The Cell Cycle and Cell Division Part One: Interphase, Mitosis, And Cytokinesis

Question 1

Eukaryotic Cell Division Consists Of

Answer 1

Mitosis, the division of the nucleus
Cytokinesis, the division of the cytoplasm
Meiosis reduces the number of chromosomes in the parent cell by half and produces four gamete cells

Question 2

Meiosis

Answer 2

Meiosis reduces the number of chromosomes in the parent cell by half and produces four gamete cells

Question 3

The cell cycle consists of four phases

Answer 3

Start of interphase: G1 - cell growth, makes more proteins, ribosomes, cytoplasm
S - DNA replication
G2 - Prep for mitosis
End of interphase
M - Mitosis and cytokinesis

Question 4

Interphase

Answer 4

Stage of Cell inbetween divisions
Consists of G1, S, G2
75-80% of cell life is spent in interphase

Question 5

G1

Answer 5

Cells do most of their growing by synthesizing proteins and organelles

Question 6

S

Answer 6

S stands for synthesis -
DNA condenses in preparation for S
DNA is synthesized when the chromosomes are replicated
By the end of the S phase, the cell contains twice as much DNA as it did before

Question 7

G2

Answer 7

Usually shortest phase of interphase

Many of the organelles and molecules required for cell division are produced, prep for M phase

Question 8

M

Answer 8

Produces two daughter cells
Takes place quickly in contrast to interphase
First - mitosis, division of the nucleus
Second - Cytokinesis, division of the cytoplasm

Question 9

Stages of mitosis

Answer 9

Produces two genetically identical daughter cells
Occurs in somatic cells
Prophase
Metaphase
Anaphase
Telophase

Question 10

Centromere

Answer 10

Duplicated strands of the DNA attach at the centromere

Question 11

Chromatid

Answer 11

Each DNA strand in the duplicated chromosome is referred to as a chromatid or sister chromatid
Divide evenly between the two new daughter cells

Question 12

Centrioles

Answer 12

Spindle fibers extend from the area centrosome, where centrioles are located.
Spindle fibers are a system of microtubules that help separate the duplicated chromosome
Duplicated during interphase

Question 13

Prophase

Answer 13

First stage of mitosis
Usually longest, may take up to half of time

Genetic material inside the nucleus condenses and the duplicated chromosomes become visible.
Outside of the nucleus a spindle starts to form from the centrioles

Centrioles start to move towards opposite ends of the cells, chromosomes condense, nucleolus disappears, and the nuclear envelope breaks down

Question 14

Metaphase

Answer 14

Second stage
Generally the shortest phase
Centromeres of duplicated chromosomes align at the center of the cell,
spindle fibers connect to the centromeres of each chromosome

Question 15

Anaphase

Answer 15

Third Stage
Begins when sister chromatids separate and move apart
Each sister chromatid is now considered a chromosome

During anaphase, the chromosomes separate and move along spindle fibers to opposite ends of the cell

Anaphase ends when this movement stops and the chromosomes are completely separated into two groups

Question 16

Telophase

Answer 16

Final Stage
Distinct and condensed chromosomes begin to spread out into chromatin

A nuclear envelope forms around each group of chromosomes
Spindle begins to break apart, a nucleolus becomes visible in each daughter nucleus

Question 17

Cytokinesis in animal cells

Answer 17

The cell membrane is drawn inward, forming a cleavage furrow, until the cytoplasm is split into two halves.
Each daughter cell contains it’s own nucleus and cytoplasmic organelles

Question 18

Cytokinesis in plant cells

Answer 18

The cell membrane is not flexible enough to draw inward because of the rigid cell wall

A structure called the cell plate forms between the divided nuclei. The cell plate gradually develops into cell membrane, separating the two daughter cells. A cell wall then forms in between the two new membranes