Cell Structure and its Function

• Organelles perform a variety of functions:

  • protein production
  • storing important materials
  • harvesting energy
  • repairing cell parts
  • digestion of substances
  • maintaining cell shape and structure
• Plasma Membrane


  aka Cell Membrane - Separates the cell from external environment and controls the passage of organic materials (ions, water, oxygen, wastes) in and out of the cell
• Important functions of the plasma membrane

  1. Isolates content of the cell
  2. Regulates interchange of substances between the cytoplasm and the environment
  3. Communicates with other cells
• Cytoplasm


  Provides structure to the cell; site of metabolic reactions; medium where organelles are found
• Location of cytoplasm in the two kinds of cells

  1. Prokaryotic cell - interior
  2. Eukaryotic cell - between nucleus and plasma membrane
• Nucleus


  houses the DNA and directs synthesis of ribosomes & proteins
• Parts of the nucleus

  1. Nuclear envelope - double membrane structure enclosing the nucleus and is perforated by pores
  2. Nucleolus - structure involved in production of ribosomes
  3. Chromatin - material consisting of DNA and proteins
• Ribosomes


  Small brown dots that make protein
• 2 kinds of Endoplasmic Reticulum (ER)

  1. Smooth ER - without ribosomes
  2. Rough ER - with ribosomes
• Mitochondria


  The powerhouse of the cell; responsible for ATP production and cellular respiration
• Parts of the Mitochondria

  1. Cristae
  2. Inner Membrane
  3. Outer Membrane
• Peroxisomes


  Oxidizes and breaks down fatty & amino acids

  Produces hydrogen peroxide (H2O2) as a by-product then converts it into water (H2O)
• Vesicles and Vacuoles


  storage and import; digestive function in plant cells
• Centrosome


  Has an unspecified role in animal cells; a pair of centrioles that is the organizing center of microtubules
• Lysosomes


  Digests hydrolyzed macromolecules; recycles worn-out organelles
• Cell Wall


  Protects the cell and maintains its shape

  It is made of cellulose, other polysaccharides, and protein
• What is the Cell Wall made up of?

  cellulose, other polysaccharides, protein
• Polysaccharides in the Cell Wall

  • cellulose
  • hemicellulose
  • pectin
  • glycoprotein
• Chloroplast


  Where photosynthesis takes place

  Energy to sunlight to chemical energy in sugar molecules
• Process of Photosynthesis

  Energy to sunlight to chemical energy in sugar molecules
• Endoplasmic Reticulum

  • Attached to the nucleus
  • serves as storage that modifies proteins and synthesizes lipids
  • a network of membranous sacs and tubes
  • responsible for membrane synthesis
• Golgi Apparatus

  • Modifies, sorts, tags, packages, and distributes lipids & proteins
  • Active in synthesis
  • Modification, sorting, and secretion of cell products