Download Lesson 3.1– CELL CYCLE AND CELL DIVISION

Lesson 3.1– CELL CYCLE AND CELL DIVISION (NB p. 106-108)
Explain the cell cycle:
It’s the cycle of growth, development and division that all living cells go through.
Organize the information about the 2 main phases of the cell cycle.
Interphase – longest phase, where cell grows, organelles and DNA are duplicated in preparation of cell division
Mitotic phase – shorter phase, where nucleus divides and cell splits into two identical daughter cells.
Complete the sentence:
The length of a cell cycle depends on the type of cell it is, because eukaryotic cells (the only cells that undergo mitosis –
the division of the nucleus) are specialized and contain different types and numbers of organelles.
Represent the relative length of each stage of interphase by labeling the time line:
|__________________G1____________________|________S_______|_____G2______|
Describe each stage of interphase:
G1 – the first stage of interphase when the cell grows and functions according to its specialization; organelles are
beginning to be copied.
S - the second stage of interphase when most cell organelles and the DNA are replicated in preparation for cell division;
the two strands of DNA are called sister chromatids; the cell still continues to function according to its specialization
G2 - the third stage of interphase when the copied DNA is organized around sister chromatids that bound together as
chromosomes; the cell continues to function according to its specialization
True or False – Organelle replication occurs only during the S stage of interphase (false – it begins in the G1 phase)
Organize information to describe the stages in the mitotic phase of the cell cycle:
Mitosis - the part of the cell cycle when the nucleus divides.
Cytokinesis - the final part of the cell cyclewhere the cytoplasm and cell contents divide and the parent cell splits,
resulting in 2 identical 'daughter' cells
Identify each stage of mitosis:
Prophase – the stage of mitosis when DNA is condensed into chromosomes and the nuclear membrance dissolves
Metaphase – the stage of mitosis when the chromosomes line up in the center of the cell
Anaphase – the stage of mitosis when the chromosomes split and are pulled to opposite sides of the cell
Telophase – the stage of mitosis when new nuclear membranes form around the separated chromosomes and the cell
begins to pinch or divide into 2 separate cells
Describe cytokinesis in plant and animal cells:
In animals, the cell membrane contracts around the middle of the cell until the cell pinches in two.
In plants, a cell plate forms in the middle of the parent cell that grows outward to the cell wall and two new daughter cells
form.
Summarize the 4 results of the cell cycle:
1.
2.
3.
4.
Reproduction – in some unicellular organisms, cell division is a form of reproduction.
Growth – allows multicellular organisms to grow from one cell to many
Replacement – replaces worn-out or damaged cells with new cells
Repair – cell division can also repair damage by producing new cells
Not all cells can be repaired – nerve cells stop the cell cycle in interphase and do not divide, so that nerve damage is often
permanent
Apply what you have learned to explain what probably happened when the bean plant grew overnight in Jack and the
Beanstalk.
The seeds must have germinated and began rapid cell division, producing an unprecedented giant beanstalk in a few hours
(not possible, making this story fiction)