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Chap 3 - Cells

Chap 3 - Cells. Learning Objectives: Describe the structure and function of the major cell organelles. List the phases of the cell cycle and describe the key events in each phase. Describe DNA replication.

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Chap 3 - Cells

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  1. Chap 3 - Cells Learning Objectives: Describe the structure and function of the major cell organelles. List the phases of the cell cycle and describe the key events in each phase. Describe DNA replication. Homework: Read Chapter 3, pgs 78 – 91 (Beginning with “The Cytoplasm” through “Chromatin”). Review Table 3.3, “Parts of the Cell: Structure and Function” pgs 88 – 89.

  2. OPENING ACTIVITYCSI: Solving Crimes with DNA Evidence http://www.cbs.com/primetime/csi_miami/ Goal: To learn more about how DNA is used in crime-scene investigation Instructions: ∙ Work in a group of 5-6 people. ∙ Quickly review the CSI case (there are 3 identical copies enclosed – share amongst yourselves). ∙ Use the CSI resource cards in the packet to help you formulate answers to the 5 questions on the first page (left-hand side) of the case. Try to formulate answers in your own words (re-state) rather than copying word-for- word. ∙ Be prepared to share and discuss your conclusions with the class.

  3. Follow-Up Discussion • What is DNA? • What kinds of cells is DNA typically isolated from? • How is DNA tested for a possible match? Site at least 2 different types of tests and explain what they reveal. • What does “epithelials” refer to? • When a cell no longer has a nucleus, how can DNA be extracted form that cell?

  4. PREDICT How many cells in your body? How many different kinds?

  5. Typical Cell Structure, page 60 Instructions: Individually, practice labeling the organelles on the handout.

  6. The Plasma Membrane • Surrounds the entire cell • Made of phospholipids and ___________ • Is __________ permeable (it allows some substances to pass through but not others) • Substances move through the membrane _________ (not requiring any energy as in diffusion and filtration) or __________ (requiring energy form ATP) Plasma membrane Question: What is ATP? (*homework from Ch 2)

  7. The Cytoplasm • The _______ _______ between the plasma membrane and the nucleus • Gelatin-like • Consists of organelles – helps everything hang together

  8. Nucleus • ______ _______ of the cell • Larger than most other cell organelles • Most cells have one nucleus but some are multinucleated • 3 recognizable regions: 1. nuclear _________ (a double semi-permeable membrane surrounding the nucleus) 2. _________ (dark spherical area on the nucleus where ribosome subunits are assembled) 3. _________ (DNA containing area; when a cell is preparing to divide, the chromatin coils and condenses to form short chromosomes.)

  9. Mitochondria • ______ _______ of the cell providing ATP • Contain both ____ and ____ • Sausage-shaped membranous organelles • In living cells they squirm, elongate, and change shape • Consists of 2 membranes (an outer and an inner membrane called the _______ which folds back and forth upon itself)

  10. Ribosomes • Small, dark-stained granules of ______ and a type of RNA called ________ RNA • Sites of _______ synthesis

  11. Endoplasmic Reticulum (ER) • A network within the cytoplasm (interconnected tubes and membranes enclosing fluid-filled cavities or cisternae) • Continuous with the nuclear membrane • There are 2 types: 1. ___________ (no part in protein synthesis – they help with lipid metabolism, steriod-making hormones, detox of drugs, breakdown of stored glycogen) 2. ________ (studded with ribosomes which produce all proteins secreted form cells)

  12. Golgi Apparatus • Principle ‘traffic director’ for cellular _______ • Main function is to modify, concentrate, and package the ______ and ______ made at the rough ER

  13. Lysosomes • Spherical organelles containing _________ enzymes • Digest _______, viruses, and toxins • Degrade worn out or nonfunctional __________ • Perform glycogen breakdown and release • Breakdown nonuseful tissues such as the webs between the developing fingers/toes of a fetus • Break down ______ to release Ca+ into the blood

  14. Peroxisomes • Contain powerful enzymes like _________ (molecular O2 to detox harmful alcohols and formaldehyde). Also, neutralize dangerous free radicals.

  15. Cytoskeleton(NOTE: Visible only when the cell is getting ready to _________) • Centrioles – small, barrell-shaped organelles oriented at right angles to one another

  16. Cellular Extensions • Cilia – ________ motile extensions • Flagella – ________ undulating motile extensions

  17. Review • Which organelle is the command center of the cell and contains chromatin? Which organelle contains oxidases to detox harmful substance?

  18. Review Continued • Organelle that contains digestive juices? Organelle that supplies ATP?

  19. The Cell Cycle • _______ – cell carries out all routine functions; resting from dividing • a. ______ (G_) – growth phase; several minutes to hours in length • b. _________ (S) - DNA is replicated • c. ________ (G_) – growth and final preparations for division • Mitotic phase – series of events that parcel out the replicated DNA of the original (mother cell) into two new cells (________ cells) • Cytokinesis – ________ __ of the cytoplasm during late mitosis Centrioles appear

  20. A Closer Look at DNA Replication (S phase) • Before a cell can divide, its DNA must be _________ so that identical copies of the cell’s genes can be passed on to each of its offspring • Helix _______ • 2 complimentary strands are in place exposing the _________ _____ • Each strand serves as a template

  21. DNA Replication Instructions: Complete the two new strands of DNA. Lagging Strand Leading Strand A - 1. ? - T 5. ? C - - G 2. ? 6. ? T - 3. ? 7. ? - A G - 4. ? 8. ? - C

  22. A Closer Look at Mitosis http://www.cellsalive.com/mitosis.htm

  23. Interphase (Before Mitosis) • Cell carrying out ________ activities • In late Interphase, ________ condenses and two pairs of _______ appear • The nuclear membrane also begins to disintegrate Nucleoli disappear also

  24. Early and Late Prophase • Asters are seen • Chromatin condenses into chromosomes • Chromosomes connected at midpoint (kinetochore) by centromere Centrioles separate from one another; spindle fibers form between them

  25. Metaphase • Chromosomes cluster at the ______ of the cell with centromeres precisely at center/ equator of spindle An enzyme called separase triggers separation of the chromosomes

  26. Anaphase • Chromosomes are _____ ____ (now called _________ ) • Moving chromatids look V-shaped

  27. Telophase and Cytokinesis • __ new cells forming • Nucleus begins to _____ with new nuclear envelope, nucleolus, etc. • _________ (pinching-in of cytoplasm) completes the division of the cell into 2 _______ cells

  28. Review of the Mitosis 1. ? 2. ? 3. ? 4. ?

  29. Abnormal Cell Cycles Can result in _______ formation (cells growing and dividing much faster than normal) Click to see: http://hcd2.bupa.co.uk/fact_sheets/html/skin_cancer.html

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