Cells

• Cell Membrane

  Composed of protein and lipid molecules

  Regulates movement of substances in and out of the cell.
• Endoplasmic Reticulum


  Complex of interconnected membrane sacs and canals

  Transports materials within the cell, provides attachment for ribosomes and synthesizes lipids.

  
  

  Rough ER

  Studded with Ribosomes

  Synthesizes protein and lipids

  
  

  Smooth ER

  Breaks down drugs

  Synthesizes lipids
• Ribosomes

  Particles composed of protein and RNA Molecules

  Synthesizes proteins
• Golgi Apparatus

  Made of flattened membranous sacs

  Packages protein molecules for transporting and secreting. Also can be called "Fedex".
• Mitochondria

  Membranous sacs with inner partitions

  Releases energy from molecules and change energy into a useful form.
• Lysosomes

  Made of membranous sacs

  Digest worn out substances or cell parts that enter the cell
• Peroxisomes

  Made of membranous sacs

  Break down organic material like hydrogen peroxide and fatty acids.
• Microfilaments and Microtubules

  Made of thin rods and tubules

  It supports the cytoplasm. Also help move substances and organelles throughout the cytoplasm
• Centrioles

  Its nonmembranous and its composed of two rod-like centrioles

  It helps distribute chromosomes to new cells.

  Makes microtubules
• Cilia and Flagella

  Made of motile projections that is underneath the cell membrane

  1. Cilia propels fluid on the cell surface. Traps mucus in the respiratory tract move upward and out of the body
  2. Flagellum enables a sperm cell to move
• Vesicles

  Made of Membranous sacs

  Contain and transport various substances
• Nuclear Envelope

  The outer layer of the nucleus

  Its a double membrane that separates nuclear contents from the cytoplasm.

  It protects the nucleus

  It controls the passageway of the materials between the nucleus and the cytoplasm.
• Nucleolus

  Dense non-membranous; contains RNA and protein

  Site of where ribosomes are made
• Chromatin

  Has fiber and contains DNA and protein

  Has information for synthesizing proteins
• Passive Mechanism: Diffusion

  When molecules move through the phospholipid bilayer going from higher concentration to lower concentration.

  Relies on kinetic energy and concentration gradient

  Ex: Exchange of oxygen and carbon dioxide in the lungs
• Passive Mechanism: Facilitated Diffusion

  When molecules move across the membrane through channels or by carrier molecules that go from higher concentration to lower concentration.

  Ex: Movement of glucose through a cell membrane
• Passive Mechanism: Osmosis

  Water molecules going through a selectively permeable (semi-permeable) membrane towards the solution with the greater osmotic pressure.

  Ex: Distilled water entering the cell
• Passive Mechanism: Filtration

  Smaller molecules are forced through porous membranes from regions of higher concentration to lower concentration.

  Ex: Water Molecules leaving blood capillaries
• Active Mechanism: Active Transport

  When the carrier molecules transport ions or molecules through the cell membranes from lower concentration to higher concentration.

  Ex: Movement of various ions, sugars and amino acids through membranes.
• Active Mechanism: Endocytosis

  Pinocytosis

  1. Membrane is engulfed droplets containing dissolved molecules
  2. Ex: Intestinal absorption of dissolved nutrients

  Phagocytosis

  1. When the membrane engulfs particles.

  2. Ex: White blood cell engulfing bacterial cell.

  
  

  Receptor-mediated endocytosis

  1. Membrane engulfing selected molecules combined with receptor protein.
  2. Ex: Cell removing cholesterol molecules from surroundings.
• Active Mechanism: Exocytosis

  When the vesicle fuses with membrane and releases contents outside the cell.

  Ex: Neurotransmitter release
• Hyperlasia

  • Uncontrolled cell division
  • Cancer cells make telomerase which keeps chromosomes tips long and signals to stop division.
• Dedifferentiation

  • Losing specialized structures and functions of the normal cell which cancer cells can descend.
• Invasiveness

  • Ability for cancer cells to break through boundaries or called basement membranes that separate cell layers.
• Angiogenesis

  • Ability for cancer cells to go into nearby blood vessels.
• Metastasis

  • Spread of cancer cells to other tissues through the lymphatic system
• Benign Tumor

  A tumor or mass that does not contain cancer cells.

  Usually does not need to be surgically removed
• Malignant Tumor

  A tumor or mass that does contain cancer cells. A malignant tumor usually is surgically removed
• Transcytosis

  Endocytosis followed by exocytosis

  Transports a substance rapidly through a cell HIV crossing a cell layer3-24