Cells Tissues Organ systems Organs Organisms

 1665 – Robert Hooke observes cork is made of little compartments he calls “cells”  1674 – Leeuwenhoek observes living cells for the first time - animalcules  1838 – Schleiden determines all plants are made of cells  1839 – Schwann determines animals are made of cells

 1850 – Brown discovers the dense centers of certain cells and names the nucleus  1855 – Virchow discovers cells make more cells

 All living things are made up of one or more cells  Cells are the basic unit of structure and function in living things  Cells come from previously existing cells – NO spontaneous generation!

There are two major types of cells: Prokaryotes: literally means “before nucleus” - primitive single celled life, the first! - example: bacteria - DNA found in cytoplasm (nucleoid) - no membrane bound organelles - extremely small (even for a cell!)

Charomatin nucleoid

 Prokaryotic Cells are BACTERIA (single cell, no nucleus, no membrane- bound organelles)  Bacteria have 3 BASIC shapes  (simple cytoskeleton just inside the membrane) s/bio141/lecguide/unit1/shape/s hape.html

 Eukaryotic

Compare the sizes, the line represents 1 mm (1000 nm) Typical Eukaryotic Cell This prokaryotic cell Is similar in size to a eukaryotic organelle Prokaryotic cell Virus

Prokaryotes Vs. Eukaryotes Eukaryotes: - literally means “true nucleus” - DNA enclosed by the nuclear membrane - Can be single celled like protists (amoebas, paramecium) - Or can be part of a multicellular organism like: plants, animals or fungi

Prokaryotes Vs. Eukaryotes Eukaryotes: - significantly larger than prokaryotic cells - have many more organelles than prokaryotic cells

 The membrane system in a eukaryotic cell is connected.  The nucleus is connected to the ER. Smoothe ER is connected to rough ER,  ER is connected to the cell membrane  Vesicles can be formed by any membrane bound organelle or by the cell membrane.  Vesicles transport food, enzymes and waste

 Cell Wall and Cell Membrane  Vacuoles – Large and small  Lysosomes and Vacuoles  Centrioles vs no Centrioles  Mitochondria vs. Chloroplasts.

 Cell pictures show a cell with “all organelles.  In reality, some cells have more of some organelles than others.  Some organelles are not present in some cells or present in small quantities (like Smooth ER), but are present in specialized cells (like liver cells).

 Liver cell ◦ Synthesizes lipids ◦ Metabolizes drugs and toxins  Enucleated RBC

 All cells must perform certain tasks to stay alive  Just how they go about it might be a little different depending on what organelles they have to work with.

 Be able to list the functions of all organelles  Describe why these jobs are important to survival of the cell  Describe how different cells accomplish these tasks  Compare and contrast the differences between cell types!

 Note Cilia

 How do we see animalcules and other small organisms (and parts of organisms).

 Tools ◦ Objects used to improve the performance of a task  Microscopes ◦ Extend human vision by enlarging, with high resolution, things that might be impossible to see.

 Use light (photons) to view specimens ◦ Two types ◦ Stereo (dissecting) microscope  40x – 70x magnification (in general)  3D view (two eye pieces)  Live specimens can be viewed, but often used to compare two things (ballistics, etc) ◦ Compound Light Microscope  Magnifies using two lenses – 1000x – 2000x  Thick objects must be sliced thin enough so that light passes through

 Gather light from the tiny area where a specimen is located (thinner  more light transmitted)  Image is brought into focus by the objective lens (in a fairly short distance), then magnified by a second lens (the eye piece)  Resolution and magnification from the objective lens, magnification only from the eyepiece.

 Magnification ◦ Increase in an object’s apparent size. ◦ Calculated in light microscopes by multiplying the magnification of each of the lenses  Resolution ◦ Minimum distance between two objects at which the objects can just be determined as separate. Depends on the wavelength of the light and the light gathering capability of the lens. (cannot go > 2000x; most 1000x ◦ D min = 1.22 x wavelength / N.A. objective + N.A. condenser

 A beam of electrons  enlarged image  Higher magnification (up to 2,000,000x) and resolution (use electrons rather than photons) than light microscopes  Always black and white (color is added by computer, electrons do not emit a color)  Always dead (specimen must be in a vacuum chamber so… no air)

 Surface scanning  3D  Gold coated and electrons are “fired” at the metal coating (metal emits other electrons and these are projected onto a photographic plate (100,000 – 200,000x)

 Transmits electrons THROUGH a very thinly sliced specimen  Magnetic lenses enlarge the image (focuses charged particles rather than a light image)  Magnification 200,000x to 2,000,000x (this number may vary depending on the source)

 Metric system ◦ Consists of base unit  Length = meter (m)  Mass = gram (g)  Volume = liters (l)  We will use units of length (meters) to describe the size of organisms

Prefix prefix abbr unit = 1 x ____ meters  Nanonnm10 -9  Microu or   m  Millimmm10 -3  Centiccm10 -2  NO prefixA Angstrom10 -10

 What types of microscopes use light?  Which microscopes show “3D”  Which show only black and white  Which would be used to view details of cell organelles?  Which would be utilized to compare ballistics?

 Read information on the first pages. Fill in the “blanks” on the microscope, use your lab to help with this  Answer questions on second page, be sure to think about the characteristics of viruses vs. living things!