Download Cell Growth and Reproduction

Cell Growth and
Reproduction
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Growth and Reproduction of Cells

Cell growth and reproduction of cells are the most fundamental of all
living functions and together constitute the cell life cycle

Cell growth—depends on using genetic information in DNA to make the
structural and functional proteins needed for cell survival

Cell reproduction —ensures that genetic information is passed from one
generation to the next
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Growth and Reproduction of Cells

Cell growth —a newly formed cell produces a variety of molecules and
other structures necessary for growth using the information contained in
the genes of DNA molecules; this stage is known as interphase

Production of cytoplasm—more cell material is made, including growth and/or
replication of organelles and plasma membrane; a largely anabolic process
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Growth and Reproduction of Cells

Cell growth (cont.)
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DNA replication
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Replication of the genome prepares the cell for reproduction;
mechanics are similar to RNA synthesis
DNA replication
DNA strand uncoils and strands come apart

Along each separate strand, a complementary strand forms

The two new strands are called chromatids, instead of chromosomes
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Chromatids are attached in pairs, and the centromere is the name of their point
of attachment
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Growth and Reproduction of Cells

Cell growth (cont.)

Growth phase of the cell life cycle can be subdivided into the first
growth phase (G1),
the [DNA] synthesis phase (S), and the second growth phase (G2)
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Growth and Reproduction of Cells

Cell reproduction—cells reproduce by splitting themselves into two smaller
daughter cells (Table 4-5)

Mitotic cell division—the process of organizing and distributing nuclear DNA
during cell division has four distinct phases (Figure 4-31)
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Growth and Reproduction of Cells

Mitotic cell division (cont.)

Prophase—“before-phase”

After the cell has prepared for reproduction during interphase, the nuclear envelope
falls apart as the chromatids coil up to form chromosomes, which are joined at the
centromere (Figure 4-30)

As chromosomes are forming, the centriole pairs are seen to move toward the poles of
the parent cell and spindle fibers are constructed between them
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Growth and Reproduction of Cells

Mitotic cell division (cont.)

Metaphase—“position-changing phase”

Chromosomes move so that one chromatid of each chromosome faces its respective
pole
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Each chromatid attaches to a spindle fiber
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Growth and Reproduction of Cells
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Mitotic cell division (cont.)

Anaphase—“apart phase”

Centromere of each chromosome has split to form two chromosomes, each consisting
of a single DNA molecule

Each chromosome is pulled toward the nearest pole, forming two separate but
identical pools of genetic information
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Growth and Reproduction of Cells

Mitotic cell division (cont.)

Telophase—“end phase”

DNA returns to its original form and location within the cell

After completion of telophase, each daughter cell begins interphase to develop into a
mature cell