SAmple

• The heart does not usually get cancer due to the cell division process
• Healthy heart

  • Cell division is slow and rare in adult heart because the heart is very active and pumps blood through our life time
• Cancer


  Uncontrolled growth of cells
• Types of cells

  • Somatic cells (n→2n) mitosis
  • Meiotic cells (2n→n) meiosis
• Somatic cells

  • Responsible for growth and maintenance of our body
  • Equational division = haploid to daughter cell
• Meiotic cells

  • Divide by meiosis (testis or ovaries) results in reductional division
  • Haploid to diploid chromosomes
• Cell cycle

  Multiplying cells/ replicating cells-cutting cells into numerous divisions<|>Repetitive pattern of growth and division that occurs in both prokaryotic and eukaryotic cells
• Eukaryotic cell division


  Differentiation
• Stages of cell cycle

  • G1
  • S
  • G2
  • M
• G1

  Growing phase is the duplication of cell parts (all cell parts are duplicating except the chromosomes)<|>Interface/ living face of the cell<|>Primary growth phase
• S

  Copying DNA/DNA Synthesis<|>Interface/ living face of the cell<|>Replication<|>At the end of this phase there are now two identical chromosomes which will end
• G2

  Preparing for division<|>Interface/ living face of the cell<|>Secondary growth phase<|>Centriole (for animals) duplication which means they are now ready to divide (the duplication includes: cell parts, nutrients, DNA, 2 chromosomes and 2 centrioles)
• M


  Mitosis<|>Nucleus divides into two nuclei<|>One set of DNA will be transferred to the daughter cells (dividing)<|>Interface/ living face of the cell<|>Non-dividing stage
• Chromosomes


  Most important part of the DNA<|>Holds the DNA<|>If damaged, you will end up with amputated cells like cancer cells<|>Organized structure of your DNA
• Histones


  DNA are coiled in your proteins and the condensed structure of your DNA
• Mitosis

  1. Division of the mother cell into 2 daughter cells with the same amount and quality of genetic materials

  2. Should have 2 identical daughter cells at the end of the process

  3. For Somatic cells
• Mitosis steps

  1. Breakdown the nuclear envelope

  2. Prophase

  3. Metaphase

  4. Anaphase

  5. Telophase

  6. Cytokenisis
• Chromatids


  One of the two identical halves of a chromosome that has been replicated in preparation for cell division. The two "sister" chromatids are joined at a constricted region of the chromosome
• Chromosomes


  X like structure
• Signal for Anaphase: The chromosomes will be pulled towards the opposite poles
• Telophase


  The nuclear envelope will start to reform and the chromosomes will start to relax also<|>Where the spindle fibers are now visible as disappearing<|>In the resting stage the chromosomes will turn into chromatin<|>Appearance of the cleavage or it is called as the cleavage furrow
• Cytokenisis

  1. Ones the cleavage furrow disappears

  2. Where the cytoplasm will divide

  3. Final stage of mitosis
• The parent cell now becomes two daughter cells with identical genetic information
• Importance of cell cycle

  For the repair of our cells<|>Cell cycle is important for the reproduction of cells<|>Creation of offspring especially for higher life forms (meiosis)
• Meiosis

  1. Reductional process/division

  2. For diversification

  3. Type of cell division that produces gametes

  4. Takes place in the reproductive organ

  5. Genetically unique cells with half number of chromosomes as the original cells
• Synapsis


  Chromatin lies side by side. Forming a tetrad or bivalent chromosomes (changing segments or crossing over)-makes the difference in siblings or children
• Meiosis steps

  1. Prophase I

  2. Metaphase I

  3. Anaphase I

  4. Telophase I

  5. Cytokenisis

  6. Prophase II

  7. Metaphase II

  8. Anaphase II

  9. Telophase II

  10. Cytokenisis
• From the mother cell it will end with four daughter cells (through four sperms or spermatogenesis)
• Oogenesis


  The three other bodies or what we call polaris or curp (which means they also disintegrate)<|>Largest cell in the body is egg cell<|>4 products of meiosis 1 and 2 dissolves and other one becomes a part of an egg cell<|>The other 3 will just serve as a nutrient (one egg cell per month)
• Menstruation

  Thickening of the lining in the endometrial system
• Menopausal stage

  Consumed all the egg cells (400,000-500,000 egg cells- adult period)
• Smallest cell in the body is the sperm cell
• Computation of Egg cells: 400 eggs in a year = 400/12 = 33.33 years
• Menopause= Number of years base on egg cells + age of menarche
• Sperm

  Can only carry 1 type of chromosomes
• Humans have 23 pairs of egg cell each and 23 pairs of sperm cells each = 46 pairs
• Determining factor


  X+X= daughter<|>X+Y= son
• Difference in the sperm cell

  The speed of chromosomes they carry<|>Faster swimmer when it comes to carrying chromosomes for female creation<|>Slower swimmer but survive longer when it comes to carrying chromosomes for male creation
• Human karyogram


  Way for them to identify chromosomes
• Ex:46 pair, 23 for each sex, 22 (autosomal)