1. Chapter 5 Review Powerpoint Science 9 Mitosis

2. Why do some cells divide more often than others? Do red blood cells or stomach cells divide more often? • Cells that get more wear and tear divide more often. • Stomach cells divide every 2 days, but red blood cells divide ever 120 days.

3. Why is it important for cells to divide? • To produce new cells that replace old cells that die or mutate so that the whole organism is not hurt. • To produce new organisms through asexual reproduction

4. If you start with one cell, how many cells do you have at the end of one cell cycle? • Two

5. What is the original cell called? What are the two new cells called? • Parent cell • Daughter cells

6. What are the three main stages of the cell cycle? • Interphase • Mitosis • Citokinesis

7. Describe the three stages of interphase. • 1) Growth and preparation of the cell by gathering nutrients and making proteins and molecules needed for mitosis. • 2) DNA is replicated: An enzyme splits the DNA strand down the center, then new bases pair with the original DNA to make two DNA molecules. • 3) Growth and preparation again to duplicate organelles and prepare for mitosis

8. Why is DNA replication during interphase so important? • DNA needs to replicate so there is a copy of each DNA strand in the two daughter cells.

9. Draw and label the cell during interphase

10. Explain the difference between chromatin and chromosomes. In which parts of the cell cycles are each of them found? • Chromatin is loosely coiled DNA in interphase and cytokinesis • Chromosomes are tightly coiled, X-shaped DNA strands during mitosis

11. Draw and label a chromosome.

12. What are the four stages of mitosis? Draw and label a diagram for each stage.

13. What happens to the organelles during the cell cycle? • Organelles are duplicated during interphase so that one of each organelle is in each daughter cell.

14. What happens during the last stage of the cell cycle? • Cytokinesis: The cell splits to make two daughter cells. • In animal cells the cell membrane pinches together. • In plant cells a cell wall and membrane form along the center to split the cells.

15. Why is it useful for DNA to be loosely coiled during interphase but tightly coiled during mitosis? • In interphase the DNA is loosely coiled so it is easier to replicate the DNA • In mitosis the DNA is tightly coiled to make it easier for it to be moved around the cell

16. What are the checkpoints of the cell cycle? Why are they important? • Check if the cell has enough nutrients and has grown • Check if the DNA has been replicated • Check that the DNA is not damaged • These are important to regulate the cell cycle and make sure that no cells pass on mutations or replicate constantly without stopping.

17. What can happen when the checkpoints in a cell aren’t regulated? • The cells can pass on mutations and start dividing uncontrollably. This can lead to cancer.

18. What is asexual reproduction? • Reproduction that requires only one parent to produce offspring that are genetic copies of the parent

19. What is binary fission? • A single-celled organism replicates using mitosis to get two daughter cells.

20. What is budding? • An organism has certain cells repeatedly undergo the cell cycle to grow a new organism from the parent cell. The daughter cell can detach and go to another environment.

21. What is fragmentation? • An organism breaks apart then each fragment grows into an identical daughter cell

22. What is vegetative reproduction? What is grafting? • Vegetative reproduction: specialized plant cells divide repeatedly to grow a new organism from the parent. • Grafting: Humans join the parts of different plants together. • They do this to grow more crops and help a plant grow by joining it to another.

23. What is spore formation? • Spores (individual reproductive cells) are made by the parent and can be carried by the wind to a new location. An offspring identical to the parent grows from each spore.

24. What are three advantages and disadvantages to asexual reproduction? • Advantages: • Fast – can make many offspring quickly because you only need one parent cell • Requires less energy for the organism • If many are made they can compete against other species for the territory or area. • Disadvantages: • Genetic copies – mutations are passed down and can harm many of the offspring • Can compete for food and space • Entire colonies can be wiped out by bad conditions because there is no genetic diversity

25. What is a clone? • A clone is a genetic copy of an organism.

26. What is the difference between reproductive cloning and therapeutic cloning? • Reproductive cloning duplicates the whole organism, but therapeutic cloning only duplicates a desired part using stem cells.

27. What are advantages and disadvantages of therapeutic cloning? • Advantages: Used to correct health problems by growing tissues and organisms to replace damaged ones. • Do not need to clone the whole organism for one tissue or organ • Disadvantages: Need to use specific types of cells (stem cells)

28. What are advantages and disadvantages of reproductive cloning? • Advantages: gives you a duplicate of a desired organism • Disadvantages: only 10% of clones survive • Need to grow the organism to be an adult – takes time