sets of chromosomes, each in its own nucleus.

Question 20

heterochromatin

Answer 20

Associated with several functions, from gene regulation to the protection of the integrity of chromosomes. Some roles can be attributed to the dense packing of DNA, which makes it less accessible to protein factors that usually bind DNA or its associated factors.

Question 21

haploid

Answer 21

A cell that has only one set of chromosomes. A normal eukaryote organism is composed of diploid cells, one set of chromosomes from each parent. Human sex cells (egg and sperm cells) are haploid.

Question 22

sister chromatin

Answer 22

Either of the two identical copies (chromatids) formed by the replication of a single chromosome, with both copies joined together by a common centromere. In other words, a sister chromatid may also be said as ‘one-half’ of the duplicated chromosome.

Question 23

G1 phase

Answer 23

Growth 1/Gap 1 phase, is the first of four phases of the cell cycle that takes place in eukaryotic cell division. The cell grows in size and synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis. G1 phase ends when the cell moves into the S phase of interphase.

Question 24

G0 phase

Answer 24

A period in the cell cycle in which cells exist in a dormant state.

Question 25

anaphase

Answer 25

The stage of mitosis or meiosis when chromosomes are split and the sister chromatids move to opposite poles of the cell.

Question 26

aster

Answer 26

A cellular structure shaped like a star, formed around each centrosome during mitosis in an animal cell. Astral rays, composed of microtubules, radiate from the centrosphere and look like a cloud. It is one of the variants of microtubules like kinetochore- and interpolar microtubules.

Question 27

chromosome

Answer 27

In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.

Question 28

euchromatin

Answer 28

A lightly packed form of chromatin (DNA, RNA and protein) that is rich in gene concentration, and is often (but not always) under active transcription. Euchromatin comprises the most active portion of the genome within the cell nucleus. 92% of the human genome is euchromatic.

Question 29

diploid

Answer 29

A cell or organism that has paired chromosomes, one from each parent. In humans, cells other than human sex cells, are diploid and have 23 pairs of chromosomes.

Question 30

centromere

Answer 30

The part of a chromosome that links sister chromatids. During mitosis, spindle fibers attach to the centromere via the kinetochore.

Question 31

S

Answer 31

The part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Precise and accurate DNA replication is necessary to prevent genetic abnormalities which often lead to cell death or disease.

Question 32

prophase

Answer 32

The first phase of mitosis, the process that separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells. During prophase, the complex of DNA and proteins contained in the nucleus, known as chromatin, condenses.

Question 33

telophase

Answer 33

The fifth and final phase of mitosis, the process that separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells. Telophase begins once the replicated, paired chromosomes have been separated and pulled to opposite sides, or poles, of the cell.

Question 34

polar microtubule

Answer 34

Any of the spindle microtubules that come from each pole and overlap at the spindle midzone. This interdigitating structure consisting of antiparallel microtubules is responsible for pushing the poles of the spindle apart.