Q4 Lesson 2: Cell Cycle and Mitosis

LESSON 2:

CELL CYCLE

AND MITOSIS

Pre- Activity:

Cell Cycle and Mitosis

(10 mins)

(see canvas modules)

Cell Cycle
and Mitosis

CELL CYCLE:
The Checkpoint of Life

A regular pattern of
GROWTH , DNA
DUPLICATION, & CELL
DIVISIONthat occurs in
eukaryotic cells.

G2

MITOSIS

S

The first gap phase.
The cell increasesin mass in
preparation for cell division.

For most cells, this is the
longest phase.

G1 phase or
first gap

KARYOTYPE

WHERE DID YOUR
CHROMOSOMES COME
FROM?

23 CHROMOSOMES (MOTHER)
23 CHROMOSOMES (FATHER)

TOTAL:
23 PAIRS OR 46 CHROMOSOMES
IN EVERY CELL IN YOUR BODY
(except in your gametes)

DNA is synthesized or
replicated.

S phase
or
Synthesis

Each of the 46
chromosomes is
REPLICATED by
the cell.

= 92
chromatids

Second gap phase.
The cell synthesizes
proteins and continues
to increase in size.

G2 phase or
second gap

“DOUBLE CHECKS”
the duplicated chromosomes
for error, making any needed
repairs.

MITOSIS

A process of nuclear division.
The most dramatic
biological processes.
It has four stages:
PROPHASE,
METAPHASE,
ANAPHASE, &
TELOPHASE.

Also, a process
where
single cell divides into
two identical daughter
cells.

The major purpose of
mitosis is for growth
and replace worn out
cells.

PHASES OF

MITOSIS

PROPHASE

The
NUCLEAR
MEMBRANE
is beginning to disappear.

CHROMOSOMEScondense
and become visible.

CENTRIOLESmove to opposite
poles and
SPINDLE FIBERSbegin to
form.

METAPHASE

Thick, coiled
CHROMOSOMESare
lined up in the
center of the cell
(equatorial plate).

The SPINDLE FIBERS
are attached to the
chromosomes

ANAPHASE

Sister chromatids of each
chromosome
separate and are being
pulled by spindle fibers
and moving to the ends of
cell as their
kinetochore
microtubulesshorten

Each chromatid
becomes
an individual
chromosomes.

TELOPHASE

The chromosomes
cluster and decondense
at the opposite poles.

The spindle fibers
dissolve and
a nuclear
membrane forms

The physical process of cell
division, which divides the
cytoplasm of a parental
cell into TWO daughter
diploid cells (46 chromosomes).

CYTOKINESIS

In animal cells, a cleavage
furrow forms when cell
divides.

CYTOKINESIS

In plant cells, a cell
plate forms when cell
divides.

At the end of S phase,
92 CHROMATIDS

46
CHROMATIDS or
CHROMOSOMES
in each cell

At the end of
Mitosis,
TWO IDENTICAL
CELLS

What will happen when a
significant event in a
particular stage failed to occur?

What Happens When Mitosis Goes Wrong?

By Scott Auerbach, March 13, 2018

When a cell divides, it creates two identical

daughter cell’s DNA - the name for this process is
Mitosis, and errors in the process result in incorrect DNA
copies. The effects of these errors in the health of the
organism range from benign to deadly, depending in
their number of errors and type. One potential
consequence is cancer; scientist trace all cancer types
back to harmful mutations multiplied by mitosis.

Cancer occurs when mutated cells ignore or

override the normal “checkpoints” regulating mitosis
and begin to reproduce uncontrollably.

How can the production of
cancer cells be avoided

G1
S Phase
G2

The cell cycle is
controlled mainly by
regulatory proteins.
These proteins control
the cycle by signaling
the cell to either start or
delay the next phase of
the cycle.

DNA replication

uncontrollable growth or production of
cancer cells

​Mitosis

or NUCLEAR CELL
DIVISION

It has four stages:
PROPHASE,
METAPHASE,
ANAPHASE, &
TELOPHASE.

It divides the
cytoplasm of a
parental cell into
TWO daughter
diploid cells

It consists the following
phases:

*G1 or first gap
(cell increases in size)

*S phase
(DNA synthesis)

*G2 or second gap
(double checks)

Multiple Choice

During which phase of the cell cycle does a cell copy its DNA?

• S phase

• G2 phase

• Interphase

• G1 phase

Match

Read the following events and match them to their respective phase of mitosis

• nuclear membrane form again around chromosomes.

• Thick, coiled chromosomes are lined up in the center of the cell (equatorial plate)

• The nuclear membrane is beginning to disappear. Chromosomes are condensed and thicken.

• The chromatids of each chromosome have separated, and the daughter chromosomes are moving to the ends of cell as their kinetochore microtubules shorten.

Telophase

Metaphase

Prophase

Anaphase

• Telophase

• Metaphase

• Prophase

• Anaphase

Reorder

Arrange the following events in a way that shows a sequential order during the process of mitosis.

• The nuclear membrane starts to disappear

• The chromosomes are lined up at the center of the cell

• Each sister chromatid starts to separate.

• The spindle fibers dissolve, and nuclear membrane starts to reappear

• The cleavage furrow is visible and about to form two diploid cells.

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

LABORATORY CLASS (next pd)
For roomies:

Hands-on Activity (Under the Microscope)

For zoomies:

Whitefish and Onion Interactive

Announcement:

SUMMATIVE ASSESSMENT 1 on Week 3

Topics:

Lesson 1: Organelles Involved in Cell Division
Lesson 2: Cell Cycle & Mitosis:
Prophase, Metaphase, Anaphase, Telophase