Biology

• Inhalation


  Oxygen enters the body through nose or mouth
• Oxygen Exchange in lungs

  1. Air travels down trachea

  2. Through Branchi into Branchides

  3. Alveali (tiny sacs in lungs)

  4. Oxygen diffuses across thin alveolar
• Oxygen binding to Hemoglobin

  In pulmonary capillaries, oxygen binds to Hemoglobin molecules in red blood cells = OXYHEMOGLOBIN
• Transport to Heart


  Oxygen rich blood transported from lungs to heart by pulmonary veins
• Entering Left Atrium


  Oxygenated blood enters left atrium of the heart from pulmonary veins
• Left Atrium to Left Ventricle

  Left atrium contracts, Oxygenated blood shed through mitral valve to Left Ventricle
• Pumping to body


  Upon contraction of left Ventricle, oxygenated blood is pumped through aortic valve into Aorta, then distributed to the body
• Inhalation


  Diaphragm contracts (moves down), rib cage expands, air rushes into lungs
• Exhalation


  Diaphragm moves (moves up), rib cage falls, thoracic activity reduces, air is pushed OUT
• Prokaryotic Cells


  Simple, single-celled organisms without a nucleus
• Prokaryotic Cells


  • Bacteria
• Prokaryotic Cells


  • DNA is a single circular strand, no membrane-bound organelles
• Eukaryotic Cells


  Complex cells with a nucleus
• Eukaryotic Cells


  • Plant and animal cells
• Eukaryotic Cells


  • DNA is enclosed in a nucleus, contain membrane-bound organelles (e.g., mitochondria, chloroplasts in plant cells)
• Plant Cells


  • Cell Wall: Made of cellulose, provides support and structure
  • Chloroplasts: Site of photosynthesis, contains chlorophyll
  • Large Central Vacuole: Stores cell sap and maintains turgor pressure
• Animal Cells


  • Nucleus: Contains genetic material (DNA)
  • Mitochondria: Site of aerobic respiration, produces energy
  • Cell Membrane: Controls the movement of substances in and out of the cell
  • Cytoplasm: Jelly-like substance where chemical reactions occur
• Microscope Components


  Eyepiece lens, objective lenses, stage, light source, focus knobs
• Magnification Calculation


  Total magnification = eyepiece lens magnification × objective lens magnification
• Magnification Formula


  Magnification = Image size / Actual size
• Magnification Formula Example


  • If the image size is 5 mm and the actual size is 0.05 mm, magnification = 5 mm / 0.05 mm = 100x
• Mitosis


  Produces two genetically identical daughter cells for growth and repair
• Mitosis Stages


  1. Interphase: DNA replication, cell growth

  2. Prophase: Chromosomes condense, nuclear membrane dissolves

  3. Metaphase: Chromosomes align at the cell equator

  4. Anaphase: Chromatids separate to opposite poles

  5. Telophase: Nuclear membranes reform around each set of chromosomes

  6. Cytokinesis: Cytoplasm divides, forming two daughter cells
• Cell Cycle


  Interphase (G1, S, G2 phases) and M phase (mitosis and cytokinesis)
• Stem Cells


  Undifferentiated cells with the potential to become different cell types
• Stem Cell Types


  • Embryonic Stem Cells: Can differentiate into any cell type
  • Adult Stem Cells: Limited to differentiating into cell types of their tissue of origin
• Diffusion


  Movement of particles from an area of higher concentration to an area of lower concentration
• Diffusion Example


  • Oxygen and carbon dioxide exchange in the lungs
• Osmosis


  Diffusion of water across a semi-permeable membrane from a region of low solute concentration to a region of high solute concentration
• Osmosis Example


  • Water uptake by plant roots
• Active Transport


  Movement of substances against the concentration gradient, requiring energy (ATP)
• Active Transport Examples


  • Uptake of glucose in the intestines, mineral ions into plant roots
• Animal Cell


  • Nucleus: Contains genetic material (DNA) and controls cell activities
  • Cytoplasm: Gel-like substance where chemical reactions occur
  • Cell Membrane: Surrounds the cell, controls what enters and leaves
  • Mitochondria: Powerhouse of the cell, produces energy through aerobic respiration
  • Ribosomes: Site of protein synthesis
• Plant Cell


  • Nucleus: Same function as in animal cells
  • Cytoplasm: Same function as in animal cells
  • Cell Membrane: Same function as in animal cells
  • Cell Wall: Provides structural support and protection
  • Chloroplasts: Site of photosynthesis, contains chlorophyll
  • Vacuole: Stores water and nutrients, maintains cell shape
• Cell Division (Mitosis)


  1. Interphase: Cell prepares for division, DNA replication occurs

  2. Prophase: Chromosomes condense, nuclear membrane dissolves

  3. Metaphase: Chromosomes line up in the middle of the cell

  4. Anaphase: Sister chromatids separate and move to opposite poles

  5. Telophase: Chromatids reach the poles, nuclear envelope reforms
• DNA Structure


  Double helix composed of nucleotides (sugar, phosphate, base)
• Genes


  Segments of DNA that code for specific proteins
• Chromosomes


  DNA tightly coiled around proteins, found in the nucleus
• Alleles


  Different forms of a gene (e.g., dominant and recessive)
• Mendelian Genetics


  Laws of segregation and independent assortment