The Cell Cycle

The Cell Cycle & Types of Reproduction

SWBAT - Determine stages of cell life based on cell cycle

SWBAT - Compare and contrast sexual and asexual reproductive methods.

Suppose you had a papercut on your finger. Although the cut may have bled and stung a little, after a few days the cut may have completely healed. Consider:

• How do you think your body repairs and injury such as a cut?

• How long do you think this repair process continues?

• What do you think causes cells to stop the repair process?

Open Ended

How do you think your body repairs an injury, how long may it take, and what causes cells to stop the repair process?

Our cells divide for the following reasons:

• Maintain size

• Help our bodies grow

• Heal our injuries

• Replace worn-out cells

Multiple Select

Which stages of the cell cycle are part of interphase (select all that apply)

• G1

• G2

• S phase

• M phase

The Cell Cycle

• There are 2 main stages in a cell's life:

• Interphase, where the cell grows, carries out cellular functions, and replicates its DNA

• Division, where the cell divides in 2

• G1, S & G2 make up Interphase

• M stands for Mitosis, which is cellular division

Interphase - Stage G1

• This is the FIRST stage of interphase

• The cell is growing, carrying out normal functions, and preparing for replication of its DNA

Multiple Choice

What is the first stage of interphase?

• G1 phase

• S phase

• G2 phase

Interphase - Stage S

• The "S" stands for synthesis

• At this stage the cell copies its DNA in preparation for cell division

• **remember that "synthesis" means "to make", so in stage S, DNA is being made.

Poll

What does the S stand for in stage S and why?

• synthesis, because DNA is being replicated

• synthesis, because new cells are being made

• synesthesia, because DNA is being replicated

• stenography, because DNA is being translated

Interphase - Stage G2

• DNA has already been replicated

• Continued cell growth

• The cell prepares for division of its nucleus

Now we've come to the M phase, where the cell actively divides

• There are 2 main stages in a cell's life - interphase and division

• During Mitosis (M phase) the cell's nucleus and nuclear material divide

• Mitosis happens in 4 phases: Prophase, Metaphase, Anaphase, and Telophase

Multiple Choice

How many phases does the M-phase of the cell cycle contain?

• 1

• 2

• 3

• 4

Cytokinesis

• Cyto = cell/cytoplasm

• kinesis = motion

• cytokinesis = the cytoplasm of the cell divides, creating a new cell

• At the end of the M-phase, cytokinesis occurs, resulting in 2 cells

Multiple Choice

What occurs during cytokinesis?

• The cell's nucleus divides, creating 2 new cells

• The cell's cytoplasm divides, creating 2 new cells

Abnormal Cell Cycle: Cancer

• Cancer is the uncontrolled growth and division of cells

• Cancer can be due to mutations or environmental factors

Multiple Choice

Which is NOT a phase of the cell cycle?

• cytokinesis

• interphase

• apoptosis

• mitosis

Multiple Choice

At what stage does a cell spend most of its life?

• cytokinesis

• interphase

• mitosis

• synthesis

Multiple Choice

What happens during cytokinesis?

• The cell grows and carries out normal functions

• The cell copies its DNA and forms chromosomes

• The cell's nucleus and nuclear material divide

• The cell's cytoplasm divides

Multiple Choice

What happens during the S phase?

• DNA is replicated so the cell can divide in the M phase

• DNA is replicated so the cell can divide in the G2 phase

• RNA is transcribed so the cell can divide in the M phase

• DNA is translated into proteins for the cell to use

Now that we know our cells divide, it's time to learn about types of reproduction!

• There are 2 main types of reproduction

• Sexual reproduction

• Asexual reproduction

Open Ended

What are the 2 main types of reproduction?

Sexual Reproduction

• 2 parents are required to mate

• Cells divide by Meiosis (sex cell division, resulting in 4 cells with 1/2 the usual amount of chromosomes each)

• Advantages: genetic variation (offspring and parents don't have the same exact DNA)

• Disadvantages: requires 2 organisms, requires more energy

Multiple Choice

How many organisms are required to reproduce sexually?

• 1

• 2

• 3

• 4

Asexual Reproduction

• Only one parent is needed

• Reproduce through budding, binary fission, or regeneration

• Advantages: time efficient (don't have to search for mate), takes less energy

• Disadvantages: no genetic variation

Open Ended

Why do you think no genetic variation between parent and offspring would be a disadvantage?

On the next slide, you will watch an amoeba sisters video.

Open your assignment for today to get some answers!