Biology Cell Division Homework Packet #1 Name Hour DUE:

HW #1

Mitosis Questions ________

Lab Diagram ________

HW #2

Time for Analysis ________

Mitosis Lab Graph ________

HW #3

Cell Division Questions ________

Read Chapter 7.1

_______ / 5 possible points

Biology Homework #3: Cell Division

1. Label the following diagram with the following terms: chromosome, chromatid, centromere. Also, add spindle fibers to the drawing on the left.

Centromere

Chromosome Chromatid Chromatid

2. At what stage of mitosis does this step happen? This step happens during anaphase. 3. Cell division is extremely important to an organism. If cell division doesn’t work properly, there can be severe consequences. A. What is the cell cycle? Cycle of cell growth and division involving interphase, prophase, metaphase, anaphase, and telophase B. What is meant by “checkpoints”? Checkpoints are places within the cell cycle in which the cell “checks” that the cycle is proceeding properly. C. What can happen if the cell ignores these checkpoints? If the cell ignores these checkpoints, cancer may occur.

Mitosis is the process in which a cell duplicates its chromosomes to generate two identical cells. It is generally followed by cytokinesis which divides the cytoplasm and cell membrane. This results in two identical cells with an equal distribution of organelles and other cellular components. 4. Using one body cell with four chromosomes, draw the products of mitosis. Be sure to include the correct number of cells with the proper number of chromosomes in each. 5. Recognizing the steps of mitosis will be something that you are quizzed on (count on it!). Label the following pictures with the correct stage of mitosis.

Telophase

Interphase

Prophase

Metaphase

Anaphase

6. During a trip to Devil’s Lake, you discover a new variety to tree frog. To learn more about these frogs, you decide to study their skin cells. When you look at the skin cells under a microscope, you see the following image: A. Based on the evidence, which stage in these tree frog skin cells takes the longest to complete? Explain. In these cells, anaphase takes the longest time to complete. Based on the field of view above, there are more cells in anaphase indicating a longer length of time needed to complete the stage. B. You do a little research on tree frog cell reproduction and find that their cells can complete the cell cycle in 10 hours (600 minutes). How long does it take for tree frog cells to complete anaphase? Show your work. 11 cells in anaphase X 600 = 276 minutes in anaphase 24 cells total

7. While you and your lab partner are studying for the quiz, your lab partner comments that you don’t need to study the events that occur during interphase. “So much happens during the other stages of mitosis, but interphase is boring – nothing happens”, he says. Your gut reaction is to tell your lab partner that he is crazy. Are you right? Is there more to interphase? If so, describe two events that occur during interphase. You are correct, there is more to interphase. During interphase the cell does all normal functions (ribosomes make proteins, mitochondria make energy, diffusion, active transport, etc.) The DNA in the nucleus also undergoes replication. In addition to the above questions, type or neatly hand-write a response to the following questions in your book – Read Chapter 7.1 first: 8. Page 181 #2 Each daughter cell will also contain 12 chromosomes. Each cell must have a complete set of genetic information. 9. Page 181 #3 Most cells would be in interphase, the longest stage of the cell cycle. Interphase is the longest stage in order to ensure proper DNA replication and it is also the time when normal cell functions occur. 10. Page 194 #4 The cell cycle would stop at that point. Until DNA has been replicated, the events of mitosis will not begin.

together to form chromosomes.

toward ends of ce

Spindle fibers attach to centromere

Lined up along center of cell. Nuclear membrane

Yes.Now at opposite ends of

membranes; appear as chromatin

cell; enclosed in newly formed nucle

Spindle fibers

Centromere

Two

They are equal Split at centromere into separate

sister chromatids.

Answers will vary

Through mitosis cells are abl

produce more cells with identical genetic information.

Chromatin

Nuclear Membrane

Nuclear Membrane

Copied Chromosome

Copied Chromosome

Centriole

Chromosom

Spindle fibers

Metaphase Interphase Prophase

Nuclear Membrane Chromatin

Pinching in of

Cell membrane

Nuclear Membrane

Centromere

Anaphase

Interphase Telophase