Happy Monday Buffs!! 11/2/15
BELLWORK: WRITE DOWN THE ESSENTIAL QUESTION
FOR TODAY.
ESSENTIAL QUESTION:
HOW AND WHY DOES A CELL DIVIDE?
STANDARD: 5A THE STUDENT WILL BE ABLE TO
DESCRIBE THE STAGES OF THE CELL CYCLE, INCLUDING
DEOXYRIBONUCLEIC ACID (DNA) REPLICATION AND
MITOSIS, AND THE IMPORTANCE OF THE CELL CYCLE
TO THE GROWTH OF ORGANISMS
Cell Cycle Video...
CELL CYCLE: series of events that cells
go through to grow and divide
• The cell cycle is used for the growth and
repair of organisms.
• Made up of two main sections: Interphase &
Mitosis
INTERPHASE:
• Majority of a
cell’s life
• Includes 3 phases
(G1, S, G2)
G1 phase: grow, make proteins,
make new organelles
Label the G1 phase on your diagram:
G1 phase
S phase:
DNA is
replicated;
longest part
of
interphase
Label the S phase on your diagram:
G1 phase
S
phase
Reminder…
WHY does the DNA have to
replicate before the cell divides?
G2 phase:
organelles &
proteins required
for division are
produced
When G2 is complete, the
cell is ready to divide.
Label the G2 phase on your diagram:
G1 phase
S
phase
G2 phase
Checkpoints:
points when the cell checks for problems
Sometimes the cell has
problems it can’t fix.
Problems in the cell
cycle can lead to
cancer.
We’ll talk about that
more next week.
Label the checkpoints on your diagram:
G1
phase
✔ DNA damaged?
Cell big enough?
All chromosomes
aligned?
✔
S
phase
G2
phase
✔
DNA replicated?
Cell big enough?
DNA damaged?
CELL DIVISION: process where a cell grows and
divides into TWO identical daughter cells
The last two parts of the cell cycle are
M phase (mitosis)
and
Cytokinesis
MITOSIS (M phase):
division of the cell’s
nucleus
*divided into FOUR PHASES:
prophase,
metaphase,
anaphase, and
telophase
*PMAT*
PROPHASE: chromosomes become visible, the
centrioles separate to opposite sides of the cell, the
chromosomes attach to the spindle, the nucleolus
disappears, nuclear envelope breaks down
DRAW THIS!
The centrioles are
two tiny structures
located in the
cytoplasm that help
organize the
spindle.
The spindle is a
fanlike microtubule
structure that helps
separate the
chromosomes.
METAPHASE:
chromosomes line
up along the
equator (center) of
the cell
DRAW THIS!
ANAPHASE: the centromeres
joining the sister chromatids
split; chromosomes move away
to opposite sides of the cell,
near the poles of the spindle.
TELOPHASE: chromosomes begin to disperse; nuclear
envelopes reappear to form two new nuclei
(nuclei = more than 1 nucleus)
Cell division is not complete after telophase! Then comes…
CYTOKINESIS: division of the cytoplasm;
two identical cells are produced
• Fold your paper windowpane style (writing on the
inside).
• Write Interphase on the
left and Mitosis on the
right.
Debrief:
Answer your essential
question
• I’m coming around to stamp “good answers”
–Good answers: Are in complete sentences;
explain how and why; aren’t copied from the
notes.
Partners:
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5th period
Arianna and Kyle W.
Reaven and Alexis R.
Dustin and Alina
Alex and Joceline
Claudia and Romeo
Eliezer and Alyssa
Stegia and Kayli
Lui and Brianna
Izreal and Angel
Marcus and Fausto
Maleny and Haley
Ariel and Cindy
Kyle M. and Matthew
Anyjah