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

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Flashcards in The Cell Cycle and Cell Division Part One: Interphase, Mitosis, And Cytokinesis Deck (18):
1

Eukaryotic Cell Division Consists Of

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

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Meiosis

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

3

The cell cycle consists of four phases

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

4

Interphase

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

5

G1

Cells do most of their growing by synthesizing proteins and organelles

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S

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

7

G2

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

8

M

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

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Stages of mitosis

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

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Centromere

Duplicated strands of the DNA attach at the centromere

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Chromatid

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

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Centrioles

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

13

Prophase

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

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Metaphase

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

15

Anaphase

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

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Telophase

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

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Cytokinesis in animal cells

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

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Cytokinesis in plant cells

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