Transcript The Cell Cycle

Grade/Subject
Liberty Middle School – EDI 2013
1 Phases
LO:
- The steps in a process.
Students will be able to explain and diagram the phases1 of the
cell cycle.
APK:
Last unit we learned about the cell theory and cell organelles, including the nucleus.
Connect APK to LO:
Students, you already know that all cells come from preexisting cells. Today, we will learn
how that happens.
CFU: What are the statements of the cell theory?
CFU: What is the function of the nucleus?
1
Grade/Subject
Liberty Middle School – EDI 2013
Concept Development:
1 Phases
- The steps in a process.
The cell cycle describes the growth, development, and reproduction of a cell.
The phases1 of the cell cycle are:
Phase 1: Interphase
Phase 2: Mitosis
Phase 3: Cytokenisis
How does
one single
cell
become a
complex
organism,
like a
human?
2
Grade/Subject
Skill Development/Guided Practice:
Foldable
Liberty Middle School – EDI 2013
2replicate
– make an identical copy
The Cell Cycle:
You’ll spend most of your life growing and developing. Only a small portion of a human’s life cycle is spent in the
reproductive phase1. The same is true for cells. The cell cycle describes the growth, development, and reproduction of a
cell. The phases1 of the cell cycle are: interphase, mitosis, and cytokinesis.
What is the cell cycle?
The cell cycle describes the
__________________,
growth, development , and
__________
reproduction_ of a cell.
CFU
What are the 3 phases of the cell cycle?
Interphase
Mitosis
Cytokinesis
CFU
Interphase:
A cell performs specific functions during interphase. During interphase, the chromosomes in the nucleus are like a
bunch of thin spaghetti noodles. Each chromosome is so thin that it cannnot be observed with a light microscope.
The three phases1 of interphase are G1, S and G2. During G1 phase1, a cell grows and carries out its usual cellular
functions. For example muscle cells are using oxygen and glucose to produce ATP necessary for your body to move.
Growth continues into S phase1. During S, the chromosomes inside a cell’s nucleus replicate2. The copies of a
chromosome made during S phase1 are called sister chromatids. Sister chromatids are held together at a region near the
middle of each chromatid called the centromere. The replication2 of chromosomes during S phase1 ensures that the two
new cells formed by cell division are identical.
A cell continues to grow and carry out cellular functions during the final G2 phase1. It also replicates organelles during
this phase of interphase.
*During G1 phase a cell _____
grows and
__________________________
carries out its cellular functions.
*During S phase chromosomes _______
replicate
and ______________
sister chromatids form.
*During G2 phase ________
organelles replicate.
CFU
3
Grade/Subject
Liberty Middle School – EDI 2013
Skill Development/Guided Practice:
2replicate
– make an identical copy
Prophase:
Phases of Mitosis:
The first phase1 of mitosis is prophase. Two major events happen during prophase. First, the DNA that makes up
a replicated2 chromosome twists into tight coils. The other major event during prophase is that the membrane
around the nucleus breaks apart.
The ___
first phase of mitosis is prophase. The
DNA of the ___________
chromosome twists into tight
coils. The _________
membrane around the _______
nucleus
breaks apart.
_
CFU
Metaphase:
During the second phase1 of mitosis, metaphase, the replicated2 chromosomes move to the middle of the cell .
The pairs of sister chromatids line up end to end across the center of the cell. Hair-like spindle fibers pull and push
the chromosomes to the middle of the cell.
What is the cell cycle?
The ________
replicated chromosomes and ____
sister
chromatids line
__________
lineup
upatatthe
thecenter
centerofofthe
thecell.
cell.
Spindle fibers
________
__ push
pushand
andpull
pullthe
thechromatids
chromatids
into position.
CFU
4
Grade/Subject
Skill Development/Guided Practice:
Liberty Middle School – EDI 2013
2replicate
– make an identical copy
Anaphase:
Phases of Mitosis:
In the third phase1, anaphase, the sister chromatids of each replicated2 chromosome begin to separate. The
spindle fibers pull the centromere apart and chromatids move away from each other, toward opposite ends of the
cell. Now the chromatids are called chromosomes.
The replicated chromosomes begin to
separate. Spindle fibers ______________
pull chromatids to
opposite ends of the cell.
_____________________.
CFU
Telophase:
The final phase1 of mitosis is telophase. During telophase, a new membrane forms around each set of
chromosomes. The chromosomes become less tightly coiled. At the end of telophase, there are two new nuclei
that are identical to each other and the original nucleus. However the cell has not divided.
A membrane forms around each set of
chromosomes and they __________
become less
tightly coiled. Two
___________.
________________are
identical nuclei are
formed.
CFU
5
Grade/Subject
Skill Development/Guided Practice:
Liberty Middle School – EDI 2013
2replicate
– make an identical copy
Cytokinesis:
Cytokinesis is the final phase1 of cell division. During cytokinesis, the cytoplasm and its components divide to form two
identical cells called daughter cells. During cytokinesis the cell membrane squeezes inward similar to squeezing the
middle of a balloon.
Cytokinesis is the final phase of cell
division. The cell membrane squeezes
inward dividing the cell into ___________
two identical
_____________.
daughter cells.
CFU
6
Grade/Subject
Liberty Middle School – EDI 2013
Relevance: So why is knowing about mitosis important??
1. Understanding mitosis provides us with a mechanism (the how)
behind organisms evolving from unicellular to multicellular
organisms.
2. Understanding mitosis provides a foundation for meiosis
(next lesson).
3. Science jokes are awesome!
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Grade/Subject
Liberty Middle School – EDI 2013
Closure / Exit Ticket:
Type in your closure task here.
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Grade/Subject
Liberty Middle School – EDI 2013
Do Not Print For Students
Delivery Strategies Legend – Consider putting these symbols as reminders to use the
strategies at first.You can delete them as you get used to the pattern of the delivery.
Word Transfer
T
S
T/S
PS
NV<3>
V
PS<SF>
CFU
CFU
WB
Ex. “When I say determine, you say figure out. When I say figure out, you say determine”
Teacher pre-reads
Students read
Teacher and Students read
Pair Share on a higher order question
Non-volunteer, about 3 students
Take a Volunteer
Pair Share on a higher order question and give them a sentence frame
Ask a higher order question to check for understanding
(in the Skill Development) Asking a process question may not be necessary
Students use a whiteboard for short response
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