7th grade
Section 1
Essential Questions
Cell Division
1. Why is it important  Cell division deals with coping a cells DNA and dividing the cell in two identical
for a cell to copy its
halves.
hereditary
 Cell cycle: Is the life of the cell. It includes growth of the cell and all the steps
information before
through division.
dividing?
 Interphase is the first and longest part of the cell cycle. And has three stages
o G1: Cell Grows and organelles duplicate
2. What would
o S: DNA is Copied, Chromosomes duplicate (Synthesized)
happen if oyster
o G2: Cell grows and prepares for division
farmer collected sea
 Muscle and Nerve cells do not undergo division they are constantly in
stars, cut them into
interphase. Skin cells are constantly dividing so they undergo the entire cell
pieces, and threw
cycle.
them back into the
 Before a cell divides, copy of hereditary material must be made so that each of
ocean?
the two new cells will get a complete copy of the instructions for what the cell is
suppose to do to carry out life functions.
3. How does mitosis
 After interphase, cell division begins. The nucleus divides and the cytoplasm
differ in plants and
separates to form two new cells.
animals?
 Mitosis: the process in which the nucleus divides to form two identical nuclei.
Each nucleus is identical to the original nucleus. Mitosis is describes through a
4. How is the
series of stages: Prophase, Metaphase, Anaphase, and Telophase
difference between a  During division chromosomes play an important part. Chromosomes are a
chromosome and
structure in the nucleus that contains DNA. During Interphase Chromosomes
chromatid?
duplicate and when its time for the cell to divide the chromosomes coil up into
two tightly packed strands called Chromatids and then are separated.
5. Be able to identify
 Prophase: The chromatid pairs are now visible and the spindle fibers are
each phase based on
beginning to form from the centrioles in animal cells. Spindle fibers attach to the
description and
cell wall in plant cells.
image.
 Metaphase: the chromatid pairs are lined up in the center of the cell and the
spindle fibers attach to the centromere. The fibers are on opposite sides of the
6. Describe the
cells.
structure of sister
 Anaphase: the centromere divides and the spindle fibers pull the chromatids to
chromatids.
opposite ends of the cell. The separated chromatids are now called
chromosomes.
7. What is vegetative
 Telophase: the spindle fibers disappear, the chromosomes start to uncoil and
propagation? Provide
the two new nuclei start to form.
an example.
 During cell division in animal cells the cytoplasm separates and the cell begins
to pinch creating a cleavage or furrow. In a plant cells a new cell plate (wall) is
8. What are some
built between the two new nuclei.
examples of
 The final separation of the two new cells is called Cytokinesis.
organisms that
There are 3 important facts about Mitosis
undergo budding and
 1. Mitosis is the division of a nucleus.
regeneration?
 2. It produces two new nuclei that are identical to each other and the original
nucleus. The two new cells are called daughter cells and the original cell is called
9. What type of cell
the parent cell.
division do bacterium
 3. The original cell no longer exists
undergo?
7th grade
10. How do the
daughter cells
compare to the
parent cells during
mitosis and asexual
reproduction?
11. How many
chromosomes does a
normal human cell
contain?
Section 1
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Images:
Cell division allows growth and replaces worn out or damaged cells.
Except for sex cells each normal human cell contains 46 chromosomes.
Asexual reproduction: a new organism is produced from one organism. The new
organism’s DNA is identical to the parent’s DNA. (Strawberries like many fruit
plants and weeds undergo a special type of asexual reproduction called
vegetative propagation.)
Since bacteria do not have a nucleus they do not undergo mitosis. Instead the go
through Binary Fission. This is where one bacteria’s DNA is copied and divides
into two new bacteria.
Hydra reproduces by budding. Budding is a type of asexual reproduction made
possible because of mitosis. When the bud on the adult becomes large enough, it
breaks away to live on its own.
Some organisms can regrow damaged or lost body parts. Regeneration is the
process that uses mitosis to regrow body parts.