1 / 27

Cell Growth

Cell Growth. Cells cannot continue to grow indefinitely because: Too much volume, not enough surface area Not enough genetic material Cannot keep up with waste and nutrients. Chromosomes. sister chromatids. Chromosomes are made of DNA Chromatin?

drenfro
Télécharger la présentation

Cell Growth

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cell Growth • Cells cannot continue to grow indefinitely because: • Too much volume, not enough surface area • Not enough genetic material • Cannot keep up with waste and nutrients

  2. Chromosomes sister chromatids • Chromosomes are made of DNA • Chromatin? • Before cell division, each chromosome is replicated and consists of 2 identical “sister” chromatids • Where they attach is the centromere centromeres

  3. Cell Division in Eukaryotes • Eukaryotes divide by a process called MITOSIS. • A eukaryotic cell lives through a Cell Cycle with different phases: • Interphase = the time between cell divisions • G1 Phase • S Phase • G2 Phase • M Phase = • Mitosis • Cytokinesis

  4. The Cell Cycle —Draw this Diagram on your paper and label all parts Complete Cell Cycle = about 24 hours (in typical animal cells) 12 hr 0.5 hr Mitosis 6 hr 6 hr

  5. Interphase— Draw arrows to each phase of your drawing and write the following • Interphase is divided into 3 phases: • G1 – cell growth (organelles increase in number and size, many proteins are synthesized, and growth is fast) • S – DNA replication (synthesis of DNA) • G2 – preparation for Mitosis (more and more proteins, centrioles are replicated, more growth)

  6. Interphase • technically not part of mitosis, but it is included in the cell cycle • resting phase? • performing cell functions • DNA replicates (copies) • organelles double in number, to prepare for division

  7. Interphase(inter = between)

  8. MITOSIS • nuclear division • number of chromosomes remains the same

  9. Prophase: Draw the following on the back of your paper(pro=primary,first)

  10. ProphaseKey Events Write these notes out to the side of your drawing of prophase. • Chromatin coils to form visible chromosomes • In animals, centrioles begin to migrate to opposite poles • Spindles form at opposite ends of the cell • The nuclear envelope breaks down

  11. Metaphase: Again with the drawing…(meta is like middle) • In metaphase, the chromosomes are aligned at the middle of the cell. The spindles form the framework of the dividing cell.

  12. Anaphase: Draw some more…ana=upward,back The centromeres divide and the paired chromosomes (sister chromatids) move to opposite ends of the cell.

  13. Telophase/Cytokinesis: Should we draw?(telo=end) (cyto=cell, kinesis=movement) • In this last stage, two distinct daughter cells are formed after the chomatids have migrated to the opposite poles. Cytokinesis is also occurring at this time.

  14. What about Prokaryotes? • Most Prokaryotic Cells divide through binary fission, during which 2 identical cells are created from 1 cell.

  15. Onion Root Tip Lab • Be careful with the slides!

  16. Checkpoints in Cell Cycle • Ras cyclin—protein that checks to see if the cell is big enough to continue (occurs during G1) • p53—protein that checks for DNA damage during G1 (most common cause of cancer)

  17. Cancer- Why the checkpoints are important • Occasionally, cells lose control of the cell cycle • This results from: • failure to produce certain enzymes, • the overproduction of enzymes • Or the production of enzymes at the wrong time.

  18. Cancer • Cancer is a malignant growth resulting from uncontrolled cell division • Malignant =dangerous to health; marked by uncontrolled growth

  19. Tumors • Tumors are abnormal growth of cells • Benign tumors are non cancerous and only grow locally • Malignant tumors are cancerous and spread to other areas of the body

  20. Abnormal Cell Growth

  21. Abnormal Cell Growth

  22. A Large Abdominal Tumor

  23. Surgical Removal of Tumor

  24. Body without Tumor

  25. Cancer • Cancer is the second leading cause of death in the U.S. • Lung, colon, breast, and prostate cancers are the most prevalent types

  26. Causes of cancer Genetics Environmental Factors • Cigarette smoke • Air and water pollution • Exposure to UV radiation However, there are still unknown causes and researchers are working to discover these factors.

  27. Cancer prevention • Healthy Lifestyle • Low fat, high fiber diet • Exercise • Not smoking • Taking daily vitamins and minerals • Carotenoids, Vitamins A, C, E, and calcium

More Related