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Warm-Up

Warm-Up. The creation of energy by plants is called? The movement of water through a cell membrane? What is the net flow of molecules during diffusion? List the following from smallest to largest—organ, organ system, tissue, organism, cell The cell membrane is made up of what molecule?

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Warm-Up

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  1. Warm-Up • The creation of energy by plants is called? • The movement of water through a cell membrane? • What is the net flow of molecules during diffusion? • List the following from smallest to largest—organ, organ system, tissue, organism, cell • The cell membrane is made up of what molecule? • What is the shape of that molecule? • What green pigment absorbs sunlight in plant cells? • During Photosynthesis, plant cells use energy to breakdown water into what two elements? • Diffusion uses no energy, so it is a _____ process. • Name two organelles in plant, but not animal cells.

  2. Warm Up • What are the two types of reproduction in organisms? • First experiments in heredity were by who? • A unit of heredity occupying a place on a chromosome. • The sex chromosomes in humans (alleles). • What scientists developed the DNA model? • What is the process that uses cell division to replace missing or damaged parts? • Name the four phases of mitosis? • What type of reproduction is used by ferns, mushrooms? • What is the normal life span of a cell called? • How large do cells normally grow?

  3. Cell Division Asexual Reproduction Science 7 Darren Nigh

  4. The Cell Cycle • The cell cycle is the normal sequence of development and division of a cell • The cell cycle consists of two main phases Interphase: The cell engages in normal life activities Mitosis and Cytokinesis: The cell undergoes division of the nucleus and cytoplasm

  5. Interphase • Interphase is part of the cell cycleduring which a cell is not dividing • During Interphase the cell grows to about twice its original size • The cell engages in normal life activities such as transporting materialsin and transporting wastes out. • During this phase the DNA is copied into a new set.

  6. What is DNA? • DNA is deoxyribonucleic acid • DNA is a chemical that contains information needed for an organisms growth and functions • The Watson and Crick Model- showed that DNA is made of two strands of molecules joined in a structure that resembles a twisted ladder or double helix

  7. Info Break • What is DNA? • What is the commonly accepted DNA model known as? What Shape? • During what phase does the cell engage in normal activities?

  8. Interphase • When the nucleus and nuclear membrane are visible, the cell is in interphase. In addition, the chromosomes are not condensed at this point, so they are not visible. The part labeled A is a centrioles

  9. Interphase-nucleus is in place

  10. Mitosis • Mitosis is the part of the cell cycle during which the nucleus divides • The shortest periodin the cell cycle. • The function of mitosis is to move the DNA and other material in the parent cell into position for cell division. • When the cell divides, each new cell gets a full set of DNA and other materials

  11. Prophase • During the stage of mitosis known as prophase, the centrioles are still moving to opposite poles, and the chromosomes are not lined up at the equator yet. Animal cell

  12. Animal cell-Prophase

  13. Actual electron microscope view Prophase inside a plant cell

  14. Metaphase • The stage of mitosis illustrated below is metaphase. • The chromosomes shown below are lined up along the equator (equatorial plate). Animal cell

  15. Metaphase-Animal cell

  16. Actual electron microscope view Inside a plant cell

  17. Info Break • What is the shortest period in the cell cycle? • During what phase are the chromosomes lined up at the equator? • During what phase are the centrioles still moving toward the poles?

  18. Anaphase • Anaphase is identified when the chromosomes are pulledaway from the equator of the cell toward the poles. Inside an animal cell

  19. Animal Cell

  20. Actual electron microscope view Inside a plant cell

  21. Telephase and Cytokineses • The cell below is in Telophase, the stage of mitosis where a new nuclear membrane has formed • Cytokinesis or cytoplasm division is also occurring simultaneously.

  22. A is the cleavage furrow which will become the cell membrane

  23. Plant cell A is the cell plate which will become the cell wall

  24. Info Break • During what phase are the chromosomes pulled away from the equator toward the poles • During what phase does a new membrane form? • During what phase is the cytoplasm divided between cells?

  25. Is this an example of a plant or animal cell in mitosis?

  26. Why is cell division important? • Cells go through a process called mitosis to divide. • Specific cells use certain pieces of the information to become particular types of cells. Ex:liver cells that work together to become the liver organ vs. skins cells that work together to become skin. • Cell division allows for growth and healing of an organism Ex:when your skin is cut/wounded, cell division causes re-growth of those skin cells. Also, individuals experiencing puberty are going through rapid growth caused by cell division.

  27. www.youtube.com/watch?v=n2Fg9tcjkQM&feature=PlayList&p=3D9371E659BE5BBA&playnext=1&playnext_from=PL&index=28 www.youtube.com/watch?v=n2Fg9tcjkQM&feature=PlayList&p=3D9371E659BE5BBA&playnext=1&playnext_from=PL&index=28

  28. Cell Division, Asexual Reproduction Part 2

  29. Reproduction Reproduction is the process by which one organism or species produces others of its same kind.

  30. Types of Reproduction There are 2 types of reproduction: • Asexual : A new organism is produced from 1 organism. • Sexual : A new organism is produced from 2 organisms.

  31. Asexual Reproduction • InAsexual Reproduction organisms are produced fromone parent • The new organism contains genetic information identical to the parent. • There is muchless genetic diversity compared to sexual reproduction

  32. Binary Fission • Binary Fission is a form of AsexualReproduction occurring in Prokaryotes • A parent splits into two • completely independent • daughter cells exactly alike • Since all Prokaryotes are single celled, cell division and reproduction are the same process Example: bacteria Textbook Pg. 89

  33. Given this information, Can you explain how people get sick so quickly from a virus? • They simply just divide in half. • It only takes about 15-20 minutes for a bacterium to reproduce, so one bacterium can reproduce millions of offspring in just a few days!

  34. Budding • Both unicellularand • multicellularorganisms • reproduce by budding. • An organism develops tiny buds on its body • Each bud forms from the parent cells, so it is exactly the same as the parent. • A Budgrows until it is a complete or a nearly complete organism. • It breaks free and becomes a new, separate organism. Bud Example: hydra Page 89

  35. Spore Formation • Spore formation is a process in which cell divisioncreates more spores. • Spores are reproductive bodies, that are produced by mushrooms, plants, bacteria, and Protozoa and that are widely dispersed. Ex: Fungi (mushrooms) and the spores on the underside of fern plants.

  36. Regeneration • A Process that uses celldivision to re-grow damaged or lost body parts is regeneration. Ex: Sponges, starfish, sea stars, planarians and human beings Pg. 89 textbook

  37. Humans, for example, are able to regenerate skin and bone tissue to mend wounds and fractures, but are unable to re-grow even a finger if one should be lost. Some internal organs can be regenerated if a large enough part remains as a starting point. The liver is an example; so too are the adrenal glands. The replacement of worn-out tissues is a form of regeneration and goes on throughout life. The most obvious is the replacement of skin (over 27 lbs in a lifetime) from below as the outer layers rub off.

  38. Info Break • What are the two types of reproduction? • What type of asexual reproduction is used by bacteria? • How do fungi reproduce? • Are human beings able to regenerate any body parts? • What type of sexual reproduction is used by the Hydra?

  39. Conclusion • Mitosis is used by eukaryotic cells whenever genetically identical cells are needed for the following reasons: • during growth of the organism • for asexual reproduction (some creatures can re-grow missing limbs, or when cut in two, can grow into 2 complete organisms). • when tissues have been damaged and need to be repaired (as in a cut). • The complete life cycle of a cell is known as the cell cycle or the cell division cycle.

  40. Sexual reproduction - Part3 • A cell containing genetic information from the motherand a cell containing genetic information from the father combine into a completely new cell in Sexual Reproduction • The new cell becomes the offspring

  41. Heredity Heredity—the passing of genes from parents to offspring

  42. A Chromosome is a threadlike linear strand of DNA and associated proteins in the nucleus of eukaryotic cells that carries the genes and functions in the transmission of hereditary

  43. Gene- a section on a chromosome - a trait example: Hair color, eye color Allele-a specific gene in a genetic pair RR tt Rt Example: red hair, green eyes

  44. Humans have 23 sets (46 chromosomes total) that contain all of the specific genes (alleles) for traits that they possess . Each can be distinguished by size and by unique banding patterns. This set is from a male, since it contains a Y chromosome. Females have two X chromosomes.

  45. This is a picture of an X Chromosome. It contains hundreds of sex linked genes also called traits.

  46. How genetic diseases spread through generations of a family

  47. Phenotype-what traits you see when you look at an organism Example: plant with purple flowers, white flowers Genotype-the name for the genes (allelles) Example: TT RR BB bb rr etc.

  48. Dominant allele-expressed even if only one gene of that type is present example: Rt RR Bb BB Recessive allele- expressed only if two genes of that type are present example: rr tt bb

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