Cell Structure SNC 2D

Cell Theory All living organisms are made of one or more cells. The cell is the basic organizational unit of life. All cells come from pre-existing cells. Why study cells? Didn’t we learn enough in grade 8? Most diseases/disorders can be explained due to a default at the cellular level.

single circular molecule of DNA in prokaryotes Cell Characteristics Genetic material single circular molecule of DNA in prokaryotes double helix located in nucleus in eukaryotes – nuclear envelope (double membrane Cytoplasm fills cell interior – sugars, amino acids, proteins - organelles Plasma membrane encloses the cell – phospholipid bilayer Phospholipid Membrane proteins

Generalized Eukaryotic Cell

Cell Size Most cells are relatively small because as size increases, volume increases much more rapidly. longer diffusion time

Visualizing Cells using Microscopes On separate paper, make a chart like the one below: Resolution - minimum distance two points can be apart and still be distinguished as two separate points Type of Microscope Description Advantages Disadvantages Compound Light microscope Transmission electron microscope Scanning electron Microscope

Visualizing Cells Compound light microscopes - magnify in stages using multiple lenses Transmission electron microscope - electrons transmitted through specimen Gives a 2D image magnified 100 000 x Scanning electron microscope - electrons beamed onto surface of the specimen 3D image

Visualizing Cells

Cell Organelles and their Functions Please create your own t-chart, like the one below. ORGANELLE FUNCTION nucleus nucleolus endoplasmic reticulum Golgi body vesicles lysosomes vacuoles ribosomes mitochondria chloroplasts cytoskeleton

Nucleus contains genetic material (DNA) directs activities of the cell usually single, some cells several, RBC none nuclear membrane surrounds nucleus nuclear pores – controls the movement of molecules in and out of the nucleus Nucleolus found inside nucleus makes ribosomes

Nucleus

Endoplasmic Reticulum transport molecules throughout the cell made of membranes that act as channels or passageways

Golgi body (also called “apparatus” or “complex”) packages proteins and other molecules for transport out of the cell Does this by surrounding the protein with membranes and puts the proteins in a “vesicle” (tiny vacuole)

Cisternae cis face Proteins trans face Protein Ribosome Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cisternae cis face Proteins trans face Transport vesicle Golgi apparatus Protein Vesicle budding from rough endoplasmic reticulum Migrating transport vesicle Fusion of vesicle with Golgi apparatus Ribosome

Organelles made of just a membrane Vesicles – transport materials out of the cell or transports and stores materials inside the cell Lysosomes - membrane-bound vesicles containing digestive enzymes Vacuoles - contain water and other materials; used for storage plant cells have usually 1 large vacuole animal cells have several small vacuoles

Cytoplasm Extracellular fluid Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cytoplasm Endoplasmic reticulum Phagocytosis Food vesicle Golgi apparatus Lysosomes Transport vesicle Old or damaged organelle Plasma membrane Digestion of phagocytized food particles or cells Breakdown of old organelle Extracellular fluid

Ribosomes make proteins some ribosomes float around in the cytoplasm while others are attached to the endoplasmic reticulum

releases energy from glucose (cellular respiration) Mitochondria releases energy from glucose (cellular respiration) glucose + oxygen ----- carbon dioxide + water + energy Structure- outer and inner membranes, (folds called cristae) C. Have their own DNA

Chloroplasts traps energy from the sun to make glucose in photosynthesis carbon dioxide + water --- glucose + oxygen Grana – closed compartments of stacked membranes Thylakoids – disc shaped structure – light capturing pigment Stroma – fluid matrix

Cytoskeleton Network of protein fibers supporting cell shape and anchoring organelles Actin filaments cell movement Microtubules Hollow tubes Facilitate cell movement Centrioles – barrel shaped organelles occur in pairs – help assemble animal cell’s microtubules Intermediate filaments Stable - don’t break down Actin Microtubules Intermediate filaments

Cytoskeleton

Cytoplasm includes the cytosol (liquid), organelles and dissolved sugars etc. within the cell membrane every chemical reaction takes place within the cytoplasm

Classwork / Homework Complete both sides of the handout. Complete your structure-function chart. Draw a Venn diagram to compare the plant cell and the animal cell. Cell Structure videoclip Bill Nye Cells