Cell

• Cytology


  Study of cells
• Robert Hooke


  • English scientist
  • Used a microscope to examine cork (plant)
  • Called what he saw "Cells"
• Cell Diversity


  • Diversity in size
  • Diversity in shape
  • Diversity in internal organization
• Cell Size


  • Largest cell: Female egg cell
  • Smallest: Sperm cell
• Cell Shapes


  • RBC
  • WBC
  • Epithelial cell
  • Heart cell
  • Neuron
• Cell Types


  • Bacterial
  • Animal
  • Plant
• Body Cells/Somatic Cells


  • Heart cells
  • Liver cells
  • Muscle cells
  • Hair cells
  • Skin cells
  • Brain cells
  • Stomach cells
  • Intestine cells
  • Blood cells
  • Kidney cells
  • Pancreas Cell
  • Gallbladder cell
  • Bone cells
  • Esophagus cell
• Sex Cells/Gametes


  • Sperm cell
  • Egg cell
• Cell Cycle


  Cycle of alternating stages of division and rest from division

  
• Interphase


  1. Resting stage

  2. Gap 1 (G1) Phase - cell increases in size in preparation for cell division

  3. Synthesis (S) Phase - genetic material and chromosomes are duplicated

  4. Gap 2 (G2) Phase - cell synthesizes proteins and continuous to increase in size
• All Living Things are Made of Cells
• MITOSIS


  Part of the cell cycle in which chromosomes in a cell nucleus are separated into two identical sets of chromosomes, and each set ends up in its own nucleus

  
• Why Cells are Small

  • As cells get bigger, more of its cytoplasm is located farther from the cell membrane
  • If a cell gets too big, it would take too long to get materials into the cell and too long to get waste out of the cell
  • Smaller cells are more efficient
• Cell Division


  • All cells come from other living cells
  • Cells get bigger and their number increases to allow growth
  • Cells divide to replace old cells that die
• MITOSIS


  1. Prophase - Condensed chromosomes are formed, Nucleoli and nuclear membrane disappear, Spindle fibers are formed

  2. Metaphase - Rod-shaped double-stranded chromosomes arrange themselves at the equatorial plate, Kinetochores attaching the chromosomes to the spindle fibers

  3. Anaphase - the centromeres divide and chromatids separate and move towards the corresponding poles

  4. Telophase - daughter chromosomes arrive at the poles and microtubules disappear, The condensed chromatin expands and nuclear envelope reappears, Cytokinesis- cytoplasm divides

  
• MEIOSIS


  Special type of division where the cell undergoes two rounds of cell division to produce four daughter cells, Contributes to genetic variety, Reduction division
• MEIOSIS

  1. Prophase I - Exchange of genetic materials to produce different recombinants

  2. Metaphase I - The paired chromosomes arrange themselves along the equatorial plate, Spindle fibers get attached to two centromeres of each homologous chromosome

  3. Anaphase I - Spindle fibers form and attach to the centromeres of the chromosomes, The homologous chromosomes separate from each other completely and start their movement toward the poles of the cells as they pulled by the spindle fibers, Sister chromatids remain together

  4. Telophase I - Chromosomes reach their respective poles, Cytokinesis follows and two daughter cells are formed

  
• Cell Cycle


  • Regular sequence of growth and division that eukaryotic cells undergo
  • Prokaryotic cells undergo binary fission
• Stages of Cell Cycle

  • Interphase
  • Mitosis
  • Cytokinesis

  
• MEIOSIS II


  1. Prophase II - Beginning phase of Meiosis II, Occurs without interphase

  2. Metaphase II - Chromosomes are arranged at the equatorial plate, Spindle fibers get attached to one centromere from both sides

  3. Anaphase II - Two spindle fibers are attached to the same centromere of a single chromosome, Sister chromatids are separated, Two sister chromatids are being separated by splitting the centromere

  4. Telophase II - Complete movement of separated sister chromatids to the opposite poles of the cell occurs

  
• Interphase


  Cell grows into its mature size, makes a copy of its DNA, and prepares for division

  
• Gametogenesis


  Process whereby a haploid cell (n) is formed from a diploid cell (2n) through meiosis and cell differentiation
• Stages of Interphase


  • G1
  • S
  • G2
• Spermatogenesis


  Origin and development of the sperm cells within the male reproductive organs, the testes
• Sister Chromatids


  • Copy of chromosome from mom or dad
  • Chromosome made in S phase of Interphase
• Homologous Chromosomes


  Human somatic cells have 23 pairs - one from mom and one from dad
• Oogenesis


  Creation of an ovum (egg cell), Female form of gametogenesis
• Meiosis is a cellular process that undergo in gametes
• Chromosome Structure


  • Chromatin condenses into chromosomes
  • Each chromosome is made up of two identical sister chromatids attached by a centromere

  
• Meiosis is a process that contributes to genetic variety
• G1 Phase


  • Cell doubles in size
  • Cell produces all of the structures it needs to carry out its functions
• Before the meiosis happens, interphase occur

  
• S Phase


  Cell makes a copy of its DNA (replication)
• Meiosis consists of Prophase I and II, Metaphase I and II, Anaphase I and II, Telophase I and II
• G2 Phase


  • Cell prepares to divide
  • Cell produces structures needed for cell division

  
• Mitosis


  • Cells' copied genetic material separates and the cell prepares to split into two cells
  • Resulting daughter cells are genetically identical
• Stages of Mitosis


  • Prophase
  • Metaphase
  • Anaphase
  • Telophase

  
• Prophase


  • Nucleus disappears
  • Spindle fibers form in the cytoplasm
  • Spindle fibers attach to sister chromatids
• Metaphase


  • The sister chromatids are pulled to the center of the cell
  • They line up in the middle of the cell
• Anaphase


  • Spindle fibers begin to shorten
  • The sister chromatids are pulled to the opposite ends of the cell