The Cell Cycle: an ordered set of events, culminating in cell growth and division into two daughter cells.

Parts of the cell cycle:

G1 phase:

• Sometimes called Interphase.
  • The formation of two daughter cells from a parent cell in cytokinesis is an energy-consuming process. The time needed by the new cells to replenish their energy causes this "gap".
• After cell energy reserves are restored, the daughter cells begin to grow.
• This is the longest phase of the cell cycle.

• Synthesis means to make.
• After a period of growth, each cell's original DNA is duplicated in the process of replication.

• The replication of DNA is another energy-consuming process for the cell. The time taken by a cell to build up its energy reserves produces this second "gap".

The process by which the DNA is divided into two identical sets before the cell divides.

1. Prophase
   • Early prophase: chromatin coils to form chromosomes, nuclear membrane disappears, and centrioles migrate to opposite poles of the cell.
   • Middle prophase: spindle fibers, microtubules of protein, begin developing.
     • Polar fibers extend across the cell from centriole to centriole.
     • Kinetochore fibers extend from the centromeres of a chromosome to the centrioles.
   • Late prophase: protein fibers called asters radiate from each centriole in animal cells.
2. Metaphase:
   • Kinetochore fibers move the chromosomes to the equator of the cell.
3. Anaphase:
   • The centromere of each pair of chromatids divides, the chromatids separate and are pushed to opposite poles of the cell by the combined efforts of the spindle fibers. This movement is done in one quick motion.
4. Telophase:
   • All spindle fibers disappear, chromatids unwind and stretch to form chromatin, and a nuclear membrane forms around each mass of chromatin.

• Cytokinesis is the division of the cytoplasm of a parent cell. The cell pinches together roughly in the center.
• You may either consider it the end of Mitosis or the beginning of Interphase.
• While each daughter cells gets identical sets of DNA, the cytoplasm and organelles are only roughly divided equally between the two cells.

In any growing tissue, cells will be found in all phases of the cell cycle.

 

Meiosis occurs only in gametes:

It is the process of nuclear division that reduces the number of chromosomes by half.

Two nuclear divisions: These are similar to, but different from the single division of mitosis. The process is complicated, providing more opportunity for genetic variation like crossing-over to occur. For our purposes, this summary of events is sufficient.

Meiosis I DNA replication takes place. A parent cell produces two daughter cells with one member of each original pair of homologous chromosomes. Meiosis II There is no DNA replication. The chromatids of each chromosome separate and each daughter cell divides. At the end of Meiosis, there are four daughter cells from each parent cell. Each daughter cell has half the number of chromosomes of the parent.

Day 3,4 Assignment - Cells and the Cell Cycle
Scoring Rubric Word doc version

PowerPoint is a "presentation graphics" program. It is used to visually provide information to a group of people - not just one person sitting in front of a computer. Color combinations and font size must make the slides easily read from a distance.

1. Make a PowerPoint presentation that you will use to teach the class about the Cell Cycle, Mitosis and Meiosis. Be prepared to show your power point to the class and teach them about your topic. The requirements below are provided as a minimum standard. Feel free to make a more complex slide show if you wish (higher scores can be earned by adding items like music, animation and video, etc). Your slide show should include the following:
   Slide (1) - Title page including:
   • title of presentation - should catch the audiences attention
   • a picture related to the topic of the presentation
   • also include the following on this slide:
     • your name or names
     • class period
     • date

   Slide (2) - An introduction slide showing an overview of the cell cycle.

   • include some type of graphics on this slide

   Main body Slides (6-10) - Includes information and graphics on the cell cycle process in the correct order.
   (important: do not overload one slide with to much information split it up on different slides).
   

   Cell Cycle

   • G1
   • S (replication)
   • G2
   • M, parts of mitosis (P.M.A.T.)
   • Cytokinesis

   Main body slide (2-5)

   Meiosis

   • How is it different then mitosis
   • What is the purpose
   • Meiosis I & II
   • Only occurs in certain types of cells

   Concluding slide(s) - Restates the overall importance and process of the cells cycle.
   

   Work cited slide - Site all sources used to make presentation (must have at least two sources)

   _____________________________________________________________________________________________________

   Honors biology: the following option is required

   Extra credit can be earned by setting your power point to run on its own once started allowing you to read (and the audience) your presentation without long pauses or going to fast. *Warning* practice makes perfect: Setting the timing and slide transitions may run different on computers with different windows versions such as window 2000 and windows xp (always save the power point in windows 2000 version as that is what our school currently runs).

   
   Important: Use scoring rubric to self evaluate power point.

   Presentation day:

   • Presentation saved to disk and server file for access in the classroom (always have a backup).
   • Bring a hard copy of presentation (6 slides to a page format) and rubric stapled together with rubric on top.

   Student Examples: These are a few examples from past students.

   Student example 1

   Student example 2

Research Links:

• Biological Macromolecules - IMB Jena WWW Service
• Human Genome Sequencing - National Center for Biotechnology Information
• Cells and Chromosomes - Access Exellence, Genentech
• Human Genes, By Chromosome - Johns Hopkins University School of Medicine
• Meiosis animation - Dr.Chromos school (click on film strip)
• What is Meiosis - University of Arizona
• Cells alive - The Cell Cycle: animation
• Cells alive - Mitosis: animation
• Access Excellence, the national health museum - comparison of mitosis & meiosis
• North Carolina State University School of Veterinary Medicine - Meiosis animation
• California State University-Chico - Meiosis animation
• The Biology place - Meiosis 1 animation
• The Biology place - Meiosis 2 animation

Gametes are sex cells, sperm and egg.