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Copyright © by Holt, Rinehart and Winston. All rights reserved. When are sister chromatids formed? When are they separated? When are homologous pairs separated?

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Presentation on theme: "Copyright © by Holt, Rinehart and Winston. All rights reserved. When are sister chromatids formed? When are they separated? When are homologous pairs separated?"— Presentation transcript:

1 Copyright © by Holt, Rinehart and Winston. All rights reserved. When are sister chromatids formed? When are they separated? When are homologous pairs separated? Question of the Day 3-7

2 Copyright © by Holt, Rinehart and Winston. All rights reserved. 1. What is cancer? 2. What causes cancer? Question of the Day 3-8

3 Copyright © by Holt, Rinehart and Winston. All rights reserved. How Cancer Grows Quiz make ups Read Section 8.3 in the Owl Book and answer #s 1-6 on page 156 Today 3-7

4 Copyright © by Holt, Rinehart and Winston. All rights reserved. What is a haploid cell (there are multiple correct answers)? Question of the Day 3-9

5 Copyright © by Holt, Rinehart and Winston. All rights reserved. 1. What are the four stages of mitosis in order? Question of the Day 3-10

6 Copyright © by Holt, Rinehart and Winston. All rights reserved. Plan for the Unit # 6 Test at the end of next week (Thursday 3-17 or Friday 3-18) Announcement 3-10

7 Copyright © by Holt, Rinehart and Winston. All rights reserved. Control of Cell Division Cell division in eukaryotes is controlled by many proteins. Cell division in eukaryotes is controlled by many proteins. Contact Inhibition = when normal cells come in contact with one another, growth stops Contact Inhibition = when normal cells come in contact with one another, growth stops

8 Copyright © by Holt, Rinehart and Winston. All rights reserved. Cancer may result if cells do not respond to proteins and/or contact inhibition. Cancer may result if cells do not respond to proteins and/or contact inhibition. Contact Inhibition - –Cancer cells do not stop dividing when they come in contact. Cancer

9 Copyright © by Holt, Rinehart and Winston. All rights reserved. Cancer = uncontrolled cell growth = uncontrolled cell growth causes = mutated DNA (genetic or environmental) causes = mutated DNA (genetic or environmental)

10 Copyright © by Holt, Rinehart and Winston. All rights reserved. Mitosis vs. Meiosis Mitosis produces 2 daughter cells while meiosis produces 4 daughter cells Mitosis produces diploid cells while meiosis produces haploid cells

11 Copyright © by Holt, Rinehart and Winston. All rights reserved. Mitosis Review Genetically – how similar are the daughter cells in mitosis? Genetically – how similar are the daughter cells in mitosis? –They are identical When is the DNA copied for the new cell? When is the DNA copied for the new cell? –S phase of interphase What are two things make up chromosomes? What are two things make up chromosomes? –DNA and histones (protein) What is the middle part of the chromosome? What is the middle part of the chromosome? –Centromere What gets separated during mitosis? What gets separated during mitosis? –Sister chromatids NOT homologous pairs

12 Copyright © by Holt, Rinehart and Winston. All rights reserved. Meiosis Objectives Compare the end products of meiosis with those of mitosis. Compare the end products of meiosis with those of mitosis. Summarize the events of meiosis I. Summarize the events of meiosis I. Explain crossing-over and how it contributes to the production of unique individuals. Explain crossing-over and how it contributes to the production of unique individuals. Summarize the events of meiosis II. Summarize the events of meiosis II. Compare spermatogenesis and oogenesis. Compare spermatogenesis and oogenesis. Define sexual reproduction. Define sexual reproduction.

13 Copyright © by Holt, Rinehart and Winston. All rights reserved. Assignment #s 1-6 on page 156 – Owl Book

14 Copyright © by Holt, Rinehart and Winston. All rights reserved. Poster Contest 3-8 Topics: The S-phase of Interphase Prophase Metaphase Anaphase Telophase Cytokinesis The chromosome MAKE SURE YOU GET A CHECKLIST FOR YOUR TOPIC!!! Creativity Slogan / Title Aesthetically pleasing Accurately descriptive and understandable

15 Copyright © by Holt, Rinehart and Winston. All rights reserved. What does DIPLOID mean? What does DIPLOID mean? –Cells having 2 homologous copies of each chromosome (homologous pairs) What does HAPLOID mean? What does HAPLOID mean? –Number of chromosomes in a sex cell (half the number in a diploid cell) What are sister chromatids? What are sister chromatids? –Identical copies of the same chromosome Important vocab. review

16 Copyright © by Holt, Rinehart and Winston. All rights reserved. What is are sister chromatids? What is are sister chromatids? –Identical copies of the same chromosome When does the cell produce the copy of the chromatid? When does the cell produce the copy of the chromatid? –S phase of interphase Important vocab. review

17 Copyright © by Holt, Rinehart and Winston. All rights reserved. What are homologous chromosomes? What are homologous chromosomes? –Chromosomes that carry genes for same traits (though variation of the trait may differ) –Allele – variation of a trait Trait = flower color Trait = flower color Alleles = genes for either white or purple flowers Alleles = genes for either white or purple flowers Important vocab. review

18 Copyright © by Holt, Rinehart and Winston. All rights reserved. Formation of Haploid Cells Meiosis – the process of making sex cells. Meiosis – the process of making sex cells. makes sperm and eggs makes sperm and eggs Four new haploid cells result (gametes) Four new haploid cells result (gametes) Meiosis is broken down into Meiosis I and Meiosis II. Meiosis is broken down into Meiosis I and Meiosis II.

19 Copyright © by Holt, Rinehart and Winston. All rights reserved. How is meiosis different from mitosis (there is more than one correct answer)? Question of the Day 3-14

20 Copyright © by Holt, Rinehart and Winston. All rights reserved. Plan for the Unit # 6 Test on Friday 3-18 Announcement 3-14

21 Copyright © by Holt, Rinehart and Winston. All rights reserved. Reviewing Objectives Describe the structure of a chromosome. Describe the structure of a chromosome. How is a prokaryotic chromosome different than a eukaryotic chromosome? How is a prokaryotic chromosome different than a eukaryotic chromosome? How many chromosomes do you have? How many chromosomes do you have? How are diploid and haploid cells different? How are diploid and haploid cells different?

22 Copyright © by Holt, Rinehart and Winston. All rights reserved. cell division in prokaryotes = ??? cell division in prokaryotes = ??? What happens during interphase? What happens during interphase? 4 stages of mitosis in order = ??? 4 stages of mitosis in order = ??? How is cytokinesis in animal cells different from cytokinesis in plant cells? How is cytokinesis in animal cells different from cytokinesis in plant cells? How is cell division controlled? What happens if it is not? How is cell division controlled? What happens if it is not? Reviewing Objectives

23 Copyright © by Holt, Rinehart and Winston. All rights reserved. Meiosis I: crossing over takes place homologous chromosomes get separated 2 new haploid cells result

24 Copyright © by Holt, Rinehart and Winston. All rights reserved. Meiosis II: sister chromatids get separated (like in mitosis ) 2 new haploid cells result from each of the cells from meiosis I (total 4 new cells)

25 Copyright © by Holt, Rinehart and Winston. All rights reserved. During meiosis… Synapsis – pairing of homologous chromosomes – this did not occur in mitosis Synapsis – pairing of homologous chromosomes – this did not occur in mitosis

26 Copyright © by Holt, Rinehart and Winston. All rights reserved. Formation of Haploid Cells Crossing-over – when portions of homologous chromosomes exchange genes Crossing-over – when portions of homologous chromosomes exchange genes Results in genetic recombination. Results in genetic recombination. Genetic recombination – Genetic recombination – Regrouping of genes in an offspring that results in a genetic makeup that is different from the parents Regrouping of genes in an offspring that results in a genetic makeup that is different from the parents

27 Copyright © by Holt, Rinehart and Winston. All rights reserved. Crossing Over

28 Copyright © by Holt, Rinehart and Winston. All rights reserved. Crossing Over

29 Copyright © by Holt, Rinehart and Winston. All rights reserved. Asexual Reproduction = genes identical to parents Asexual Reproduction = genes identical to parents –PRO: Offspring well adapted to survival Offspring well adapted to survival Need only one parent Need only one parent Fast Fast –CON: If susceptible to a disease, may kill off the entire population (b/c all genes are the same) If susceptible to a disease, may kill off the entire population (b/c all genes are the same) Types of Reproduction

30 Copyright © by Holt, Rinehart and Winston. All rights reserved. Sexual Reproduction Sexual Reproduction –PRO: Leads to genetic diversity from parents Leads to genetic diversity from parents Not all members will die from a disease (leads to species evolution) Not all members will die from a disease (leads to species evolution) –CON: Need two parents Need two parents Takes longer Takes longer Why is genetic recombination important?

31 Copyright © by Holt, Rinehart and Winston. All rights reserved. Poster Contest 3-14 Topics: The S-phase of Interphase Prophase Metaphase Anaphase Telophase Cytokinesis The chromosome MAKE SURE YOU GET A CHECKLIST FOR YOUR TOPIC!!! Creativity Slogan / Title Aesthetically pleasing Accurately descriptive and understandable

32 Copyright © by Holt, Rinehart and Winston. All rights reserved. Error in Meiosis Nondisjunction - when a set of homologous chromosomes do not separate Nondisjunction - when a set of homologous chromosomes do not separate –Means "not coming apart" –Results in gametes with incorrect chromosome #


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