Cytogenetic

• Table of Contents


  • Basic components of the mammalian cell
  • Human cell cycle
  • Cellular division
  • Basic structure of a human chromosome
  • Mendel's Law of Inheritance
  • Gametogenesis and fertilization

  
• Plasma membrane defines the cell boundary and delimits the cell from its immediate external environment
• Plasma membrane actively controls movement into and out of the cell
• Cell wall


  Found in plant cells, made of cellulose
• Glycocalyx


  Found in animal cells, made of glycoproteins and polysaccharides, provides biochemical identity at the cell surface
• Glycocalyx


  Contains receptor molecules
• Nucleus


  Membrane-bound structure that houses the genetic material, DNA
• Nucleus in non-divisional phases of the cell cycle

  Chromatin fibers are uncoiled and dispersed
• Nucleus in cellular division

  Chromatin fibers coil and condense into chromosomes
• Nucleolus


  Where ribosomal RNA (rRNA) is synthesized and initial stages of ribosome assembly occur
• Nucleoid


  Site where the genetic material, present as a long, circular DNA molecule, is compacted in prokaryotes
• Prokaryotes lack a nuclear envelope and membrane organelles
• Prokaryotes are Eubacteria and Archaea
• Cytoplasm


  Extracellular nuclear organelles, includes cytosol and cytoskeleton
• Cytoskeleton


  Maintains cell shape, facilitates cell mobility, and anchors the various organelles
• Endoplasmic reticulum


  Compartmentalizes the cytoplasm, increases surface area for biochemical synthesis
• Smooth ER


  Site for synthesizing fatty acids and phospholipids
• Rough ER


  Studded with ribosomes
• Ribosomes


  Sites where genetic information in mRNA is translated into proteins
• Mitochondria


  Sites of the oxidative phases of cell respiration, generate ATP
• Chloroplasts


  Associated with photosynthesis
• Centriole


  Cytoplasmic bodies associated with the organization of spindle fibers that function in mitosis and meiosis
• Centriole


  Derived from basal body, associated with formation of cilia and flagella
• Spindle fibers


  Play an important role in the movement of chromosomes during cell division
• Spindle fibers


  Composed of arrays of microtubules consisting of polymers of the protein tubulin
• Centromere


  Constricted region of a chromosome
• p arm


  Short arm of a chromosome, "p" for petite
• q arm


  Long arm of a chromosome
• Mitosis


  Zygote is the foundation for growth and development, adult cells are the basis for wound healing and replacement of certain tissues
• All somatic cells derived from the same species consist of an identical number of chromosomes, the diploid number (2n)
• Exceptions: bacteria and viruses have only 1 chromosome
• Diploid


  2n = 46 chromosomes
• Haploid


  n = 23 chromosomes
• Genome


  Genetic information contained in a haploid set
• Locus


  Gene sites located along homologous chromosomes
• Biparental inheritance


  1 member of each chromosome pair from maternal parent (ovum), other member from paternal parent (sperm)
• Meiosis


  Converts diploid number of chromosomes to haploid number, 2n to n
• Meiosis


  Followed by fusion of two gametes at fertilization, diploid number is reestablished
• Exception to homologous chromosomes: 1 pair are sex determining chromosomes, female XX, male XY
• Y chromosome is smaller and lacks most of the genes found on the X chromosome