BELL WORK! Name one difference between a prokaryotic and a Eukaryotic Cell? Class Answer: Prokaryotic – no nucleus, no membrane bound organelles. Eukaryotic – Have a Nucleus and organelles

Learning Goal Understand Cell Structures and functions

Chapter 7.1, 7.2 Notes Take out paper to take notes.

Cell Discovery and Theory Section 7.1

Cell Theory- 3 main ideas All organisms are composed of one or more cells The cell is the basic unit of organization of organisms All cells come from preexisting cells.

Microscope Technology Compound Light Microscope ~1000X Has a series of lenses and uses visible light to magnify an image Electron Microscope ~ 500,000X TEM: transmission electron microscope SEM: scanning electron microscope

Cell Diversity Cells vary in shape, which relates to their function Skin cells are flat to cover the body Nerve cells are branched to transmit impulses Cell size is limited by the surface area-to-volume ratio

Section 7.1 Summary – pages 171-174 Two Basic Cell Types Prokaryotic cells : cells that do not contain internal membrane-bound structures Examples: Bacteria and some other single celled organisms Section 7.1 Summary – pages 171-174

Prokaryotic cells Basic structure

Section 7.1 Summary – pages 171-174 Two Basic Cell Types Eukaryotic cells: contain membrane-bound structures . Examples: all plant and animal cells Section 7.1 Summary – pages 171-174

Eukaryotic cells

Eukaryotic v. Prokaryotic

Section 7.1 Summary – pages 171-174 Basic Parts of a Cell Plasma membrane – Cell’s outer boundary Organelles- membrane-bound structures within eukaryotic cells. Cytoplasm-The fluid within the cell Nucleus-The central membrane-bound organelle in eukaryotes. Section 7.1 Summary – pages 171-174

The Plasma Membrane Section 7.2

Purpose: To act as a barrier between a cell and its environment To maintain homeostasis in a cell (a balance of conditions suitable for life)

Selective permeability The plasma membrane is selectively permeable, so it allows certain substances (like oxygen and nutrients) in, while getting rid of others (like waste.)

Summary Section 2 – pages 175-178 Plasma Membrane Oxygen Amino acids Water Glucose Wastes Wastes Carbon dioxide SELECTIVE PERMEABILITY Summary Section 2 – pages 175-178

Membrane structure It’s composed of a phospholipid bilayer Polar heads (phosphate) on the outside hydrophilic Nonpolar tails (fatty acids) on the inside hydrophobic Two layers of phospholipids back-to-back

Polar heads: face outward and stay in contact with water inside and outside of cell Nonpolar tails: point inward toward one another.

Fluid Mosaic Model the phospholipids and proteins move within the membrane. It is flexible

What does that mean? “Fluid” means it can move “Mosaic”

What are the other parts of the p.m.? Cholesterol keeps the fatty acid tails from sticking together, keeps the membrane stable. Carbohydrates stick out from the cell surface to help cells identify chemical signals.

Membrane Proteins Channel protein – always open Transport proteins allow things to move through the plasma membrane Channel protein – always open Carrier protein – only open to certain substances

Membrane Proteins