Chapter 4: Cell Reproduction Section 1: Cell division and reproduction

1. Chapter 4: Cell
Reproduction
Section 1: Cell Division
and Mitosis
Mr. Motuk
Minersville Area Jr./Sr. High School

2. Chapter 4
Vocabulary
Terms
Section 1: The Cell Cycle (1) 2

3. I. Cell Cycle
A. Cell Cycle: Organisms to through stages, or a life cycle,
while they are alive.
1. A simple life cycle would be birth, growth and
development, and death.
2. Cells go through a life cycle.
a. The cell cycle is a series of events that take place in a
cell from one division to the next.
b. Different types of cells divide differently
i. Nerve cells cannot be replaced while skin cells are
constantly being replaced.
Section 1: The Cell Cycle (1) 3

4. I. Cell Cycle
B. Steps of the Cell Cycle- The cell cycle is a series of events
that cells go through as they grow and divide.
1. Interphase, Prophase, Metaphase, Anaphase, Telophase,
and Cytokenesis.
C. INTERPHASE- First step in the Cell Cycle has three parts.
1. G1 Phase
a. During the G1 phase cells do most of their growing.
b. During this phase, cells increase in size and synthesize
(make) new proteins and organelles.
Section 1: The Cell Cycle (1) 4

5. I. Cell Cycle
C. Interphase (Continued)
2. S-Phase
a. The G1 Phase is followed by the S Phase
b. Chromosomes are replicated and the synthesis of DNA
occurs.
3. G2 Phase
a. G2 is usually the shortest phase of interphase.
b. During G2 phase, many of the organelles and
molecules required for cell division are produced.
c. When the events of the G2 Phase are complete, the
cell is ready to enter the Mitosis and cytokinesis
phases, and begin the process of cell division.
Section 1: The Cell Cycle (1) 5

6. Section 1: The Cell Cycle (1) 6

7. Cell Cycle: Time breakdown
Section 1: The Cell Cycle (1) 7

8. Duplication of Chromosomes
Section 1: The Cell Cycle (1) 8

9. I. Cell Cycle
D. Mitosis- Biologists divide the events of Mitosis into four
phases: prophase, metaphase, anaphase, and telophase;
Mitosis is the process in which the nucleus divides to form two
identical nuclei.
1. Prophase- First and longest phase of mitosis.
a. Chromosomes become visible.
b. Centrioles separate and locate on opposite sides of the
nucleus.
c. Between the centrioles threadlike spindle fibers begin to
stretch across the cell.
d. Nuclear membrane and nucleolus fade and disappear.
Section 1: The Cell Cycle (1) 9

10. Section 1: The Cell Cycle (1) 10

11. Section 1: The Cell Cycle (1) 11
2. Metaphase
a. The chromosomes
line up across the
center of the cell.
b. Each chromosome is
connected to a
spindle fiber at its
centromere.

12. Section 1: The Cell Cycle (1) 12
2. Anaphase
a. Each centromere
divides.
b. The two strands of
each chromosome
separate.
c. The separate strands
begin to move
towards opposite
ends of the cell.

13. I. Cell Cycle
D. Mitosis- (Continued)
4. Telophase
a. The final step of mitosis.
b. Centrioles and spindle fibers
start to disappear.
c. Chromosomes stretch out and
become harder to see.
d. Nuclear membrane form
around each mass of
chromosomes.
e. New nucleolus appears in each
nucleus.
Section 1: The Cell Cycle (1) 13

14. I. Cell Cycle
E. Cytokinesis
1. Cell membrane pinches the
cytoplasm in half.
2. Each daughter cell has an
identical set of duplicate
chromosomes.
a. In plants, a structure
known as the cell plate
forms midway between
the divided nuclei.
b. The cell plate gradually
develops into a
separating membrane.
c. A cell wall then begins to
appear in the cell plate.
Section 1: The Cell Cycle (1) 14

15. I. Cell Cycle
F. Results of Mitosis
1. Mitosis is the division of the nucleus, it produces
two nuclei that are identical to each other and
the original nucleus.
2. Each cell in your body, except sex cells, has a
nucleus with 46 chromosomes, 23 pairs.
3. All of your cells use different parts of the same
hereditary material to become different types of
cells. (see pg 100 in your book)
Section 1: The Cell Cycle (1) 15

16. I. Cell Cycle
F. Results of Mitosis
4. Mitosis allows growth and replaces worn
out or damaged cells.
a. If you cut yourself, the wound heals because
cell division replaces damaged cells.
b. You are much larger and have more cells than
a baby mainly because of cell division.
Section 1: The Cell Cycle (1) 16

17. Cell Type Life Span Cell Division
Lining of Esophogus 2-3 days Can divide
Lining of small intestine 1-2 days Can divide
Large Intestine 6 days Can divide
Red Blood Cells Less than 120 days Cannot divide
White Blood Cells 10 hours to decades Cannot divide
Smooth Muscle Long lived Can divide
Cardiac Muscle Long lived Cannot divide
Skeletal Muscle Long Lived Cannot divide
Neuron (nerve cell) Long Lived Cannot divide
Section 1: The Cell Cycle (1) 17

18. II. Asexual Reproduction
A. Asexual Reproduction
1. There are two types of reproduction.
a. Asexual reproduction
b. Sexual reproduction
2. In asexual reproduction, a new organism
(sometimes more than one) is produced from
one organism.
a. The new organism will have hereditary material
identical to the hereditary material of the parent
organism.
b. How many organisms are needed for asexual
reproduction?
i. One
Section 1: The Cell Cycle (1) 18

19. II. Asexual Reproduction
A. Asexual Reproduction
3. Your body forms two types of cells.
a. Body Cells
i. Skin, liver, muscle, etc.
ii. Your body has far more body cells than sex cells.
b. Sex Cells
i. Eggs and sperm found in reproductive organs.
c. Reproduction is the process by which an organism
produces others of the same kind.
d. Mitosis is an example of asexual reproduction.
i. The DNA of the offspring (new cell) is identical to the parent.
Section 1: The Cell Cycle (1) 19

20. II Asexual Reproduction
B. Cellular Asexual
Reproduction
1. Organisms with
eukaryotic cells (have a
nucleus) asexually
reproduce by cell
division. (mitosis)
a. New strawberry plants
can be reproduced
asexually from
horizontal stems called
runners.
Section 1: The Cell Cycle (1) 20

21. II Asexual Reproduction
B. Cellular Asexual
Reproduction
Section 1: The Cell Cycle (1) 21

22. II. Asexual Reproduction
B. Cellular Asexual Reproduction
2. Bacteria do not have a nucleus, so they
cannot use mitosis.
a. Instead bacteria reproduce asexually by
fission; fission is a type of asexual
reproduction where an organism splits into
two equal parts.
b. During fission, an organism whose cells do not
contain a nucleus copies its genetic material
and then divides into two identical organisms.
Section 1: The Cell Cycle (1) 22

23. II. Asexual Reproduction
B. Cellular Asexual
Reproduction
3. Budding
a. Budding is a type of
asexual reproduction in
which a new organism
grows from the body of
the parent organism.
b. When the bud on the
adult becomes large
enough, it breaks away
to live on its own.
Section 1: The Cell Cycle (1) 23

24. II. Asexual Reproduction
B. Cellular Asexual Reproduction
4. Regeneration – The process that uses cell
decision to re-grow body parts.
a. Sponges, planaria, sea stars, and some other
organism can use regeneration for asexual
reproduction.
b. Because sea stars eat oysters, oyster farmers dislike
them.
Section 1: The Cell Cycle (1) 24

25. Section 1: The Cell Cycle (1) 25