Laboratory Introduction

My Rules for the Laboratory Be ready for the laboratory exercise you are performing that day! Read the exercise introduction. Be on time for the laboratory! I will start the laboratory ON TIME with a lecture or a discussion covering what we are doing that day (a foundation). I will check, periodically, to see if you are keeping up with doing lab exercises and reports.

Figure 3.1 Why does the abundance of water allow life to exist on the planet Earth?

Aseptic Technique Whenever working in the lab, special care should be taken… Use a soft hand; a gentle touch Everything you use should be sterile and clean Solutions should always be prepared fresh Transfer-ware should never be reused Containing-ware should be clean Cadaver specimens are handled with gloves

Now lets look around the lab and identify our reagents and equipment… Microscopes and Slides Skeletal and Muscular models Neurological Models Tissue specimens

“Care and Use of the Microscope” Laboratory Exercise “Care and Use of the Microscope”

Care and Use of the Microscope In this exercise, we will study the application of a compound and a dissection microscope, know their parts and function, and learn to use and take care of them. These terms should be familiar to you: magnification, resolution, stereoscopic- (dissection), simple-, compound-, and electron- microscopy (scanning or transmission).

What procedures are we doing? We will know the parts of-, the proper use of- and the clean up procedure for a bright-field compound and dissection microscope. You will examine a prepared slide and a slide with the letter “e” affixed to it using a compound microscope. You will examine a sample of your own hair using a dissection microscope.

Resources available… Anatomy and Physiology Laboratory Study Pages; submenu: Microscope http://ctle.hccs.edu/biologylabs/AP1/AP1index.html

Laboratory Lecture

Concept: Cell Biology tools - microscopy & chemistry The quality of an image depends on Magnification, the ratio of an object’s image size to its real size Resolution, the measure of the clarity of the image, or the minimum distance of two distinguishable points Contrast, visible differences in parts of the sample (can be enhanced by stains/markers)

-Electron Microscope 2 nm Scale of Resolution -Naked Eye .2 mm -Light Microscope .2 mm -Electron Microscope 2 nm 10 m Human height 1 m Length of some nerve and muscle cells 0.1 m Unaided eye Chicken egg 1 cm Frog egg 1 mm 100 µm Most plant and animal cells Light microscope 10 µm Nucleus Most bacteria 1 µm Mitochondrion Figure 6.2 The size range of cells Smallest bacteria Electron microscope 100 nm Viruses Ribosomes 10 nm Proteins Lipids 1 nm Small molecules 0.1 nm Atoms

Light Microscopy In a light microscope (LM), visible light passes through a specimen and then through glass lenses, which magnify the image Various techniques enhance contrast and enable cell components to be stained or labeled Most subcellular structures, including organelles (membrane-enclosed compartments), are too small to be resolved by a Light Microscope

Viewing Techniques for: Imaging Naked Eye Light Microscope Electron Microscope TECHNIQUE RESULTS (a) Standard/Brightfield (unstained specimen) Imaging 50 µm (b) Standard/Brightfield (stained specimen) Imaging w/ stain (c) Phase-contrast Imaging & density The microscope manipulates optics to improve contrast between the structures (d) Differential-interference- contrast (Nomarski) Imaging & optics (e) Fluorescence Imaging w/ Labeling Figure 6.3a-d Light microscopy 50 µm (f) Confocal Imaging & focal planes 50 µm

Electron microscopy Two basic types of electron microscopes (EMs) are used to study subcellular structures Scanning electron microscopes (SEMs) focus a beam of electrons onto the surface of a heavy metal stained specimen, providing images that look 3-D Transmission electron microscopes (TEMs) focus a beam of electrons through a heavy metal stained specimen, used mainly to study the internal structure of cells

(b) Transmission electron TECHNIQUE RESULTS Cilia 1 µm (a) Scanning electron microscopy (SEM) SURFACE Longitudinal section of cilium Cross section of cilium 1 µm Figure 6.4 Electron microscopy (b) Transmission electron microscopy (TEM) SECTION OR SLICE

A quick note… I have presented an introductory review of laboratory Exercise 1. This is because the class has just started and I want you to get off on the “good foot.” From now on, you are responsible for reading the introduction before the exercise. All the stuff we do in lab is covered in theory during a lecture (BIOL2301) and is also covered on the internet on the Anatomy and Physiology Lab Pages (let’s take a look at awesome central!): http://ctle.hccs.edu/biologylabs/AP1/AP1index.html

Lets get familiar with each other; we will be working in groups to complete exercises (3 groups total in this class – groups A, B and C). Finally, lets look in the laboratory manual... Within your group, who is the group leader for the Exercise? Who is going to do which experiment(s) of that Exercise? You must decide amongst yourselves. Next step: decide who is going to get the materials to complete the exercise. This is collaboration!