Italicized font represents information to be shared orally or physically completed with the students at this time.

The non-italicized font represents additional information included to support the teacher’s understanding of the content being introduced within the CELL.

ASK WHY

Remind students that all cancers begin in cells, the body’s basic unit of life and, to understand cancer, it’s helpful to know what happens when normal cells become cancer cells. By completing this core experience learning lab, students will gain insight into the transition from healthy to abnormal cells. They will also gain awareness about this disease. Early awareness saves lives.

BRANCH OUT

Remind students that oncology specialists perform a wide variety of diagnostic procedures to ascertain the condition of tissues and to detect cancer. Diagnostic procedures include scanning techniques, such as x-ray and magnetic resonance imaging, as well as surgical operations and biopsies. They also devise treatment options which include chemotherapy, radiation therapy, and the surgical removal of cancer.

GET FOCUSED

Inform students that the Investigation is designed to help them to answer the following Focus Questions:

• How do tissues replenish the cells contained within them? Tissues replenish cells through cell division. Cell division has four phases, G1, S, G2, and M phase.

• What controls the process of cell division? The cell cycle is regulated by different proteins.

Note: These questions are located in students’ SDRs at the beginning and end of the Investigation.

Note: These are succinct responses to the Focus Questions and are placed here for your reference at this time. Fu

GO DEEPER

As a class, read the Background(s) in the Investigation. Have students read the information aloud or silently to themselves. When students have finished, discuss the following concepts as a class:

• Cells within the body are produced from other cells in a process called cell division.
• This process requires that the original (parent) cell copies all of its contents, including DNA and organelles, and splits these materials evenly into two new (daughter) cells.
• In this way the cell has made an exact copy of itself.
• Too much or too little cell division interferes with normal tissue function.
• The process that controls cell division is called the cell cycle.
• The cell cycle is an ordered set of events that results in cell division – the production of two identical cells from a single parent cell.
• The cell cycle can be broken down into 4 distinct phases:
  • 1. G1 or GAP phase
  • 2. S or DNA synthesis phase Interphase
  • 3. G2 or GAP2 phase
  • 4. M or Mitosis phase
• During the G1 phase, the cell produces proteins and grows in size. The G1 phase ends when the cell has reached a certain size.
• Then, the S phase, or DNA synthesis phase, begins. During this phase the cell will make an exact copy of the DNA contained in the cell nucleus through DNA replication. At the end of the S phase, each chromosome inside the nucleus of the cell consists of 2 identical sister chromatids.
• Next, the G2 or GAP 2 phase occurs. During this phase the cell has very little activity.
• Finally, the M phase, or Mitosis phase, occurs. During this phase, the sister chromatids produced in the S phase are separated and cell division (cytokinesis) occurs. 
• The M phase or Mitosis phase of the cell cycle is made up of four distinct stages. These stages are:
  • 1. Prophase
  • 2. Metaphase
  • 3. Anaphase
  • 4. Telophase.
• When a cell is not in one of these stages it is said to be in interphase.
• Mitosis begins with prophase. In prophase, the chromosomes, which each contain sister chromatids produced in the S phase of the cell cycle, condense in the nucleus of the cell. At this stage, the nuclear membrane dissolves. The cell then enters metaphase.
• During metaphase, the duplicated chromosomes line up on the spindle fibers in the center of the cell.
• The cell then enters anaphase, in which the sister chromatids separate and move down the spindle fibers to the opposite ends of the cell.
• Finally, during telophase, the chromatids have moved to the ends of the spindle fibers. The spindle fibers disappear and new nuclear membranes form around each set of chromosomes. At this point, the cytoplasm splits in half and cell division (cytokinesis) occurs.
• The length of time for a cell to complete one full cell cycle (from one phase of mitosis to the next) varies depending on cell type.
• The length of time of the full cycle varies primarily in the G1 (GAP1) phase. Cells can stay in the G1 phase for up to 1 year.
• Control of the cell cycle occurs through specific proteins which are translated from specific genes in the cells DNA. When the cell makes these proteins they allow the cell to transition into the next phase of the cell cycle. These proteins induce or turn on the cell cycle.
• There are also genes that code for proteins that block the cell from moving into the next phase of the cell cycle. These proteins inhibit or stop the cell cycle.
• It is the balance of these cell cycle inducing and inhibiting proteins that control the cell cycle.
• Different cell types have different amounts of these proteins and therefore different lengths of time that they will stay in each phase of the cell cycle. 

Note: These concepts are integrated into the Background(s) and are used to deepen students’ comprehension of the big ideas.

LEARN THE LabLearner LINGO

The following list includes Key Terms that are introduced in the Investigation Background(s). They should be used, as appropriate, by teachers and students during everyday classroom discourse.

• cell division
• cell cycle
• mitosis
• chromosome
• chromatid

Note: Definitions of these terms can be found on the Introduction page to the CELL.

Note: Additional words may be bolded within the Background(s). These words are not Key Terms and are strictly emphasized for exposure at this time.

SET FOR SUCCESS

• Direct students to complete the Recall section in their SDRs. Student answers may vary.

• How do cells multiply?
• Do cells continue to multiply without any kind of controls?

• Play the video below. Stop to ask students questions or answer students’ questions when necessary. Remind students to follow along with their SDRs and make any notes that they think might be helpful.
• After the video, direct students to divide into their lab groups to discuss their strategy for the lab. For example, they may assign certain group members to perform specific functions during the lab.

Note: The purpose of the video is to allow students to anticipate the laboratory experience they will soon encounter. Students should leave this PreLab session with a firm idea of what to expect and how to perform in the lab.

Note: Homework is posted below the video.

HOMEWORK

Tell students that they should review the Investigation in preparation for the Lab.