HISTO W2 CELLS

• Different organelles that make up the human cell:

  • Plasma membrane
  • Mitochondria
  • Ribosomes
  • Endoplasmic reticulum
  • Golgi apparatus
  • Secretory vesicles or granules
  • Lysosomes
  • Proteasomes
  • Peroxisomes or microbodies
• Structure of cellular membranes:

  • Cells are eukaryotic with distinct membrane-limited nuclei surrounded by cytoplasm containing varied membrane-limited organelles
  • Cells are partly constructed by macromolecules such as carbohydrates, lipids, proteins, and nucleic acids
  • Plasma membrane actively controls the movement of materials in and out of the cell
  • Most animal cells have glycocalyx or cell coat
• Different stages of mitosis:

  • Interphase: G1 phase, S phase, G2 phase
  • Prophase: Chromosomes condense, nuclear envelope disperses, mitotic spindle apparatus assembles
  • Metaphase: Centromeres of each chromosome are aligned at the equator of the cell
  • Anaphase: Mitotic spindle apparatus pulls sister chromatids of each chromosome apart
  • Telophase: Chromosomes begin to disperse, spindle fibers disperse, cytokinesis begins
• Cells are the basic structural and functional unit in all tissues

  • Human cells come together to form tissues that perform specific functions in the human body
• Cytoplasmic organelles include plasma membrane, mitochondria, ribosomes, endoplasmic reticulum, golgi apparatus, secretory vesicles or granules, lysosomes, proteasomes, and peroxisomes or microbodies
• Cytoskeleton includes microtubules, microfilaments, and intermediate filaments
• Somatic cells:

  • Bone, blood, nerve, and muscle cells are somatic cells
  • Somatic cells have two copies of the genome and are diploid
  • Sperm and egg cells have one copy of the genome and are haploid
• Prokaryotes lack a nucleus as opposed to the nucleated cells of eukaryotes

  • Specialized organelles are present in eukaryotic cells
• Carbohydrates provide energy

  • Lipids form membranes and hormones, provide insulation, and store energy
  • Proteins have diverse functions in the body and are important in various biological processes
  • Nucleic acids DNA and RNA are important in genetics
• All cells are surrounded by a plasma membrane that actively controls the movement of materials in and out of the cell

  • Most animal cells have glycocalyx or cell coat
• Nucleus is a membrane-bound structure that houses DNA complexed with proteins into thin fibers

  • Mitochondria provide energy by breaking down nutrients from food and storing it in ATP
  • Centrioles are associated with the organization of spindle fibers in cell division
  • Endoplasmic reticulum serves as a site for synthesis of fatty acids and phospholipids
• Microtubules are long and hollow, providing cellular movements

  • Microfilaments are solid and narrower, enabling cells to withstand stretching and compression
  • Intermediate filaments have diameters between microtubules and microfilaments, abundant in skin and nerve cells
• Whitefish blastula is used for studying mitosis as it represents a period when most cells are dividing and has easily visible chromosomes

  • Mitosis is an essential process that produces two cells with the same complement of chromosomes as the parental cells
• Interphase consists of G1 phase for growth, S phase for DNA duplication, and G2 phase for preparing for mitosis

  • Prophase involves chromosome condensation and assembly of the mitotic spindle apparatus
  • Metaphase shows chromosomes aligned at the equator of the cell
  • Anaphase involves pulling sister chromatids apart to opposite poles
  • Telophase includes chromosome dispersion, spindle fiber dispersion, and cytokinesis for daughter cell formation
• Cells are highly varied and organized structures, with forms and functions dependent on genetic expression by each cell type
• The remainder of the cell within the plasma membrane, excluding the nucleus, is called the cytoplasm and includes a variety of organelles
• The cytoskeleton is a meshwork of protein rods and tubules that molds the distinctive structures of a cell, positioning organelles and providing three-dimensional shape
• Microtubules are long and hollow, providing many cellular movements and composed of tubulin

  • Microfilaments are thin rods composed of actin, enabling cells to withstand stretching and compression
  • Intermediate filaments have diameters between microtubules and microfilaments, abundant in skin and nerve cells
• Whitefish blastula is used for studying mitosis due to its easily visible chromosomes and representation of a period of constant cell division
• Mitosis is an essential process in humans and all multicellular organisms, producing two cells with the same complement of chromosomes as the parental cells
• Light microscopy is based on the interaction of light and tissue components and can be used to reveal and study tissue features
• Microscope is an instrument used to observe microorganisms that cannot be seen by our naked eye
• Different kinds of microscopy that use light to observe the morphology and arrangement of tissue specimens include: Bright-field microscopy, fluorescence microscopy, phase-contrast microscopy, Differential Interference Microscopy, confocal microscopy, and Polarizing Microscopy
• Histological stain is used to make various tissue components conspicuous, allowing for distinctions on the cell organelles. Tissue components with positive charge stain more with basic dyes (basophilic), while proteins with many ionized amino groups (negative charge) have an affinity for acidic dyes (acidophilic)
• A Brightfield microscope allows light rays to pass directly through to the eye without being deflected by an intervening opaque plate in the condenser. It is a conventional type of instrument encountered by students
• Parts of a Brightfield microscope:

  • Framework: supports the microscope, including the arm and base
  • Stage: a horizontal platform that supports the microscope slide
  • Light source/Illuminator: illuminates the specimen
  • Diopter adjustment ring: adjusts diopter on the left eye
  • Rotatable head
  • Lens systems: Oculars/eyepiece and Objectives
  • Condenser
  • Diaphragm/iris diaphragm
  • Revolving nosepiece
  • Focusing knobs: Coarse and Fine adjustment knobs
• Parfocal refers to objectives that can be changed with minimal or no refocusing, allowing objects to be visualized on a single focal plane
• Resolution/Resolution Limit/Resolving Power:

  • Extent of the detail of the magnified object
  • Optimum resolution (oil immersion): 0.2 um
  • Factors affecting resolution include the blue filter, condenser position, diaphragm adjustment, and use of immersion oil
• Contrast is needed to make objects stand out from the background and can be improved by staining techniques
• Care of the microscope includes proper transport, keeping the work area clear, avoiding hazards with electrical cords, regular lens care, and using dust covers for protection during storage
• Cells are the basic structural and functional unit in all tissues, with human cells being eukaryotic cells containing membrane-limited nuclei surrounded by cytoplasm and organelles
• Cytoplasmic organelles include the plasma membrane, mitochondria, ribosomes, endoplasmic reticulum, golgi apparatus, secretory vesicles or granules, lysosomes, proteasomes, and peroxisomes or microbodies
• Cytoskeleton includes microtubules, microfilaments, and intermediate filaments
• Mitosis is a form of cell division that produces two cells, each with the same complement of chromosomes as the parental cells
• Cells are highly varied and organized structures, with forms and functions dependent on genetic expression by each cell type. Somatic cells like bone, blood, nerve, and muscle cells are diploid, while sperm and egg cells are haploid
• Prokaryotes lack a nucleus and specialized organelles compared to eukaryotic cells
• Cells are composed of macromolecules such as carbohydrates, lipids, proteins, and nucleic acids, each serving important biological processes
• Functions of proteins in the body:

  • Important in blood clotting, nerve transmission, muscle contraction, and immunity
  • Some proteins serve as catalysts
• Most important nucleic acids in genetics:

  • DNA and RNA
• • Prokaryotic DNA is not associated with proteins like in eukaryotes
  • The remainder of the cell within the plasma membrane, excluding the nucleus, is called the cytoplasm and includes various organelles
  • Endoplasmic reticulum serves as a site for synthesis of fatty acids and phospholipids
  • Ribosomes are sites of protein synthesis guided by mRNA
  • Mitochondria provide energy by breaking down nutrients from food and storing it in ATP
  • Centrioles are located in the centrosome and organize spindle fibers for cell division