1 / 49

Mitosis & Meiosis

Mitosis & Meiosis. Key Vocab. Chromosome- long thread of DNA that consists of many genes Humans ( body ) have 46 chromosomes ( 23 pairs ) Gametes- sex cells such as egg and sperm (meiosis) Somatic cells- body cells (mitosis)

pendergrass
Download Presentation

Mitosis & Meiosis

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. Mitosis & Meiosis

  2. Key Vocab • Chromosome-long thread of DNA that consists of many genes • Humans (body) have 46 chromosomes (23 pairs) • Gametes-sex cells such as egg and sperm (meiosis) • Somatic cells-body cells (mitosis) • Homologous chromosomes- two chromosomes; one from mom and other from dad

  3. Diploid-a cell has two copies of each chromosome (cells at end of mitosis) (46)body cells • Haploid-a cell has only one copy of each chromosome (cells at end of meiosis) (23) sex cells/gametes • Sexual reproduction- type of reproduction that requires 2 parents ( an egg and a sperm) to produce offspring (young/baby) • Asexual Reproduction- Type of reproduction needing only ONE single parent. Offspring is Identical to the parent. No genetic variation. Cloning.

  4. Mitosis • Uses: growth, cell replacement, healing and repair • Asexual reproduction: one parent produces offspring that are identical to parent • Cell division- one cell separates into two cells • Each new cell contains the SAME amount of chromosomes as the original cell • The DNA is copied before the cell divides • One copy of the genetic information is distributed to each new daughter cell • Mitosis My toes Are body cells My to/2 Represents 2 cells

  5. Process of Mitosis • DNA REPLICATES- DOUBLES • Double-stranded chromosomes (replicated) line up at the center of the cell before division. • Double-stranded chromosomes split into 2 identical single strands and move toward opposite ends of the cell • The cytoplasm divides resulting in two smaller, but genetically identical cells • Cells are diploid at beginning and end of mitosis

  6. Phases of Mitosis

  7. Microscopic View of Mitosis

  8. Tumor Cancer • Uncontrolled cellular division (change in DNA=mutation). • Cancerous cells keep dividing; crowding outand stealing nutrients from healthy tissue. • Cancer “kills” when a mass of cancer cells called a tumor interferes with the functions of major organs. • The spreading of cancer to other organs and tissues is known as metastasis.

  9. Asexual Reproduction • One parent • No genetic variation • Identical to parent= CLONES • Offspring has the same # of chromosomes as parent • RESULTS IN 2 IDENTICALOFFSPRING

  10. Types of Asexual Reproduction • BINARY FISSION • BUDDING • VEGETATIVE PROPAGATION • SPORULATION • REGENERATION

  11. Binary Fission- EQUAL DIVISION --Examples: bacteria, amoeba, paramecium

  12. Budding- a cell of a parent develops a bud. - Uneven divisionExamples: yeast, hydra

  13. Sporulation-eachspore contains DNA --each spore can develop into a new organism --Examples: Bread Mold

  14. Regeneration-Replacement of lost or damaged body partsExamples: lobster, starfish, planaria, some reptiles

  15. Vegetative Propagation-new plant develops from part of a parent plantExamples: onion, potato, tulip

  16. Let’s Practice! 1. The diagrams represent a cell process. If the cell in Diagram 1 contains 4 chromosomes, what is the total number of chromosomes in each cell in Diagram 3? • 8 • 2 • 16 • 4

  17. 2. Which process is represented by the series of diagrams? • photosynthesis • fertilization • mitotic cell division • meiotic cell division

  18. 3. Normal mitotic cell division results in each daughter cell having • half the number of chromosomes as the parent cell • the same number and kinds of chromosomes as the parent cell • the same number but different kinds of chromosomes as the parent cell • twice the number of chromosomes as the parent cell

  19. 4. A colony of red bacteria is allowed to reproduce for 16 generations.  A scientist examines the colony at the end of this time and notes that all the individuals are almost identical in all characteristics.  This evidence suggests that the bacteria • did not receive the proper nutrients • reproduced sexually • exchanged genetic material • reproduced asexually

  20. 5. Which phrases best identify characteristics of asexual reproduction? • one parent, union of gametes, offspring similar to but not genetically identical to the parent • one parent, no union of gametes, offspring genetically identical to parents • two parents, union of gametes, offspring similar to but not genetically identical to parents • two parents, no union of gametes, offspring genetically identical to parents

  21. 6. Which activity most directly involves the process represented in the diagram below? • a gamete reproducing sexually • a white blood cell engulfing bacteria • a zygote being produced in an ovary • an animal repairing damaged tissue

  22. 7. Which statement regarding this process is correct? • Cell B contains the same genetic information that cells A and C contain. • Cell C has DNA that is only 50% identical to cell B. • Cell A has DNA that is only 75% identical to cell B. • Cells A, B, and C contain completely different genetic information.

  23. 8. The diagram can be used to illustrate a process directly involved in • tissue repair • meiosis • cellular respiration • sexual reproduction

  24. 9. Warts result when certain viruses cause skin cells to reproduce at a high rate. This rapid reproduction of skin cells is due to the viruses stimulating • cellular digestion  • mitotic cell division  • synthesis processes • meiotic cell division

  25. Meiosis • Sexual reproduction • Occurs in gametes or sex cells (eggs and sperm) ONLY • Meiosis produces haploid cells that have one half the chromosomes of the original cell • Gametes or sex cells (sperm/eggs) have one half the amount of chromosomes as the original cell mEiosis= mE= sEx cells= gamEtEs

  26. Phases of Meiosis • First Phase of Meiotic Division- double stranded chromosomes line up in pairs in the center and then divide into two cells • Second Phase of Meiotic Division- division of the two newly formed cells • Each chromosome in the two cells still consists of two strands that will separate resulting in 4 cells

  27. Phases of Meiosis Crossing Over 4 Sex Cells/Gametes

  28. Meiosis in Testes of Males Haploid sex cells /Gametes

  29. Meiosis in Ovaries of Females Egg Cell (Nonfunctioning Cells)

  30. Meiosis Comparison 4 Gametes

  31. Meiosis: Source of Variation • During meiosis, genetic variation occurs. • Sources of Variation (Different genes that code for traits) • Crossing over • Genetic Recombination- during fertilization (Egg and Sperm) • Random fertilization of Gametes-

  32. 1. Crossing Over- Random exchange of chromosome pieces (genetic information between chromosomes) Same Genes on Chromosomes

  33. 2. Genetic Recombination- during (Egg and Sperm) Meiosis --Different combinations of chromosomes can be produced (about 8 million different combinations)

  34. 3. Random Fertilization of Gametes-random combination of gametes or egg and sperm --About 70 trillion possible combinations of the egg and sperm

  35. Let’s Practice! 1. Each body cell of a chimpanzee contains 48 chromosomes. How many chromosomes would normally be present in a gamete produced by this chimpanzee? • 24 • 36 • 48 • 96

  36. 2. Which process is represented by the diagram? • fertilization • production of gametes • cloning • evolution

  37. 3. The process of meiotic cell division in a human male usually forms • one diploid cell, only • four diploid cells • one monoploid/haploid cell, only • four monoploid/haploid cells

  38. 4. Cell with a diploid chromosome number of 12 divided two times, producing four cells with six chromosomes each. The process that produced these four cells was most likely • internal fertilization • external fertilization • mitotic cell division • meiotic cell division

  39. 5. Most cells in the body of a fruit fly contain eight chromosomes.  How many of these chromosomes were contributed by each parent of the fruit fly? • 8 • 2 • 16 • 4

  40. 6. Which diagram best represents part of the process of sperm formation in an organism that has a normal chromosome number of eight? 1. 3. 2. 4.

  41. 7. The diagram below shows a process that can occur during meiosis. The most likely result of this process is • a new combination of inheritable traits that can appear in the offspring • an inability to pass either of these chromosomes on to offspring • a loss of genetic information that will produce a genetic disorder in the offspring • an increase in the chromosome number of the organism in which this process occurs

  42. 8. A particular species of shark normally reproduces sexually. In captivity, it was found that a female could also reproduce asexually. One negative result from asexual reproduction is • increased gene recombinations • increased number of males produced • decreased number of eggs used • decreased biodiversity within the species

  43. References • http://www.tokresource.org/tok_classes/biobiobio/biomenu/index.htm • McDougal Littell Biology Living Environment Textbook

More Related