Meiosis Lecture Notes PDF

Dear Lord, As we gather to begin this class today, we ask for your presence and guidance. We know that without you, we can do nothing. We ask that you open our minds and hearts to receive the knowledge and understanding we will be taught. Help us to be attentive and respectful to our teachers and c...

Dear Lord, As we gather to begin this class today, we ask for your presence and guidance. We know that without you, we can do nothing. We ask that you open our minds and hearts to receive the knowledge and understanding we will be taught. Help us to be attentive and respectful to our teachers and classmates. We pray for the ability to apply what we learn to our daily lives. We give you all the glory and honor. AMEN. ATTENDANCE  CLASS RULES be KIND! PRACTICE the acronym be RESPECTFUL! KRP… be PARTICIPATIVE! IDENTIFY THE CORRECT LETTER OF THE ANSWER BEING DESCRIBED BY EACH STATEMENTS.  1. It is the first stage of Mitosis where the chromatin condenses into the chromosome and where the nucleolus disappears. A. Prophase B. Metaphase C. Anaphase D. Telophase  1. It is the first stage of Mitosis where the chromatin condenses into the chromosome and where the nucleolus disappears. A. Prophase B. Metaphase C. Anaphase D. Telophase 2. It is the stage where chromosomes break at centromeres, and sister chromatids move to opposite ends of the cell. A. Prophase B. Metaphase C. Anaphase D. Telophase 2. It is the stage where chromosomes break at centromeres, and sister chromatids move to opposite ends of the cell. A. Prophase B. Metaphase C. Anaphase D. Telophase 3. It is the stage in which chromosomes align along the equatorial plane of the mitotic spindle. A. Prophase B. Metaphase C. Anaphase D. Telophase 3. It is the stage in which chromosomes align along the equatorial plane of the mitotic spindle. A. Prophase B. Metaphase C. Anaphase D. Telophase  4. It is the phase where the chromosomes decondense, and the nuclear envelope begins to reform around them. A. Prophase B. Metaphase C. Anaphase D. Telophase  4. It is the phase where the chromosomes decondense, and the nuclear envelope begins to reform around them. A. Prophase B. Metaphase C. Anaphase D. Telophase 5. It is during this phase that the genomic DNA within the nucleus is replicated. A. S Phase B. G1 Phase C. G2 Phase D. G0 phase 5. It is during this phase that the genomic DNA within the nucleus is replicated. A. S Phase B. G1 Phase C. G2 Phase D. G0 phase 6.2 The Cell Cycle – Concepts of Biology – 1st Canadian Edition 6.2 The Cell Cycle – Concepts of Biology – 1st Canadian Edition 6.2 The Cell Cycle – Concepts of Biology – 1st Canadian Edition CELL REPRODUCTION; MEIOSIS  TODAY’S TARGET For this learning session, you will be able to: Describe the stages of mitosis/meiosis given 2n =6 Discuss crossing over and recombination in Meiosis JUMBLE THE LETTERS TO FORM THE WORDS. HCIAASTAM CHIASMATA YSNPAISS SYNAPSIS KERTINNIEISS INTERKINESIS SIPAMRESOGTNESE SPERMATOGENESIS GENOOSISE OOGENESIS  CONCEPTS TO LEARN – Mitosis: a parent cell transmits one copy of every chromosome to each of its two daughter cells – Meiosis: in organisms that reproduce sexually, chromosome number is reduced in half to produce eggs and sperm, then the original number is restored in the zygote MEIOSIS I SEPARATION OF HOMOLOGOUS CHROMOSOMES PROPHASE I -Longest and most complex phase among the meiosis -90% of the time for cell divisions -Synapsis occurs; homologous chromosomes to form tetrad MONAD, DYAD, TETRAD CHROMATIDS CHROMOSOMES HOMOLOGOUS CHROMOSOMES SISTER CHROMATIDS BIVALENT DEFINITION OF TERMS; Synapsis – pairing of homologous chromosomes; aligning themselves lengthwise Synaptonemal complex – protein structure which helps to line up homologous chromosomes gene by gene Chiasma – the points where chromosomes cross over; (Multiple points; chiasmata) MEIOSIS I SEPARATION OF HOMOLOGOUS CHROMOSOMES METAPHASE I -Shortest phase -Tetrads align at the metaphase plate -Each pair has lined up independently of other pairs MEIOSIS I SEPARATION OF HOMOLOGOUS CHROMOSOMES ANAPHASE I Homologous chromosomes separate and move towards the poles Sister chromatids remain attached at their centromeres. MEIOSIS I SEPARATION OF HOMOLOGOUS CHROMOSOMES TELOPHASE I -usually occurs simultaneously with cytokinesis -two haploid daughter cells formed SSINTERKINESIS a period of rest that cells of some species enter during meiosis between meiosis I and meiosis II. No DNA replication occurs during interkinesis MEIOSIS II SEPARATION OF SISTER CHROMATIDS PROPHASE II -A spindle apparatus form -Similar with prophase in mitosis, but prophase II takes place with a haploid number of chromosomes MEIOSIS II SEPARATION OF SISTER CHROMATIDS METAPHASE II -Chromosomes are positioned at the metaphase plate same with the mitosis -because of crossing over happens in Meiosis I, the two sister chromatids of each chromosome are not genetically identical MEIOSIS II SEPARATION OF SISTER CHROMATIDS ANAPHASE II -Sister chromatids separate -Breakdown of proteins holding the sister chromatids at the centromere allows the chromatids to separate and move toward opposite poles MEIOSIS II SEPARATION OF SISTER CHROMATIDS TELOPHASE II -Nuclei form, the chromosomes begin decondensing, and cytokinesis occurs -four haploid daughter cells, unique from one another and from parent cell  GAMETOGENESIS: SPERMATOGENESIS AND OOGENESIS SPERMATOGONIA – DIPLOID CELL; UNDERGO MITOTIC DIVISION PRIMARY SPERMATOCYTE – DIPLOID SECONDARY SPERMATOCYTE – HAPLOID SPERMATOZOA – fully mature; motile; ready for fertilization AMETOGENESIS: SPERMATOGENESIS AND OOGENESIS All primary oocytes are formed by the fifth month of fetal life After puberty… meiosis continues – secondary oocyte 3 polar bodies and ovum QUESTIONS?