Cells

• Cell - smallest unit that is capable of living. It makes all the tissues of an organisms. Its main parts are DNA, Cytoplasm, and Cell membrane
• Extracellular matrix - anything outside the cells
• How to view a cell?

  >Light Microscope

  >Electron Microscope

  >TEM (Transmission) - used for viewing internal structure

  >SEM (Scanning) - used for 3d picture of the cell
• Prokaryotes - unicellular organisms that do not have a nucleus. Came very first in the world.
• Eukaryotes - organelles are surrounded by a membrane and are enclosed by a membrane
• Prokaryotic Cell

  • Plasmids – are small, circular pieces of DNA that are separate from the chromosome and often contain genes that confer specific traits, such as antibiotic resistance.
  • Flagella – Flagella are long, whip-like structures that protrude from the cell and are used for locomotion.
  • Pili – thin, hair-like structures that protrude from the cell and are used for attachment to surfaces and other cells.
  • Fimbrae - shorter and more numerous than flagella, another type of bacterial surface structure that is used for movement.

  
• Prokaryotic Cell

  • Cell membrane – a thin layer of lipids and proteins that encloses the cell and regulates the passage of molecules into and out of the cell.
  • Cell Wall – protects the cell membrane and provides structural support for the cell.
  • Cytoplasm – a gel-like substance that fills the cell and contains enzymes, ribosomes, and other molecular compounds.
  • Nucleoid: The nucleoid is a region within the cell where the genetic material (DNA) is located, usually in the form of a circular chromosome.

  
• Animal Cell

  • Mitochondria – membrane-bound organelles that are responsible for energy production through aerobic respiration. They generate ATP (adenosine triphosphate), the main energy currency of the cell.
  • Endoplasmic reticulum – network of membranous tubes and sacs that are involved in protein and lipid synthesis, as well as the detoxification of drugs and other harmful substances.
  • Golgi Apparatus – a stack of flattened membranes that receive and modify proteins and lipids from the ER, sort them into vesicles, and send them to their final destination.
• Animal Cell (Nucleus)

  • Nucleus – large, membrane-bound organelle that contains the cell's genetic material (DNA) and is responsible for controlling gene expression and cell division.
  • Nucleolus – a dense region within the nucleus that is involved in synthesizing ribosomal RNA and assembling ribosomes.
  • Chromatin – a mixture of DNA and proteins.
  • DNA – the genetic material of the cell

  
• Animal Cells (Endomembrane System)

  • Mitochondria: Organelles that produce energy for the cell through aerobic respiration, generating ATP.
  • Endoplasmic reticulum: A network involved in making proteins and lipids and detoxifying drugs and harmful substances.
  • Golgi apparatus: Membrane stacks that modify, sort, and package proteins and lipids from the ER for transport.
  • Vesicles: Sacs that transport molecules within the cell and to the cell membrane for secretion.

  
• Animal Cells (Endomembrane System)

  • Lysosomes: Organelles with enzymes that digest macromolecules like proteins, nucleic acids, and lipids.
  • Peroxisomes: Organelles with enzymes that break down fatty acids and handle other metabolic processes.
  • Plasma membrane: The cell's outer layer that controls the passage of molecules into and out of the cell.

  
• Animal Cells (Cytoskeleton)

  • Cytoskeleton: A network of protein fibers providing structural support, helping maintain cell shape, and playing roles in cell movement and division.
  • Microtubules: The thickest cytoskeleton components made of tubulin.
  • Function: Cell division, transport of organelles and vesicles, maintaining cell shape, and cell movement (cilia and flagella).

  
• Animal Cells (Cytoskeleton)

  • Intermediate filaments: Medium-sized cytoskeleton components made of various proteins like keratin and vimentin.
  • Function: Provide structural support and maintain cell shape.
  • Microfilaments: The thinnest cytoskeleton components made of actin.
  • Function: Cell movement, division of the cytoplasm during cell division (cytokinesis), and maintaining cell shape.

  
• Plant Cells

  • Chloroplasts: Organelles that carry out photosynthesis, converting light energy into chemical energy in plants.
  • Cell Wall: A rigid layer surrounding the cell membrane that provides support and protection to the cell.
  • Large Vacuoles: Large sacs that store water, nutrients, and waste products.

  
• Extracellular Matrix - is a complex network of macromolecules that surround and support cells in tissues. Composed of Collagen, Glycoaminoglycans (GAG’s), and Proteoglycans

  Function: Support and anchorage, Regulation of cell behavior, and Signaling pathways