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9-1 Cellular growth

9-1 Cellular growth. Déjà vu. What are the 3 parts of the Cell Theory? All living things are made of one or more cells Cells are the smallest unit of living organisms Cells arise only from existing cells. Why are cells so small?.

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9-1 Cellular growth

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  1. 9-1 Cellular growth

  2. Déjà vu What are the 3 parts of the Cell Theory? • All living things are made of one or more cells • Cells are the smallest unit of living organisms • Cells arise only from existing cells

  3. Why are cells so small?

  4. Cells grow until they reach their size limit, then they either stop growing or divide.

  5. Cell Size Limitations Ratio of Surface Area to Volume Transport of Substances Cellular Communication

  6. Cellular Reproduction As the cell grows, its volume increases much more rapidly than the surface area. Ratio of Surface Area to Volume Surface Area = the area covered by the plasma membrane Volume= the space taken up by the inner contents of the cell (organelles, cytoplasm, nucleus Back to Outline

  7. Transport of Substances

  8. Transport of Substances • So…The cell might have difficulty supplying nutrients and expelling enough waste products. (It gets harder to get the good stuff in and the bad stuff out)

  9. Think About It… Back to Outline

  10. Cellular Reproduction Cellular Communications • Cell size affects the ability of the cell to communicate instructions for cellular functions.

  11. How do cells stay small?

  12. Cell Cycle Cells reproduce by a cycle of growing and dividing Each time a cell goes through one complete cycle, it becomes two cells.

  13. Reasons for cell division:-Repair-growth-development-asexual reproduction-gamete formation About 2 trillion cells are produced by an adult human body every day. This is about 25 million new cells per second! Cells go through different types of cell division depending on the organism and the reason for the cell dividing.

  14. CHROMOSOMES “packages of DNA”

  15. Eukaryotic Chromosomes

  16. When genes are being used to make proteins, the DNA is stretched out so it can be easily read. This “relaxed” form of DNA is call chromatin. • As a eukaryotic cell prepares to divide, the DNA associates itself with histone proteins. DNA coils tightly around the proteins and forms a beadlike structure called a nucleosome. Nucleosomes pack together to form thick fibers, forming a chromosome. The “X” chromosome that we are used to seeing is actually two exact copies of one chromosome, each one is called a chromatid. The two chromatids of a chromosome are attached at a point called a centromere.

  17. DEMO

  18. YARN = TAPE = CLOTHES PIN = DNA Genes Proteins

  19. Journal • Explain the role of chromosomes during cell division.

  20. Cell Cycle • Interphase is the stage during which the cell grows, carries out cellular functions, replicates DNA, and prepares for division. • Mitosis is the stage of the cell cycle during which the cell’s nucleus and nuclear material divide. • Cytokinesisis the method by which a cell’s cytoplasm divides, creating a new “daughter” cell with identical nuclei

  21. Eukaryotic Cell Cycle

  22. Think about it… • How can we tell how much time the cell spends in each phase?

  23. Thought Question How do you think cell division in eukaryotes compares to cell division in bacteria (binary fission)?

  24. Prokaryotes vs. eukaryotes EUKARYOTES Prokaryotes Reproduce by a method called binary fission • Cell Cycle is the process by which eukaryotic cells reproduce themselves

  25. Chapter Diagnostic Questions CDQ 3 Which is not a phase of the cell cycle? • A • B • C • D cytokinesis interphase apoptosis mitosis

  26. Section 1Formative Questions FQ 1 Which can more efficiently supply nutrients and expel waste products? • A • B • C • D larger cells smaller cells cells with lower surface area to volume ratio cells shaped like a cube

  27. Section 1 Formative Questions FQ 2 At what stage does a cell spend most of its life? • A • B • C • D cytokinesis interphase mitosis synthesis

  28. Cellular Reproduction Section 1Formative Questions FQ 3 What happens in the cell during cytokinesis? The cell grows and carries out normal functions. The cell copies its DNA and forms chromosomes. The cell’s nucleus and nuclear material divide. The cell’s cytoplasm divides. • A • B • C • D

  29. Section 2 Formative Questions FQ 4 In what stage of the cell cycle does the cell’s replicated genetic material separate? • A • B • C • D cytokinesis interphase mitosis prophase

  30. C B A Standardized Test Practice STP 1 Which cell has the lowest ratio of surface area to volume? • A • B • C

  31. Standardized Test Practice STP 2 At what stage of interphase does the cell take inventory and make sure it is ready for the division of its nucleus? • A • B • C • D G1 S G2 M

  32. The Stages of Interphase • G1 (Gap 1)-The cell is growing, carrying out normal cell functions, and preparing to replicate DNA. Nerve cells, muscle cells, and some other highly specialized cells do not leave the G1 phase, and therefore do not replicate in the body under normal conditions.

  33. The Stages of Interphase • S (Synthesis) -The cell copies its DNA in preparation for cell division.

  34. Cellular Reproduction The Stages of Interphase • G2 (Gap 2) -The cell prepares for the division of its nucleus.

  35. Surface Area : volume activity, page 245

  36. Surface area lab • Is the distance of diffusion the same for all blocks? Explain. • List the cubes in order of size, from largest to smallest. Now list them in order of surface area:volume ratio, from largest to smallest. How do these lists compare? • What is the relationship between surface area:volume ratio and diffusion in a cell? • Are large organisms, such as redwood trees and elephants, large because they contain extra-large cells or just more regular sized cells?

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