Lab 2 The Cell—Anatomy and Division, Transport Mechanisms and Cell Permeability G.R. Pitts, Ph.D., J.R. Schiller, Ph.D. & Amy L. Thompson, Ph.D.

Lab 2 Activities Identify cells and their organelles on a slide, diagrams, and models Identify stages of mitosis on slides and diagrams, and events of each stage Understand diffusion and osmosis (wet lab-set this up first!) Complete PhysioEx® 9.1 Exercise 1: Cell Transport Mechanisms and Permeability (computer simulations of diffusion and osmosis) Activities 1 & 3

Cells and Their Organelles Nucleus Plasma membrane Cytoplasm all cellular contents between plasma membrane and nucleus organelles = specialized internal structures

The Nucleus Cell’s control center Usually visible Nuclear envelope double membrane nuclear pores in membrane allow passage of substances between cytoplasm and nucleus Contains the hereditary material = DNA carries instructions for making proteins determines cell structure, coordinates activities of the cell

The Nucleolus (pl. nucleoli) Darker staining, oval/spherical bodies within the nucleus Clusters of DNA, RNA, and protein Site of ribosome assembly

Membrane Chemistry and Anatomy 50-50 weight ratio: lipid/protein More lipid molecules than protein molecules because of proteins’ larger sizes Membrane lipids Phospholipids 75% Glycolipids 5% Cholesterol 20%

Membrane Proteins Determine the functions a cell can perform Composition varies widely among cell types Integral proteins – located within the membrane channels transporters receptors intercellular junctions enzymes cytoskeleton anchors cell identity markers Peripheral proteins – similar list of functions Located on either face of membrane

Glycocalyx The collective glycolipids and glycoproteins of membrane Function as cell identity markers

Organelles of the Cytoplasm Mitochondria Ribosomes Rough endoplasmic reticulum = Rough ER Smooth endoplasmic reticulum = Smooth ER Golgi apparatus Lysosomes Peroxisomes Nucleus Nucleoli cytoskeleton Be able to identify these structures and their functions on models and figures!

Simple Diffusion Diffusion through the plasma membrane selective permeability water and lipid-soluble molecules move freely through membrane small non-lipid-soluble substances may move through specific channels

Factors Affecting Diffusion Increased temperature increases diffusion rate Greater concentration gradients increase diffusion rate Larger surface area increases diffusion rate Smaller particles diffuse faster (faster rate) Time: more time = more diffusion (all other factors being equal)

Osmosis Osmosis is the movement of water from an area of higher [H2O] to an area of lower [H2O] across a selectively permeable membrane osmotic pressure (σ) – a measure of the potential energy of the concentration gradient hydrostatic pressure (h) = pressure of fluid in a system h σ

Solution Tonicity Isotonic solution Hypertonic solution [solutes] inside cells = [solutes] outside cells no net movement of water, e.g., “normal” saline solution Hypertonic solution [solutes] outside cells > [solutes] inside cells water moves out of cells, cells shrink (crenate) Hypotonic solution [solutes] outside cells < [solutes] inside cells water moves into cells, cells swell, may rupture

A Quick Look at Some Organelles Under the Microscope Simple Squamous Epithelium Approx. 400X 100X © Lisa A. Caviness

Pseudostratified Columnar Epithelium Trachea 100X

Pseudostratified Columnar Epi. Approx. 400X

Ciliated Columnar Epithelium from Oviduct 100X 40X 400X 400X © Lisa A. Caviness

The Cell Cycle Interphase Mitosis = nuclear division Normal cell growth Three phases G1 growth protein replication S (“synthesis” of DNA) preparing for division DNA replication G2 further preparation enzymes, proteins for mitosis Mitosis = nuclear division

Mitosis in Whitefish Embryo 40X 100X © Lisa A. Caviness © Lisa A. Caviness 400X

Stages of Mitosis: PMAT Prophase Metaphase Anaphase Telophase 400X A M T P P

PhysioEx 9.1 You May Run PhysioEx at home or in lab Exercise 1: Cell Transport Mechanisms and Permeability Activity 1: Simulating Dialysis (Simple Diffusion) Activity 3: Simulating Osmotic Pressure Note: Print the data tables you generate so you can turn them in with your lab report!

End Lab 2 Presentation