Grade/Subject
Liberty Middle School – EDI 2013
LO:
Students will be able to explain and diagram the
phases1
of the cell cycle.
1 Phases
- The steps in a
process.
Concept Development:
The cell cycle describes the growth, development, and reproduction of a cell.
Skill Development/Guided Practice:
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.
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 phase, 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 replicates2 organelles during this phase1 of interphase.
1
Grade/Subject
Skill Development/Guided Practice:
Liberty Middle School – EDI 2013
1Phases
– The steps in a
process
2Replicate
- make an
identical copy
Phases of Mitosis
Prophase:
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.
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.
Anaphase:
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.
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.
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.
Relevance:
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!
2
Grade/Subject
Liberty Middle School – EDI 2013
1) Use the guide below to draw each phase of cellular reproduction. Draw a box around
and label the steps that together make up mitosis.
2) What are the 3 phases of the cell cycle?
3) Why is it important that the DNA replicates during interphase?
4) Explain what happens during each phase of cellular reproduction.
Interphase:
Prophase:
Metaphase:
Anaphase:
Telophase:
Cytokinesis:
5) How is mitosis different from cytokinesis? If cytokinesis failed to happen what would be
the outcome for the cell?
3
Grade/Subject
Liberty Middle School – EDI 2013
Closure / Exit Ticket:
In your own words, explain why
cellular reproduction is important
to organisms.
In your own words, explain why
cellular reproduction is important
to organisms.
In your own words, explain why
cellular reproduction is important
to organisms.
In your own words, explain why
cellular reproduction is important
to organisms.
In your own words, explain why
cellular reproduction is important
to organisms.
In your own words, explain why
cellular reproduction is important
to organisms.
4
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
5