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

Happy Monday Buffs!! 11/2/15

Cell Cycle Video...

• The cell cycle is used for the growth and repair of organisms.• Made up of two main sections: Interphase &

Mitosis

CELL CYCLE: series of events that cells go through to grow and divide

•Majority of a cell’s life• Includes 3 phases

(G1, S, G2)

INTERPHASE:

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

Sphase

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

Sphase

G2

phase

✔

✔

✔

Cell big enough?

DNA damaged?

DNA replicated?Cell big enough?

DNA damaged?

All chromosomes aligned?

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

ANAPHASE: the centromeres joining the sister

chromatids split; chromosomes move away to opposite

sides of the cell, near the poles of the spindle.

DRAW THIS!

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 window-pane 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: 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