Cells

• The human body is comprised of cells, tissues and organs within complex systems that work together to maintain life
• Cytoplasm


  The liquid medium of the cell, in which all the organelles are suspended. Many substances are dissolved in it, and it assists these substances in moving around the cell.
• Nucleus


  Contains the genetic material (DNA) of the cell, which controls the functions of the cell.
• Ribosomes


  Used by the cell for protein synthesis. They can be found floating freely in the cytoplasm, or attached to various organelles (Golgi Apparatus, ER).
• Endoplasmic reticulum (ER)


  Rough ER has ribosomes attached and is used to transport proteins. Smooth ER does not have ribosomes attached. ER are membranes that connect the nucleus to the cell membrane. Chemical reactions occur in the ER, and it also stores and transports materials within the cell.
• Golgi Apparatus


  Modifies and packages proteins for secretion from the cell in vesicles.
• Lysosomes


  Contain digestive enzymes that break down substances and remove waste.
• Mitochondria


  Allow for the release of energy through the process of cellular respiration.
• Centrioles


  Rod-like structures, found in pairs or small groupings, located near the nucleus. They are involved in the reproduction of the cell by separating chromosomes during mitosis or meiosis.
• Cilia


  Look like small hair-like structures, found in places like the respiratory system.
• Flagella


  Appendages of a cell which aid in its movement, like in an amoeba or sperm cell.
• Cytoskeleton


  Proteins that give cells a structure for shape and support, made up of microfilaments and microtubules.
• Inclusions


  • Melanin
  • Haemoglobin
  • Glycogen
  • Lipids
• Cell Membrane (Plasma Membrane)

  The outer boundary of the cell, a phospholipid bilayer with proteins and molecules embedded. It is mostly fluid and allows selective permeability, only allowing certain substances to enter the cell.
• Phospholipid bilayer


  Forms a boundary, restricts passage of hydrophilic substances. Cholesterol increases strength, decreases fluidity when temperature increases, and decreases permeability to water-soluble substances.
• Transport Proteins


  • Channel proteins (pores that allow passage of ions and smaller molecules)
  • Carrier proteins (bind molecules and change their shape for delivery across the membrane)
  • Recognition proteins (identification tags for molecules, oligosaccharides aid in cell recognition)
  • Receptor proteins (docking for molecules outside of the cell membrane)
• Diffusion


  The tendency for particles to move from an area of higher concentration to an area of lower concentration, a passive process.
• Osmosis


  The diffusion of water across a selectively permeable membrane, from an area of higher concentration to an area of lower concentration.
• Facilitated diffusion


  Molecules diffuse across cell membranes with the assistance of transport proteins.
• Endocytosis


  Uses vesicular transport to bring solids or liquids into a cell, including phagocytosis (solids) and pinocytosis (liquids).
• Exocytosis


  When contents of a vesicle in a cell are passed outside.
• Metabolism


  Biochemical processes, including anabolic and catabolic reactions in the cell, controlled by specific enzymes. Cellular respiration occurs to catabolise organic compounds and release energy in the form of ATP.
• Anabolic pathways


  Pathways that consume energy to build larger molecules, such as polymerization, gluconeogenesis, and photosynthesis.
• Catabolic pathways


  Pathways that release energy by breaking down complex molecules into smaller compounds, such as cellular respiration.
• Adenosine triphosphate (ATP)


  Used to transport energy between catabolic and anabolic reactions. Energy is released from ATP through the loss of phosphate groups.
• Phosphorylation


  When ATP gives a phosphate group to another molecule, making that molecule have 'more' energy and able to do work in the cell.
• Cellular respiration


  The making of ATP through the breakdown of foods, including aerobic cellular respiration and fermentation. It has three stages: glycolysis, Krebs cycle, and electron transport chain.
• Total ATP created through cellular respiration is 4 from glycolysis, 2 from Krebs cycle, and 34 from the electron transport chain.
• Oxygen is needed in cellular respiration because it is used to keep the electron transport chain running. Without oxygen, the rest of cellular respiration would only yield 4 ATP per cycle, which is not enough for most organisms to survive.
• Magnification


  To get total magnification, multiply the power of the objective lens by the power of the eyepiece.
• Epithelial tissue


  • Covers the body, lines cavities, tubes, ducts, and blood vessels, and covers organs. Functions include protection, filtration, secretion, and reabsorption.
• Connective tissue


  • Includes bone, cartilage, adipose tissue, and blood. Functions include connecting structures, protecting organs, insulating, and transporting.
• Muscle tissue


  • Located in bones, the heart, and hollow organs. Functions include movement, locomotion, maintaining posture, producing heat, facial expressions, pumping blood, and peristalsis.
• Nervous tissue


  • Located in the nervous system. Functions include regulating body functions, generating and transmitting nerve impulses, and supporting, insulating, and protecting neurons.